This is topic Rough idle, lots of exhaust in forum Tech Talk at Northern California Ford Owners  .


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Posted by overkil5.0 (Member # 3358) on :
 
Just put in a new 5.0 HO crate motor into my 87 GT and it's running really rough. It is also spitting out a lot of exhaust. I changed the O2 sensors, that helped a little. I changed the EGR valve with only mild changes to idle. I know my air check valve is bad, not sure if this would cause these conditions. I think it might have something to do with the fuel system. Any help would be greatly appriciated.
 
Posted by Quick 88LX (Member # 1950) on :
 
Is it a stock 5.0 motor? If so, I would definitely grab a chiltons manual and do everything listed in there for a normal tune up. I bet you are just missing something like a vacuum line or something... But since you just dropped an entire motor it could be anything.

-Start by checking everything electrical like spark plugs, cap and rotor etc. -Check all fuel related components. -Make sure all your vacuum lines are good and you have no leaks. -Check all of your smog shit to make sure that works as well.

If all else fails, pull some codes and you will be able to fix her right up.
 
Posted by SALEENx5 (Member # 1605) on :
 
quote:
Originally posted by overkil5.0:
Just put in a new 5.0 HO crate motor into my 87 GT and it's running really rough. It is also spitting out a lot of exhaust. I changed the O2 sensors, that helped a little. I changed the EGR valve with only mild changes to idle. I know my air check valve is bad, not sure if this would cause these conditions. I think it might have something to do with the fuel system. Any help would be greatly appriciated.
Double check all the basics first (correct firing order, ignition timing, vacuum leaks, etc.)
You may have just missed something. Some more information on your combination may help us out in helping you out also (stock spec motor? aftermarket cam? MAF conversion done?).
 
Posted by overkil5.0 (Member # 3358) on :
 
Thanks for the info guys, much appreciated. It turned out to be a vacuum.
 




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