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green ones make me horny
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Discussion Starter #1
Well guys here we go again. ran fine for a bit then back to square one. basically this time i was driving truck got all screwy idle was acting retarded and all, then it "smoothed" itself out and i was basically idling at 1500 or so RPM i could come to a stop and just take my foot off of the brake and i would go down the street at 30MPH like i had cruise set. so i let it high idle and started disconnecting sensors one at a time. disconnected the IAC and it smoothed out. drove it home it was fine. connect the sensor and high idle again. is that saying the sensor is bad it is not even two months old, or is there something else to check as far as reference voltage goes? does the iac get a signal from somewhere else, like the PIP or anything like that? thansk in advance for all the help

ken
 

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yo
These units may become dirty, and need cleaning. Many idle and stalling issues tend to be blamed on these units. Cleaning is achieved by removing the electrical connector, and two screws holding it on. Once off of the vehicle, clean with throttle body cleaner (or a good carburetor cleaner). Continue cleaning until unit is clean, like new; reinstall unit. This is also a good time to clean the intake, and EGR ports (if applicable). Testing may be achieved by bringing the engine to operating temperature, noting the idle speed (should be within spec). Unplug the unit’s electrical connector, and the idle should drop to about 650 RPM. When the unit is reinstalled, it should return to normal idle speed. If the vehicle does not idle at proper RPM (too low), there are no vacuum leaks, and the TPS calibration is correct, than the unit is most likely fault..."
I had to clean the EGR ports, etc.
I did have a DTC
And the Ford MC IAC tested good
 

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yop Ken;
Comcast shut me down..
Did you test for DTCs yet?

Is it a Ford MC IAC?

Overview & Testing; "First let me say this little thing has many names. But they all talk about the same item under the hood. Here all the names I’ve had the torture of learning throughout the years: Idle Air Bypass •Idle Air Control •Idle Speed Control •Throttle Bypass Air •Idle Bypass •Inlet Air Controller •Inlet Air Bypass •Intake Air Bypass •Intake Air Control..."
Source: by Ryan M (Fireguy50) at http://fordfuelinjection.com/index.php?p=39

I above doesn't solve it; check this out
Idle Speed Check & Adjustment
Source: by Steve83 (Steve, That dirty old truck) at http://fullsizebronco.com/forum/showthread.php?t=121309AN EXCERPT:
"...NOTE: The curb idle and fast idle RPMs are controlled by the Powertrain Control Module (PCM) and the Idle Air Control (IAC) valve. The Idle Air Control (IAC) valve is not adjustable. A large increase or decrease in closed plate airflow from the calibrated level will not allow this device to effectively control the rpm.

Throttle bodies with sludge tolerant design are clearly identified with a yellow/black attention decal. Refer to Figure 23 for the location of decal. This decal advises that the throttle return screw must not be adjusted counter-clockwise (backed off), as this will not reduce the engine speed but may cause the throttle plate to stick in the bore in the closed (idle) position. Backing out the screw may be required if the throttle body had been previously serviced (a plug may be present in the throttle plate orifice) or if the throttle return screw has been tampered with (TP sensor self-test output out of range), refer to the appropriate procedure for details. The decal also advises that these throttle bodies must not be cleaned inside the bore, as cleaning will impair the sensitive coating. The sludge accumulation will not affect the throttle body idle air flow. (The cleaning procedure for the Idle Air Control (IAC) valve may still apply. Refer to the Service Manual.)

Throttle bodies should not be cleaned because cleaning will remove the sludge tolerant coating.

Follow these steps to service the throttle body:

1. Remove the throttle body.
2. Hold it up to a light. No light should be visible between the plate and bore with the throttle plate closed. The hole in the plate should be visible and unobstructed.
3. Rotate the throttle lever and allow it to return. It should not stick or bind. It should return to the closed plate (idle) position freely when released.

If the problem cannot be corrected (an obstruction cannot be removed, free sticking, etc.), the throttle body must be replaced.
 

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Got shut down again!
I'm figuring on a vacuum leak

Vacuum Leak Test; "...On idling engine...Check for vacuum leaks using a mechanic's stethoscope with the probe removed, or a ~3' garden hose. Don't spray flammables on a running engine. Also check the brake booster, the 2ndry air (coffee can) & HVAC vacuum reservoirs..." (around intake manifold; and maybe under dash behind control panel vac line area
Source: by miesk5 & Steve83
 

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green ones make me horny
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11,135 Posts
Discussion Starter #5
thanks for the input. the IAC is not a motorcraft one it is from autozone i believe. it is only a few months old. There are not vacuum leaks i have checked multiple times. at first i was thinking sticking EGR Valve or faulty EVP Sensor but that is not the case now. with the idle air control connected it is all screwy. like i said i idle at 30 mph and that isnt right. it was also causeing a no power issue as well. meaning that i could hit the gas and i wouldnt go anywhere. as soon as i unplugged it it was fine. i dont know what the problem is right now. im going to go test the IAC and the tps according to the haynes manual. if the iac is bad the new one is under warranty i will replace it.
 

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green ones make me horny
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11,135 Posts
Discussion Starter #6
ok update. A friend of mine has a script to mitchells online and in line with my problems he told me to test the egr valve and the sensor on top of it. egr valve i cant test without a vaccuum pump, and when i tested the Sensor on top of it, it was a bit out of whack. According to the haynes manual says with the sensor off the resistance should be between 5000 and not greater then 5500 ohms (sensor shaft extended) to no less the 100 ohms (sensor shaft retracted) so i did that and extednded i get 3750 ohms and retracted all the way in i get 45 ohms. that tells me that it is bad and needs to be replaced. would this cause the idle problems as described. but wouldnt that throw a Check engine code? i do not get the codes for anything....just idle problems. either or no matter what test i get i cannot get the ohms up to 5000 like the manual says.
 

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green ones make me horny
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Discussion Starter #7
You're stabbing in the dark. This is the correct procedure to pinpoint a high idle concern:
That would be good if i had high idle all the time but i do not. it idles great and runs great most of the time. but at times it starts acting up (no stored codes) it idles high and stays that way till i disconnect the idle air control valve. oh yeah where are the diagnostic procedures that are mentioned in that chart.
 

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Throttle bodies should not be cleaned because cleaning will remove the sludge tolerant coating.


But they CAN be cleaned, done so for years at FORD
 

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green ones make me horny
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11,135 Posts
Discussion Starter #9
I thought the only ones with that coating had a sticker on them. Pro i see you are in or have been in for 22 years. Thats awesome ive been in 15. Im not messing with it anymore right now. Im at the beach with family.
 

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green ones make me horny
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11,135 Posts
Discussion Starter #10
Still cant get this figured out anyone want to take a stab at it. tell what i should test out or check
 
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