High idle
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From: Abbotsford BC
High idle
In July I replaced the 5L in my 93 with a 5L of the same year with lower mileage but higher compression and oil pressure. It ran perfect until about ten days ago when the idle starting running at about 2100 rpm. I have replaced the throttle position sensor and the idle air control sensor and cleaned the idle control sensor valve and the idle is stillrunning at 2100 rpm.But with the really cold weather starting, now the idle is very slow to return to 2100 rpm after shifting. I am at my wits end.I just hope it ain't the PC module.Any ideas?
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From: 3rd Rock
Originally Posted by Galdorian
In July I replaced the 5L in my 93 with a 5L of the same year with lower mileage but higher compression and oil pressure. It ran perfect until about ten days ago when the idle starting running at about 2100 rpm. I have replaced the throttle position sensor and the idle air control sensor and cleaned the idle control sensor valve and the idle is stillrunning at 2100 rpm.But with the really cold weather starting, now the idle is very slow to return to 2100 rpm after shifting. I am at my wits end.I just hope it ain't the PC module.Any ideas?
…..See you on the boards.
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I have a similar problem with a customer's truck. It was idleing at 1800-2000 consistantly. I found I could back the timing by moving the distributor and it would idle great, but then it would not even rev up at all. I think it's the advance in the distributor or whatever controls ignition advance is stuck or inoperative. I'm still trying to figure it out though.
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From: Abbotsford BC
Shop tested
Took the truck into the shop and got them to test it...they said I have a leaking manifold gasket and possibly the o rings on the injectors. they wanted 650 bucks to do the work....
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I have the same engine in a 94 with the same problem. Have replaced the throttle position sensor and idle control valve. When slowing the truck to a stop the idle steps down some, but does not return to normal. Cannot find a vac leak. Would not think that a manifold and o-rings would go all at once. Have you resolved the problem yet? If so, please post the fix. Thanks, Lon.
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Nope, not fixed yet, Which sucks because I'm still not sure what it is. I think at this point my only option is to inform the customer that I will need to just replace the intake gaskets upper AND lower and HOPE it fixes it--something I HATE to do, but in this case I cannot find anything else wrong.
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From: Oak Harbor, OH
sam. before you tear it down that far, pull the electical connector that is hooked to the IAC (it looks like an electric motor attatched to the side of the throttle body) if the idle falls to normal then test the throttle position sensor. Do a search here and you'll find all sorts of information on it. If the idle doesn't fall replace the IAC and see what happens. I think the shop it trying to give you the shaft. Pull the codes, your check engine light may not be on but that doesn't mean there aren't codes stored.
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From: Abbotsford BC
High idle
Yeah was a little hesitant whne they said both the lower intake man gasket and the injector o-rings went so quickly together..have replaced the tps and the IAC sensor even pulled the IAC valve to check if it was seating properly and cleaned the carbon deposits. But still no change. Not sure about pulling the codes...Iknow where the self test plugs(?) are but not sure how to read the results...
Last edited by Galdorian; Nov 28, 2005 at 06:58 AM. Reason: Spelling and added sentence
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From: Oak Harbor, OH
Go <a href="http://www.broncodata" target="new">Here</a> (bronco data) or <a href="http://www.fordfuelinjection.com" targer="new">here</a>(Ford Fuel Injection). Both had a pretty straight forward instruction on how to pull them and what they mean. Out of curiosity when you replaced the TPS and IAC did you also change the gaskets on the throttle body and IAC? If not I'd start there. If that checks out go to the parts store and get some carb cleaner like 2 cans. Hose down the entire lower manifold where it meets the heads have the truck running while you do this. If the RPMS go up (meaning more fuel IE carb cleaner) then replace the those gaskets. Also use the same method to test your vacuum lines.
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I did pull the IAC connector--no change. It is newer too, and clean.
I checked the TPS--Voltage from .91 to 4.54 closed to full throttle.
Sprayed the carb cleaner ALL over the place with no effect(which is why I can't figure out how there could be a vac. leak.
I did notice one effect--RMPS came down a lot when I pulled and plugged the PCV valve, which is almost whistleing from so much air being pulled from the crankcase. This led me to believe maybe the lower intake gasket between the block and manifold at the bottom may be leaking...but then again, can't get it to change by spraying around there. Hmmmm.
I checked the TPS--Voltage from .91 to 4.54 closed to full throttle.
Sprayed the carb cleaner ALL over the place with no effect(which is why I can't figure out how there could be a vac. leak.
I did notice one effect--RMPS came down a lot when I pulled and plugged the PCV valve, which is almost whistleing from so much air being pulled from the crankcase. This led me to believe maybe the lower intake gasket between the block and manifold at the bottom may be leaking...but then again, can't get it to change by spraying around there. Hmmmm.
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From: Abbotsford BC
took the suggestion about using carb cleaner to check for vacumn leaks and found a leak in the lower intake gasket. so was thinkin of using a gasket seal paste for a temperary fix until i can find a dry place to pull the intake manifold.