hard start when warm

[Talon__22]

91 talon tsi fwd. car starts fine when cold, but when warm it will fire and stall. if the throttle is held down will flare up to 4000 and stall out like its cutting fuel or something. any help would be great. thanks.

 

[AWD1GTSI]

ME 2, and emissions probs, maby its related, here's the thread on that: http://www.dsmtuners.com/forums/showthread.php?s=&threadid=116841

I think this may be the answer to my stalling prob maby you should look into it: http://www.dsmtuners.com/forums/showthread.php?s=&threadid=117113

 

[Talon__22]

i forgot to add that the car runs fine and idles fine once started. i just replaced the o2 sensor cuz it was bad, but i didnt think it would take care of the problem. the mods i have are a mbc and no cat. im wondering if the ecu would cause that if its running too rich and cutting fuel or somethin. i know its running rich, and the oil has a gassy smell. im currently running 15psi of boost, but that wouldnt matter at startup any way. thanks for the reply but i dont think any of that is going to help me. and it doesnt have an egr valve. it has a thermo vaccum valve whatever that is. thanks for any help.

 

[tylerdurden801]

Here's my fairly uneducated guess. You have a leaky injector. After you turn the car off, fuel puddles in one or more cylinders. If the car is started 20-30 minutes after you last started it there is still a decent amount of unburnt fuel in the cylinder, making for a hard start. Once the fuel is completely burned off (may take a few seconds of revving), the car runs normally. If you leave the car longer than that, the fuel washes down the cylinder walls as the piston/ring clearance gets greater when they cool. This contaminates your oil, and you smell fuel in it. My advice is to get the car up to operating temp, then turn it off, wait 15-20 minutes, then pull the plugs. My guess is one will reek of fuel. You've found the problem cylinder. It could be an injector or it could be the seals, I don't know, I'd just replace both. I'm having the exact same problem as you and that's my diagnosis. Now I just need to track down someone who wants to sell me one injector . . . You'll probably end up having to buy a used set of four, no biggie, shouldn't cost more than $50. Now go see if I'm right!

 

[Talon__22]

that seems to be a very logical explanation. thanks alot, i have a feeling you are right cuz if i start it right after i turn it off it still starts fine, but i wait more than a couple minutes its starts hard. i will take a look at it this weekend. thanks for the help.