88flyer

did a head and cam job on my 88, SR manifold with base, patriot heads 195 runners, crane cam 214/221 with488/508 lift, 1.6 rollers ect. took it to a tuner to do the ECM but I can get it to idle, rode around with the lap top hooked up to the car and noticed the IAC counts all over the place, one minute the car will idle at 700rpm's the next minute it will rise to 1400rpm or just die, replced the IAC followed the instrucion to set it up and still no good, Iam running the car with the IAC unpluged but it idles at 1400 rpm a PITA when driving in the city other than that it feels strong and drives good. any ideas out there ?

FICINJECTORS

sounds like a vac leak somewhere.. get out the propane and go find it

88flyer

done that already can't find any leaks

FICINJECTORS

for the idle to race from 700 to 1400 it is getting air somewhere.. Is your throttle cable hanging, take it off and see how it idles. plug off the brake booster also.

AGENT 86

There is no setup for the IAC, other than the extended pintle measurement, for installation.
Have you set the minimum idle and TPS ??


http://www.lbfun.com/warehouse/tech_...ch%20Paper.pdf

88flyer

yeah I did followed all the steps mentioned in this site, disconecting the ignition advance, adjusting idle to 450 rpm,turn off engine hook up IAC,adjust tps to.54 vlts let it run for 20scds shut it off for 5scds and try again, and still the same probelm, I am starting to think that something got screwed up in the ECM and it si not sending a correct signal to the IAC

AGENT 86

When you jump ALDL terminals "A" and "B", with ignition in "run", the IAC should be closing. You should hear and feel the IAC motor running. If it does close, the only idle air should be what is getting past TB blades.
After you unplugged IAC and started motor, did the motor struggle to run, or was it still revving high ?

engle1147

Get a long piece of hose hold one end up to your ear and use the other end to probe over every inch of the intake while listening for a tell-tale suction sound.

Also, it is possible to have a gasket leak going from the intake to the head and it is sucking extra air through from inside the block.
How to know: Start the car. Pull the hoses that run from the intake to the valve covers and stick you thumbs over each valve cover hole and ensure that there is no heavy vacuum being generated inside the block....remove 1 thumb at a time....you hear it suck heavy if you have a problem.

FICINJECTORS

check the pcv valve also

loaded vet

If you are certain you have no vacuum leaks and the IAC motor runs when you jumper "A" and "B" sockets on the ALDL, then disconnect the MAF sensor. then see if it starts up and idles correctly. If so, your MAF is bad.

Hope this is helpful,

Gary