Jeep Girl hopes to upgrade 1976 cj7 jeep to gm tbi...Please Advise..

[76cj7chick]

Hi fellow jeepers!

I am almost finished with rebuilding my llittle CJ7 jeep but am in current need of gm tbi swap...

I've read a lot of information on the internet about the swap but would love to have additional information before jumping into the swap...

I know a few of you have done the junkyard swap and some have done the howell or affordable fuel injection conversion...
I am finding the biggest issue for doing a junkyard swap is getting the intake/throttle body adapter at a reasonable price, getting the correct prom (I understand the 1227727 is the correct ECM) and that the vehicle needs to have a "z" in the vin so as to be correct 4.3l v6 engine. But I also worry about the wiring.-Just where do the wires all go?

I also have the stock distributor and coil. So, I don't know if I need the tach filter... And then there is concern what sensors and relays I need.
I have the GM GM Turbo 400 Transmission (3 speed auto) and wonder if that will require anything special for the conversion?

PS: I've already converted from one barrel intake to an intake from an 85 CJ7 jeep...


The issue with the New kits are really expensive...

If anyone has the complete kit at a decent price please let me know.. I may be interested in purchasing it from you..

 

[Old Dog]

I'd try someone like Howell or ebay for the adapter.
The GM Turbo 400 is pre computer so you don't need anything there.
Here's a good read on the wires.
Wiring - Binder Bench

 

[Torxhead]

There is a lot of info out there on the junk yard t.b.i. system, I assume where you are from a smog inspection is not required. I have learned quite a bit on these setups just by working from a kit that I purchased, and still continue to pick things up as I work with that system. Good luck with your what you decide to do.

 

[76cj7chick]

Thanks for your quick replies...

I checked out the adapter plate through affordable fuel injection and its a whopping $175!
I also checked out Howell's adapter plate and it costs $95... That is if Its the correct one. (ADAPTER PLATE: Holley 500 2-bbl to GM TBI, .5" thick CODE: H2J)


Howell, or Affordable would definitely be the easiest route for me... But not the cheapest...

If anyone has a kit they don't need anymore please let me know how much for the kit.

The main two things keeping me from going "junkyard"... Is getting/making the correct adapter plate and making sure I get the correct prom for the ecm.. That is If one is needed..

I'll keep researching about the junkyard swap.. In the meantime, if anyone has any additional helpful information PLEASE share with me...

 

[harleydragon]

I never had a jeep 400 turbo but if that is what you have then it may not have the same bolt pattern as a chevy..I'm pretty sure that it would not

 

[76cj7chick]

I'd try someone like Howell or ebay for the adapter.
The GM Turbo 400 is pre computer so you don't need anything there.
Here's a good read on the wires.
Wiring - Binder Bench

Hi Olddog,

Thanks for the information on the tranny... And the great detailed wiring information.
Now I just need to find pictures for how the tbi system is supposed to look on a 76 CJ7 (now with a 2 bbl intake)...

 

[76cj7chick]

I never had a jeep 400 turbo but if that is what you have then it may not have the same bolt pattern as a chevy..I'm pretty sure that it would not

I have the AMC 258 i6 / 4.2l AMC 258 i6 / 4.2l engine and GM Turbo 400 Transmission and the Dana 20 Transfer Case out of a full sized jeep truck.. A previous owner did the swap.

Since my cj is a 76 it only came with a 1 bbl intake that was "married" to the exhaust manifold. I installed a 2 bbl intake manifold and separate exhaust manifold. Thankfully the exhaust manifold has a o2 sensor port.

So, the conversion shouldn't be a problem...

 

[harleydragon]

sorry..for some reason I had chevy on the brain

 

[jeepardy]

First...Unless you use a Holley adapter plate too, that Howell adapter plate won't work. I tried that on mine and could never get it to seal and had vacuum leaks. I ending up making mine. $7.00 worth of scrap 1/2" aluminum plate, a drill press, taps and hand file. Took about an hour.

Second...Don't get to hung up on the Prom. The AMC 258 i6 / 4.2l and 4.3 are so close in size, factory fuel tables work real well unless you run amodified cam, high compression and headers. I haven't touched/reprogrammed mine. "Don't fix something that's working" Best advise I can give you about that is just make sure it comes out of a vehicle with an automatic and stay away from any with a 3 digit BCC which would be in 1987 vehicles. I'm actually using a 16144288 ECM BCC AUMH out of a 1990 G20 van

 

[76cj7chick]

First...Unless you use a Holley adapter plate too, that Howell adapter plate won't work. I tried that on mine and could never get it to seal and had vacuum leaks. I ending up making mine. $7.00 worth of scrap 1/2" aluminum plate, a drill press, taps and hand file. Took about an hour.

Second...Don't get to hung up on the Prom. The AMC 258 i6 / 4.2l and 4.3 are so close in size, factory fuel tables work real well unless you run amodified cam, high compression and headers. I haven't touched/reprogrammed mine. "Don't fix something that's working" Best advise I can give you about that is just make sure it comes out of a vehicle with an automatic and stay away from any with a 3 digit BCC which would be in 1987 vehicles. I'm actually using a 16144288 ECM BCC AUMH out of a 1990 G20 van

So it looks like the biggest challenge for me is to make or find a decent adapter plate that doesn't break the bank..
Thanks for the information about the prom and that I should get the ecm from an automatic... For a while I was really worried about not getting the correct one for my CJ7 .

I've priced parts at my local junkyard and some of the prices are the same as new parts.. (ex. o2 sensor and fuel filter to name a couple)...

What is the difference between the 16144288 ecm and the 1227747, if anything?

Would aluminum or steel be best for the adapter plate? Any ideas where I can find a good scrap piece? I may check out the bin at our local recycle center... I may be able to cut my own adapter.. I have some tools...

Thanks for your help!

 

[76cj7chick]

First...Unless you use a Holley adapter plate too, that Howell adapter plate won't work. I tried that on mine and could never get it to seal and had vacuum leaks. I ending up making mine. $7.00 worth of scrap 1/2" aluminum plate, a drill press, taps and hand file. Took about an hour.

Second...Don't get to hung up on the Prom. The AMC 258 i6 / 4.2l and 4.3 are so close in size, factory fuel tables work real well unless you run amodified cam, high compression and headers. I haven't touched/reprogrammed mine. "Don't fix something that's working" Best advise I can give you about that is just make sure it comes out of a vehicle with an automatic and stay away from any with a 3 digit BCC which would be in 1987 vehicles. I'm actually using a 16144288 ECM BCC AUMH out of a 1990 G20 van

Oh by the way could you give me the measurements of the adapter plate? Also, do you think 1/2" thick is the best or thicker?

 

[jeepardy]

No real differences in the ECMs. I live in Michigan, home to both Howell and Affordable EFI. I think they have standing orders on ECM 1227747 at the junk yards for their inventory because I found it hard to find any.

If you end up making your own adapter, use aluminum. Easier to work with and keeps the TBI cooler without a phenolic separator. (heat sink) I woulda used 3/4" but none in the scrap bin.

Here are some pics and measurements of the adapter. They aren't mine and I can't remember what website I grabbed them off of, so no offense if they are someones here on the forum. I found it easier to just take both gaskets and laying them out on the block and used a sharpie to trace them out.

 

[76cj7chick]

No real differences in the ECMs. I live in Michigan, home to both Howell and Affordable EFI. I think they have standing orders on ECM 1227747 at the junk yards for their inventory because I found it hard to find any.

If you end up making your own adapter, use aluminum. Easier to work with and keeps the TBI cooler without a phenolic separator. (heat sink) I woulda used 3/4" but none in the scrap bin.

Here are some pics and measurements of the adapter. They aren't mine and I can't remember what website I grabbed them off of, so no offense if they are someones here on the forum. I found it easier to just take both gaskets and laying them out on the block and used a sharpie to trace them out.

WOW! That adapter plate is complex..

Well after a long time looking and looking for a deal for the Howell kit at UNDER $1000... I finally found one today listed.. :drool: I've already purchased some items like a reman gm tbi with intake- don't need the intake but was the only one who bid... a o2 sensor, fuel filter and aluminum plates to make my own... So, to get some money back I will be selling the items...

I appreciate all the help you guys offered. and will keep you all up to date on the howell efi conversion...

 

[Torxhead]

I would like to hear about how much fun you have when you put it together. It is quite an educational experience. One comment about the Howell system, They seem to be underwired, as they saved money by installing as small of a gauge of wire as they could get away with. From what I hear the Howell guy was the one who designed the fuel injections for GM.

 

[jb8376]

Check this out

Jeep / AMC 258 / 4.2 DIY GM 4.3 TBI Fuel Injection adapter system