Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: mtrembl1 on July 11, 2011, 06:23:15 PM

Title: A/C killing the engine, except...
Post by: mtrembl1 on July 11, 2011, 06:23:15 PM
Whenever I turn on the A/C in my 86 Cougar 5.0, it kills the engine.  I've never tried while driving, for fear of death...  but I noticed the other day that if i turn on the defrost with the temp all the way on cold, it will blow nice cold air out through the defroster.  Any idea's?
Title: A/C killing the engine, except...
Post by: Bruce M on July 11, 2011, 07:40:45 PM
Idle might be low.
Title: A/C killing the engine, except...
Post by: 88turbo on July 11, 2011, 09:29:20 PM
I agree, or it could be over charged...
Title: A/C killing the engine, except...
Post by: mtrembl1 on July 11, 2011, 09:30:43 PM
i'm thinking so.  tried turning it on while driving tonight, and it ran fine, even when i came to a stop.  once i got home to my driveway, i put it in park and it stayed running.  was even able to pop the hood and look at what's going on underneath.  i had to replace the IAC not too long ago.  how do i go about raising my idle?
Title: A/C killing the engine, except...
Post by: 88turbo on July 11, 2011, 09:33:09 PM
there is an idle screw on the throttle body that will increase the idle
Title: A/C killing the engine, except...
Post by: mtrembl1 on July 11, 2011, 10:14:54 PM
that fixed it.  thanks guys!  never saw that screw all the other times i tried to look for it...
Title: A/C killing the engine, except...
Post by: TOM Renzo on July 11, 2011, 10:18:32 PM
The idle is not set with that SCREW. That screw is a MIN idle screw that balances out the TPS and MIN idle speed. The IAC controls the idle on that engine. Their is a Procedure to adjust that in the service manual. May i suggest doing it by the BOOK. Thanks
Title: A/C killing the engine, except...
Post by: mcb82gt on July 12, 2011, 08:41:42 AM
I bumped my idle speed up with that screw and then checked my TPS voltage and brought it down to .98 volts.  Not sure if that is the correct way or not?
Title: A/C killing the engine, except...
Post by: TOM Renzo on July 12, 2011, 03:27:28 PM
That works GOOD enough. Because if the tps goes out of range the idle can FLAIR UP quite high. Good job!!