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Motor Swap Issues - 97 into an 02

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Old 03-11-2014, 10:31 PM   #1
CJCuster89's Avatar
Join Date: Dec 2013
Vehicle: 2002 Ford Mustang GT
Location: Maryland
Posts: 32
Default Motor Swap Issues - 97 into an 02

Alright so I've successfully swapped my motor. I got a 97 NPI for 400 bucks because I blew the bottom end of my old 02 motor. I know its a decrease in power, I just need transportation and a mustang that sounds like... well a mustang. So here are the issues I'm having.

The car starts and runs for as long as I want it to, however... The idle is high. It's sitting at like 1500 at all times. And if I rev the engine up to say like 4,000 it stays up there at 4,000 and gradually falls back to 1,500. When I say gradually, I mean like over 10 seconds.

Another thing is, my headers are getting red hot. They are glowing orange. And it's not every header. Only 2 on the passenger side.

My alternator isnt working properly either, but this is because the clip that goes into it is broken. I have a new one on the way but I'm not sure if this could account to my idling problem.

Any help or advice would be great and very helpful. Thanks.
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Old 03-15-2014, 03:24 PM   #2
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No one knows I guess?
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Old 03-15-2014, 05:40 PM   #3
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Sounds like you have multiple problems.

If your PI top end is still good, I'd put the heads/intake on the NPI bottom end. Compression bump will scoop you a few extra ponies over the stock PI motor.

Hot exhaust can also mean a clogged cat.
1998 Roush: M112'd Aluminum block 4.6L 2V 6 speed track car
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Old 03-15-2014, 05:53 PM   #4
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I'd pull the spark plug on #2 and see if its running lean, should be light brown, if lean it will be white.
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Old 03-15-2014, 05:53 PM
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