This is topic 1990 5.0 keeps dying... in forum Tech Talk at Northern California Ford Owners  .


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Posted by LXman25thANNV. (Member # 5359) on :
 
I got a 1990 5.0 lx with upper and lower edelbrock intake manifolds, stock air intake , jet computer chip, and stock exaust. Anyways when im coming to a stop and i pull it outa gear it will almost always die unless i tap the gas. The check engine light will rarely come on, and i can rev it all i want and it wont die, it will always go back to idleing fine. Do you think that it could be a bad o2 sensor and the comp is going into "crap mode"? Is this a common problem with 5.0's? Why wont it die if i tap the gas? Any info will help so i hopefully dont have to get the codes read...
 

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Posted by white92FOX (Member # 5846) on :
 
It could be a bad IAC(idler air control valve). This is a very common problem on the fox bodies. Does it surge when it is idling? I assume it is an aod car right?
 

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Posted by v-town50 (Member # 4920) on :
 
it could be an O2 sensor or even the mass air. the same thing happened to mine, could be the idle sensor too.
 

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Posted by two-gun kid (Member # 5325) on :
 
sorry to jack the thread, but this also happens to my notch but i was told its a intake manifold leak?
 

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Posted by underconstructionlx (Member # 5514) on :
 

quote:

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Originally posted by two-gun kid:
sorry to jack the thread, but this also happens to my notch but i was told its a intake manifold leak?

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yup thats wat was wrong with mine until i replaced the gaskets on the upper and lower.
 

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Posted by two-gun kid (Member # 5325) on :
 
sorry to jack the thread, but this also happens to my notch but i was told its a intake manifold leak? and its not making a good vacumm.
 

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Posted by LXman25thANNV. (Member # 5359) on :
 
yes it was an AOD car before i threw in a t5...
Its not a manifold leak.
Its not the MAF.
What exactly is the IAC and where is it located, is it on top of the throttle body?
-and it does occasionally "surge" when idleing but not very often.
 

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Posted by BCINGUU (Member # 2397) on :
 
I was having the same problem, it turned out to be a wierd problem with my TPS (see today's post on that).

You can remove your IAC and clean it with carb cleaner, it's easy to do, just two small bolts and a connector.

I would suggest checking your TPS voltage between the black and green wires at idle, should be slightly less than a volt.

Limp mode would not cause this nor would bad or clogged O2s. If you're not having any other drivability problems besides idle, you need to look at components that affect your idle such as IAC, TPS, EGR, and vacuum.
 

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Posted by LXman25thANNV. (Member # 5359) on :
 
ok I think it may be cool enough now to go outside and try cleaning the sensor and check the voltage. Thanks for the input everyone.
 

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Posted by blind (Member # 3052) on :
 
this can also be caused by the VSS - vehical speed sensor, its plugged into the side of the trans, if the computer isn't getting a signal from this (you said this is a 5spd conversion car) then the computer wont keep the idle up while the car is moving to help keep it running.

its the same location as the speedo cable, the cable goes into the VSS.
 

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Posted by LXman25thANNV. (Member # 5359) on :
 
"this can also be caused by the VSS - vehical speed sensor, its plugged into the side of the trans, if the computer isn't getting a signal from this (you said this is a 5spd conversion car) then the computer wont keep the idle up while the car is moving to help keep it running.

its the same location as the speedo cable, the cable goes into the VSS."

...um...i..didnt plug that in because the plug was messed up.. ...I was wondering what that was for...guess it's off to Pick and Pull.
 

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