New Engine Put In 2000 Mustang Gt, Need Help!

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StangGt2000

New Member

Apr 22, 2016

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Aug 4, 2016

#1

• Aug 4, 2016

• #1

So I had to drop a new motor into my 2000 mustang gt. The engine is from a 2005 crown victoria. The engine ran perfect when we got it. We got it into the mustang and hooked everything up but now when we started it, it idles at 700 rpm then will jump to about 2000 rpm and will stay there. If we rev it, it will slowly drop back down. We checked IAC, checked the vacuum lines. Any help would be appreciated!

 

squeak93

15 Year Member

Jun 2, 2005

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Joplin, Missouri

Aug 4, 2016

#2

• Aug 4, 2016

• #2

Check vac leaks again. Also did you swap all sensors from mustang into the new engine?

 

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StangGt2000

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Apr 22, 2016

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Aug 4, 2016

#3

• Aug 4, 2016

• #3

GoING to check for vacuum leaks tomorrow, had 2 injectors that wereno working so replaced those and they are good. I didn't switch any sensors from the engine blocks. Only things I changed over was oil pan, intake plenum(which is after market), cold air intake, transmission stuff. Wasn't sure if I should have changed the cam and crankshaft sensors so I didn't touch them.

 

squeak93

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Aug 4, 2016

#4

• Aug 4, 2016

• #4

I don't think they are different but I'd personally use all the mustang sensors.

 

wmburns

SN Certified Technician

Aug 14, 2009

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Aug 4, 2016

#5

• Aug 4, 2016

• #5

I have done nearly the same swap. IMO your problem isn't because of the difference in the motors. I suspect there's a typical cause for the issue with VAC leak being at the top of the list.

Of course this assumes that you did use the Mustang fuel injectors, MAF, FRPS. For the other sensors, there isn't a difference.

BUT. If you didn't reuse the IAC with the black vent, I could see this causing an idle issue.

Here's some information on how to trouble shoot IAC/Idle issues:
http://www.stangnet.com/mustang-forums/resources/troubleshoot-iac-idle-problems-1996-2004.13/

http://www.allfordmustangs.com/forums/2260649-post200.html

 

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StangGt2000

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Apr 22, 2016

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Aug 4, 2016

#6

• Aug 4, 2016

• #6

I did use all those from the mustang. So I will definitely be checking all the vacuum lines tomorrow. And I will look into the IAC as well. I will update you guys tomorrow after I go through it all.

 

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StangGt2000

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Apr 22, 2016

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Aug 5, 2016

#7

• Aug 5, 2016

• #7

Still no leaks found yet, still going to keep looking though. Did notice I have a coil plug not working and still having a problem with an injector.

 

Last edited: Aug 5, 2016

J

jeno_labanca

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Oct 10, 2014

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Aug 5, 2016

#8

• Aug 5, 2016

• #8

StangGt2000 said:

Still no leaks found yet, still going to keep looking though. Did notice I have a coil plug not working and still having a problem with an injector.

Click to expand...

Fix those issues first the see how it does

Sent from my SM-N910T using Tapatalk

 

wmburns

SN Certified Technician

Aug 14, 2009

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Aug 6, 2016

#9

• Aug 6, 2016

• #9

StangGt2000 said:

Still no leaks found yet, still going to keep looking though. Did notice I have a coil plug not working and still having a problem with an injector.

Click to expand...

Consider an injector cleaning and flow test service such as InjectorRX.com. Once cleaned and tested they are as good as new.