Hey guys...ive been having gremlins with this car for weeks now. Sometimes it will crank and start right up, and sometimes itll just crank and wont start. Ive replaced the fuel pump, relay, and even the afm. Still experiencing the same problems. Mind you it does it very intermittently...so when it actually runs and starts, its very hard to pinpoint....any input will help...thx guys....

 

When it has problems is the engine always cold, hot or doesn't matter?

 

Seems to be after I drive it for a bit....coil packs maybe?

 

Hot start issue most likely. Engine could be flooding do to leaking injectors or your compression is rather low.

 

My car has this same issue but once it sits for an hour after its been running.. I can't figure it out either

 

Engine has 11k on the rebuild and runs great when it starts. Doubt its a compression issue. Looking at the schematics for the fuel pump, one side of the relay coil is actually controlled by the ecu, and the other circuit of the coil is grounded by the afm. Any advice? Possible ecu issue?....im gonna do some more diving into this and ill keep you guys updated...

 

The only problem that can relate to your previous statement is the resistance in the fuel circuit increases w/heat and causing your problem.

You might want to check the reading of your Water Thermosensor as it helps to decide how much fuel is used upon startup. Too much and the car can have trouble starting. Generally, a cold engine needs more fuel upon startup while a warm engine requires less but if its getting the same amount hot as it is cold then that could be problematic. Pin 2I of the ECU should read 2 to 3 volts w/key to on and .4 volts fully warmed.

 

Ok thx...ill check that too...any other thing that come to mind that I should check?

 

And so when I check voltage at pin 2I, I should be getting 2-3v koeo and .4v fully warmed koeo as well? Or koer?

 

Doesn't matter whether the engine is running when taking measurements.

 

Ok thx

 

Have another question....what about the injector resistor pack near the afm and rf headlight? Could that be an issue as well?

 

If you test for spark and always have it then it's likely not a problem.

 

Hey champ, my fc would do the same after ecu change. If I stalled after driving it it would t start til it cooled down or bout half an hr later. Took it to my tuner after it happened again one day and turns out my crank angle sensor wasn't receiving enough volts. So try and check that out. He played around with the tune/volts going to cas and shes been fine since. I've got a s5 turbo