Stalling. Please help
 

I'm about to throw in the towel and take my 94 FWD SVX to the shop. I hate to give up, so I'm hoping someone out there can give me some advice.

Here's the problem:
Most of the time, the car runs superbly. Starts right up, idles smooth and runs strong.
Sometimes, during about the first 3 miles of driving, it will stall out. It generally starts right back up. Sometimes it starts up, sputters and stalls. But, then it will start up and run fine until it stalls again. After about 3 miles, everything is fine.

Here's what I've done:
1. Replaced air filter.
2. Replaced fuel filter.
3. Replaced all plugs.
4. Replaced all coil packs ($$$$)
5. Cleaned throttle body.
6. Cleaned fuel system (gas tank additive)
7. Replaced and set the throttle position sensor (0.51 Volts at the TPS).

Other than spending a lot of money and time, the only real change I've seen is that the transmission shifts very smooth now. I attribute this to the old TPS being set wrong.

Ok, does anyone have a good idea of what to do next? I could go for the MAF, but it's starting to get expensive and I'm just shotgunning.

By the way....THERE IS NO CEL.

Thanks,
Bill

Try cleaning the element inside the MAF. Do a search, some found vinegar works well. What RMP does it idle at? Search for throttle cable mod. Resetting the ECU might not be a bad either, just disconnect the battery over night. These are all of the low buck things I could think of.

I was wondering about cleaning the MAF filament. I will try it.
The car idles cold at about 1200-1500 rpm and gradually comes down to about 700 rpm when warm. The idle is very smooth.

One other thing I noticed. When I start up from idle at a light, for an instant the tach shows a very slight drop in the rpm, before it starts to increase. This occurs every time. Just a little dip on the gauge, then back up. If I accelerated from a speed of say 40mph, I don't see the little dip.

What is the throttle cable mod?

This sounds more like either the MAF and/or the crank/cam sensors.

Does the CEL ever come on?

No CEL. It only comes on when you start the car. Then goes out.

my car was doing the same thing too. it would stall when put in gear and so on. try this. turn up the tps sensor to .53 or .54 volts and clean your maf sensor with electronics cleaner from advance auto parts.mine runs better now and stopped stalling too so try it out.

BTW let me know if you need further help and maybe we can get together and check it out.

Hey thanks. I'm going to try cleaning the MAF today. I might change the PCV valve too, since I have a new one sitting here. I'll let you know how it works out.

yeah the pcv would be a good idea since you'll already be at it.keep me informed.:)

Guys,
I'm still struggling with this intermittent stalling problem. Since my last posts I have cleaned the MAF, replaced the PCV, replaced the coolant temp sensor, thoroughly cleaned the IAC and Aux air control valve and replaced an O2 sensor (CEL light came on, this was the code). I really thought cleaning the aux air control valve was going to cure it.

Any ideas?

The stall (if its going to occur) will occur when the engine is fairly warm but not fully warm. After its fully warm, it runs perfectly. When its cold, it runs fine too. Its like at the point where the aux air valve is about to completely close. Classic case is to drive it for a while, shut it off for about an hour and start it again. It's likely to stall then.

check your cat. mine used to sputter and the cat was clogged. doesnt sound like it but worth a shot.

Stalling out.
 

You will have to isolate it to either fuel or air, as it has to be one. Try holding the throttle open when you start it up. This will provide the air, so if it still stalls, it has to be the fuel.

There is another action that could cause it, and that is the spark. When the engine is idleing the speed is set by the Idle air valve, but this unit is slow to react, so the ECU uses the spark setting to quickly change the idle speed till the Idle air valve adjusts its position to hold the new setting.
For instants, if you move the steering wheel the load of the pump will slow the idle speed down. To prevent the stall the ECU advances the spark, this picks the idle speed up instantly, once the Idle air valve has opened the hold the speed the spark goes back to normal. When you stop turning the wheel, the loan comes off, the ECU will retard the spark to drop the idle speed, till the Idle air valve takes over.

May be your Idle air valve is too slow to react, and misses the pick-up time.

Harvey. ;)

I still haven't fixed this problem, but I've been doing some more research. What about the EGR? Could I have a problem where the EGR is not closing all the way? Would that cause stalling during warmup? From what I've been reading, it seems like a possibility. I'm hoping some of the experts will weigh in on this one.

It looks like it can be cleaned but it might be hard to get to. Does anyone know if it can be cleaned without removing it? If it has to be removed, how tough is it?

Thanks for any help.

usually if there is a problem with the EGR it will throw a code.

My 94 L had the same exact problem. It was fine at startup and fine at complete warm up. But Just as the car was hitting the "warmed up" stage, I would go through about 2 minutes of hell. Sputtering, and if I didn't shift to a lower gear, it would die.

It was the temp sensor. I replaced it and all went back to normal. I know you said you replaced yours......Could it have been bad also? Did you test the new one?

Oh Yeah..... It never gave me a temp sensor code either. It never gave any code at all. The check engine light would come on when it would act up every morning, but then no codes would be registered.