Intermittent High Idle

[larrym1961]

I have a intermitten Idle issue that has been driving me crazy for several years! in 2005 I built and installed a 306 with a Ford Racing E 303 cam, TFS Twisted Wedge heads, TFS Street Heat Intake w/ 70mm throttle body, BBK full length headers, #24 injectors w C&L 73mm mass air meter tubed for the #24 injectors. I also converted from an AOD trans to a Tremec 3550 5 speed.
Anyway every since I put this motor in I have had an idle issue that I can not seem to solve. after a cold start it will do it's regular cold Idle routine, Idle @ about 1200 rmp then come down to 850 rpm, where I have it set. After driving it around and it gets up to operating temp. I can come to a stop, push in the clutch and the idle will hang @ 1200 rpm again and stay there either for minute or two or it just continues there until I shut the motor off then restart it. then it idles right @ 850 rpm like it should and runs fine until the next cold start, then same routine again but not all the time. sometimes I can go for a month and not have any issues, then it starts doing it all over again. I have written to YO KEN @ Muscle Mustangs Magaziene and Ray Bochaz @ Hemmings Muscle Machienes Mag. And they both pretty much said it is either the Idle control solonoid is bad or TPS voltage out of ajustment! Well as the case may be I have put on 3 different ICM solonoids, the original, an after market and another new Motorcraft one, and the TPS(I've changed twice) voltage has allways been set @ .98V.
Plus I have also installed a new EGR valve & solonoid and tryed 3 different EEC IV computers and all with the same results!
I am at witts end with this problem Is there any body out there in the Mustang world that possibly knows what the problem may be?

And one other Question, why would my combo only run well with the C&L air meter and not either a Pro Flow or Pro M Racing air meter, All trimmed for #24 injectors. Other than the C&L the others work fine until the motor gets to operating temps then it bairly wants to idle @ 600 rpm no more! I don't have the problem w/ the C&L?

 

[BlackGT89]

Ah yes, the old hanging idle routine. Try cleaning your 10-pin connectors, sometimes called the salt and pepper shakers (the black & white round connectors just behind the upper intake plenum). I clean them with contact cleaner and then replace the dielectric grease and connect them back up. That usually does the trick. Some guys even spread or close the the pins for better contact. Here's a good link on the subject:
Ford Fuel Injection » 10-pin Connector Fix

 

[HISSIN50]

The TPS can still be the issue. It's not the base setting that's important (if it doesn't set a code, it's is within adaptive limit specs. I'd leave it alone), but the wiper can have issues as the TPS ages and degrades.

If you have a spare Motorcraft TPS (ergo no cost output), I would swap it out.

 

[larrym1961]

BlackGT89
thanks for that info That 10 pin connector has always been in the back of my mind. I have yet to try that fix and I sure thank you for the info you are the first person to suggest that to me. I've been replacing sensors and every thing else maybe two or three times I even swapped Intake manifolds and chased every vaccume leak possible because I was told that was a possible problem also, as I said nothing has worked! All except for the 10 pin conenector! Hopefully that will fix a problem I have dealt with for over 5 years!

 

[larrym1961]

Hissin50 Thank you for your input also, I have also changed the TPS and that did not cure the problem either. And a code reader showes me a code 11 no dtc's. I have done every sensor twice, but I have never checked or cleaned the pins @ the 10 pin connector in the 23 years I've owned my Mustang, so I will give that one a try.

 

[BlackGT89]

BlackGT89
thanks for that info That 10 pin connector has always been in the back of my mind. I have yet to try that fix and I sure thank you for the info you are the first person to suggest that to me. I've been replacing sensors and every thing else maybe two or three times I even swapped Intake manifolds and chased every vaccume leak possible because I was told that was a possible problem also, as I said nothing has worked! All except for the 10 pin conenector! Hopefully that will fix a problem I have dealt with for over 5 years!

It's a pretty common problem with these cars. Still could be other things as mentioned, but if the 10 pins have never been cleaned it's worth a try. These connectors relay some very important circuits, including the injectors, TPS and some other things. Check out this Stangnet thread also.
http://www.stangnet.com/mustang-forums/698148-help-me-create-surging-idle-checklist.html

 

[4rdnut]

Check to be sure the pcv valve and grommet are tight. The pcv valve grommet never fits in the intake tight on these engines. Pull up on the 3/8" vacuum hose on the pcv valve and see if the grommet comes out of the intake easy.

 

[larrym1961]

It's a pretty common problem with these cars. Still could be other things as mentioned, but if the 10 pins have never been cleaned it's worth a try. These connectors relay some very important circuits, including the injectors, TPS and some other things. Check out this Stangnet thread also.
http://www.stangnet.com/mustang-forums/698148-help-me-create-surging-idle-checklist.html

Did the 10 pin clean throughly, did the pin spred and New dilectric grease, have not had a chance to test run it on the road as we have snow on the roads here, the thing is squirrely enough on dry pavement. But after running the car now I can rev it up and It goes back to idle a lot faster now and throttle response seems to be crisper too! Can't wait to get it out on the road when they dry out and give it a test run. That hanging up idle had been a pain in my ass for over 5 years, hopefully it is gone for good! As I mentoned experts I have written to and mechanics I have taken my Mustang to never even considered the 10 pin connector!

 

[BlackGT89]

Did the 10 pin clean throughly, did the pin spred and New dilectric grease, have not had a chance to test run it on the road as we have snow on the roads here, the thing is squirrely enough on dry pavement. But after running the car now I can rev it up and It goes back to idle a lot faster now and throttle response seems to be crisper too! Can't wait to get it out on the road when they dry out and give it a test run. That hanging up idle had been a pain in my ass for over 5 years, hopefully it is gone for good! As I mentoned experts I have written to and mechanics I have taken my Mustang to never even considered the 10 pin connector!

Ya gotta love Stangnet !!

 

[FirstFox89LX]

Hey, I know this thread is almost ten years old. But I’m dealing with my first ford product, and 89LX hatch 302 t5 car.
And having the same issue. The car either runs great, or wants to idle up around 1200, and if I’ve been on, or touch throttle when it’s high idle it jumps to 2k and sits there until i turn it off/it decides to come down. And pulls the car like cruise control if I just let off the gas sometimes.
That being said. I tried to click on the link that BlackGT89 posted for ford fuel injection about the 10 pin connector cleaning and stuff. And the link took me to a Mercedes Benz page.

This car is supposed to be my daily driver, so I’m not trying to mess it up any worse doing something new, for me, to it.

 

[General karthief]

Do this checklist: http://forums.stangnet.com/showthread.php?t=698148

 

[FirstFox89LX]

Do this checklist: http://forums.stangnet.com/showthread.php?t=698148

I was looking for the info on spreading or closing the pins mostly.
Trying the electrical cleaner and dielectric grease now, just not sure what the spreading/closing pins was

 

[General karthief]

If you pull the connector apart, the pins are kinda pointed with a slit, you'll see what it means when you look at them.

 

[jrichker]

Hey, I know this thread is almost ten years old. But I’m dealing with my first ford product, and 89LX hatch 302 t5 car.
And having the same issue. The car either runs great, or wants to idle up around 1200, and if I’ve been on, or touch throttle when it’s high idle it jumps to 2k and sits there until i turn it off/it decides to come down. And pulls the car like cruise control if I just let off the gas sometimes.
That being said. I tried to click on the link that BlackGT89 posted for ford fuel injection about the 10 pin connector cleaning and stuff. And the link took me to a Mercedes Benz page.

This car is supposed to be my daily driver, so I’m not trying to mess it up any worse doing something new, for me, to it.

I am the guy who wrote the Surging Idle Checklist, and I will tell you that the answer is in there. The text was updated to clarify the cause of a creeping increase in idle speed.

You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. It includes how to dump the computer codes quickly and simply as one of the first steps. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix.

It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 250,000 hits, which indicates it does help fix idle problems quickly and inexpensively.