4.3 tbi to 3.4 on 2.8 manifold - Off-Road Forums & Discussion Groups
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post #1 of (permalink) Old 10-26-2000, 04:29 AM
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4.3 tbi to 3.4 on 2.8 manifold

I'm in the midst of a 2.8 to 3.4 swap for my 86 jimmy. my ? is about the throttle linkage stuff. it looks to me that the swing plates are opposite. anybody run into this or know of a solution. thanks jeff p.s. see below for more detail

jeff
86 4x4 2.8 jimmy
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post #2 of (permalink) Old 10-27-2000, 12:47 AM
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Re: 4.3 tbi to 3.4 on 2.8 manifold

On rereading my post I thought a little clarity might help. I have removed my 2.8l engine from my 86 jimmy. I have purchased a 3.4 from a 95 firebird. I have removed the manifold and multiport fuel injection equipment and accessory brackets from the 3.4 in anticipation of swapping in a bored out 2.8 intake manifold and the 2.8 accessories. On inspection of the 4.3 used TBI I have noticed the throttle hook up is a little different from the 2.8 TBI. They appear to be opposite to each other. I have read a few posts here and elsewhere suggesting a solution involving grinding down the cable but I can't picture the solution. Everything else seems to be falling into place, ie: 4x4 oil pan and timing cover to fit, water pump, intake manifold, exhaust manifolds, distributor, sensors. I would like to thank everyone here for contributing their time and knowledge for "the greater good". One thing I will remember is to retorque the intake manifold after bringing the engine up to operating temperature. If anybody can help me to understand how to work the TBI hookup I would appreciate it. Thanks, Jeff.

jeff
86 4x4 2.8/3.4 jimmy
post #3 of (permalink) Old 10-28-2000, 02:24 AM
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Re: 4.3 tbi to 3.4 on 2.8 manifold

I have heard of guys claiming to use a 4.3 TBI on an S10 2.8, but I noticed that the 4.3 TBI is not really compatable for use on the 2.8. At least thats what I concluded after peeping a freinds spare 4.3 TBI and finding out that the shaft swung opposite. Who knows, maybe there are two types of 4.3 TBI's but Either way I really have no Idea how these guys came up with the shaft solution. Maybe one of em will post it, cause Id also like to hear how crazy it is.614streets

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post #4 of (permalink) Old 10-28-2000, 10:21 PM
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Re: 4.3 tbi to 3.4 on 2.8 manifold

I know of several guys with the GM 3.4 swap in a Trooper, and they have used the 4.3 TBI. They did mention that they had to use the throttle bracket that came with the 4.3, and that it would be a hassle to adapt cruise control if you had it. Apparently the stock throttle cable off the 2.8 was long enough to be used with the 4.3 throttle cable bracket. HTH...................ed

post #5 of (permalink) Old 10-31-2000, 09:56 PM
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Re: 4.3 tbi to 3.4 on 2.8 manifold

That's the info I needed. Thanks people, I'm off to the wreckers yet again! jeff

jeff
86 4x4 2.8/3.4 jimmy
post #6 of (permalink) Old 11-01-2000, 01:07 PM
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Re: 4.3 tbi to 3.4 on 2.8 manifold

Here it goes- the plastic around the the cable gets cut off, careful not to damage the cable itself, a dremel works well. I actually found that grinding is not necessary on the cable linkage itself - the pulley on the tbi is ground off a little on the top to allow the cable linkage to be inserted into the larger center slot - the sides of that same slot I bent outward to allow the cable to fit in the slot. The shorter 4.3l tbi throttle cable bracket is used instead of the longer 2.8l bracket. The cable wraps around from the bottom of the pulley and mounts to the top. A metric allen screw attaches the cable to the pulley. The picture is kind of crappy but you can see some detail. The circle is around the allen screw. I hope this helps for the throttle linkage. I have a five speed and did not have to hook up a automatic transmission cable that might be difficult - you may have to you part of your old 2.8l throttle bracket cut up and welded to your 4.3l throttle bracket. My truck had cruise control before the swap but never did work so not being able to hook it up was no problem for me -I hate cruise control anyway. -Peter


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post #7 of (permalink) Old 11-02-2000, 08:50 PM
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Re: 4.3 tbi to 3.4 on 2.8 manifold

Some day I too will learn how to do the fancy stuff like attachments but for now iwould like to say thanks again for the help. next ? is what year is the pulley from? I haven't found it at the wreckers yet. This is the final piece of the puzzle (i hope) Jeff

jeff
86 4x4 2.8/3.4 jimmy
post #8 of (permalink) Old 11-07-2000, 02:36 PM
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Re: 4.3 tbi to 3.4 on 2.8 manifold

I just replaced the tps sensor on the 4.3 tbi about a month ago and I think the year was a 91 or later. I think the main difference in the years is the tps sensor. The older being the generation 1 series and the later being the non-adjustable generation 2 type tps sensor.

post #9 of (permalink) Old 11-08-2000, 02:57 AM
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Re: 4.3 tbi to 3.4 on 2.8 manifold

Murphy law should be revoked. Maybe whoever gets elected in the u.s. will do that. Today i dropped a washer into my 3.4 when i was putting on the intake manifold, i haven't found it yet! I'm glad this 2.8 to 3.4 is a simple swap, i don't think my abilities could handle anything more complex. I hope the weather holds up (no garage). There is a certain satisfaction with this stuff as you all know. I still have to get to the wreckers to find the pulley for the 4.3 tbi. thanks for the help. jeff

jeff
86 4x4 2.8/3.4 jimmy
post #10 of (permalink) Old 11-19-2000, 12:27 AM
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Re: 4.3 tbi to 3.4 on 2.8 manifold

I pulled the cam to get the #@%*&^ washer. A magnet didn't do it. I went to a place called J&J cores. They have sooo many parts in really big boxes! Anyway I got a TBI with a pulley throttle linkage for $30. A wrecker wanted $150 if they could find one. HA! So thats another option when looking for parts. The guys there were Quite helpful and knew their stuff. They did say bringing in the part to be replaced would be helpful. the swap saga continues and its snowing ( i have no garage) jeff

jeff
86 4x4 2.8/3.4 jimmy
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