First, I want to thank all of the folks here that helped me with schematics and with my thought process in figuring out how exactly to accomplish a running vehicle through sorting and cleaning up a "rats nest" of a factory harness....It was here that I gained the courage to believe that moving a factory GM harness to a vehicle could even work....

It's been a couple of years journey building my van to incorporate simple 90s era GM TBI...
I decided to use a TBI305/700r4/323posi from a crashed 91 wagon because I also drive one as a daily and have several good wiring schematics and the Factory Service Manual (FSM)....



I was going to use a TBI454/4L80e from a 95 burb, but it just didn't look like it would fit comfortably when I started measuring....
I accepted the challenge of massaging the factory TBI harness to fit the vehicle, keeping all of the sensor utilities that I thought might matter to the ECM and even putting toggle switches on a few unused wires in case they matter.....
So my question today is about Timing.....
I timed it at 0 degrees with a timing light with the "base timing" link unplugged as the FSM says to do it....This resulted in 17 degrees while idling at 500rpm with the connector plugged back in....
This van runs freakin AWESOME!....It idles good, no dead spots, no misfires, no gasping of the IAC......
The problem I'm having is that within about 10 minutes of heading out, the temp creeps past 230 degrees and was past 250 yesterday after about 15 minutes out....
I set it up with an ebay aluminum radiator slung pretty low with an electric fan from an 84 z28 and custom shroud.....It has a thermostat housing radiator cap and I also have a factory 7 blade fan and clutch moving air through.....I have the heater hose looped (no heater) and the 700r4 is cooled by the radiator only.....And I'm running without a thermostat...
I'm going to install one of my custom locked fan clutches and maybe put a separate cooler for the trans.... Also some type of large heater core with a fan on it as an additional radiator, but I want to start simple (and cheap)

Is there any point in pulling back on the timing, or is the ECM just going to override any adjustment I make physically?

I think ultimately, adding cooling capacity and air movement is going to be the answer, but if I can solve the issue more simply, I'd be thrilled!

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