Okay guys this is my last ditch idea for actual help. My gf bought a Jeep that has a 4.3 swapped into it with a hack job swap. Been trying to fix it but I have no idea with these engines and need some guidance. Is there a way to tell year? It has vortec on its valve covers. Also wiring, any idea because the harness has been spliced together with about 50 dead ended wires that I have began to fix but I’m not exactly sure how to supply power to the ecu. I’m wiring the lights, fuel, and fan up to switches but in general I just need some advice. I attached some photos of the engine and the crap wiring just to give you guys a laugh. Thank you for anything




Interior wiring

Mess of the interior wiring

The ecu that is in it with no information on it

 

You have a CPI engine for sure. Could be from a 92-95 truck. If I'm seeing the distributor correctly, it looks to be one with vertical towers off the cap which would make it an early 95 if it is one or earlier. Are there any numbers on the ECM? If there are, that could help narrow things down further.

As far as the wiring goes, I would get a hold of a set of factory service manuals for whatever year we can figure out for the engine. You could also look into an AllDataDIY.com subscription if electronic data works for you. It would likely be cheaper for AllData than to buy the FSM set.

 

Solid advice by swartlkk. For the service manuals the more important for the wiring is the Electrical & Diagnostic Manual but will probably also need the Service Manual as part of the electrical systems descriptions is in there as well. Both can be found around 150$.

The ECU seems strange to me, could be GM. The part number will have the answer.

And, yes, had a good laugh because of the wiring. A fire waiting to happen. Not so waterproof if you plan to use it offroad.
I like that engine bay light on the hood. Looks Blazer to me.

 

Yeah I’ve had all data before and it worked wonders on my old Monte Carlo. Thank you for at least giving me a timeframe cause that’s what’s been killing me. I thought it might have been newer since it has an electric shift transfer case but that wasn’t limiting the years. I took a picture of the computer and the eprom chip( or whatever it is called) inside to see if anyone can help on that side. Also got one of the distributer to help identify if possible.


Guy really helped me out and decided not to put any info on it.

 

The fact that it has an eeprom chip means it has to be the earlier OBD1 computer which is what I was thinking it was to begin with. The vertical towers on the distributor confirm that as well.

If the spreadsheet I have is correct, 9087 BMCF corresponds to a 1994 L35 (4.3L) from a 2wd S10 with a manual transmission.

 

Thank you so much for that. I’ve been trying to google it different ways to get any information. This guy really just threw some stuff together because the harness was from an auto with a 4l60 connector and he threw a 700r4 in there with a 233c transfer case. This at least let’s me get an idea of where to get a wiring diagram tho so thank you very much.

 

I do not envy you and the endeavor you have in front of you! You basically have to work through the wiring one wire at a time verifying what is there, where it goes, and if it is good.

It looks like the ECM is mounted inside the truck which is good as those early eeprom ECMs were not meant to be out in the elements!

 

Lucky you, the 1994 manual is available at rockauto even on CD-ROM for some 22$ plus shipping.

I'll go and order one the next time I need parts from them. And a discount code is available here in the Forum.