Engine harness question

[kcorleyap]

So, I have a 89 TBI that years ago put a 305 in and lifted. Van has been great but the years have taken there toll. The body is shot and not worth the time the fix. I picked up a 94 cargo that had a "Z" VIN with a much better body. Since It was a "Z" VIN I thought this should be pretty straight forward.....well.....now that I have the 305 installed I have noticed that there is a big diffrence between the harness contections. The 89 engine harness has one large connection and the 94 engine harness has several smaller connections. The number of wires are differnet also. The ECM connectios are different too. The 89 ECM was out of a truck and was set up perfect for my install with a 700R4 and correct gear ratio. The 94 cargo was equiped with what looks like a 4L60 since there was no T.V. cable on it just a electical connector. Can anyone shed some light on this for me? Is it possible to make this work or have just spent time on another of my many deadend projects. Thanks, J.R.

[1Gary]

One of the tools you should have in hand is the factory service manuals electrical supplements for both the van your working on and for the donor engine your swapping.Those can be bought on Ebay.

[LiftedAWDAstro]

Any chance you can swap the correct working harness from the old 89 into the new 94? Since you know the old one worked good, it would be less painful than trying to splice it in.

[Cobra]

the transmission will be a problem though unless he swapped the 700r4 and the linkages as well

[kcorleyap]

Here is what I'm thinking. Running the entire harness that came with the 94 cargo so I can keep the gages working with the sending units and changing the engine to a HEI distributor and going carburated. Any thoughts?

[LiftedAWDAstro]

Are you running the 700R4 or 4L60E? If you run the 4L60E, you need to have the engine talking to the ECM so the ECM can control the tranny. If you are running the 700R4, go with a carb, HEI dizzy and keep the stock gauges and harness like you said.

[1Gary]

Over the "YRS"<ask anyone how long I have been planning my swap>I have found going back to a carb is a kin to moving back to the stone age.The advantages of any EFI far,far,out wt any carb.In fact we had a member that went with a carb V8,"Chops",that said how much he regretted it.Time is long passed that all of us learn these EFI systems because certainly that is the future.Upgrade the wiring harness to the newer style and once done stand back proud of what you got done.Use the very cheap to be had on Ebay factory service manuals.My twenty dollars worth opinion discounted to this home base to two cents.

[Mr_Roboto]

Take the 1994 ECU and swap the chip for a 305 truck with the same ECU. After this, pull the pod off your 305's TBI and swap it on to this one. Should let you swap it in. Oh, you should get a knock sensor for this year they did change and yours is not compatible. Happy swapping!

[kcorleyap]

Alll great suggustions. I have spent the last two nights trying make a decision on what route to go. I hear ya 1Gary, its hard to beat the EFI. This 305 ran great when it was in my 89. I loved just touching the key and hearing her run. I'm going to look into the service manual you recommended on ebay, are these better than the wiring diagrams in my Haynes manual? The Haynes wiring diagram is a bit of a joke. My manual only shows the 94 with SFI and not even an option of TBI so trying figure out what wires have to be spliced in is difficult at best. I have started pulling the harness out of 89 and I am hoping I can splice it into the 94. Do you have any words of wisdom on removing the harness? I currnely have the fuse box pulled back from the firewall and seperated. It appears that there is about 40 some wires running under the instrument panel. Is this a good place to start cutting? My final goal is to have the 89 TBI 305 and 700R4 running off its original harness and ECU and still retain the gauges of the 94. Thanks for the information and I am open to any suggestions or recommendations on accomplishing this. Thanks to all.
J.R.

[1Gary]

Alll great suggustions. I have spent the last two nights trying make a decision on what route to go. I hear ya 1Gary, its hard to beat the EFI. This 305 ran great when it was in my 89. I loved just touching the key and hearing her run. I'm going to look into the service manual you recommended on ebay, are these better than the wiring diagrams in my Haynes manual? The Haynes wiring diagram is a bit of a joke. My manual only shows the 94 with SFI and not even an option of TBI so trying figure out what wires have to be spliced in is difficult at best. I have started pulling the harness out of 89 and I am hoping I can splice it into the 94. Do you have any words of wisdom on removing the harness? I currnely have the fuse box pulled back from the firewall and seperated. It appears that there is about 40 some wires running under the instrument panel. Is this a good place to start cutting? My final goal is to have the 89 TBI 305 and 700R4 running off its original harness and ECU and still retain the gauges of the 94. Thanks for the information and I am open to any suggestions or recommendations on accomplishing this. Thanks to all.
J.R.

J.R.-do not cut anything before you have the electrical service manuals.I am saying the factory manuals for the electrical system and not just the factory service manuals.And yes,they are tons ahead of a dumb bass Haynes.

[kcorleyap]

Thanks 1Gary. I found a 88 electrical diagnosis service manual supplement in a stack of old books. Great info. Now all I need is one for the 94 and I'm on my way!

[kcorleyap]

After following the advice of 1Gary and waiting for my electircal manuals before cutting everything on my harness, all seems to have gone well. 89 V8 runs in a 94 cargo. A few wires were not in the corrrect location according to the wire schematic, but all has been corrected, even my SES light and port work! Engine runs great and once the brake lines are bled I should be able to drive it down the road.

[1Gary]

Good to hear you got it worked out.It's really nice to see positive feedback.Thanks for that.That FSM will be a great ref for the whole time you have your van.

Enjoy the ride and maybe some pics would be good to if you can.