RPM surging 99 SL2

[Mooseparade]

First post here, and I'm at a total loss. I've read the posts on this from years ago but I think I still may have missed something.

The RPM's will surge between 800 and 1300 while idling and driving. It's an 99 SL2 DOHC auto. I've already replaced Valve Cover gasket, PCV Valve, ECTS, IAC, cleaned the MAP sensor and EGR valve. After cleaning the EGR valve the problem wasn't as noticeable but still there especially once the car warms up.

Any help is appreciated guys.

[Mooseparade]

Sorry, couldn't find the edit button on mobile. I also replaced the spark plugs with ac Delco and the ects with a duralast brass one. The connector to the ects is corroded (probably from the original ects) but I can't find anywhere online to order one. Thanks for the help guys.

[slugbug]

The EGR valve may need to be replaced altogether.

[toggenburg]

You need to replace that corroded ECTS connector.
Last time I went to a computer repair shop, for a dollar, they sold me a
similar 2-pin plug from a computer PC chassis.
I stripped off the jacket insulation, soldered the copper ends together, and finished it off with a (previously applied) shrink tube.
Never failed after that.

[fdryer]

The egr valve may not be the problem because it regulates exhaust gases fed into the intake air system and would drop rpm at idle or while accelerating resulting in hesitation problems. The egr valve doesn't cause surging, raising rpm.

The corroded coolant sensor connector may be the problem. The sensor works on less than 5 volts so any corrosion means resistance to alter signal output to the pcm. Either visit a junk yard and search for Saturn intake air temperature sensor connectors and cut one for reuse or buy a two pin pc connector that fits the spacing in the coolant sensor. Most two pin pc connectors like fan cooling connections are the ones to look for. Splicing into and soldering with shrink tubing seals the solder connections. Silicone sealant to seal the push on connections. Just enough silicone smeared to cover the plastic, wiring and coolant sensor. This can be undone later if necessary since silicone is rubbery and didn't work it's way into the male/female terminals.

[Saturn Night]

As previously stated, you will want to fix the corroded ECTS pigtail harness, before additional troubleshooting.

Grab a pair of side cutters and head to a local wrecking yard for cutting the harness section off a dead Saturn S-Series. 1991-2002 all use the same plug and sensor.

Butt connectors and wire caps are NOT the recommended repair here. Solder the ends of the wires together before sealing them with electrical tape or some form of insulator.

[DonP1]

Originally Posted by Mooseparade

Sorry, couldn't find the edit button on mobile. I also replaced the spark plugs with ac Delco and the ects with a duralast brass one. The connector to the ects is corroded (probably from the original ects) but I can't find anywhere online to order one. Thanks for the help guys.

I just ordered one from Rock Auto this morning. For a link go to the General forum and find my thread about a new Saturn. Someone posted a link to the connector. It was under $10 with shipping.

[Mooseparade]

I found one through autozone (3 minutes from my house) for $9 and it will be here tomorrow. I think it's a Doorman. Hopefully this fixes it. Now I just gotta get rid of the slam when going into reverse.

I tried Wolf's fix, new fluid and spin on filter, run it in reverse for 30 minutes. Didn't fix it.

[fdryer]

^ Are you describing a coolant sensor or two wire sensor connector?

[Cheyne]

Dorman 645-900

[Waiex191]

https://www.rockauto.com/en/catalog/...connector,2564

[toggenburg]

The computer part I described above works just as good, and is cheaper and no shipping charges.

[Saturn Night]

Originally Posted by Mooseparade

I found one through autozone (3 minutes from my house) for $9 and it will be here tomorrow. I think it's a Doorman. Hopefully this fixes it. Now I just gotta get rid of the slam when going into reverse.

I tried Wolf's fix, new fluid and spin on filter, run it in reverse for 30 minutes. Didn't fix it.

Send a PM to Special Forces, a forum member here. He is an experienced Valve Body rebuilder for over 10 years, and can set you up with a replacement valve body that permanently solves that problem. The problem is the design of the stock valve body being cast aluminum and the seals for the boost pressure valve being steel. This causes wear on the bore, and internal leakages, which drop line pressure and delays the clutch engagement.

My Valve Body has just under 33,000 miles on it, currently, and just got a fresh filter, cleaned magnet, and new fluid with Lucas additive. Shifts so smooth you can't even feel it shift in "Performance" mode. And this VB has seen multiple trips to the drag strip.

[Mooseparade]

Originally Posted by fdryer

^ Are you describing a coolant sensor or two wire sensor connector?

The connector

[fdryer]

Ok, let's hope the new connector eliminates this surging problem. I checked a member's link to rockauto for the connector.

[Mooseparade]

Ordered the l ects connector from Rockauto (part number 1P1439) and installed it and let it idle to operating temp. After about 15 minutes there wasn't a single fluctuation in the idle at 800 rpm. I went for a quick drive around the block and floored it at one point and it idle at 800 and ran smooth the whole time. Temp sat right at 3/8 the whole drive and never went over 1/2 while idling.

Next question, I'm replacing the intake manifold gasket and cleaning the intake. I also want to replace the fuel filter and was thinking of going with a Premium Guard PF5501 from rockauto for $22.79. Any thoughts or recommendations?

[Saturn Night]

Originally Posted by Mooseparade

Ordered the l ects connector from Rockauto (part number 1P1439) and installed it and let it idle to operating temp. After about 15 minutes there wasn't a single fluctuation in the idle at 800 rpm. I went for a quick drive around the block and floored it at one point and it idle at 800 and ran smooth the whole time. Temp sat right at 3/8 the whole drive and never went over 1/2 while idling.

Next question, I'm replacing the intake manifold gasket and cleaning the intake. I also want to replace the fuel filter and was thinking of going with a Premium Guard PF5501 from rockauto for $22.79. Any thoughts or recommendations?

There is a WIX fuel filter, for the 1998-up Saturn S-Series and it is the ONLY recommended filter because of the fuel pressure regulator design on the returnless fuel injection system.

[Waiex191]

My research on SaturnFans led me to the Wix 33731 for my '99 SL2. We snapped the bolts for the bracket and had to drill and tap.
One of the many threads:
http://www.saturnfans.com/forums/sho...d.php?t=186901

Mine after replacement: