idle issue question

[stangbangin69]

okay, first i got a 86 gn. mods... scanmaster, fmic, te44, motron 60's tt chip, aftermarket cam, 3" dp w/external wg, ported and polished 8445's, t.b. and intake. homemade cold air intake. fuel pressure set to 44lbs (line off) and overall fuel added like 2.8%
the iac and tps set correctly. when the car is sitting in park it will go from normal idle (800-825) down to 650-700 rpms. idle's real slow and "lopes" down like it's almost dying out. it acts like your pulling a choke or something (if it were carb'd). once you rev it up or put it in gear the rpms come up fine. every now and again the rpm's won't come up quick enough and it will die when you put it in gear.
it does not throw any malfunction codes.
anything i'm leaving out just let me know and i'll post it. thnx anthony

 

[blackgn1]

Have you checked for vac leaks. I would check for cracked or dry rotted vac lines first.

 

[turbojd]

Did you try and clean the IAC with some carb cleaner, also spray out the whole throttle body and throttle plate area.

 

[TurboBuickSix]

My car does this if the base fuel pressure is a little too high causing a richer idle. If I turn it down the smooth idle returns.

 

[stangbangin69]

i did the spring cleaning when i got the car back in the beginning of the summer. as far as i can tell there are no vacuum leaks. i thought it would idle faster with a vacuum leak? i did clean the iac and t.b. before. i suppose the next step would be taking it back apart and recleaning. as far as the fp goes. i tried adjusting it down to 41psi and all the way up to 45psi with no noticeable difference. do u think it's where i have fuel added through the chip at wot messing with the idle part of it somehow?

i had a kr problem a few weeks ago. turned out to be the exhaust hitting the starter cable. well, i fixed that problem, put a torque strap on the drivers side and tightened all my clamps. it drove like a beast for about five miles after all that stuff was fixed. then the idle problem came about. fixed 3 problems and created another one.

turbobuicksix, what was ur sweet spot on ur fuel pressure?? should i just try to drop it more?

 

[daily driver]

I feel your PAIN.

A really good way to help search for vac leaks is to lightly pressurize the intake tract after the MAF . They make fixtures for this so you can search this site for that. Some people make their own. 10 psi helped me find leaks which I fixed and now I am hoping that fixing my throttle shaft seal leaks helps my idle. Mine will do the same thing and when cold will set off code 34 (MAF-low air flow) but after multiple MAFs it does not seem that the MAF is the real issue.

 

[stangbangin69]

man, i feel like i'm just chasing my tail.:tongue: the idle problem hasn't happened this afternoon but now i'm getting some popping around 19psi of boost. i thought i had that problem fixed man, this car is gonna make me go bald!

 

[ryan george]

I feel your PAIN.

A really good way to help search for vac leaks is to lightly pressurize the intake tract after the MAF . They make fixtures for this so you can search this site for that. Some people make their own. 10 psi helped me find leaks which I fixed and now I am hoping that fixing my throttle shaft seal leaks helps my idle. Mine will do the same thing and when cold will set off code 34 (MAF-low air flow) but after multiple MAFs it does not seem that the MAF is the real issue.

I don't mean to take over this thread, but how did you find the throttle shaft seal was leaking? I saw your thread and wondered at that time how you figured that out. I'm chasing a stalling issue that seems to point to a vac leak. I made my own fixture (less than $8) and that helped find vac leaks, but I'm still struggling. Thanks!

 

[daily driver]

I think my ho-made fixture cost me $12 so you beat me there! With the fixture installed in place of the MAF and at 10psi going to it as read by my air comp reg guage, in a quiet garage I can hear the air flowing out of the seals and can feel it on one side. Smaller leaks may need soapy water sprayed on them so they will bubble and show themselves.

 

[ryan george]

I think my ho-made fixture cost me $12 so you beat me there! With the fixture installed in place of the MAF and at 10psi going to it as read by my air comp reg guage, in a quiet garage I can hear the air flowing out of the seals and can feel it on one side. Smaller leaks may need soapy water sprayed on them so they will bubble and show themselves.

Sorry to jump in on this thread...again...but thanks for the info. Yeah, mine was actually under $7, but I already had an extra connector for the air. I just had to pickup a piece of pcv and an end cap. I just can't find this little gremlin. i can hear something small, just not sure where. I've leaned all over the engine compartment. will try the soapy water. so frustrating!