High idle

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Nov 22, 2012 | 11:05 AM

#16

Puddy

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From: Edmonton, Alberta

Yea mine has the nipple, but I don't see why you couldn't try the other, just plug it with a rubber or silicone Vac port plug.

Nov 22, 2012 | 12:16 PM

#17

rla2005

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From: Kentucky

Quote:

Originally Posted by Puddy

just plug it with a rubber or silicone Vac port plug.

Nov 22, 2012 | 12:34 PM

#18

mr.fordneck

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Alright, I'll try putting the other one on and see how it does. I'll keep you updated

Nov 24, 2012 | 03:21 PM

#19

mr.fordneck

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Back to square one

I put on the new used throttle body. The truck still idles at 1400-1500 rpm. I plugged the side nipple coming out of the throttle body. My truck had 2 vacuum lines coming into 2 separate ports on the side of the throttle body. The new throttle body didn't have the side vacuum nipples so I plugged up those lines as well. I detected no vacuum leaks from any lines off the tree. I think I may be having an ecu issue???? I'm going to go scan for codes and put up another post

Nov 24, 2012 | 03:55 PM

#20

mr.fordneck

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Here are the codes I pulled with the self test:
67-Park/Neutral circuit fault - PNP
67- Park/Neutral circuit fault - PNP
11- system ok
12- Idle Speed Control motor or Air Bypass not controlling idle properly (generally idle too low) - ISCI just cleaned and put on another used Idle Air Control valve?? Could both be bad. I didn't think you have to replace them if you clean them regularly like I do. New ones are 42 bucks on rockauto

Nov 24, 2012 | 05:27 PM

#21

rla2005

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From: Kentucky

Quote:

Originally Posted by mr.fordneck

Back to square one

Back to my questions and statements in Post#3: https://www.ford-trucks.com/forums/1...l#post12456792

Looks like you have eliminated the throttlebody as the cause. Still not 100% what you did to the other one to get the idle RPM down.

Nov 24, 2012 | 08:56 PM

#22

mr.fordneck

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I think since the codes said the IAC was bad, it's faulty. I guess I should order a new one instead of getting used ones. I will put the original throttle body back on since that has all my vacuum hookups. I got some mud in one of the coolant ports when I set it on the grass to spray cleaner. I'll clean it out and swap it back on.

Nov 24, 2012 | 10:58 PM

#23

mr.fordneck

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Quote:

Originally Posted by rla2005

You put a used IAC and TPS on the truck a few weeks ago with pretty much the same results. I do not recall if you have unplugged the IAC when the idle is high to see if it returns to normal. If it does that points to a bad sensor. Maybe not bad enough to trigger a code. If the idle remains high you have a vacuum leak somewhere or you have a throttle body issue (Sticking, warped, ?)

That's what I did and the idle goes down, I guess I'll need a new idle air control valve

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Nov 25, 2012 | 10:17 AM

#24

Bad Bad Leroy Brown

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That extra vacuum nipple is for the fuel vapor box mounted down by the battery. It looks just like the throttle body on my 351, there are three fuel vapor nipples on the TB, that one and two on the opposit side. They all meet up at T junctions and go to a valve that then connects to the vapor box. Sounds like you don't
Have any of that.
I bet the tb would still work for you if you just cap the vacuum ports, but your problem is obviously the IAC, like you said.

Nov 25, 2012 | 10:36 AM

#25

texaskid22

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My idle air control valve would always stick on my last truck, I'd pull it off every now and then and soak it in wd40. I'd order one off of rockauto.com , they are affordable and easy to change.. and if yours looks old than its better to just change it anyways.

But if your having a high idle and your getting a code for a low idle fault on the idle air control valve wouldn't that indicate that the idle air control valve is almost closed and the idle is still high?

Like I said the IAC valve is cheap and easy to throw at the problem, if that doesn't solve it the next thing to check is vacuum leaks, it could even be a brake booster failing.

Nov 25, 2012 | 10:39 AM

#26

rla2005

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From: Kentucky

Quote:

Originally Posted by mr.fordneck

I think since the codes said the IAC was bad, it's faulty. I guess I should order a new one instead of getting used ones. I will put the original throttle body back on since that has all my vacuum hookups. I got some mud in one of the coolant ports when I set it on the grass to spray cleaner. I'll clean it out and swap it back on.

I disagree with your statement in bold.

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The test failed because the base idle is too high.

Nov 25, 2012 | 10:46 AM

#27

rla2005

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From: Kentucky

Quote:

Originally Posted by mr.fordneck

That's what I did and the idle goes down, I guess I'll need a new idle air control valve

What idle RPM does the truck go down too? Does it almost die? If the latter happens that means the base idle screw is properly set and that also points to a bad sensor "telling" the PCM to drive the idle higher. If the idle is still in the 700+ or higher range that most likely means you have unmetered air, aka vacuum leak. Least likely is a bad ECT or MAP sensor.

I noted before, you may be passing the KOEO tests, but that does not mean all the sensors are 100% correct. It just means they are within the normal range the PCM is looking for.

You have had multiple TPS sensors and I think IACs with the same result. It's time to start actually measuring something with a meter. Ryan has some great info here: Fuel Injection Technical Library » Home

Invest in a cheap DVM, hopefully one that can also measure frequency. It will pay for itself in short order. Harbor Freight has several meters under $20 USD. Even one with a frequency range to measure your MAP sensor.

Nov 25, 2012 | 02:30 PM

#28

mr.fordneck

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Quote:

Originally Posted by texaskid22

My idle air control valve would always stick on my last truck, I'd pull it off every now and then and soak it in wd40. I'd order one off of rockauto.com , they are affordable and easy to change.. and if yours looks old than its better to just change it anyways.

But if your having a high idle and your getting a code for a low idle fault on the idle air control valve wouldn't that indicate that the idle air control valve is almost closed and the idle is still high?

Like I said the IAC valve is cheap and easy to throw at the problem, if that doesn't solve it the next thing to check is vacuum leaks, it could even be a brake booster failing.

I've cleaned the iac valve multiple times. I also just checked for vacuum lines from all the lines coming off the tree. All were fine (when I pulled one off, the idle would go higher until I plugged it back in). I also checked the main brake booster vacuum line and it was good

Nov 25, 2012 | 02:33 PM

#29

mr.fordneck

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Quote:

Originally Posted by Bad Bad Leroy Brown

That extra vacuum nipple is for the fuel vapor box mounted down by the battery. It looks just like the throttle body on my 351, there are three fuel vapor nipples on the TB, that one and two on the opposit side. They all meet up at T junctions and go to a valve that then connects to the vapor box. Sounds like you don't
Have any of that.
I bet the tb would still work for you if you just cap the vacuum ports, but your problem is obviously the IAC, like you said.

My replacement throttle body has the one vacuum port between the 2 chambers but not the 2 coming off the right side. My old throttle body I thought was bad had the 2 coming off the right side but not the single one on the left side. I'm swapping the old one back on so I can plug the vacuum lines in again that run to the fuel vapor box. Right now they are plugged.