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Unread 03-15-2012, 10:29 AM   #1
TCrook
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1994 YJ Wrangler 
 
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2.5 to 4.0 throttle body swap. Help!!!

I have a 94 4 banger that I am trying to get a little more juice out of. I swapped to a 4.0 throttle body that I got from a junkyard yesterday. Everything hooked up fine. Crank her up and the engine goes wide open. I shut it off tried again, same thing. Any ideas on what I did wrong? Need some help here.
Thanks,
Tom

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Unread 03-15-2012, 10:46 AM   #2
OKwranglerYJ
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Did you use the sensors from your 2.5 tb or the one for the 4.0. And it sounds like the throttle position sensor.
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Unread 03-15-2012, 10:48 AM   #3
idskot
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Quote:
Originally Posted by OKwranglerYJ View Post
Did you use the sensors from your 2.5 tb or the one for the 4.0. And it sounds like the throttle position sensor.
I'd say this. This or the idle air control? Those two are the only sensors in the TB.
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Unread 03-15-2012, 03:25 PM   #4
TCrook
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That was it. Swapped the sensors. Runs like a scalded turtle now. Thanks for the replies.
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Unread 03-15-2012, 04:03 PM   #5
benmar2000
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Quote:
Originally Posted by TCrook View Post
That was it. Swapped the sensors. Runs like a scalded turtle now. Thanks for the replies.
It will give them squirrels more air to breath.. Makes them run faster in their cages..
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Unread 03-15-2012, 04:13 PM   #6
Xpress
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Well that's step one. Step two would be to open up that intake and exhaust. Let it really breathe..
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Unread 03-16-2012, 10:26 PM   #7
jaredmausteller
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I have a 92 yj w a 2.5 in it. I was looking to do the 4.0 tb xchange. My question is what year tb should I be looking for, and is it a direct bolt on?
And do I use the stock 2.5 iac and tps or do I use the 4.0 sensors??
Thanks in advance.......
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Unread 03-16-2012, 10:46 PM   #8
benmar2000
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Quote:
Originally Posted by jaredmausteller View Post
I have a 92 yj w a 2.5 in it. I was looking to do the 4.0 tb xchange. My question is what year tb should I be looking for, and is it a direct bolt on?
And do I use the stock 2.5 iac and tps or do I use the 4.0 sensors??
Thanks in advance.......
I think any TB from a 91 or 92 4.0L (Can't remember what year they switch to the 4.0L) forward will work.. I have a 95YJ but my TB came off a 94 Cherokee.. But you want to make sure it has 4 bolt holes that mount it to the intake.. At least it was on mine.. Also, you want to move over the IAC and Throttle sensor.. You will need a size T20 Tamper Resistant Torx bit to get the IAC sensor off.. It isn't a hard swap.. It will take maybe 10 minutes to do the swap..
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Unread 03-16-2012, 11:25 PM   #9
jaredmausteller
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So use the 2.5 sensors on the 4.0 tb?
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Unread 03-17-2012, 05:08 AM   #10
benmar2000
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Quote:
Originally Posted by jaredmausteller View Post
So use the 2.5 sensors on the 4.0 tb?
Correct.. On the 4.0L TB, remove the sensors and then take the sensors on the 2.5L TB and put them on the 4.0L TB.. Then bolt the 4.0L TB on and hook up the sensors and throttle cable.. Your done.. As added insurance, I would get a new TB gasket.. I could have reused mine, but decided why take the chance.. It's only $1.99 from Advanced Auto..
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Unread 03-17-2012, 05:14 AM   #11
wendell
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You need to use a 4.0 tb from a 91-95 yj and change to the 2.5 sensors.
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Unread 03-17-2012, 05:30 AM   #12
benmar2000
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Originally Posted by wendell View Post
You need to use a 4.0 tb from a 91-95 yj and change to the 2.5 sensors.
A TB from a 4.0L XJ will work also..
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Unread 03-17-2012, 08:02 AM   #13
Xpress
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Yup, I believe the XJ's and YJ's got essentially the same powerplants for FI, seeing as how a lot of components are interchangeable (FI, TB's, manifolds, etc).

I could be wrong
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[URL="http://www.jeepforum.com/forum/f12/another-5-2l-yj-thread-1503048/"]My 5.2L Build thread[/URL]

-1989 Jeep Wrangler 2.5L, soon to be 5.2L
-1996 Jeep Grand Cherokar 5.2L, donor and rainy day driver
-2004 Kawasaki KLR650 sunny day driver
[QUOTE=mudsweatNgearz;21162729]Leave em off and weld an I beam on. Bumperetts just scream homo.[/QUOTE]
"A well regulated Militia, being necessary to the security of a free State, the [B][I]RIGHT[/I][/B] of the people to keep and bear Arms, [B][I]SHALL NOT BE INFRINGED[/I][/B]."
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Unread 03-17-2012, 08:50 AM   #14
hesserdude07
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Jp (i think it was) did a nice write up on this, this month or last month... gave good years to get the TB from and other swaps to do.
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Unread 03-17-2012, 08:53 AM   #15
jaredmausteller
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Thanks for the info. I'm looking to put power steering in it so any extra power I can get will help tons....
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