2001 explorer won't idle when cold
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2001 explorer won't idle when cold
My wife's 2001 explorer won't idle when cold. It is a 4.0 SOHC with an automatic. The ambient temperature must be 20 degrees or lower for the problem to happen. The truck has not set any codes. Once it warms up there are no further problems of any kind for the rest of the day but the next morning it has the same problem.
I have ruled out the IAC as the problem. The IAC passed all electrical tests, was cleaned, and finally replaced with a valve of known good operation with a friends valve off his truck. My valve worked fine on his truck also.
I can't find any vacuum leaks by spraying carb cleaner around all hoses and connections. I have checked the MAF electrically and removed it and cleaned it. (it was not dirty but I cleaned it anyway)
I am told that Ford fixed the intake manifold leak problems when they went to the one piece manifold in 2001. Can anyone confirm this or is it bull? Any help would be greatly appreciated. I hate parts replacement as a trouble shooting strategy.
I have ruled out the IAC as the problem. The IAC passed all electrical tests, was cleaned, and finally replaced with a valve of known good operation with a friends valve off his truck. My valve worked fine on his truck also.
I can't find any vacuum leaks by spraying carb cleaner around all hoses and connections. I have checked the MAF electrically and removed it and cleaned it. (it was not dirty but I cleaned it anyway)
I am told that Ford fixed the intake manifold leak problems when they went to the one piece manifold in 2001. Can anyone confirm this or is it bull? Any help would be greatly appreciated. I hate parts replacement as a trouble shooting strategy.
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From: Titusville, FL
Sounds like the computer may be involved. My IAC passed all electrical tests but the idle speed did not change when disconnected, the computer was not controlling it. I now have two good IACs which I accumulated while trying to find a very similar problem.
You might also check the Air Temperature sensor, the test for that is an ohms resistance to air temperature relationship - repair manuals usually have the table.
You might also check the Air Temperature sensor, the test for that is an ohms resistance to air temperature relationship - repair manuals usually have the table.
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Sounds like the computer may be involved. My IAC passed all electrical tests but the idle speed did not change when disconnected, the computer was not controlling it. I now have two good IACs which I accumulated while trying to find a very similar problem.
You might also check the Air Temperature sensor, the test for that is an ohms resistance to air temperature relationship - repair manuals usually have the table.
You might also check the Air Temperature sensor, the test for that is an ohms resistance to air temperature relationship - repair manuals usually have the table.
With accessories on, the idle speed should DROP immediately upon disconnecting the IAC; if it does not, something is wacko with it's operation. Why? Since you tried a known good IAC, AND yours worked properly in another engine, how about continuity of electrical connection? The contacts within IAC connector, possibly, wire broken, burned through, etc. on it's way back to PCM (computer), POWER supplied to IAC solenoid (maybe no voltage present?); finally, PCM not operating IAC...........
At that point, how about plugging YOUR PCM into that other guy's system? Would he go for such a radical proposal? I know of no other easy way to test the PCM. DO let us know what you find out!
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I am back and trying to work on this Explorer. It has warmed up here so I am shooting in the dark trying to find a problem that only surfaces at 20 degrees or below.
I would love to test the resistance on the IAT sensor but it is not where the manual says it should be. The manual says it is in the air tube between the MAF and the throttle body but there are only 2 tubes in the side of that air inlet tube on this truck. One goes to the valve cover and one goes to the IAC valve. So my question is where did they put the IAT on the 2001?
I taped in on the back of the intake at the hose that leads to the PCV valve and got a rock steady 15 inches of vacuum which is a little low but within specs for 3000 ft above sea level.
Does anyone know of a web site that has a pin read out for the computer as to voltage at each pin and what each pin goes to?
I would love to test the resistance on the IAT sensor but it is not where the manual says it should be. The manual says it is in the air tube between the MAF and the throttle body but there are only 2 tubes in the side of that air inlet tube on this truck. One goes to the valve cover and one goes to the IAC valve. So my question is where did they put the IAT on the 2001?
I taped in on the back of the intake at the hose that leads to the PCV valve and got a rock steady 15 inches of vacuum which is a little low but within specs for 3000 ft above sea level.
Does anyone know of a web site that has a pin read out for the computer as to voltage at each pin and what each pin goes to?
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Website no, but best bet for ALL troubleshooting is Ford Electrical Schematic Diagrams, along with Ford Shop Manual available at Helm Incorporated, their official printer of tech. info.
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Joined: Jun 2009
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From: Cedar Rapids, IA
Your library may have a subscription to the EBSCO website which will contain some information on wiring diagrams and pinouts, as well as some repair information. If you are a library card holder you might contact your library to see if they offer such a service.
-Rod
-Rod
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Motoshrump
Explorer, Sport Trac, Mountaineer & Aviator
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Apr 24, 2011 09:08 PM
