SaturnFans.com Forums

SaturnFans.com Forums (http://www.saturnfans.com/forums/index.php)
-   S-Series Tech (http://www.saturnfans.com/forums/forumdisplay.php?f=39)
-   -   specifics on compression testing, P0301 (http://www.saturnfans.com/forums/showthread.php?t=269836)

billr 12-04-2021 09:12 PM

Re: specifics on compression testing, P0301
 
STFT was between -33 and -36
[COLOR="red"]I can't really say whether this is good without knowing what the units are. If that is "-33" as a raw value ranging from -127 to +127 (a common 8-bit range), it OK. If, however, it is -33% of theoretical fuel required, it is a significant rim, something to be investigated, but still not a definite problem.[/COLOR]
LTFT was -17.2 (Are these good values?)
[COLOR="red"]Same problem here, units unknown. However, if this is percentage, it is probably too much.[/COLOR]
MAP sensor was reading 9 inches of mercury, a vacume guage had read 34 inches of mercury previously in the same hole (is the sensor bad?)
[COLOR="red"]9" Hg is pretty normal, about equal to 21" Hg on a vacuum gauge. Since no vacuum much past 30" Hg is even possible, I question the gauge. In fact, I wonder why they even bother with numbers beyond 30" on the dial...[/COLOR]
O2 sensor 1 reading fluctuates between about 0.35V, and 0.75V
[COLOR="Red"]That range is normal, but we need to know the rate; and you need to correlate the sensor reading changes to STFT[/COLOR]
O2 sensor 2 reading fluctuates between about 0.28V, and 0.68V (are the sensors bad? What do good readings look like?)
[COLOR="red"]Same comment[/COLOR]
spark ADV was between 16 and 20 (Does this matter?)
[COLOR="red"]Spark advance certainly matters. but that range and variation seems about right for idle[/COLOR]
TPS was 0%, I was not touching the throttle
O2 sensor readings are listed again for some reason, with the same values, except they are positive
STFT was listed again as sensor 2, 99.2% (Does that represent the amount of air, or fuel?)[COLOR="Red"]That would be fuel, a percentage of theoretical fuel required for the current engine running conditions (rpm, MAP, CLT, IAT[/COLOR]

What specific problems are you trying to solve now? A recap or update, please, it has been a long thread.

TomM96 12-07-2021 06:52 PM

Re: specifics on compression testing, P0301
 
> The turn signal switch also seems to only work intermittently.

On some vehicles that can be caused by poor connections, as from
bulb-to-socket ... or socket/harness-to-ground.

TomM96 12-07-2021 07:08 PM

Re: specifics on compression testing, P0301
 
> I sometimes have to shift it in and out of park before it will crank, because I have become so used to it that I barely notice. I suspect that this problem is likely caused by a problem with the neutral safety switch.

Very interesting. On my '97DOHC with TAAT, there was a problem of
an "unexplained SES". The one-time Satty dealer (now Mitsubishi) looked
at it for a couple hours ... and thought there might be an issue in the
instrument panel. I then drove a couple hours to a junkyard to get an InPnl.
The used InPnl was itself useless, but I noticed en route, that the SES
extinguished at about the 1-1/2 hour driving time. That became a persistent pattern, and convinced me that the PRNDL/Neutral-Safety SW took 1-1/2 hr
driving to Dry out moisture/salt within. So I procured a new switch from
Standard Motor Products ... which I mis-placed until after i lost possession of the car.
That car never had proper/acceptable starter-motor behavior, although
renewal of the Ig Sw improved it somewhat ... with which I also suspected the PRNDL/Neutral-Safety SW of involvement.

lanxer57 12-15-2021 04:11 PM

Re: specifics on compression testing, P0301
 
When I tightened the input shaft nut, I stuck a screwdriver inside it to hold it in place, the hole was slightly elongated. Could this cause a P0733?

lanxer57 12-15-2021 04:19 PM

Re: specifics on compression testing, P0301
 
I am trying to solve P0733, and P0172. The automatic transmission is also leaking a very slow drip. If I solve these problems, I expect more to appear.

billr 12-15-2021 04:22 PM

Re: specifics on compression testing, P0301
 
I doubt it. The ISN holds the 1st gear clutch; the clutch for 3rd is much deeper in the trans.

billr 12-15-2021 04:31 PM

Re: specifics on compression testing, P0301
 
[I][B]"When I tightened the input shaft nut, I stuck a screwdriver inside it to hold it in place, the hole was slightly elongated."[/B][/I]

I don't think it matters, but that statement above has me confused. The only hole I know of in the ISN is the threaded one in the ID. I don't see any possible way to use a screwdriver in that hole to hold things while tightening the ISN. Did you mean a hole in the [I]clutch drum?[/I]

lanxer57 12-15-2021 06:07 PM

Re: specifics on compression testing, P0301
 
Yes, the one in the side of the "clutch drum".

lanxer57 12-28-2021 02:49 PM

Re: specifics on compression testing, P0301
 
could the codes P0172, and P0733 have anything to do with the fuel that sat in it for at least 6 months, and needed fuel stabilizer to run at all?

billr 12-28-2021 04:43 PM

Re: specifics on compression testing, P0301
 
No on the P0733; that is strictly a trans issue.

Maybe on the P0172, but I kind of doubt it. I have let fuel sit for far longer than 6 months with no apparent problems. Carbs, EFI, diesel; none of them seem especially sensitive to that "old fuel" bogeyman.

lanxer57 12-28-2021 10:06 PM

Re: specifics on compression testing, P0301
 
could it be the ECTS that I replaced a few months, and less than 10 miles ago? Are they often defective when brand new? (it is brass, shows up on the guage, and on the obd2 reader)
could it be an oxygen sensor? (those show voltage on obd2 as well)
Is there a list of possible causes for it to run rich but dad not to smell it?
What about an incorrect gear ratio that feels normal while driving? (at speeds not greater than 30mph)

billr 12-29-2021 12:43 AM

Re: specifics on compression testing, P0301
 
Do you have live-data that shows ECT? If live-data as 190F or more when the engine is hot, then ECT is not the cause of rich running.

There are many reasons why the engine could be (detected as) running rich. Here are some common ones:

"Intake blocked, EVAP canister purge valve, fuel pressure, EGR system, injector(s), HO2S"

I'm not sure what your question is regarding the P0733. That indicates a trans problem, and it seems you are saying the car will not operate normally over 30 mph. Why does that puzzle you that a car with a bad trans has trouble going over 30? Does your live-data show "Trans Turbine Speed? That can be compared to "Vehicle Speed", in 3rd (or any) gear to verify something is slipping and the P0733 is valid.

lanxer57 12-29-2021 04:07 AM

Re: specifics on compression testing, P0301
 
The ECT is above 190 when warm. The reason I am not driving faster than 30mph is because I am only driving on small residential streets, and do not want to get pulled over. This vehicle can not pass an emissions test, meaning it can not get registered. If it gets pulled over, it will get impounded, and I do not have the money to get it out of an impound. This cowardice has nothing to do with the capabilities of my car, it could go faster, I am simply reluctant to take more risks.

fdryer 12-29-2021 11:47 AM

Re: specifics on compression testing, P0301
 
Can you post intake air temperature, coolant temperature and map sensor value on a cold engine, ignition on (engine off) and outside temps? IAT and coolant sensor should be the same or close to outside temperatures. Map sensor should be the same as local barometric pressure from weather sites (currently 29.87 in hg@7:30 am today in Aurora). These are baseline values to help verify sensors are operating before an engine start. On startup, a cold engine coolant sensor should be showing rising coolant temps until reaching thermostat operating temps then remain within 5-10 degrees of t-stat rating. Your coolant sensor is fine from posted data. The t-stat is fine since it's within operating range of its rating. The intake air temperature is known to be reliable but if it fails, it can contribute to P0172 so checking its output at cold engine/ambient temp/before starting compares its output to outside air temps. Plus or minus a few degrees is fine. Intake air temps will vary from airflow at speed, stopped when engine heat flows towards it, etc. The coolant sensor does the same, data for the pcm to vary fuel mixtures. The map sensor is basically the engine load sensor measuring manifold vacuum as throttle opening and engine rpm vary as data for the pcm to vary fuel mixtures on a larger scale compared to iat and coolant sensors. The exhaust manifold O2 sensor measures oxygen leftover from combustion as data to the pcm to quickly alter fuel mixtures several times per second to regulate air/fuel mixtures as close to 14.7:1 for tight emissions control. This upstream sensor fluctuates quickly between 0.3v-0.7v but switches too quickly for digital millimeters to see unless a quick acting bar meter is seen. An oscilloscope for geeks shows the speed of O2 sensor cycling rates. A worn out, slow cycling O2 sensor can alter fuel mixtures to either lean or rich conditions.

billr 12-29-2021 02:13 PM

Re: specifics on compression testing, P0301
 
OK, I understand that operation over 30 is simply unknown, not necessarily "bad". Do you hold it in lower gears manually sometimes and accelerate fast (or up steep hills), so the engine is seeing some operation at higher rpm and load? Regardless, let's ignore the P0733 until you can take this beast up to highway speeds routinely. Will the trans code prevent it from passing emissions test?

If (live-data) temp on the engine warmed-up is 190F, that is good enough that the ECT can also be ignored regarding the P0172.

So, that leaves you back to that list I quoted a few replies ago. There are other possibilities too, I sure, but start with those.

lanxer57 12-29-2021 07:37 PM

Re: specifics on compression testing, P0301
 
I may inspect the components listed tomorrow.
The websites that describe colorado emissions testing requirements/criteria are not very clear on what exactly will cause a vehicle to fail a test.
"A check engine light on a vehicle at least 12 years old may still pass if the I/M 240 test can be run and the car can pass the test."
It does not appear to list anywhere what the criteria for these 4 minute dynamometer tests are.
It also mentions that smoke beyond 5% opacity will cause it to fail, as well as any "obvious fluid leaks, worn tires, etc". I do not know how obvious these fluid leaks would need to be, the trans is leaking enough to leave a spot on the driveway, but not enough to see it dripping. It also mentions a visual inspection, but does not say weather they look at horns, or turn signals (which are not currently working).
It does not mention anything about coolant lights, but the do flash when sitting in the driveway.
It also says that "Catalytic Converter, Oxygen Sensor, and Heated Oxygen Sensor (if so equipped) monitors set to “Ready” during the inspection. Vehicles model year 2000 and older can have two remaining monitors “Not Ready”". I do not remember ever seeing these symbols turn green on the obd2 reader, and they are definitely not ready now.

lanxer57 12-30-2021 12:00 AM

Re: specifics on compression testing, P0301
 
Should I just try to take an emissions test, just to see how it goes?:stoplight
maybe take one every month, just in case? I think that is what they want us to do... it is only 25$ per test. (unless it gets impounded):arr:

fdryer 12-30-2021 12:48 PM

Re: specifics on compression testing, P0301
 
Prior to 1991, on board diagnostics (OBD I or OBD II) didn't exist. Every vehicle manufacturer did their own thing as EFI systems became complicated then tighter emissions controls added to EFI complications. My Mercury Sable wagon was required to run on emissions inspection rollers as the inspector varied drive wheel speeds following a screen displaying a programmed road drive to create loads and speeds with an exhaust pipe analyzer sniffing the exhaust. This was testing the emissions system as speed and loads changed. After this program ended, a report was generated for pass or fail. 1991 vehicles became the first to utilize emissions self tests incorporated into engine computers to eliminate inspection stations having one dedicated service bay for emissions inspections. Every vehicle made for the USA market since '91 performs emissions self tests on every engine startup with constant monitoring while driving. In effect, as long as the check engine/service engine soon/malfunction indicator light remains OFF, a vehicle has passed emissions self tests before driving into a state inspection station.

Your '99 uses OBDII because '96+ vehicles incorporated tighter emissions control programs. It's still on board emissions self testing. This means no rollers or exhaust sniffing analyzers (outdated). Your reader or scantool, if it displays emissions monitors in READY or NOT READY status is all that's needed to tell you long before visiting a state emissions inspection station whether or not your vehicle passes its on board emissions self tests or not with details on which monitors failed for you or mechanic to address. You have options. Either continue here and try understanding your situation with the two error codes and any not ready monitors and make repairs or search for a mobile mechanic with expertise in EFI systems, experience in diagnosing and troubleshooting error codes or ask a friend who's experienced in these matters. Expertise in repair shops are hit or miss.

fetchitfido 12-30-2021 01:11 PM

Re: specifics on compression testing, P0301
 
The OBD-II emissions 'ready monitors' require a completed drive cycle , which itself requires something the OP is unable to do ([URL="http://obdii.com/drivecycle.html"]DC explained[/URL]). Until a drive cycle can be completed it'll never pass an OBD-II scan based emission's test.

fdryer 12-30-2021 02:38 PM

Re: specifics on compression testing, P0301
 
I'm aware of his predicament.


All times are GMT -4. The time now is 09:19 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.
SaturnFans.com. The Saturn Enthusiasts Site.