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1991 V3500 tbi wiring harness

1-ton

1-ton

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I have a 1991 V3500 with a 350, 4L80E trans, and 205 transfer case, and I was wanting to replace the engine bay wiring harness. I have talked to the techs at Painless Wiring, but since they do make a TBI wiring harness specificly for my truck, they will not make any commitments or sugestions.

With this "rare bird" of a truck I am on my own to build one. Most of the aftermarket TBI wiring harnesess look like the ECM engine control input connections are the same as mine. The question is the 4L80E/ECM connector itself is what they do not supply, or the 4L80E transmission harness. Most of of the "pig tail" connectors for this truck are available at parts stores (even the transmission ones), but no complete harness is made for it. Any suggestions on this situiation?
 
could you use a harness from a non Vortec 2wd application like a Van or other TBI type vehicle with a 4L80E and combine?
 
How much work are you willing to do?

I would assume that if you spend some time researching, you can get all the terminals necessary. Normally the connectors are pretty easy to get new or used, the terminals are the harder to figure out.

Then buy all the proper wire you need.

I know the 4L80E apps used a PCM vs ECM in the other trucks, which got the '747 ECM, so I don't know if the terminals and connectors are the same between the two, or specific to that PCM.
 
Greg Ducato said:
could you use a harness from a non Vortec 2wd application like a Van or other TBI type vehicle with a 4L80E and combine?
Click to expand...

I got the impression from the Painless company that no TBI wiring harness for a 4L80E equiped vehicle was specificly available. Would you happen to know where something like this was available?
 
dyeager535 said:
How much work are you willing to do?

I would assume that if you spend some time researching, you can get all the terminals necessary. Normally the connectors are pretty easy to get new or used, the terminals are the harder to figure out.

Then buy all the proper wire you need.

I know the 4L80E apps used a PCM vs ECM in the other trucks, which got the '747 ECM, so I don't know if the terminals and connectors are the same between the two, or specific to that PCM.
Click to expand...

This PCM is somthing I need to investigate further. I have taken almost this entire truck apart at one time or another, and I am familiar with most all of it, but I have never gotten into the kick panel too get a good look at the PCM module. It sucks having build this harness myself from bits and pieces of available aftermarket wiring harnesess, pigtails, and raw wiring. But having a road worthy 1991 V3500 crew cab on the road is something you don't see every day any more.

Truck_Desert_3.jpg
 
I don't know of any new harnesses like this, just saying maybe a used harness could be secured and used for bits and pieces. I have some of the harness from a one ton Van with TBI 454 and 4L80E that I have rat holed somewhere, if you can use it then it is yours just send me a shipping address and give me a little time to dig it out.
 
Greg Ducato said:
I don't know of any new harnesses like this, just saying maybe a used harness could be secured and used for bits and pieces. I have some of the harness from a one ton Van with TBI 454 and 4L80E that I have rat holed somewhere, if you can use it then it is yours just send me a shipping address and give me a little time to dig it out.
Click to expand...

Thanks for the offer, but am looking for all brand new stuff. My wiring harness still works, but it is getting dry rotted out, and all the plastic connectors are cracking when when trying to remove them. More old stuff will do the same thing. The PCM connector is where I have to be careful. If this is not available anymore, I do not want to put my hands on it, and crack it.
 
PCM should be behind the glove box, no?

PCM number should be pretty easy to find (its on the case of the PCM in any case) once you get that shouldn't be too hard to find what, if any, ECM's/PCM's the terminals and connectors cross with. Then a matter of buying the right pieces.

I use Mouser pretty much exclusively. Takes some time to find things there unless you have the actual part number, but their prices are so much cheaper I normally buy a bunch of spares just in case.

I found ebay was a pretty good place to buy the assorted colored wires, some of the color combinations GM used are somewhat hard to find. Realistically, no reason you couldn't use proper rated/gauge wire of any color you like, since all the terminals are numbered/labeled on the connector, diagnosis can be done that way, vs. color.
 
dyeager535 said:
PCM should be behind the glove box, no?

PCM number should be pretty easy to find (its on the case of the PCM in any case) once you get that shouldn't be too hard to find what, if any, ECM's/PCM's the terminals and connectors cross with. Then a matter of buying the right pieces.

I use Mouser pretty much exclusively. Takes some time to find things there unless you have the actual part number, but their prices are so much cheaper I normally buy a bunch of spares just in case.

I found ebay was a pretty good place to buy the assorted colored wires, some of the color combinations GM used are somewhat hard to find. Realistically, no reason you couldn't use proper rated/gauge wire of any color you like, since all the terminals are numbered/labeled on the connector, diagnosis can be done that way, vs. color.
Click to expand...

Yes, it probobly is behind the glove. You probobly know better than me. I was just assuming because the kick panel was where American cars used to locate them in the early days. I went to this "Mouser Electronics", and when I found an Delphi 48-pin connector, the minimum purchace quanity was 38,000. These guys must be wholesalers. If the PCM/ECM connector and wire harness is good on my truck, I am just going to have to put in the tedius work of piecing this thing together myself.
 
The ECM is definitely behind the glove box on that truck.
 
dyeager535 said:
Some of the stuff is in large quantity, but trust me, it's where I get the majority of my stuff and the most I've probably ever purchased of anything is 50. I've never bought weatherpacks or metripack connectors in quantities over 10ea.

It's a 48-pin connector? Male or female? Any of these? Plenty with minimum qty 1. http://www.mouser.com/Connectors/Automotive-Connectors/_/N-1ehb5?P=1z0wx1l&Keyword=delphi&FS=True
Click to expand...

It is a female. The link you posted are the ones I was looking at. I am only guessing that these are correct.

After doing some more research on the internet, I have found some good imiges of my ECM/PCM (ECM part #16147060) connectors. They are definitly different from the after market harnesess available, so I am going to have to cut the wires down a foot or so from the EPM/ECM connectors, and get all the pigtail conectors for my truck, and some rolls of the correct wire (gauge), and wire this whole thing together myself.
 
What about purchasing the Painless harness and adding the Trans leg to it and changing PCM plugs if needed. At least most of the work would be done. Adding the trans leg would be easier than custom making an entire harness. IIRC painless sells most stock GM wire colors in 10ft +/- sections for adding trans stuff.
 
I currently have 2 of these trucks & just recently sold my my 3rd one minus the trans/tcase & wiring harness :D.
Its not that hard to make up your own, especially if you already have one to go by.
Ive installed painless harnesses in a couple trucks (been more than a few years back) & thought there quality totally SUCKED.
Unless there products have improved greatly, I would build my own.

I'm in the process right now of finishing up a 96 L31/4L80/205 build in an 86 cucv. I had originally planned on the tbi/4L80 swap into the cucv but came across this low mileage 96 that was complete, wrecked & CHEAP.
So the plans changed.

I forgot what my point was :doah:.
Do you plan to stay tbi forever ?

Just buy the connectors & build your own.
One wire at a time.
 
1-ton said:
so I am going to have to cut the wires down a foot or so from the EPM/ECM connectors, and get all the pigtail conectors for my truck
Click to expand...

If you are going to wire it yourself, I'd strongly advocate to not get pigtails. They are normally exceedingly expensive. FAR cheaper to get more wire and the terminals and crimp the terminals to the wire, than to buy pigtails, wire, then crimp and/or solder the pigtails to the wires, use shrink tube, etc. But it is, of course, up to you. I personally find that crimping terminals is a LOT easier than crimping wires, and ends up cleaner.

If I had that PCM and the connectors in front of me, I'd probably have more luck figuring out what it is. You said 48 pin, but unless I'm mistaken, the trans connector is less than that (and same between 4L60E and 80E) and the PCM connectors are probably not 48 pins, although I can't find a definite pic of the PCM or connector. Apparently they are color coded though, any of these seem right? http://www.mouser.com/Connectors/Au...z0x3meZ1yzmtn7Z1z0yy6b&Keyword=delphi&FS=True Of course, out of stock, but knowing what series they are will get you the right terminals, seals, plugs, etc.

Personally I've never had any issues with the '87+ connectors to the ECM's being brittle or anything, if the wiring needs replaced, de-pin, make the new terminal/wire combos, and re-pin the connector.

Oh, and tom76 posted up what are apparently the trans-side components: http://www.thirdgen.org/forums/diy-prom/582495-source-4l60e-4l80e-connectors.html
 
POORBOYK5 said:
What about purchasing the Painless harness and adding the Trans leg to it and changing PCM plugs if needed. At least most of the work would be done. Adding the trans leg would be easier than custom making an entire harness. IIRC painless sells most stock GM wire colors in 10ft +/- sections for adding trans stuff.
Click to expand...

The painless harness runs the entire length from the ECM connectors to the engine control input connectors. The wire harness Painless sells has connectors for the 700R-trans ECM, which has different connectors than my 4L80E ECM has.
 
I forgot what my point was :doah:.
Do you plan to stay tbi forever ?
Click to expand...

Yes, because I need to keep it emission compliant. It would be nice if I could do any modification I wanted, such as Big Block, port injection, and stand alone computers for my engine and trans.
 
dyeager535 said:
If you are going to wire it yourself, I'd strongly advocate to not get pigtails. They are normally exceedingly expensive. FAR cheaper to get more wire and the terminals and crimp the terminals to the wire, than to buy pigtails, wire, then crimp and/or solder the pigtails to the wires, use shrink tube, etc. But it is, of course, up to you. I personally find that crimping terminals is a LOT easier than crimping wires, and ends up cleaner.

If I had that PCM and the connectors in front of me, I'd probably have more luck figuring out what it is. You said 48 pin, but unless I'm mistaken, the trans connector is less than that (and same between 4L60E and 80E) and the PCM connectors are probably not 48 pins, although I can't find a definite pic of the PCM or connector. Apparently they are color coded though, any of these seem right? http://www.mouser.com/Connectors/Au...z0x3meZ1yzmtn7Z1z0yy6b&Keyword=delphi&FS=True Of course, out of stock, but knowing what series they are will get you the right terminals, seals, plugs, etc.

Personally I've never had any issues with the '87+ connectors to the ECM's being brittle or anything, if the wiring needs replaced, de-pin, make the new terminal/wire combos, and re-pin the connector.

Oh, and tom76 posted up what are apparently the trans-side components: http://www.thirdgen.org/forums/diy-prom/582495-source-4l60e-4l80e-connectors.html
Click to expand...

When I say "pigtails" I mean what most parts stores call a connector. It is the factory weather connector...plus the length of wire coming out of it to crimp the wire to the wire run.

There is actualy 2-connectors to my ECM/PCM. One is a 48-pin for the trans control management, and the other is a 56-pin for engine control management. What I want to do is trace and replace every wire run from the 48-pin connector to my trans connectors, and then do the same for the 56-pin connector to my engine controls. Also, not every pin in the PCM/ECM connectors are being used. My truck only has a total of about 12 ECM/PCM inputs between the engine and trans, wich have a total of one-to-two wires coming from them. This would total a run of roughly 30 wire input runs to my ECM/PCM
 
I figured that is what you meant. Last time I looked at pigtails, the pigtail itself was more expensive than the sensor lol. I used to splice and solder/crimp every cut wire I had, or when I needed to add something, now I just crimp a new terminal to the wire and it's done. Really not any better, but when talking multiple wires, unless you cut each one to a different length, you end up with a knot a few inches from the connector.

I'm curious now, this is not how yours is setup? http://www.ebay.com/itm/CHEVY-GMC-C...0-HEAVY-DUTY-ECM-WIRING-PIGTAIL-/390605663310 24 and and 32 pin if my eyes don't deceive me.

I'm not certain they are correct, but the listings here if sorted by series 100 or micropack 100, seem to look like what is shown in the ebay link. Would really need to dig into the drawing to make sure, if you are lucky the PN might be on the connector body itself. http://www.mouser.com/Connectors/Automotive-Connectors/_/N-1ehb5?Keyword=delphi&Ns=Gender%7c1&No=50&FS=True&P=1z0x3me
 
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