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2.9 experimenting this friday


stevealvey24

Well-Known Member
Joined
Jan 9, 2011
Messages
194
Vehicle Year
1986
Transmission
Automatic
This friday since I'm off I'm going to do some experimenting and post the results on here.

All the parts will be cleaned in a ultrasonic cleaner at work.
For the IAC I will pull the solenoid off my new one so no bias can about.

I'll be testing both the small and big throttle bodies, as well as both the small and big IAC's for the 2.9.
 
Lol my bad. Dazed and confused. Which is better with a 88 or later computer (egr delete). Which is better low end, better throttle.response on the throttle bodies. Which iac is.correct for the.later computer. If I can get tye time to.go to my dads ill get my 86 computer and do the same with it.
 
Sounds interesting, but how exactly are you going to test it? I mean, just going by feel isn't always very reliable testing.
 
Sounds interesting, but how exactly are you going to test it? I mean, just going by feel isn't always very reliable testing.

Ditto. I was thinking the same. Either way, it's cool that you are dedicating some time to the ol 2.9.
 
@ shane96ranger: no I decided to go back to the map system for now. The maf stuff is for sale, but if I dont sell it, I'll be switching back to in the future.

You guys are right its really just a feel but unless you got good connections thats really the only way I can do it. However I did uncover some pretty interesting stuff today. The below photos are all parts off of 2.9's NOTHING ELSE. See if you can pick up whats different in the throttle bodies, I currently have the large tb on my truck. The Iac is awefully intestering as well. The first has two small holes, the second a small and a large, and the last has two large holes. I'll measure them tomorrow for exact size difference. But I think out of some of the above the rough idle answer is lingering, it may just be a question of which with which lol.

I'll use the same tps for all tb's and set the voltage to exactly .901 on each.

IMAG0191.jpg

IMAG0190-1.jpg

IMAG0192.jpg
 
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So keeping in mind that all the iacs came off of 2.9's I have goin that one has both holes measuring .510", the other .537" and .610", that last with both large holes measures .610" on both which you think I should try first? Also anyone know the deal behind hole and no hole in the throttle bodies?
 
What are you trying to accomplish with the IAC housings? If I had to make a guess, I would think the larger holed unit came off of an automatic transmission truck, and the smaller came off of a manual transmission.

The hole in the butterfly is also to help at idle. At least it was the purpose on the 5.0 Mustang. There are some guys who put an aftermarket throttle body, and a cam in their speed density Stang, and the idle fix is to drill a 1/8" hole in the butterfly.
 
That's the thing though. Either there was bunch of peoples truck from the junkyard that has a "cam" or there's something different. Some had the hole, and some didn't? I think I seen a large tb that had a hole and mine doesn't lol. But by god ill figure something out. I just put the small with a hole on my truck the battery is disconnected but in a minute ill post what it does.
 
So first test just quick spin. The smaller throttle body is definately more drivablity related. Excellency throttle control. Doesn't feel like your almost wot everytime you hit the gas. Isles very smoothly. Gunna try the big idle air in the mornin. It got cold outside lol.
 
4.0 swap it... be done.
i spent way to much time/money trying to get stuff out of the 2.9...


sorry for speaking out... not trying to start a 4.0 vs 2.9 conversation here.... carry on! lol
 
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That's the thing though. Either there was bunch of peoples truck from the junkyard that has a "cam" or there's something different. Some had the hole, and some didn't? I think I seen a large tb that had a hole and mine doesn't lol. But by god ill figure something out. I just put the small with a hole on my truck the battery is disconnected but in a minute ill post what it does.

Not all of the Mustangs had it either. Ford used it to correct idle issues because the IAC wasn't doing it. I'm not saying that you had to have a cam to have idle issues, just that some guys used the "hole" method to correct the issues when using aftermarket throttle bodies (or factory with no hole).

IIRC, this "hole" method was used on carb'd cars as well.

My 89 didn't have the hole from the factory, but the 65mm Explorer unit I put on it does have the hole. You can kind of see it in this pic:
Motor65mmTB.jpg






Or just this:

4.0 swap it... be done.
 
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