strange problem, wont idle when warm
 

alright, this is *really* frustrating... i just finished an engine swap, I put an '87 13b NA into my '83 GSL... it seems to work fine, but sometimes it seems to get into a mood where it refuses to run. After doing some gremlin chasing I've found that it runs fine when the engine is cold, and for awhile when its warm. If I shut it off, let it sit for a minute, and try to start it again, it will run for a sec then just die. No amount of throttle at any rpm will keep it running unless I rev it to nearly redline. Sometimes it will stay running if I hold the gas at ~2k rpm, but it will bounce from 1.5k to 3k holding the throttle in the same spot.... it eventually give up and just dies.
When it cools off for a couple hours it seems to run fine again.

I removed emissions and replaced all the old vaccum lines, I'm using a new 78psi inline fuel pump that isnt ECU controlled. Plenty of spark and gas. I doubt injectors would cause this problem. Can the air flow meter cause an intermittent halt to funcionality like this? Sometimes if I hold the AFM flapper slightly more open than it wants to be it will idle for a couple minutes.. but thats it, it will always eventually die. And yes, I've checked for intake leaks... but and intake leak wouldnt go away when the engine is cool anyway.

As for the computer, its the N326, and it has excellent grounds. Are there any meters that the computer needs that will make it run fine, until its been ran for awhile, and then trip and keep the engine from running right?

Any ideas? Something stupid that may or may not need to be plugged in? The TPS is the black thing with the little bobber on the front side of the throttle body right?

I NEED HELP :BANGHEAD:

Mike

If its heat related, it could possibly be some sort of sensor that is having its reading screwed up by the increased heat of the wire, which increases it resistance. Its a longshot, but if you check the wires with multimeter to all the sensors that affect your idle, one might be bad when its hot.

sooooo many wires... so what engine related things will make the engine go poop like that when they arent working/unplugged? obviously besides the CAS/coils/injectors

sounds like it runs fine in open loop but when it switches to closed, thats when your problem starts.

elaborate on this 'open loop' and 'closed loop' thing :D

when you say when the open loop is switched to closed loop, what are you referring to?

alright, it did it again, as soon as it cooled off for a couple hours it was fine, so i was able to drive it home. i messed with the throttle body for a couple hours... it turns out it was waaay out of tune.. TPS, mixture, idle, everything... now i get take it to work tomorrow and *HOPE* it doesnt crap out on me again...

could that have been the problem? seemed a little too intermittent to be an out of tune intake... unless it had something to do with the computer...

is it possible it runs on only one rotor when warm?

All I can think of is go here

http://www.fc3s.org/how_tos/manuals/...SYSTEMS_NA.pdf

and go to page 11, check all the stuff for rough idle, and page 14 for engine does not run smoothly at normal operating temp.

yeah, i already the FSM, and i already did all that... i dunno, IF it does it again, since it only does it occasionally, then it must be some bad wire somewhere.... that would be really frustrating, since I spent so much time making sure all my connections were good...

i adjusted the idle/mixture, so when it decides it wants to work, it sure does idle nice ;)

okay, i tested the resistor pack, computer (of which i have a spare), TPS, and BAC.. they all work fine. is there anything else that would cause this problem? it only does it when im driving around town... when it idles and when im on the highway it stays cool enough that it runs fine. as soon as i drive <35mph for awhile it refuses to run until i let it sit and cool for about an hour