Idle Question
Thread Starter
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Tuned
Joined: Apr 2004
Posts: 306
Likes: 12
From: Greenbush, Minnesota
Idle Question
Hey fellas,
I just came across this site the other day and I think I've learned more about my Ford vehicles than I could have anywhere else.
Anyways, I had a quick question. My '91 F-150 with a 351w EFI has a bit of an idle problem. It's been a problem that has been nagging me for over a year. I had it into the local shop once but he never did figure out what was wrong.
Heres what it is doing. It starts up just fine at first. Once she kicks off of high idle it will idle fine also, but if I have, say the heater or AC on it will start to rev up from around 650 RPM up to about 1000 RPM. And it will continue to do this whenever the AC compressor kicks in or if I have to heaters on. Funny thing is it only does it when in nuetral or in park. Once I drop her in gear, its an automatic, she runs just fine. When I brought it in to the local shop I believe he replaced the throttle position sensor. He said he couldn't get the voltage down where it should be. He also cleaned the injectors. Well, neither of those things fixed it. So, if any of you guys have any suggestions I would appreciate any input.
Thanks again,
JEV
I just came across this site the other day and I think I've learned more about my Ford vehicles than I could have anywhere else.
Anyways, I had a quick question. My '91 F-150 with a 351w EFI has a bit of an idle problem. It's been a problem that has been nagging me for over a year. I had it into the local shop once but he never did figure out what was wrong.
Heres what it is doing. It starts up just fine at first. Once she kicks off of high idle it will idle fine also, but if I have, say the heater or AC on it will start to rev up from around 650 RPM up to about 1000 RPM. And it will continue to do this whenever the AC compressor kicks in or if I have to heaters on. Funny thing is it only does it when in nuetral or in park. Once I drop her in gear, its an automatic, she runs just fine. When I brought it in to the local shop I believe he replaced the throttle position sensor. He said he couldn't get the voltage down where it should be. He also cleaned the injectors. Well, neither of those things fixed it. So, if any of you guys have any suggestions I would appreciate any input.
Thanks again,
JEV
Thread Starter
|
Tuned
Joined: Apr 2004
Posts: 306
Likes: 12
From: Greenbush, Minnesota
Well, I was tinkering around with it again this evening. I fired her up and made sure no accessories were on, i.e. AC and heater, and once she warmed up she started the fluctuating idle again. So I was checking for vacuum leaks and anything that could cause this problem. I couldn't find anything so I decided to pull the connection on the IAC. Low and behold the idle settled down and she ran like a top. I took her for a little spin and she ran just fine, and idled great. Now, unfortunatley, I don't think it is supposed to remain idling when in park. From what I have read, once you disconnect the IAC it should slowly die out. My pickup continues to run at a nice smooth idle. So, now what should I do. I did pull the IAC and cleaned it up with some carb cleaner. It did have some carbon buildup. I put it back in and it did seem to run a little better, but not as smooth as when I had the IAC completly unhooked. Should I make some other adjustments so that it dies out when the IAC is unhooked? I appreciate the help.
Thanks again
JEV
Thanks again
JEV
Cargo Master
Joined: Dec 2003
Posts: 2,735
Likes: 38
From: Sunny Florida
I am afraid I don't have enough experience now to answer your question. I can't remember if carb cleaner is safe for the IAC cleaning. There are certain sensors which are very touchy to strong cleaners from what I have read. They could get damaged. I would maybe drive it a bit and see what happens.
Senior User
Joined: Dec 2003
Posts: 148
Likes: 0
From: tukwila
89 bronco
My 89 bronco idles high in park and nuetral too. I did have someone recommend carb cleaner but I too wasn't sure if it was too strong. As soon as I hit drive or reverse it goes down below 1000. What other sensors might be affecting it?
Lead Driver
Joined: Nov 2002
Posts: 9,557
Likes: 44
From: Concord, NC
It could be a number of things. Try pulling the codes to start out with and see what comes up: http://fordfuelinjection.com and click on "Getting Codes"
Senior User
Joined: Oct 2002
Posts: 272
Likes: 1
From: Grande Prairie, AB
Trending Topics
Tuned
Joined: Oct 2002
Posts: 466
Likes: 0
From: South Central KENTUCKY
my 89 idles too high as well
looked at the site, got codes for evp, power steering, tps, and evp again. Didnt think about PS untill i got to reading the site and realized the eec raises idle is ps pressures are too high, so will look at that sensor first, if i can find it, the the evp, then the tps. Will let yall know what i find to fix it.
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