Blow-by causing IAC problems?
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Blow-by causing IAC problems?
My truck ('92 F-150 302EFI) periodically goes into an extremely high idle. I think the IAC needs cleaned. I don't have any carb cleaner, but i took the IAC and the other part it attaches to off to look at them. When I took the hoses from the airbox off, they had oil dripping out of them. The inside of the IAC and the other part had oil in/on them and the back piece had what looked like oil crud in it. Could blow-by cause this? If not, then what is it?
Thanks in advance.
Thanks in advance.
Fleet Owner
Joined: Oct 2005
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From: Kentucky
It is not common for this vintage truck to have some oil deposits in the intake. As the engine gets some miles on it the problem can be amplified. Check/replace your PCV valve and the breather element in the airbox.
Your case does appear to be more than what I would expect. Clean the intake tract out, start with the new PCV and filter. Keep an eye on it. If the build up comes back quickly, it may be time for a leak down test.
Your case does appear to be more than what I would expect. Clean the intake tract out, start with the new PCV and filter. Keep an eye on it. If the build up comes back quickly, it may be time for a leak down test.
Fleet Owner
Joined: Oct 2005
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From: Kentucky
The PCV (Positive Crankcase Ventilation) is located on the passenger side valve cover underneath the upper intake. Not a very good design IMHO. The fresh air intake filter is located underneath the engine air filter. There should be a tube running from the driver's side oil fill tube to the air filter box.
A few have tried using the breather filter you mentioned. It should work, but if you have emissions testing they may not be too keen on that setup.
A few have tried using the breather filter you mentioned. It should work, but if you have emissions testing they may not be too keen on that setup.
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so, I need to remove the upper intake? Great!lol. We don't even have the crap where they plug the truck in for emissions here. Most people run straights or glasspacks and my smog system's comin off.
Fleet Owner
Joined: Oct 2005
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From: Kentucky
It is darn near impossible on my 5.8L engine to pull the PCV without removing the upper intake, the 5.0L is a little easier like the previous reply indicates.
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