Matt, I would like to hear what you would do differently. So far, as mines not running yet, here's what I did. Instead of paying Painless Wiring, or some other harness manufacturer, 3 or 4 hundred bucks of a harness, I built my own. I bought a reconditioned ECU from EBAY, got the connectors from a junk yard, and attached the wires to it. I researched lots of sites and found all the schematics I could to do this. Since I have a manual trans., I won't need all the wires for an electronic transmission. How did you do yours, and if you already have it running, is running okay. I hope to have mine running in a few months, and would like to get your input as to what you learned and would do different next time, as I hope to build an old CJ5, with a SBC and might do the same thing with it. Thx a lot for any input on what you leaned,
I approached my project with a similar mindset. I wanted to do the conversion with my 16 year old son using as much U-pull parts. Our donor vehicle was a 1991 Chevy 1500. Our truck is a 78k15 with Gen 1 SBC and TH350. I leaned heavily on gearheadefi.com for conversion threads and schematics. There's some great guys over there and I highly encourage you to check them out if you haven't already. We salvaged the complete wiring harness, TBI, ECM, distributor, and many of the sensors required for the conversion for $120. I thought we were off to a great start.
I had many hours in cleaning up the old harness and eliminating un-needed wires. Since it was my first time I went very slowly and double/triple checked everything. My first mistake was when buying the check engine dummy light I didn't notice that it was a flashing light. Be sure to get a solid pulse light, not a flashing light. Seems simple enough, but I got caught on it. So after my initial install and fire up I got this pulsing CEL when key on, that would subsequently turn off when the engine started. The engine didn't run particularly well and had a bad stumble on acceleration. So I took that to mean the ECM went into limp mode. Long story short, I assumed I had an ECM or harness problem and out of frustration bought another ECM and ordered a complete harness from AFI. The AFI harness came with a check engine light, and it was at this point I realized my mistake. Changed the CEL out and whalaa, no blinking CEL. We got everything buttoned up and timing set correctly and it runs great.
If I had to do it over again, I would have bought the AFI harness (about $275) from the get go and salvaged the rest of the parts, making this conversion easily under $500. It was a fun challenge to do it myself, but you can't beat the pre-made harnesses for fit, finish, and functionality. My time in salvaging and dissecting a stock harness is definitely worth the money spent on an AFI harness. The harness also includes excellent written instructions. Plus, their service is excellent!
Also, Dave W over at gearhead is really great at tuning chips if you don't want to data log and burn your own chips. For me, this is a simple stock conversion that won't have any need for chip modifications and so I went with a third party tuned chip (and eliminated emissions crap at the same time)
The other thing I would recommend is make sure your base mechanical timing is as close as possible when dropping in the new dizzy. Somehow mine was off quite a bit and it made for another challenge trying to diagnose the initial startup.
Also, I'm not sure what you did for your fuel tank/pump, but ours was shot so I just upgraded the tank to an 87 square body tank with the stock pump/sending unit, as this tank has baffles and the pump correct pressure for TBI.
good luck, hope your project goes well!
