92 Jetta runs rich then stalls

Check Engine Light coming on? Has it recently?

SWAG Guesses in no particular order:

Fouled Air Mass Meter

• = where I would look first.

When is the last time you checked the plugs and wires? And how strong is your coil? As you state that it runs fine when warm, that suggests away from the cold-start system and more towards a weak spark problem.

Assuming this is a 4-cyl, gasoline engine.

If it happens to be a diesel, go immediately to your glow-plugs and check those. They are easy to reach and to check.

Peter Wieck Wyncote, PA

lol And to agree with pfjw .............. It does help when you get more info like if it is gas or diesel, 8 valve or

I will ASSuME that it is an 8V gas engine in the USA and that you have tuned it recently....RIGHT? I would suspect ground wiring to the intake manifold or coolant pipe on the rear of the cylinder head, or the flap in the air flow box is sticking or the fuel pressure regulator has ruptured. Also some possibilities are the Coolant Temperature Sensor, Oxygen Sensor or wiring.

Again, assuming gas engine...

Isn't it running open loop at the time he's having problems? If so, the air and O2 sensors don't do much.

I suspect either a bad temp sensor telling the car it's warm, a vacuum leak, or ignition problem.

But check the easy stuff first. Air filter, intake hoses, plugs, cap, rotor, wires, vacuum hoses.

Mark '95 Jetta GLS

Anything is possible, but if the thing purportedly runs properly when warm, then the coolant temp is out-of-circuit and the Oxygen sensor is limited. Generally as well, when the coolant sensor fails it will run very rich when warm or lean when cool...

Could be a loose wire or ground as you suggest, but I would start with the spark. And on general principle, I would run a can of Techron through it in a fresh tank of gas in case any injectors are fouled.

WIthall, these cars are pretty simple-minded (which does not mean "simple"). Ignition/spark, fuel, sensor(s). Given the timing of this defect (on starting), I would discount sensors until the first two are proven OK.

Peter Wieck Wyncote, PA

Sorry guys, it is a 1.8L 8v gas engine. I am in Canada, I don't know if the car will be any different or not, its probably the same as the USA version.

It seems to be intermittent because it started and ran fine yesterday. Today may be a different story as it is -30C right now but if it acts up I may just take it into a shop because I don't want to be outside in this cold trying to troubleshoot it.

What is a can of Techron? Is it just fuel injector cleaner? I've got

Techron is one of the more expensive FI cleaners, but also the only one I have used with uniformly good results.

Peter Wieck Wyncote, PA

SeaFoam is also very good and sold at some auto parts stores and some Home Improvement stores (Menards). BG 44K makes some very good cleaners too that are recommended by others. I can't seem to find them locally though. :-(

If the engine has the 3 wire 02 sensor and the wires are fused to each other it might cause a rich condition possibly within minutes of starting the engine. I have seen this happen after the wiring touched the exhaust manifold and fused together. And the engine seemed to run better when warm too but could not pass the emissions test.

Of course it is nice to only have 1 problem, but there may be more problems that need correction. ;-) Whenever I check a car for a problem I try to go down a checklist, but still need to test almost everything and assume nothing. I have even seen an oil pump cause an engine running problem! 8^o

YES check the easy & simple stuff first like the quality of the spark!

JMHO later, dave (One out of many daves)

Yes Canada and 49-state US were the same for 1991-1992 (Digifant II injection).

Also it could be a bad vaccuum line that operates the fuel pressure regulator. I had that happen to me. Easy $2 fix. :)

Oh that much huh? lol

IIRC, he didn't say how he knew it was rich other than saying it smelt of gas when cold.

I mentioned the vac leaks, etc because sometimes a 'rich report' is actually way lean. Without enough gas in the intake charge, all the gas doesn't burn, which gives more gas smell in the exhaust (at cold anyway) than a rich condition would unless it's VERY rich.

Pulling the plugs is a good idea tho', since a read of their condition can tell a lot.

Mark '95 Jetta GLS

Yes that is true. When mine had a vacuum leak to the pressure regulator it was nearly flooding the engine. When i pulled a plug it was wet and also smelled a lot of gas.