idle/ starting problems when hot

[avbcon12]

after my head/cam/intake install (check sig, everything was done over winter).

after ive driven it and gotten it hot, then shut it off. then started it again it doesnt want to stay running. the idle bounces and then drops. i can keep my foot on the gas to keep it running and its fine. its only on startups..

it only does this after the engine is warm and when i restart it. what could the problems be??

when im driving it it runs great!


i pulled the KOEO codes and there isnt anything abnormal. i just got the smog stuff. although i did get code 14 and 18 in the memory. they are (14) Ignition pickup was erratic
(18) Ignition TACH signal erratic

what does that mean????

any suggestions now?

ill do the KOER test tomorrow when i get a chance.

thanks everyone,
adam

[PKRWUD]

You really need a breakout box to properly diagnose this one, but two things you can look for are a short to ground in your spout circuit, or in your O2 sensors wiring. A bad TFI module is also possible, but doubtful. If you have a known good one to try, go for it, but don't buy one. There is one other possibility, but it's tougher to check. The wire that is the second from the bottom in the connector that goes to the TFI module (should be dark green with a yellow tracer), goes to splice that goes to the negative side of the coil in one direction, and to pin 4 on the ECM in the other direction. The wire that goes to the ECM has a 22k ohm resistor inline, and if that resistor goes bad, it could cause similar problems. To test it, you need to disconnect the harness from the coil, the TFI, and the ECM, and measure the resistance between pin 4 at the ECM harness connector, and the pin at the TFI connector that has the dark green wire with the yellow tracer.

Take care,
-Chris

[gtsr515]

I think it's the infamous VACUUM LEAK, or your running real rich for some reason, crank your pressure down and see what happens. Go back to stock timing too and see what happens.

[PKRWUD]

I agree that the symptoms are classic vacuum leak, but the codes he pulled are rather serious, and are symptomatic of a short in the TFI harness.

This is starting to become really frustrating again. I hate not being able to inspect the vehicles personally. Maybe I need to go away for a while.



Take care,
-Chris

[avbcon12]

NO CHRIS!! you have to stay!! haha

ok so this is to follow up...

i had the motor running, sprayed everywhere to detect a vac leak, i got nothing. so then i was moving stuff around and when i just touched (and i mean touched) the 10 pins the motor shut completely off!! so i took out the recall jumpers and cleaned the contacts. i plugged them back in without the jumpers and its running better now. im not getting those codes anymore.

it still has a minor idle problem but nothing major like i thought this was. im half tempted to solder those 10 pins together!!!!

thanks for all your help guys, could the 10 pins cause those codes to be thrown?? or should i still look into replacing the PIP?

thanks again,
adam

[avbcon12]

oh yea, also what i did was...

when i got my heads they were painted black, i never cleaned the paint off when i put the ground on. so i cleaned off the paint near the ground.

could that have helped as much as it did???

thanks,
adam

[PKRWUD]

The 10 pin absolutely was the source of those two codes, I have no doubt. Good fix!

A ground isn't a ground if it doesn't complete the circuit. Of course it can make a big difference, but so does the 10 pin.

Take care,
-Chris

[avbcon12]

thanks chris, i can always count on you!

adam