I see a couple of similar threads and I'm gonna monitor both but since I don't have a CEL and I have one symptom not mentioned in either I'm gonna start a new thread just in case it's a different issue...


The car is my son's 1995 Saturn SL1 SOHC AT with 120,000 miles. I have done quite a few things to it over the past couple of years to keep it in good repair and tune and it has been reliable and economical. Only issue has been that it uses about 1 qt/1k miles. The plugs and wires were replaced about 12k-15k ago.

Recently it has begun to stumble hard under low RPM load. Level driving or acceleration where the RPM is high and the gearing is low seems fine -- no missing. However, when it shifts into high gear and the RPM drops or if you start up a hill with it already in high gear, it will stumble in hard jolts. The symptom that I haven't heard others describe is that after it stumbles a few times there is a smell of raw gas in the cabin that goes away after it stops missing. There is no steady or flickering CEL.

Maybe interesting is that though the miss/stumble is hard -- as I said, feels like a little jolt in the whole car -- the engine sounds smooth and I don't see any "ticking" of the tachometer. Of course that could be, and probably is, a red herring that results from the fact that the road noise in that little car is so loud that it's really hard to be that discerning about the various noises and the tachometer is probably not that sensitive to small, momentary, changes.

I've never replaced the fuel filter -- doing so looks like a pretty tough proposition -- and don't know when it was last changed. But this seems/sounds to me more like an ignition problem than a fuel supply/flow problem.

I just swapped vehicles with him today. I confirmed the above description of the symptoms but I won't actually get a chance to start working on it before Monday morning.

Any ideas to focus my initial troubleshooting?

 

The first thing I'd do is check the plugs. They can tell you a lot about the condition of an engine. Just use your trusty Haynes manual to see what the color or condition indicates. There's a handy guide inside the back cover. After that, I'd clean the throttle body and change that fuel filter.

 

I just changed the plugs. The old ones didn't look bad but they had burned down to the point that the gap was nearer to 50 than it was to 40.


As for the fuel filter, while I was at Oreilly's I picked up a new WIX filter. Not what I expected in form factor or price. Still, it is what it is. The real surprise was when I looked a little closer at changing it out. How the heck are you supposed to get to this thing? Is there a little secret trick that makes it easier than it looks?


I figure I'll pull the fuel pump fuse and then run the engine until it runs out of gas to minimize the fuel and pressure in the line but after that I'm not sure where to start. If I pull the wheel and fender liner will I gain reasonable access? Is there a better way?


Thanks in advance.

 

I'm not sure how the hell to get at it, Howard. I went out and looked at mine and it looks like a real PITA to get to. If you change yours, please let me know how you go about it. Mine's running fine, but it looks like the original and I have no idea what the real mileage is on this car.

 

Ok, like a lot of things it looked harder than it actually was. I was able to replace it from the top without removing anything other than the throttle body air inlet. I didn't even remove the old clamp that holds it to the frame. Leaning in from the driver's side I was able to turn my right arm counter-clockwise and reach back to the hose coupler on the bottom of the filter. After a couple of minutes of wishing I had a longer thumb and forefinger nails I was able to get the bottom quick release off. Then it was just a matter of releasing the top coupler and sliding the old filter out. Putting the new one in was a snap -- pun intended.


Btw, I put a plastic tarp under the car to catch the gas that came out when I disconnected the old one and it caught probably not more than 1/8 cup or less. What had pooled on the tarp had a lot of rust particulate matter in it.


I'll take it out after a while and see if the plugs and/or fuel filter solved the cutting out problem and will post back.

 

Well, the results put me in a nether world. I'm not sure how to interpret them other than to say the plugs and filter didn't "completely" eliminate the symptoms -- just reduced them. Reduced them enough that for a while I thought the problem was fixed.


It still cuts out when under load at low RMPs (in high gear) but has to be under more load (behind the power curve) than it did before I replaced the plugs and filter. I also noticed that when the RPMs are up above 2000 in the lower gears [and not accelerating] that the engine sounds/feels like it is varying -- dropping off and then picking back up -- a bit. That may not be new -- I may not have been listening for it before.


If someone has a more directed approach to figuring this out and resolving it just let me know and I'm happy to give it a shot. Otherwise I'll clean the throttle body -- though it looked pretty good when I had the air inlet off -- and will pull and clean the EGR valve and see if that makes any difference.


Grrr...

 

Take a good look at the connector on your ECTS, Howard. Mine was cracked and I didn't realize it until I'd already bought a new ECTS and pigtail. Probably could have just gotten away with replacing the pigtail.

 

I will Charlie. I replaced it shortly after my son bought the car but will look at it again.


Does this cause the symptom -- stumbling/cutting out when behind the power curve in high gear?

 

Yep, that could be one of the things. That damn ECTS seems to effect a LOT of things. I never knew that engine temp could be so critical to the computer cars. Back when I first started farting around with cars, they had point style distributors and carburetors. Sometimes I long for those days again!

 

The ECTS looks good. It is the brass type and I put a new connector [and pigtail] on it back when he first got the car. It is making good connection and there are no leaks. Beyond that I have no idea whether it is working correctly or not.