SaturnFans.com
what's new (beta) - classifieds - forums - photos


Go Back   SaturnFans.com Forums > Models > Saturn S-Series > S-Series Tech
Register FAQ Members List Groups Calendar Chat Room Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Display Modes
Old 07-18-2018, 07:54 PM   #1
MobileSaturn
Member
MobileSaturn is on a distinguished road
 
Join Date: Sep 2016
Location: Mobile, AL
Posts: 57

1999 SL
Default Pinging / Spark Knock for Four Years on '99 SL

I was raised to believe pinging isn't a problem. Most of the vehicles I've owned in my life have been from the 80s and 90s. All of them were rated for 87 octane, and all but one of them pinged when under load. It wasn't until recently when I encountered complaints on a separate forum about pinging and the issues it can cause that I did further research, and found it can be damaging. Though, to that end, the subject seems to be steeped heavily in subjectivity rather than anything objective -- it seems there are all sorts of reasons for why spark knock happens, and what damage it can ultimately cause, none of which either make sense or have been explained well.

My situation: '99 SL SOHC 5spd and '11 Sonata GLS 2.4L auto. Both ping under load, such as when accelerating while going up a hill with enough throttle to hold a gear before needing to downshift. Both have the issue in equal measure: sounds like someone's shaking a tin can with pebbles inside, and the engines are less peppy in general when it's especially hot and humid outside (which is every day for ten months of the year in Mobile, AL).

Unable to determine a good place to start tackling the issue on either car due to the confusing nature of the subject, I just started by confirming it was spark knock by doing what was suggested elsewhere: run the tank empty, and fill it up with top-tier grade premium fuel. Did that with both cars, and the issue has disappeared entirely from both.

Not sure where to go from here. I've cleaned the throttle body on both cars within the past year, and both have new sets of spark plugs (and wires in the SL's case). The Sonata's got platinum, the SL has standard copper. Couldn't tell you what the valves are like on the SL, but the Sonata should be mostly free of carbon build-up.

So, the questions I'd like answered at the end of whatever becomes of all this:
  • What is spark knock exactly?
  • What damage can it cause?
  • How can I identify what is causing spark knock?
  • How can I fix the problem?

REWARD EXCELLENCE!

Add to MobileSaturn's Reputation
Rate the quality of this post and help MobileSaturn reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
MobileSaturn is offline   Reply With Quote
SaturnFans.com Sponsored Links
Old 07-18-2018, 08:43 PM   #2
Waiex191
Senior Member
Waiex191 has a spectacular aura aboutWaiex191 has a spectacular aura aboutWaiex191 has a spectacular aura about
 
Waiex191's Avatar
 
Join Date: Oct 2016
Location: Poplar Grove, IL
Posts: 1,106

1999 SL2
1998 SC2
Default Re: Pinging / Spark Knock for Four Years on '99 SL

There is a knock sensor on the back of the motor. Maybe start there.

...
Bryan Cotton
'99 SL2, 5SP bought new
Rebuilt at 204,067 September 2017
Engine, subframe, diff pin mod, brake lines, headliner, alternator, and so on!
'98 SC2, 5SP bought 2018

REWARD EXCELLENCE!

Add to Waiex191's Reputation
Rate the quality of this post and help Waiex191 reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
Waiex191 is offline   Reply With Quote
Old 07-19-2018, 12:39 AM   #3
billr
Master Member
billr is a glorious beacon of lightbillr is a glorious beacon of lightbillr is a glorious beacon of lightbillr is a glorious beacon of lightbillr is a glorious beacon of light
 
Join Date: Jul 2013
Posts: 4,461
Default Re: Pinging / Spark Knock for Four Years on '99 SL

^^^ +1
The PCM should prevent spark knock in either of these cars. Use live-data to see if knock is even being detected and what fuel trims are, but it is hard to believe both cars have a similar rare failure that prevents knock detection and sets no codes.

Now to your questions:

What is spark knock exactly? There are two conditions that are called "spark knock", they will sound very much the same and will cause pretty much the same problems, but the causes are quite different.

"Pre-ignition" is when there is when the fuel/air mixture is ignited before the spark event. This can happen because of too high compression, the mixture is heated in the compression stoke enough to ignite it; just like in a diesel. Or, there can be hot-spots in the combustion chamber that ignite the mixture just like glow-plugs. Carbon deposits can remain as glowing "coals", spark plug center electrodes/insulators can remain glowing if too hot a plug range is used, valve edges can glow if thinned out too much in a re-grind, or (much rarer) sharp machined edges on the piston or head can remain hotter than usual.

"Detonation" is when the mixture is ignited by the spark plug as intended, but instead of the combustion flame traveling across the chamber in a normal manner, the pressure rise causes the mixture to heat and burn everywhere at once (that "dieseling again". Pressure and temperature rise is much higher than intended with this "all at once" combustion. Generally, detonation is caused by spark advance beyond what the combination of engine design, fuel octane-rating, AFR, and compression pressure will allow. Since pre-ignition is, in effect, too much spark advance, it often (usually?) results in detonation during the same engine cycle.


What damage can it cause? Those "high pressures and temperatures" not only hammer on bearings, but can break the piston ring lands or crack pistons. Melting holes in pistons or burning valves is also possible. Blowing chunks off the spark plug insulator or blowing head gaskets, too. Most of these problems are not terribly likely with a stock normally-aspirated engine used in normal driving; but turbo/super-charging or extended high-power use (racing) can cause quick engine failure if detonation starts

How can I identify what is causing spark knock? I would start first by pulling the plugs taking compression readings, and looking at the plugs. To properly check the plugs, you need to force the engine into "knocking" and then immediately shut it off, coasting to a stop in neutral.
I suppose even adding a wide-band O2 sensor and gauge for diag purposes may even be required. Oh, yeah, a timing light to verify spark advance is as shown in live-data, too.


How can I fix the problem? Can't say right now, since we don't know what it is!

REWARD EXCELLENCE!

Add to billr's Reputation
Rate the quality of this post and help billr reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
billr is offline   Reply With Quote
Old 07-19-2018, 07:36 AM   #4
OldNuc
Super Member
OldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond repute
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 64,907
 

1998 SC2
Default Re: Pinging / Spark Knock for Four Years on '99 SL

What most people call "spark knock or pinging" in these cars is the sound produced when the exhaust valve opens and the resulting shock wave hits the manifold. This is most noticeable in the cars with NO hood liner and when operating at 55-75mph cruise. The big clue that this is not "spark knock or pinging" is the engine is still running fine after several years of hearing this.

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Old 07-19-2018, 08:13 AM   #5
DonP1
Member
DonP1 has a spectacular aura aboutDonP1 has a spectacular aura aboutDonP1 has a spectacular aura about
 
Join Date: Mar 2007
Location: Cincinnati, OH
Posts: 238

1999 SL2
Default Re: Pinging / Spark Knock for Four Years on '99 SL

But he said in his post that he drained the tanks, filled them with Premium, and the knock went away.

MobileSaturn,

To answer your questions:

1) Pinging is when gas detonates before the spark ignites it.
2) Imagine the piston trying to move up on the compression store and the gas detonating before it gets there. Lots of things get damaged, but typically the rod bearings get pounded out of round and you get a rod knock.
3) You have already identified it. By switching to Premium gas the knock when away.
4) Stick to premium gas.

REWARD EXCELLENCE!

Add to DonP1's Reputation
Rate the quality of this post and help DonP1 reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
DonP1 is offline   Reply With Quote
Old 07-19-2018, 10:22 AM   #6
1996SL11.9L
Senior Member
1996SL11.9L has a spectacular aura about1996SL11.9L has a spectacular aura about
 
1996SL11.9L's Avatar
 
Join Date: Sep 2009
Location: Stouchsburg, PA
Posts: 1,814
 

2002 SL1
Default Re: Pinging / Spark Knock for Four Years on '99 SL

My 96 SL1 did this and no amount of chemicals cleaned the carbon off the Pistons. The oil rings behaved better halving my oil usage. A 1/16" hard layer that I finally removed with a razor blade during a head gasket change. In my case hi test didn't eliminate knock.

You could try a colder spark plug.

Techtron or Gummout a few times may remove some of it.

REWARD EXCELLENCE!

Add to 1996SL11.9L's Reputation
Rate the quality of this post and help 1996SL11.9L reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
1996SL11.9L is offline   Reply With Quote
Old 07-19-2018, 12:17 PM   #7
OldNuc
Super Member
OldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond repute
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 64,907
 

1998 SC2
Default Re: Pinging / Spark Knock for Four Years on '99 SL

Quote:
Originally Posted by DonP1 View Post
But he said in his post that he drained the tanks, filled them with Premium, and the knock went away.

MobileSaturn,

To answer your questions:

1) Pinging is when gas detonates before the spark ignites it.
2) Imagine the piston trying to move up on the compression store and the gas detonating before it gets there. Lots of things get damaged, but typically the rod bearings get pounded out of round and you get a rod knock.
3) You have already identified it. By switching to Premium gas the knock when away.
4) Stick to premium gas.
There is only mechanical cam timing and the use of premium gas advances the spark timing considerably. This lowers the exhaust exit pressure and velocity. Exactly when do you hear this sound?

Modern fuel injected engines have a hot high velocity exhaust stream by design to make the 3 way CAT function correctly. The majority of them exhibit this supposed pinging and it is normal.

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Old 07-19-2018, 03:12 PM   #8
MobileSaturn
Member
MobileSaturn is on a distinguished road
 
Join Date: Sep 2016
Location: Mobile, AL
Posts: 57

1999 SL
Default Re: Pinging / Spark Knock for Four Years on '99 SL

Thanks to everyone for the responses, especially to billr for the detailed response to each question!

To answer a few points:

Quote:
Originally Posted by billr View Post
How can I identify what is causing spark knock? I would start first by pulling the plugs taking compression readings, and looking at the plugs. To properly check the plugs, you need to force the engine into "knocking" and then immediately shut it off, coasting to a stop in neutral.
I suppose even adding a wide-band O2 sensor and gauge for diag purposes may even be required. Oh, yeah, a timing light to verify spark advance is as shown in live-data, too.
I've never done compression testing or beyond within that context, but that's okay. I have an A/C shop owner who does some mechanical diagnostics and work for me, and I trust him to address this if needed. Thanks for the information, it'll definitely help.

Quote:
Originally Posted by OldNuc View Post
What most people call "spark knock or pinging" in these cars is the sound produced when the exhaust valve opens and the resulting shock wave hits the manifold. This is most noticeable in the cars with NO hood liner and when operating at 55-75mph cruise. The big clue that this is not "spark knock or pinging" is the engine is still running fine after several years of hearing this.
Quote:
Originally Posted by OldNuc View Post
There is only mechanical cam timing and the use of premium gas advances the spark timing considerably. This lowers the exhaust exit pressure and velocity. Exactly when do you hear this sound?
For both cars, the sound only occurs under heavy load and throttle, and sometimes when shifting gears.

Examples:

In the Saturn, the sound consistently occurs when giving it full throttle in fifth gear when tackling a steep hill at approx. 40mph, or giving it heavy throttle in fourth gear under similar circumstances to advance beyond that speed. It will also occasionally occur as soon as I release the clutch after shifting into a new gear, but only if I'm accelerating beyond half throttle. The sound does not occur under any other circumstances, e.g. it cannot be recreated by throttling the engine when parked or when at normal cruising speed / throttle. The Saturn has no hood liner.

In the Sonata, the same is the case under all circumstances, but the sound tends to occur with less throttle, and the noise is more pronounced when the automatic shifts gears than when shifting the manual transmission in the Saturn. The Sonata has a thick OEM hood liner.

The sound does not occur in either car under any load when temperatures drop below roughly 50F outside, and has since been eliminated after filling both vehicles with premium fuel, with outside temperatures averaging in the mid- to high-90s with high humidity.

Now, all that said, I've admittedly had no issue with the Saturn engine after years of "pinging." I can't say one way or the other with the Sonata since I've only owned it since August 2017, though it hasn't given me any troubles either. And every vehicle I've owned prior, save a '96 Jeep Cherokee with a new crate 4.0L installed in 2006, has made the same noise for years on end under similar circumstances, and never presented with any internal engine troubles. So I don't know if I've had especially bad cases of manifold noise or not, given that premium grade fuel has eliminated the noise on my two current vehicles.

REWARD EXCELLENCE!

Add to MobileSaturn's Reputation
Rate the quality of this post and help MobileSaturn reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
MobileSaturn is offline   Reply With Quote
Old 07-19-2018, 03:25 PM   #9
OldNuc
Super Member
OldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond repute
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 64,907
 

1998 SC2
Default Re: Pinging / Spark Knock for Four Years on '99 SL

The sound you are hearing only occurring under heavy throttle and load is not abnormal and as long as you have adequate fuel a non-issue. The only 2 things that would be causing an inadequate fuel condition are exhaust leaks or low fuel pressure. Fuel pressure is usually NOT an issue as long as you have the exact OEM type of fuel regulator/filter installed,WIX 33731. Below is how to check for exhaust leaks.

Exhaust leak check.
--Locate a low pressure high volume air source, reversible vacuum cleaner, large fan, leaf blower or what ever you can find.
--Loosely couple to cold exhaust at the tail pipe, or direct fan at tail pipe.
--Spray every inch of the exhaust between the head and CAT outlet flange with a mixture of 2 or 3 drops of dish soap and water in a spray bottle.
--Pay close attention to the lower flange, lower support clamp, and flex connector.
--The flex connector is under the protective braid so it requires quite a bit of solution to show any leaks.

The last thing that will cause this is abysmally low quality fuel.

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Old 07-19-2018, 03:49 PM   #10
craftsman70
Junior Member
craftsman70 is on a distinguished road
 
Join Date: Jan 2013
Location: Pittsburgh, PA
Posts: 41
 

2000 SL1
1998 SL1
Default Re: Pinging / Spark Knock for Four Years on '99 SL

Quote:
Originally Posted by OldNuc View Post
The only 2 things that would be causing an inadequate fuel condition are exhaust leaks or low fuel pressure.
OldNuc,
Can you remind me why an exhaust leak changes the way the engine runs? Assuming the leak as after the first 02 sensor in the manifold and the downstream sensor does not affect rich/lean, what is that causes a Saturn to run differently if there is an exhaust leak?

REWARD EXCELLENCE!

Add to craftsman70's Reputation
Rate the quality of this post and help craftsman70 reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
craftsman70 is offline   Reply With Quote
Old 07-19-2018, 04:58 PM   #11
fdryer
Super Member
fdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond repute
 
fdryer's Avatar
 
Join Date: Jan 2006
Location: NYC
Posts: 41,148
 

2003 L-Series 3.0L Sedan
Default Re: Pinging / Spark Knock for Four Years on '99 SL

MobileSaturn, this is a partial reprint from service manuals;

The electronic ignition system on both single overhead cam (SOHC) and dual overhead cam (DOHC) engines provides spark energy to ignite the air/fuel mixture necessary for combustion. The powertrain control module (PCM) controls spark under all engine running conditions. The system components include: the PCM, electronic ignition (EI) module/coil pack, spark plugs, spark plug wires and knock sensor.

The spark dwell (On-time) and degrees of spark advance are dependant upon engine speed, manifold absolute pressure (MAP), and engine coolant temperature (ECT). The PCM can vary spark advance from 39 degrees BTDC to 3 degrees ATDC under all engine running conditions when no spark knock is present.

SPARK KNOCK CONTROL

The PCM uses the knock sensor to determine when spark knock exists and can retard timing up to a maximum of 19 degrees. The knock sensor is a piezoelectric flat response, wide resonant band, device that produces an AC voltage of different amplitude and frequency based on engine mechanical vibration. The amplitude and frequency are dependant upon the level of knock the sensor detects.

The PCM learns a minimum noise level at idle from the knock sensor and uses stored normal noise level calibration values for the rest of the RPM band. The knock sensor signal is only used during the TDC combustion event of the firing cylinder. When in a combustion event, the PCM filters the knock signal and compares it to the normal calibration noise level for that RPM. If the PCM has determined that knock is present during the combustion event, it will retard timing on the next firing cylinders until the knock is eliminated. The PCM will always try to work back to a zero compensation level or no spark retard.

If knock is present, the PCM will increment three counters that can be read on the scan tool. The LOW, MID and HIGH SPARK MODIFIERS represent three different RPM bands the PCM uses to store knock retard degrees. The scan tool also displays the actual amount of spark retard degrees as SPARK RETARD CYL #1-4. If excessive spark knock is detected, the retarding of timing will cause a reduced power condition.


There seems to be no doubt for two different car models to suffer engine knock based on your real world tests of both cars by driving the same drive cycle at specific engine rpm and loads with regular then switching to premium fuel and eliminating it. The question is why two different car models suffering engine knock? GMs explanation to use knock sensors is to reduce ignition timing until knock goes away then advance it until knock returns, electronically adjusting timing on the fly. I presume the same applies to Sonatas with knock sensor and same electronically controlled ignition timing. Perhaps the the two cars have one thing in common that affects engine knock, your right foot. Since you have experienced this over the years in several cars with apparently little degradation in engine life, there may be factors not often discussed. 1)is the driver, 2)is engine state of health, 3)running at high rpm and loads, and 4)moderate to high ambient temperatures and humidity. Having several vehicles with the same knock conditions may be exceeding the limits of engineering taking into account the majority of drivers not using full throttle all the time and possibly going beyond the programmed ignition retard of each engine control module. Even older engines using distributor ignition systems are affected since they're mechanically limited, set within a range of timing for all around good performance and not high rpm/high load conditions where preignition can occur.

Do you use full throttle acceleration often? Does knock occur on level roads at full throttle or only going up inclines? Are these spark knock events occurring only on 4cyl engines or to 6 and 8 cylinder engines? Are each vehicle loaded with people/stuff weighing it down or driven only with you the sole occupant? When knock occurs do you experience a loss of engine performance until knocking goes away?

REWARD EXCELLENCE!

Add to fdryer's Reputation
Rate the quality of this post and help fdryer reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
fdryer is offline   Reply With Quote
Old 07-19-2018, 05:27 PM   #12
MobileSaturn
Member
MobileSaturn is on a distinguished road
 
Join Date: Sep 2016
Location: Mobile, AL
Posts: 57

1999 SL
Default Re: Pinging / Spark Knock for Four Years on '99 SL

Quote:
Originally Posted by OldNuc View Post
The sound you are hearing only occurring under heavy throttle and load is not abnormal and as long as you have adequate fuel a non-issue. The only 2 things that would be causing an inadequate fuel condition are exhaust leaks or low fuel pressure. Fuel pressure is usually NOT an issue as long as you have the exact OEM type of fuel regulator/filter installed,WIX 33731. Below is how to check for exhaust leaks.

Exhaust leak check.
--Locate a low pressure high volume air source, reversible vacuum cleaner, large fan, leaf blower or what ever you can find.
--Loosely couple to cold exhaust at the tail pipe, or direct fan at tail pipe.
--Spray every inch of the exhaust between the head and CAT outlet flange with a mixture of 2 or 3 drops of dish soap and water in a spray bottle.
--Pay close attention to the lower flange, lower support clamp, and flex connector.
--The flex connector is under the protective braid so it requires quite a bit of solution to show any leaks.

The last thing that will cause this is abysmally low quality fuel.
I can do this with a reverse-flow vacuum, perhaps over the weekend, if there isn't anything else I could check beforehand.

Quote:
Originally Posted by fdryer View Post
MobileSaturn, this is a partial reprint from service manuals;

The electronic ignition system on both single overhead cam (SOHC) and dual overhead cam (DOHC) engines provides spark energy to ignite the air/fuel mixture necessary for combustion. The powertrain control module (PCM) controls spark under all engine running conditions. The system components include: the PCM, electronic ignition (EI) module/coil pack, spark plugs, spark plug wires and knock sensor.

The spark dwell (On-time) and degrees of spark advance are dependant upon engine speed, manifold absolute pressure (MAP), and engine coolant temperature (ECT). The PCM can vary spark advance from 39 degrees BTDC to 3 degrees ATDC under all engine running conditions when no spark knock is present.

SPARK KNOCK CONTROL

The PCM uses the knock sensor to determine when spark knock exists and can retard timing up to a maximum of 19 degrees. The knock sensor is a piezoelectric flat response, wide resonant band, device that produces an AC voltage of different amplitude and frequency based on engine mechanical vibration. The amplitude and frequency are dependant upon the level of knock the sensor detects.

The PCM learns a minimum noise level at idle from the knock sensor and uses stored normal noise level calibration values for the rest of the RPM band. The knock sensor signal is only used during the TDC combustion event of the firing cylinder. When in a combustion event, the PCM filters the knock signal and compares it to the normal calibration noise level for that RPM. If the PCM has determined that knock is present during the combustion event, it will retard timing on the next firing cylinders until the knock is eliminated. The PCM will always try to work back to a zero compensation level or no spark retard.

If knock is present, the PCM will increment three counters that can be read on the scan tool. The LOW, MID and HIGH SPARK MODIFIERS represent three different RPM bands the PCM uses to store knock retard degrees. The scan tool also displays the actual amount of spark retard degrees as SPARK RETARD CYL #1-4. If excessive spark knock is detected, the retarding of timing will cause a reduced power condition.


There seems to be no doubt for two different car models to suffer engine knock based on your real world tests of both cars by driving the same drive cycle at specific engine rpm and loads with regular then switching to premium fuel and eliminating it. The question is why two different car models suffering engine knock? GMs explanation to use knock sensors is to reduce ignition timing until knock goes away then advance it until knock returns, electronically adjusting timing on the fly. I presume the same applies to Sonatas with knock sensor and same electronically controlled ignition timing. Perhaps the the two cars have one thing in common that affects engine knock, your right foot. Since you have experienced this over the years in several cars with apparently little degradation in engine life, there may be factors not often discussed. 1)is the driver, 2)is engine state of health, 3)running at high rpm and loads, and 4)moderate to high ambient temperatures and humidity. Having several vehicles with the same knock conditions may be exceeding the limits of engineering taking into account the majority of drivers not using full throttle all the time and possibly going beyond the programmed ignition retard of each engine control module. Even older engines using distributor ignition systems are affected since they're mechanically limited, set within a range of timing for all around good performance and not high rpm/high load conditions where preignition can occur.

Do you use full throttle acceleration often? Does knock occur on level roads at full throttle or only going up inclines? Are these spark knock events occurring only on 4cyl engines or to 6 and 8 cylinder engines? Are each vehicle loaded with people/stuff weighing it down or driven only with you the sole occupant? When knock occurs do you experience a loss of engine performance until knocking goes away?
Thanks for the info, fdryer, definitely helps to understand how the sensor works!

Answering the questions in order:

- I do not use full throttle acceleration often. Both vehicles are driven 3/4 city and 1/4 interstate driving conditions. In the Saturn during city driving, I typically use 1/2 to 2/3 throttle and hold each gear to anywhere between 2500-3000rpms, so the loads I give are short bursts. In the Sonata, I typically use less throttle (on average, 1/3 throttle) since the engine is more responsive and the auto has more gears to row through. Exceptions include when pulling onto the interstate, when I use a maximum of full throttle on the Saturn up to 3500rpms for each gear, and 3/4 throttle on the Sonata.

- Knock can occur on level roads in the Saturn, but seldom, and is more infrequent than in the Sonata. Typically, it's on inclines.

- Mostly 4cyl engines (Saturn, Honda, Mazda, Mitsubishi, all EFI, all pre-2002), two I6 (one 4.2L carbureted AMC engine, one 4.0L non-HO AMC engine), and one V8 (5.2L Magnum).

- They were / are driven 95% or more of the time with myself as the sole occupant with no cargo. In the Saturn's case, doubly so, as it has no spare tire or equipment.

- No noticeable loss of performance specifically when the knock occurs, but a general loss of performance between the two cold winter months and ten warmer months of the year. When the knock occurs, both engines and all previous engines to my knowledge seem to perform the same as when the sound is not occurring.

REWARD EXCELLENCE!

Add to MobileSaturn's Reputation
Rate the quality of this post and help MobileSaturn reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
MobileSaturn is offline   Reply With Quote
Old 07-19-2018, 05:55 PM   #13
fdryer
Super Member
fdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond repute
 
fdryer's Avatar
 
Join Date: Jan 2006
Location: NYC
Posts: 41,148
 

2003 L-Series 3.0L Sedan
Default Re: Pinging / Spark Knock for Four Years on '99 SL

Presuming everything is fine and maintenance hasn't uncovered anything, tried using a mid grade fuel to see if knock stays away? As you may or may not know, electronic ignition timing is programmed and cannot be altered by 'tuning'. With many 4 cyl engines exhibiting knock, you may be one of less than a handful of drivers to experience genuine engine knock/pre detonation where electronics programming cannot retard timing enough to eliminate it. On paper, as explained from service manuals, knock is supposed to be reduced or eliminated by the engine computer listening for distinct sounds of detonation thru its knock sensor. Other than broken, loose, disconnected knock sensors on every vehicle you've driven, you may have gone beyond where no one has gone by creating the perfect storm of events to have repeated knocking in several vehicles. As you know, the technical explanations states that a reduction in timing also reduces engine power temporarily during timing retard. One way to actually see timing retard is with a reader capable of live displays and/or manually capturing the moment timing is retarded when you hear knock occur. Correlating actual timing retard with a display showing it can at least verify the extent of retarded timing to see if it matches service manual descriptions.

REWARD EXCELLENCE!

Add to fdryer's Reputation
Rate the quality of this post and help fdryer reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
fdryer is offline   Reply With Quote
Old 07-19-2018, 06:04 PM   #14
OldNuc
Super Member
OldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond repute
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 64,907
 

1998 SC2
Default Re: Pinging / Spark Knock for Four Years on '99 SL

Quote:
Originally Posted by MobileSaturn View Post
I can do this with a reverse-flow vacuum, perhaps over the weekend, if there isn't anything else I could check beforehand. ...
Nothing constructive comes to mind.

I would suspect the info fdryer has provided should help you understand that this is not a harmful event as you are experiencing it and in some but not all cases may be eliminated by switching to a higher real octane gas, ethanol will not help in these cars and can even make it worse as the Saturn is not calibrated to efficiently use ethanol fuel at any percentage.

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Old 07-19-2018, 08:58 PM   #15
1996SL11.9L
Senior Member
1996SL11.9L has a spectacular aura about1996SL11.9L has a spectacular aura about
 
1996SL11.9L's Avatar
 
Join Date: Sep 2009
Location: Stouchsburg, PA
Posts: 1,814
 

2002 SL1
Default Re: Pinging / Spark Knock for Four Years on '99 SL

I programmed my ScanGauge for the active knock retard you would be supprised how active it is. Saturn is always trying to achieve max ignition advance. My 2002 SL1 will run 34 degrees lightly loaded above 2000rpm in top gear.

My water injection has cleaned my piston tops well. It was ineffective in cleaning the Pistons on my 96. It did control knock though. That 96 blew 230 on a compression test from all the carbon buildup.

Watching active knock retard with a ScanGauge will tell you is what your hearing is something to worry about or not.

REWARD EXCELLENCE!

Add to 1996SL11.9L's Reputation
Rate the quality of this post and help 1996SL11.9L reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
1996SL11.9L is offline   Reply With Quote
Old 07-19-2018, 09:37 PM   #16
OldNuc
Super Member
OldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond repute
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 64,907
 

1998 SC2
Default Re: Pinging / Spark Knock for Four Years on '99 SL

Yes, the design is to run with the max timing advance just before detectable knock. It is credible to have degraded knock sensor sensitivity. The gen-3 relocated and redesigned the sensor as a result of determining the older ones could slowly degrade. It is an expensive part so not a good idea to just throw on a new one either. As it is just a magnet and a big roll of wire when thery actually fail you get a DTC to let you know.

Degraded sensitivity is also tested for but also not always effective so observing active knock retard is a good idea.

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Old 07-19-2018, 10:25 PM   #17
billr
Master Member
billr is a glorious beacon of lightbillr is a glorious beacon of lightbillr is a glorious beacon of lightbillr is a glorious beacon of lightbillr is a glorious beacon of light
 
Join Date: Jul 2013
Posts: 4,461
Default Re: Pinging / Spark Knock for Four Years on '99 SL

Can you post a video that lets us hear this "spark knock"? Something is very screwy here. You have had a fairly wide variety of engine types that you think are knocking, yet none set trouble codes. Speaking specifically about the Saturn, I have had three DOHC SL2s and none have ever knocked, even at highest loads and always using 87 octane E10.

REWARD EXCELLENCE!

Add to billr's Reputation
Rate the quality of this post and help billr reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
billr is offline   Reply With Quote
Old 07-19-2018, 10:56 PM   #18
MobileSaturn
Member
MobileSaturn is on a distinguished road
 
Join Date: Sep 2016
Location: Mobile, AL
Posts: 57

1999 SL
Default Re: Pinging / Spark Knock for Four Years on '99 SL

Quote:
Originally Posted by billr View Post
Can you post a video that lets us hear this "spark knock"? Something is very screwy here. You have had a fairly wide variety of engine types that you think are knocking, yet none set trouble codes. Speaking specifically about the Saturn, I have had three DOHC SL2s and none have ever knocked, even at highest loads and always using 87 octane E10.
Not now that both are filled with 93 octane. I've tried each day since putting the gas in both cars, and I haven't been able to recreate the sound at all.

I did grab a clip from the dash cam in my Sonata a couple weeks ago for the other forum that has a tiny bit of the sound. Even with the windows cracked, it didn't want to pick the sound up at all, but if you listen carefully right around when the transmission shifts at about the 7 sec mark, you can hear a hint of the sound:

https://www.youtube.com/watch?v=uU5qNXMAhYw

REWARD EXCELLENCE!

Add to MobileSaturn's Reputation
Rate the quality of this post and help MobileSaturn reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
MobileSaturn is offline   Reply With Quote
Old 07-20-2018, 08:56 AM   #19
OldNuc
Super Member
OldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond repute
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 64,907
 

1998 SC2
Default Re: Pinging / Spark Knock for Four Years on '99 SL

If it goes away with 93 octane fuel then what you were hearing was the interplay between the PCM advancing the spark to maximum advance and the knock sensor signal retarding it. It is normal and expected to hear that noise when using crap fuel and high load - high throttle openings. There is a hard limit on the amount of ignition advance for any RPM range and the 93 octane is allowing your engines to run at the design limit. It is not broke so don't spend money trying to fix it. You will likely find that the 93 octane fuel will produce a sufficient MPG increase to negate the additional per gallon cost.

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
knock sensor: pinging at high rpm under load td1238 S-Series Tech 15 03-16-2017 06:20 PM
Spark knock cure? TrotFox S-Series General 9 06-19-2013 05:35 AM
spark knock, no codes shadestalker S-Series Tech 3 11-03-2009 05:52 PM
what solves excessive spark knock (besides knock sensor) geartooth94 Miscellaneous Tech 15 09-26-2004 08:36 PM
spark knock thejudgeSL2 Mods and Performance 7 10-04-2003 10:25 PM


All times are GMT -5. The time now is 11:27 PM.

Advanced Forum Search | Advanced Photo Search


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
SaturnFans.com. The Saturn Enthusiasts Site.