I'm hoping that someone here can help with this asit is really starting to be a problem.


A week ago, my 94 SL1 with 130k miles overheated. I pulled over and found that I was leaking coolant. I bought a gallon at 7/11, poured it in and thought to make it home. Well I made it about 100 yards and then the engine simply died. Still turned over fine. Restarted briefly but then wouldn't catch again.


I left it on the side of the road and got a ride home. Went back the next day, changed the upper rad hose and it started right up. Drove most of the way home but cut out on me on an onramp to a freeway (75 yard uphill grade). Started back up in 20 minutes and made it home.


I assumed that it was related to the coolant everywhere so I washed and then dried everything under the hood that I could reasonably get to. Again, started right up. I drove it for around 20 minutes. Parked fro a half hour, then on starting, it died again. I limped it over to a Saturn dealer.


They weren't really able to find anything. The only codes were for "misfiring." They suggested changing the coils, HT wires and plugs, which I did. Next day going in to work. Same thing happened after about 30 minute.


I have to assume that something occurred when it overheated. Could it be a cracked ECTS? Could this cut out if coolant is leaking in? if so, could it recover after a while?


Any help would be appreciated. This is my DD and having it sitting in my driveway does me no good at all.

 

If the car overheated due to an external leak (rad hose) and not an internal leak, I doubt the ECTS is an issue all by itself. Even when bad, it just makes the car run really rich. Can't hurt to replace it?

1) Where is the needle on the temp gauge when it stalls? Is there a correlation?

2) Is SES light coming back on since you changed wires, plugs, and coil packs? If not, at least the misfire issue may be addressed. If it is still coming on, then the misfire is likely not related to that portion of the system (which usually is not a good thing).

It is possible that the head (which is aluminum) may have warped when it overheated, such that the head may not be sealing correctly to the block, which may lead to reduced compression, etc.

3) Are you still slowly losing coolant or is the coolant level absolutely stable?

The crankshaft position sensor (CPS) is a common culprit for intermittent stalling on these engines -- they tend to fail when the engine is hot....usually won't throwa code either.....

Derf

 

Thanks Derf,


1) Needle is dead center normal when it stalls. Normal operating temp.


2) SES never really came on except when trying to restart. It certainly didn't come on inadvance of stalling and didn't stay on once it restarted. As for misfiring, i think that was more of an artifact than anything. The car runs perfectly until is stops. On restarting, there is some sputtering which I think throws the codes.


3) I haven't closely watched the coolant level. It has also been raining here so I would never have noticed smoke from the exhaust.


CPS? Interesting. Makes sense that if this was faulty that it would stall the engine, but would it be intermittent?Edited by: CALegalVette

 

Yes -- if CPS signal is not received by the PCM, there will be no spark -- = stall. They have been known to flake out intermittently.....

The other common cause of the intermittent stall is an EGR valve sticking issue. The innards get coated with carbon and the pintle valve cannot move freely. Doesn't always throw a code but will usually show up during hard accel and or decel.

If you've never had your EGR cleaned I would do it anyway.
But if there are no rpm gyrations right before it stalls, I don't think the EGR is the issue here.

Derf

 

Kind of interesting.


I put the car up on stands this morning in preperation for changing the Crankcase Position sensor and thought to check the trouble codes before starting.


Threw code 34. Camshaft position??


I've got to take my family to a movie and then will change out the crankcase sensor. I'll post after that.

 

Well that wasn't it.


I replaced the CPS and it started right up. Made it 3/4 of the way around the block and died. Can't get it restarted either. Ran fine until then though.


I do have a spare, used EGR valve as I replaced it quite some time ago and kept the original. Is there a procedure posted for cleaning? Testing?


I'm getting close to the end with this. The car is my commuter and isn't of any use to me dead or even unreliable for that matter.


All help appreciated.

 

Code 34 Manifold Air Pressure Sensor Circuit Low

Was the SES light on while driving right before you checked the codes? If not, this is getting a bit hairy, since we don't know when the MAP sensor code was set......if the problem clears up on its own, the SES turns off but the code remains in memory until it is cleared.

MAP sensor is not cheap, so the status of the SES before you checked the codes is crucial in deciding whether this is a recent issue or a historical code. I wouldn't expect this code to set from goofy sputtering at rough starts, since the minimum signal level returned to the PCM from the MAP is always significantly higher than the low low level signal that sets a code 34.


EGR can be cleaned with carb/choke cleaner. The idea is to free up the pintle valve so that it moves freely (I think you can work it with a phillips head screwdriver -- gently).

Certainly worth a try.

 

No, the light only came on briefly while sputtering and then went out again. The code is recent because I disonnected the battery to replace the coils on Wednesday.


UPDATE: Well lookie here. Before I did anything else this morning I checked the codes. The battery was unplugged for at least an hour yesterday while I changed the CPS and there was a code 34 this morning. This has to be a new error code.


I'm off to Kragen to get a MAP sensor. One question though. Where does the MAP sensor go? Presumably on the air intake or the intake manifold but the manual doesn't even mention it.Edited by: CALegalVette

 

BINGO!





I think that was it. picked up a new MAP sensor at Kragen. Even though it doesn't fit particularly well, it was good enough so that i could find the old one. When I pulled off the plug, it almost fell appart in my hand (the plug). I nylon tied the new sensor back on and tied the plug in place as well. I've been driving around all afternoon. Still runs like a 94 with 135k miles, but at least it runs!


I suppose that I'll have to replace the harness and may have to get a better fitting sensor, but at least I have a running car again.


Thanks for your help derf

 

Glad to hear your DD is back to DD status!

It's always gratifying to get to the bottom of these things....

If you get the harness from Saturn parts dept, make sure the map sensor you bought is indeed compatible/equiv to the Saturn part.

Derf