I just put a new s4 motor in an 86 GXL auto. We got it running but it won't idle. We have tried everything we can think of but no luck, It dies below 2k. There was one vaccum line that is unpluged. It is the one that goes from the middle hole on the Throttle Body to the little hole on the motor side of the LIM. We forgot about it when bolting the fuel system back up. Is this the reason it won't idle? I mean it is just one hose. Thanks for the advice,

John

 

That would do it.

 

Jim, in a simple answer, it is highly possible



Now for the technical answer why, you have left an open unmetered air source out to the atmosphere, the air the air flow sensor measured had the fuel calculated for it through the ECU, now you have given the car a source of air that the fuel is not being measured for, so in essence you are running overly lean. I highly suggest plugging the vacuum leak and trying again

 

OKay then. I guess I get to take the EFI off. Yeah, I can't wait! Thanks for the advice. I didn't want to do it unless someone was sure that this would fix my problem. Thanks alot.

John

 

John, do us a favor, post back if it did work for you, others may have your same problem in the future, and the search engine will help them as well

 

this happened in my friends car he pulled out the sensor on his intake and the car wouldnt idle it would just stall over and over again check that to see if its working

 

What sensor?