high idle

87slvrstang

New Member
Sep 12, 2009
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Hey everyone, I am new to the forum and hope to get a little help. I have a 87 notch 5.0. I removed all the smog equipment, capped the lines and plugged the back of the heads, removed the pump and changed the belt. I also changed the exhaust to an o/r h with flowmaster mufflers. I changed all this today and then sprayed the engine down with cleaner and rinsed it off. Now when the car is in park or neutral it idles around 1500 rpm. No stalling or anything crazy in gear moving or stopped, only in park or idle. When I got home from driving it, it was around 800. I started again an hour later and it was back up again. Is it something I missed with the smog removal or possibly I sprayed water in something? Other than idle in park or neutral the car runs great.:shrug:
 
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Removing the pollution control equipment from a 5.0 Mustang is a bad idea. All you have accomplished is to make the computer mad and spit codes. The pollution control equipment all shuts off at wide open throttle, so the HP losses from it on the car are 2-5 HP. The catalytic converters may soak a few more HP than that. None of the pollution control equipment reduces the HP enough to cost you a race in anything but professional drag strip competition like "Pinks".

If you removed the smog pump and still have catalytic converters, they will ultimately clog and fail.

Remove any of the equipment and you will not pass a full smog check, cannot title the car in an area that does smog checks and have broken several federal laws. Granted that the Feds are short on people to check cars, but it is still Federal law.

Know what does what before removing it. Remove or disable the wrong thing and the computer sets the check engine light and runs in "limp mode". Limp mode means reduced power and fuel economy.

Here's a book that will get you started with how the Ford electronic engine control or "computer" works.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by James Probst :ISBN 0-8376-0301-3.

It's about $20-$35 from Borders.com see http://www.amazon.com/ . Select boo...owthread.php?t=698148"]Surging Idle Checklist for help with all your idle/stall problems. Everything you need to find and fix idle problems is in there.

The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.
 
You prob have a VAC leak. What exactly did you remove?

I'd also run the codes. I agree that sometimes deleting smog equipment can do more harm than good. It can be done however.