Please help me get her back on the road

[Flint70step]

I have TBI 350/4L80E that I pulled from a 95 GMC Vandura 3500.I am in the process of putting this combo in my 72 Burb.I have the complete wiring harness and ECM still attached to the motor/trans combo.This is where I need help.I can do all the mechanical stuff no problem.....the electrical is where I am going to be lost.Has anyone on this site done this swap before keeping the fuel injection and ele. controlled trans?If one of yall knows how to do this, or have done it, can yall please help me out.Is there a Faq thread for this?

[Flint70step]

Anyone gonna point me in the right direction?Once I get the wiring under control, it will be on the road in no time.I thought I would have 15-20 posts by now telling me how to get this done.Dont let me down yall

[70cst]

Bump for you...

[72freak]

I did the exact same thing in my 72 Suburban. I used the running gear out of an 89 Suburban. What helped me was I used the entire harness front to rear and only patched in the gauges. Now...with that said....Im pretty handy electrically.....and I WILL NEVER DO IT AGAIN!

I didnt have many problems but it took forever! I had the wiring diagram from the 89 and the 72 side by side and I sat ther and crossed everything over.

It ended up being about a day per circuit becuase i had to walk away after each one. If I were to ever try that again I woul;d save the hours and hours and find a pre-made harness for that application.

[Flint70step]

Originally Posted by 72freak

I did the exact same thing in my 72 Suburban. I used the running gear out of an 89 Suburban. What helped me was I used the entire harness front to rear and only patched in the gauges. Now...with that said....Im pretty handy electrically.....and I WILL NEVER DO IT AGAIN!

I didnt have many problems but it took forever! I had the wiring diagram from the 89 and the 72 side by side and I sat ther and crossed everything over.

It ended up being about a day per circuit becuase i had to walk away after each one. If I were to ever try that again I woul;d save the hours and hours and find a pre-made harness for that application.

I knew somebody would chime in.I'm going to have a lot of questions for you over the next month lol.Did you use the fuse box from the 89 or splice the harness into the 72 wiring to make it work?Since I have the van on hand I'm using all that I can from it.I'm using the fuel system from the van as well.Any help would be greatly appreciated.I had to widen the frame rails an inch on both sides for the van tank to fit.I'm gonna go mock it up this morning and then secure the fuel lines that I pilfered from the van.

[Flint70step]

Beautiful Burb by the way

[72freak]

Originally Posted by Flint70step

I knew somebody would chime in.I'm going to have a lot of questions for you over the next month lol.Did you use the fuse box from the 89 or splice the harness into the 72 wiring to make it work?Since I have the van on hand I'm using all that I can from it.I'm using the fuel system from the van as well.Any help would be greatly appreciated.I had to widen the frame rails an inch on both sides for the van tank to fit.I'm gonna go mock it up this morning and then secure the fuel lines that I pilfered from the van.

I used every piece of the 1989 harness. Lights, fuse box, EVERTING front to rear. I only cut off the ends for sockets or plugs, I used the stock 72 tank and sending unit and an aftermarker fuel pump that I hooked to the wires at the rear that were originally the rear power window. I had NO troubles at all except the gauges in the dash and I ended up using the stock 72 front and rear AC harness and splicing it in.

[Flint70step]

What did you end up doing for the gauges in the dash?There are a lot of wires I'm sure I wont be using in the Burb.How do I terminate these wires with out messing up the ecm?Do you have any pics?Do you still have the wire diagrams for both?Where did you fing the 89 wire diagram so I can find one for the van harness?I just got done pulling the under dash harness and fuse box from the van.72Freak,thanks for your help in advance

[MARKDTN]

I have not used a stock vehicle harness with an electronic transmission. My guess is though, that when you boil it all down, if you use the modern harness complete that you will really only hook up power and ground. All the VSS, temperature, throttle position, MAP sensor, etc is all self contained in the harness. Since it is 95, you are still OBD1 so you don’t have to worry about oxygen sensors, fuel tank pressure sensors, and the like. You can use “old” sending units to drive original gauges and leave all that alone. You can look at jagsthatrun.com for info on how to get a mechanical speedo output on an electronic trans-or just have your speedo converted to electronic.

If you try to use the van harness complete and replace the truck harness, it can probably be done. You will have to change ignition switch wiring, can probably use turn signal wiring, have to move hi-low headlight switch, have to heavily modify heater and/or A/C wiring, radio no big deal, fusebox hole is different, you will need to have your speedometer converted to electronic and ammeter converted to voltmeter (the original shunt ammeter won’t handle high amps), headlight switch wiring in cab is same, dome light easily integrated. I would integrate the taillight harnesses together. The engine compartment on the lighting side, I would splice the truck front to the van harness. The engine harness on engine side is OK. The rest of the swap is like any fuel injection/OD trans swap, finding a place for the ECM, fuel tank and lines, trans mount, driveshaft, etc.

Here is a post on a TPI swap, much of the basics are similar to a TBI swap.

http://67-72chevytrucks.com/vboard/s...=239354&page=2

[Flint70step]

Originally Posted by MARKDTN

I have not used a stock vehicle harness with an electronic transmission. My guess is though, that when you boil it all down, if you use the modern harness complete that you will really only hook up power and ground. All the VSS, temperature, throttle position, MAP sensor, etc is all self contained in the harness. Since it is 95, you are still OBD1 so you don’t have to worry about oxygen sensors, fuel tank pressure sensors, and the like. You can use “old” sending units to drive original gauges and leave all that alone. You can look at jagsthatrun.com for info on how to get a mechanical speedo output on an electronic trans-or just have your speedo converted to electronic.

If you try to use the van harness complete and replace the truck harness, it can probably be done. You will have to change ignition switch wiring, can probably use turn signal wiring, have to move hi-low headlight switch, have to heavily modify heater and/or A/C wiring, radio no big deal, fusebox hole is different, you will need to have your speedometer converted to electronic and ammeter converted to voltmeter (the original shunt ammeter won’t handle high amps), headlight switch wiring in cab is same, dome light easily integrated. I would integrate the taillight harnesses together. The engine compartment on the lighting side, I would splice the truck front to the van harness. The engine harness on engine side is OK. The rest of the swap is like any fuel injection/OD trans swap, finding a place for the ECM, fuel tank and lines, trans mount, driveshaft, etc.

Here is a post on a TPI swap, much of the basics are similar to a TBI swap.

http://67-72chevytrucks.com/vboard/s...=239354&page=2

Right on ,thanks for the info.I knew there had to be some people on this site that could help.I'll have her on the road soon

[Hart_Rod]

Save yourself some time and hassle and get this....

http://www.summitracing.com/parts/PRF-60101/

[Flint70step]

Originally Posted by Hart_Rod

Save yourself some time and hassle and get this....

http://www.summitracing.com/parts/PRF-60101/

I appreciate your post Hart Rod,but I'm trying to do this low buck and utilize what I already have.The FI harness you have linked,does it control the trans as well?

[Hart_Rod]

Originally Posted by Flint70step

I appreciate your post Hart Rod,but I'm trying to do this low buck and utilize what I already have.The FI harness you have linked,does it control the trans as well?

I understand where you're coming from, been there done that, . But the time you spend trying to figure it all out you could just work some extra overtime and come out with a nicer product. Good luck with whichever route you go. It does control the the transmission also:

http://www.painlessperformance.com/w...rchAll=Classic Cars

[Flint70step]

The harness you linked for me says its for 82-93.Trans:2004r,700r4 and other non-electronic.Do you know of one that would work with the 4L80E I have?The money does seem well worth avoiding frustrating days in the Texas heat.

[72freak]

Originally Posted by Hart_Rod

I understand where you're coming from, been there done that, . But the time you spend trying to figure it all out you could just work some extra overtime and come out with a nicer product. Good luck with whichever route you go. It does control the the transmission also:

http://www.painlessperformance.com/w...rchAll=Classic Cars

AGREED!!! I would NEVER do it again....I assure you the time is NOT worthit!

[MARKDTN]

Originally Posted by 72freak

AGREED!!! I would NEVER do it again....I assure you the time is NOT worthit!

To me this is a bit too harsh. I have done a number of FI swaps using stock harness, just never done one that controlled the transmission too or tried to use it to replace the stock harness. I'm willing to bet that if you took the whole harness and unwrapped it and just kept what was needed for the engine and transmission that you will end up with just power and grounds. I know this is the case on Ford stuff, and earler TBI van. I have a 3.1 Cavilier harness that I am going to modify if I ever do another TPI conversion. Just have to add 2 injector leads and move a few wires around from what I can see. If you are good with electrical stuff, I would see this as a challenge. If you do buy a harness, I would not buy a Painless. IMHO the fit and finish is less than adequate. I have used them for street rod type rewires and if you do your own wrapping and finishing they work fine, but they come to you with small nylon tie-wraps every few inches instead of loom. For a FI harness they also use smaller gauge wire than original. Just my .02

[fastwillie 696969]

i dont go near wiring without my fluke meter and test light with power and extra ground and jump wires and my buddy eric who is a genius at electrical

[Flint70step]

I'm gonna do some research and see what I come up with.If I can find an aftermarket harness that fits my app. and is reasonably priced I may go for it.Until then I'll be on the lookout on this thread to see what yall may come up with.I really do appreciate all the input and advice that yall take the time to give.Thanks and keep the info rollin.I cant wait to get my baby on the road

[MARKDTN]

Looks like you can buy a Howell harness for the TBI/4L80E trans for $400. See http://howellefi.com/gm-tbi-products...sses-only.html

p/n H9395 at the bottom of the page

They make a super quality harness and will work with you if you need custom lengths or want fans, etc. If you don't want to deal with the stock harness, then this is the direction I would go. I will concede that for $400 it may not be worth the hassle of taking a stock one apart.

[jasons]

Check out this TBI swap thread. http://67-72chevytrucks.com/vboard/s...d.php?t=317519

[Flint70step]

Originally Posted by MARKDTN

Looks like you can buy a Howell harness for the TBI/4L80E trans for $400. See http://howellefi.com/gm-tbi-products...sses-only.html

p/n H9395 at the bottom of the page

They make a super quality harness and will work with you if you need custom lengths or want fans, etc. If you don't want to deal with the stock harness, then this is the direction I would go. I will concede that for $400 it may not be worth the hassle of taking a stock one apart.

That looks like the Harness to get.I'm going to call them and talk to a tech to make sure it will meet all my needs.Nice and clean looking harness and I'll be ble to keep my Burb wiring alone for the most part.After looking at the threads that Jasons posted up for me and seeing all the hassle they went through with the stock harness.I will also concede that the 400 is worth the easy,nicely marked out,tidy harness install and not going insane in a spaghetti bowl of spliced, electrical taped wires.I'll make a post after I talk with a Howell tech.Thanks for all yalls help.I'll be making a build thread very soon.Thanks again

[Flint70step]

I spoke with a Howell tech this morning and I'm all smilesThis is definitely the way to go from what I've read.Thanks to all who took the time to post up this valuable information,I am truly grateful.I'm sure that stock harness would have fried my brain in no timeNow I just need to procure the funds for the harness.Time to sell off some partsThanks again for the helping hands,yall be good