wont idle when cold....

[86turbo]

just another wont idle when cold thread. Only codes the eec is throwing are for egr, canister purge and the airb solenoids, codes 34, 81, 82, 84 and 85

I start the car up and it will start then die maybe 3 times immediately. I have to give it gas to keep it running and even then when i give it gas there is a delay and it still tries to surge. If I hold my foot steady at half throttle it will rev up then try to drop down again so i have to pretty much give it throttle every few seconds, its crazy.

- ect and act resistance levels and they are correct for cold and hot running.

- I sprayed my whole intake system with carb cleaner and it didnt change the idle at all.

- My tps is at .94 volts and i used an analog meter to see if it skipped which is did NOT.

-Volt drop across leads of iac give me 1.5 volts varying +/- .2 at a hot idle

Last night I installed the ford iac spacer plate and when i started it up it revved way up which was good but when i tried turning in the screw to cut off the air it dropped to a really low idle but at least it ran. Im thinkin my iac is bad....

advice?

Drew

 

[86turbo]

btw i tried clocking my maf and it seemed to affect my idle, ill probe the appropriate wires via the surging idle sticky and try to get it around .6

 

[86turbo]

couldnt get the maf voltage below 1.1 in any position, i think itd trying to put the eec in the wrong load table for being at idle..........

40 views and no replies? Is that because nobody knows??? haha I figured there would be some good troubleshooters floatin around here...

Drew

 

[LxVert]

My car had the same symptoms before and it turned out to be the Air Charge Temp Sensor, the sensor was all gummed up, once I changed it the car ran great from a cold start.

 

[HISSIN50]

couldnt get the maf voltage below 1.1 in any position, i think itd trying to put the eec in the wrong load table for being at idle..........

40 views and no replies? Is that because nobody knows??? haha I figured there would be some good troubleshooters floatin around here...

Drew

Part of the issue could be that you have multiple threads going, no mention of what parts are on the car or your tune parameters, or why you are chasing one tangent of the issue.

I'd not sweat the MAF reading you saw but that's just me.

 

[86turbo]

one thread is about my maf, the other my iac and the third is about cold start. Some of the stuff is interrelated...

This is on an 85 coupe w/efi swap. Typical h/c/i swap, 65mm bbk tb, 75mm pro m bullet. 24 pound injectors...

 

[HISSIN50]

If you've ruled out a hard part issue, and because you do your own tuning, I'd post or search in the EEC tuning sub-forum or dedicated tuning forums.
It might be easier to tune around the issue (there are several ways to tune-out an idle issue and the guys who are smarter than I will know the best work-around).

 

[86turbo]

i could pull the pms off my other car and see what i can do however i'd like to "try and get it running as well as possible. I've had two other mustangs with h/c/i efi engines and noen were this bad. Im gonna try and swap out the iac from my 86, even my turbo car has a better idle!! haha

 

[HISSIN50]

I misunderstood you earlier. I thought you were loading values into a tune (the talk about load tables).

If the car was healthy except for a bad IAC, you should be able to crack the throttle open a little to compensate for a lack of IAC DC/flow. The fact that it surges suggests some other issue.

Have you put a vac gauge on a manifold vac source to see if it's near 20" hg?