My 3.4 Won't Run Part II

[Sonyman]

Ok for those that don't know, read "My 3.4 Won't Run" thread previously to get caught up to speed. For those who I have consulted with before, here's an update....on a cold start it will crank and run but with a "miss" like a coil is bad or if you disconnect a spark plug or a wire harness from an injector. It runs for an avg. of 12 minutes and then slowly idle too low until it stalls and die. Afterwards it will not run, just turn over when starting immediately. If you wait an hour or so, it will run again and repeat the process. Before you respond think about it mechanically/logically. Everything has been either repaired or replaced. To be specific, ask me questions but i know it is something small and easy but its difficult to find and these 3.fours arent that difficult to figure out but mine is a mystery. Everyone who has a serious input on my dilima, please tell.

[pocket-rocket]

Have you checked for the right volume of fuel from the new pump? I've heard of pumps checking ok with the pressure aspect, but failing with the volume of fuel that they pumped.

[WrathOfSocrus]

If it starts up then there is something going wrong during the time it is running. Seems as if there may be some sort of heat issue. The description sounds like a coil pack even thought it has been replaced. I replaced one once only to have another go bad. Also the other old one that ohmed out good ended up having a crack in it. Did you replace all the coils at once?



Someone mentioned testing things out right when it stalls out as opposed to when it is cold. I would get a baseline ohm reading of the coils cold and check when warm. Generally speaking resistance is higher when cold and lower when warm. If any warmed coil pack has higher resistance then there is something wrong. Even a new coil could potentially do this if manufactured improperly.

I guess that resistance theory could go for the injectors as well.

Does it seem to raise in idle and act like it is leaning out? That could be a leaking intake gasket (LIM UIM throttle body) that opens up as it warms.

The only other thing I can think of is that you have replaced the original problem and accidentally caused a new one. For instance when you changed your fuel filter, was that before or after you blew the lines out and changed the fuel pump. Seems likely to try the filter first and then the pump. But if it was the pump bad to begin with and you accidentally blow/suck up gunk into the new filter. However that doesn't seem to fit with it starting OK and dying when warmed up a bit.

IAC/TPS?

[Sonyman]

Fuel Pump is new and checkout with sufficient fuel pressure. I'm with ya "Wrath" i think it is something that goes while its running. All coils and ICM have been replaced new. I even replaced all wiring and wire harness new from the ICM to their destinations. Fuel filter new as well. I have another fuel rail with injectors on hand, i may replace my old with this one to see if a differrence but my instincts tells me it may not make a difference cause i dont believe one injector or few could cause the engine act all at once to a slow stall and die. It must be somebody who is a main contributor to control the engine running...oh yeah spark is strong and white enough to kick start Frankenstein! and upper/lower intake gaskets have been replaced...yeah i know this is a tough one but i know it can be fixed.

[dohcfiend]

at this point i would recommend having a professional diagnose it if it has given you this much trouble.

[Sonyman]

a professional tucked his tail between his legs when he saw the size of the engine. a few did including one who said the car was too old. They are all a bunch of panzies!!! If it runs on gas, it can be fixed is my motto so no i'm not gonna punk out now.