1989 chevy 350 tbi transplant

[dave w]

The neutral safty switch and vss are connected together as it says to do in the painless instructions. orang/back and the black and white.

That would be correct, the orange / black (neutral / park) wire spliced with the black / white wire of the Painless Harness.

Not to cause confusion, the neutral / park switch IS NOT a neutral safety switch.

dave w

[Six_Shooter]

I would connect the Neutral/park input to actually detect when it is and is not in park, sometimes telling the ECM it is in park all the time will cause driveability issues.

I would also run a VSS. On EVERY swap I have done, where either the VSS wasn't installed or working correctly, then added or fixed the VSS, the engine ran MUCH better with zero other changes.

[EagleMark]

I've done a lot of swaps without VSS and later added them, was always an improvement even in the 1227747 $42. Hardest one I ever got to drive well without and still without is my sons IH 16197427 $0E TBI conversion. One day I will add it and see again the improvements...

[jameslleary]

First thing i noticed is that his injector plugs are swapped, compaired to how TBI comes from the factory. The green and white plug is supposed to be on the drivers side, and the red and blue on the pass side. Also, did you check the base timing the next day, with the wire unplugged, was it still at 0*?

Oh yeah, and his throttle rod is hooked to the cruise control pin...might bend or break under WOT.

[62burbdream]

I have a new problem. Whats the deal when you crank over the engine and it does turn over but no fuel coming out the injectors?When I release the the key from starting it it spurts out a tiny amount of fuel after cranking it? I poured some gas in ther throttle body and it started up and ran the engine and fuel was streaming fine through the injectors? I shut off and tried starting it again and same thing. No fuel to the injectors!? A fuel relay? Or could it be the ecm? Is the ecm giving me all my other problems? I'm really starting to think a a carb engine would be nice right about now:(

[dave w]

I've experienced an ECM that had the exact same problem you're having. I'd replace the ECM with a known good ECM first, then spend money for a remanufactured ECM.

dave w

[62burbdream]

What ECM should I look for? I have a th400 tranny. Does it matter which one for the ECM's that control the 4l60e's? Would that matter?

[JeepsAndGuns]

You sure its not just the fuel pump relay?

[EagleMark]

You could force the fuel pump relay on, there is usually a red wire hanging from them for this and priming.

Weird how it runs with gas and keeps going? Could be an ignition issue as if the ECM does not get reference pulse it does not fire fuel.

[Six_Shooter]

I would look at the fuel pump system. The relay and the OPSU (Oil Pressure Sending Unit).

If the relay fails, or the ECM does not send the prime signal, the OPSU will turn on the pump, once oil pressure is made. This is likely why it will continue to run after manually priming the engine with fuel. Your cranking speed may be too low or too thin of an oil to have the oil pressure build while cranking.

In my experience it's usually the simple solution.

[dave w]

What ECM should I look for? I have a th400 tranny. Does it matter which one for the ECM's that control the 4l60e's? Would that matter?

I'd try the same computer part number that's currently in the truck, most likely 1227747 or maybe 1228747? It's not very likely the 1227747 / 1228747 ECM connector plugs will fit a computer that is supposed to be used with a 4L60E.

dave w

[EagleMark]

I would look at the fuel pump system. The relay and the OPSU (Oil Pressure Sending Unit).

If the relay fails, or the ECM does not send the prime signal, the OPSU will turn on the pump, once oil pressure is made. This is likely why it will continue to run after manually priming the engine with fuel. Your cranking speed may be too low or too thin of an oil to have the oil pressure build while cranking.

In my experience it's usually the simple solution.

I think he's right...

[dave w]

I would look at the fuel pump system. The relay and the OPSU (Oil Pressure Sending Unit).

If the relay fails, or the ECM does not send the prime signal, the OPSU will turn on the pump, once oil pressure is made. This is likely why it will continue to run after manually priming the engine with fuel. Your cranking speed may be too low or too thin of an oil to have the oil pressure build while cranking.

In my experience it's usually the simple solution.

Unplug the OPS and try the fuel poured into the TBI method again, if the engine only runs a few seconds with the OPS unplugged then the OPS was sending voltage to the fuel pump.

dave w

[62burbdream]

Thanks for the input everybody! I really appreciate all the advive/opinions. I'll fiddle around with the fuel relay then the OPS. If that fails will look into a new or used ECM. My sneaking suspicion is that the ECM might have taken a crap.

[Six_Shooter]

What makes you think there is a problem with the ECM? In my experience ECMs rarely "go bad" without doing something stupid, like reverse voltage connection, or submerging in water, etc.

Fuel pump relays and OPSUs on the other hand are common to go bad.