Fast Idle Problem
Thread Starter
|
Freshman User
Joined: Sep 2004
Posts: 48
Likes: 1
From: Thunder Bay, Ontario
Fast Idle Problem
My 5L has developed a fast idle. The codes I'm getting are 12 and 334. I've changed the tps and IAC. I've checked for vacumm leaks and there are none. I've checked the Intake for leaking gasket and it's ok. I'm at my wits end here and would appreciate any help or suggestions. My next step is to take her into the shop and start paying big bucks to have her fixed, so any ideas I will try. Thank you.
Owl
Owl
Postmaster
Joined: Jun 2005
Posts: 2,656
Likes: 1
I'd remove the TB and clean it also clean the IAC. That was part of a tune we had to perform on every EFI car or truck. Also take some pliers and pinch all the vacuum hoses connected to the intake, if you find one that brings the idel down well that might be a good place to look...
Thread Starter
|
Freshman User
Joined: Sep 2004
Posts: 48
Likes: 1
From: Thunder Bay, Ontario
I've done all the previous...cleaned TB, new IAC, sprayed all upper intake area and found no difference. I'd really appreciate any more suggestions.
I tried covering the TB with a rag and she still idles really good. It idles fast from a cold start and keeps it up even when warm, What else could it be? It might be a vacuum leak but I can't find it, tried pinching hoses, even broke one on the top of the pleneum checking and had to fix that but nothing else. I'm ready to give in.
Help.
Owl
I tried covering the TB with a rag and she still idles really good. It idles fast from a cold start and keeps it up even when warm, What else could it be? It might be a vacuum leak but I can't find it, tried pinching hoses, even broke one on the top of the pleneum checking and had to fix that but nothing else. I'm ready to give in.
Help.
Owl
Thread Starter
|
Freshman User
Joined: Sep 2004
Posts: 48
Likes: 1
From: Thunder Bay, Ontario
The motor is stock. I haven't checked the timing and the idle screw has not been touched, the tb plates are closed. I don't have a tach but I would guess the rpm's between 1200 to 1600 rpm. Is there any other sensor that would make rpms go up? She doesn't appear to be running rich (no black smoke). I don't think the egr is leaking as that would make the idle rough and she's smooth, just too fast.
Owl
Owl
Trending Topics
Posting Guru
Joined: Nov 2005
Posts: 2,442
Likes: 1
From: La Grande, OR
Originally Posted by Kemicalburns
the idle screw hasnt been touch right? what is the rpms at?
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Ford Super Duty: 5 Things Owners LOVE, 5 Things They LOATHE!
Joe Kucinski
Every 2026 Ford Truck Engine RANKED from WORST to FIRST!
Michael S. Palmer
The Best F-150 Deal of Every Trim Level (XL through Raptor)
Joe Kucinski
Posting Guru
Joined: Nov 2005
Posts: 2,442
Likes: 1
From: La Grande, OR
(sorry for the thread hijack) What is the best way to clean the TPS/Throttle Body? I thought just carb cleaner, but some people said that it will take off some kind of special coating on the inside, and there's a sticker on it that says do not clean the inside. Also, when taking off the TPS, how do you put it back in the right spot?
Last edited by nighthawk285; Feb 14, 2007 at 12:31 PM.
Thread Starter
|
Freshman User
Joined: Sep 2004
Posts: 48
Likes: 1
From: Thunder Bay, Ontario
I've cleaned the throttle body best I can without taking it apart and still no change. What I have noticed though is the AC compressor is not kicking in at all. Is there something wrong with my AC that is making the idle go up? The fuse for AC is good so its not that. Any ideas anyone????
Owl
Owl
Posting Guru
Joined: Nov 2005
Posts: 2,442
Likes: 1
From: La Grande, OR
when you pulled codes, did you do a KOEO test, or was it KOER? A code 12 in my book says RPM unable to reach upper test limit, and a code 334 shows EGR closed voltage higher than expected.
Thread Starter
|
Freshman User
Joined: Sep 2004
Posts: 48
Likes: 1
From: Thunder Bay, Ontario
It was a KOEO test. And yes I undestand the codes but I'm now concerned with the AC compressor not working. Does anyone know id there is something that controls the AC that would affect the idle??
Owl
Owl
Thread Starter
|
Freshman User
Joined: Sep 2004
Posts: 48
Likes: 1
From: Thunder Bay, Ontario
But that's my problem, I have no AC and my compressor is not kicking in and my idle is up. According to Haynes manual, if the AC compressor is off and the idle is high, check for an open circuit between the AC control relay and the PCM (pg. 6-12). Does anyone have any experience in these relays and are they changable??
Owl
Owl