2.5 to 4.0 throttle body, Idle issues, Again! - Page 3 - JeepForum.com
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Unread 02-22-2013, 09:56 PM   #31
ROTTEN
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1994 YJ Wrangler 
 
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OK no prob. There is a gasket between the iac housing and tb. Maybe yours is cracked?

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Unread 02-23-2013, 04:14 PM   #32
az_zoner
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Well, Still no luck. I tried a new 2.5 iac today and it was not the answer. Still a hi idle. I got it from Auto Zone and it really doesn't look like the stock one. Wondering if they gave me the right one.

So I'm cleaning up my old 2.5 throttle body and going back to trying to get it all running on the stock set up.

Thanks for all the input and suggestions from everyone.

cb
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Unread 02-23-2013, 05:13 PM   #33
az_zoner
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Un Real, My engine just locked up!

This is a Engine that I bought off CL that the PO said had been rebuild. Thought it was a good deal but I guess not. So I got bigger problems than getting my 4.0 throttle body working now.

I need to go damage something!

cb
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Unread 02-23-2013, 06:09 PM   #34
ROTTEN
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Seized up? Sorry to hear
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Unread 02-23-2013, 06:29 PM   #35
az_zoner
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I'm thinking in the crank. I've had it running for a week or so with about maybe 30 miles on it. The engine sounded good compared to my old engine. Just the throttle body issue and I was ready to start heading to some easy trails.

I just got the 2.5 throttle body back on and was cranking it when bang!. Starter was trying but it wasn't turning. I tried a socket and breaker on the pulley and it won't budge. Put it in 2nd gear and tried rocking it and it's like a rock.

The bummer is that I bought the engine a while back with the intentions of putting it in when time permitted. and I sold my old engine too. Don't think theres anyway of getting hold of the guy who sold me engines. Probably a good thing! he had it listed as a rebuilt engine by a machine shop.

cb
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Unread 02-23-2013, 06:44 PM   #36
ROTTEN
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Ouch maybe you can get some $$ back on scrap?
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Unread 02-23-2013, 07:06 PM   #37
pete1991YJ
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WTF welp, time to pull the pan and see... maybe you can free it up from underneath, I wonder if its just something stupid like a rod cap came loose... I've seen some strange stuff before, my machine shop gave me 010 under bearings once, ruined a brand-new crank in 5 mins that way once...
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Unread 02-23-2013, 08:38 PM   #38
az_zoner
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Yea, I hope I can get some time tomorrow to at least pull the pan. I'd like to know for sure what happen. Man this sucks!

cb
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Unread 02-25-2013, 04:59 PM   #39
az_zoner
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Big Sigh of Relief!! It looks like the starter had a few issues and disintegrated. Or part of it did. Can't believe it hooked it up so hard that I could budge the pulley. But I put a breaker bar on the pulley nut and it rotates fine now. So I'm going to look at a few more things around the flywheel and make sure there is nothing else that may of caused the failure. I do have another starter so down time won't be long.

So back to figuring out the 4.0 throttle body issues soon. So where I was at was, completely back to stock 2.5 everything. With a new 2.5 iac.

Thanks for the support guys!

Craig
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Unread 02-25-2013, 06:27 PM   #40
Que89YJ
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Glad to hear it wasn't anything serious.
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Unread 03-01-2013, 08:01 PM   #41
az_zoner
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Back at it, Does the TPS have to be changed? I can't see any reason why but I can't say for sure that there is no difference between the two. I should be back up and running tomorrow and hope to spend some time trying to figure this out.
The plan is:
1) Install back to stock all 2.5 parts, throttle body, housing 2.5 IAC and TPS. The IAC is a new one.
If running/idling normal
2) Install 2.5 housing, new 2.5 IAC and TPS on 4.0 throttle body, and give that a shot.

Now I know I've tried all these set ups before but will try one more time.

Craig
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Unread 03-02-2013, 02:56 PM   #42
az_zoner
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Ok, My 2.5 engine is just not meant to run with the 2.5 housing and IAC on the 4.0 throttle body. I've been playing all day with different configurations and the best set up is the 4.0 throttle body with the 4.0 housing and IAC. So in my case anyway it is not cast in stone that you have to change. When I have the 2.5 housing and IAC it has a slight bog off idle. I did get it to idle at 800-900 rpm but it just not as crisp of an acceleration as the full 4.0 set up.



Good thing also is my motor is sounding good after I put another starter on it. That was a good scare!

thanks for all the input and suggestions as I worked through this.

Craig
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Unread 03-02-2013, 07:16 PM   #43
Que89YJ
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Did you open up the intake manifold throttle body mount? I just don't get why it wouldn't work.
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Unread 03-02-2013, 08:15 PM   #44
az_zoner
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Quote:
Originally Posted by Que89YJ View Post
Did you open up the intake manifold throttle body mount? I just don't get why it wouldn't work.
I put it on a mill and opened it up to the exact same size as the bore on the 4.0 throttle body.

I tried the old and a new 2.5 IAC and it just has a bog when first hitting the throttle.

The only thing that is different on this engine is that it has an inertia ring on the flywheel that I put on and I was told but have no way to check, that the head was milled and that it may have more compression that stock. The PO of the engine may of been trying to blow smoke on that one. Don't know.

But it seems to be running fine now. I'm going to try and get some miles on it tomorrow.

Craig
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Unread 03-03-2013, 08:56 PM   #45
ROTTEN
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Nutty! Hmmm
I must say my rpms were high as well with the setup. Slow to come down as well to idle. Vacuum leak somewhere?
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