Does IAC operate on a COLD start?

[jimilane]

I was wondering if the IAC worked on a cold start.

Also, what other sensors DON'T work on a cold start. This is a 1990 LX.

Does anyone have a diagram ar anything telling what each pin on the computer does. I have gathered info on most of the sensors, but there are a lot more wires!

Thanks
Jim

 

[HISSIN50]

IAC does indeed work on cold start - arguably the time it's needed most.

 

[Victor's GT]

http://fordfuelinjection.com/?p=64

 

[jrichker]

See http://fordfuelinjection.com/?p=2 and

http://fordfuelinjection.com/?p=6

Actually the site has the answers to most of your questions.

Here's a book that will get you started with how the Ford electronic engine control or "computer" works.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by Charles Probst :ISBN 0-8376-0301-3.

It's about $20 from Borders.com see http://www.amazon.com/ . Select boo...very good, and I found it to be very helpful.

 

[jimilane]

Mine seems to work fine. I had just read a post from the past that the IAC DID NOT WORK on a cold start.

I'm having some starting problem with A 1990 lx.

It does fine on cold start, as long as you pull the MAF sensor loose and the car gets a check engine light. It seems that in this "Limp Home Mode" it starts and idles fine when cold. I don't have a problem with the car after it warms up. I have a spacer with two bleeds between the IAC and the throttle body, otherwise, the car won't idle at all with the IAC disconnected.

I have checked the ACT, ECT, O2, and MAF sensors at the computer. All are normal and right on the money.

I have an "E" cam in there with everythning else stock. Well, except the exhaust.....H pipe no cats and Flowmasters. This is a fun one....

Thanks
Jim

 

[jrichker]

What codes do you get when you dump the codes?

 

[jimilane]

Thanks, I didn't know about that site. Funny how you miss things sometimes.

I'll check out that site.

Jim

 

[jimilane]

What codes do you get when you dump the codes?

This is for another car, 1990 LX

Nothing really. I have the EGR disabled right now. The ports are blocked off at the heads.

The air pump is gone.

Just the normal codes from those being gone or disabled, that's about it. I did have a bad ACT that I replaced and that fixed the hot starting problem.

I'm still looking for info on limp home mode as far as where the computer is gettng it's information.

The fordfuel injection link is very helpful. I'm still reading it right now. I've learned a lot so far. I'm still trying to find the logic for the "limp home mode".
The car will start and idle fine if the check engine light is on.

I'm going to check the "salt and pepper" connectors. Maybe something isn't connecting.

Also I'm going to disconnect the ACT and let the computer substitute ECT values and vice versa, for the cold start.

I'm getting there....

thanks
jim

 

[jimilane]

I have found the problem!!!!

It was the "salt and pepper" shakers.

I have sprayed at least five cans of electrical cleaner on them over the past year. I read that I might need to sread out the male pins, and bent in the female ones. Well, when I did that, the car started the first time and did fine. The smell of unburnt fuel that the car has always had, went away.

I just can't believe that it WAS the connectors as much as I have messed with them.

Thanks to everyones help here, the car is running right.

Jim