Condensing 1g Harness

[4g63Powered]

Alright, I'm at the point where I am wiring up the car. Since the chassis is a 90, but the engine, ECU, and cluster are out of a 91, I decided to just pull the whole engine harness out and re-work it. I de-pinned the three plugs into the ECU as well as the one body interface harness. Now I have a few questions.

1.) Any plug that is labeled as "xxxx test" I have removed. I also deleted the "ignition timing adjustment connector." Any harm done by removing them?

2.) The car will be running DSMLink with a GM MAF. I want to hardwire the MAF straight into the car. Has this been done before? I know ECMLink sells an adaptor harness but I'd rather have a cleaner install than that.

3.) The resistor pack for the injectors... forgive me but it's been forever. What does it look like?

4.) All the "hot" red wires are essentially identical, correct? Or are some 12V and some 5V? The factory harness is confusingly connected, to say the least.

Thanks,
Brad

 

[92AWDHX40]

I run link to the maft but i got the cable its more than a harness connector. ECMTuning, Inc. i wouldnt cut it just run it to the connector to the chasis thats easy, still cleans up the bay.

 

[steve]

1.) Any plug that is labeled as "xxxx test" I have removed. I also deleted the "ignition timing adjustment connector." Any harm done by removing them?

Sounds like there should be a list attached but I don't see it.

2.) The car will be running DSMLink with a GM MAF. I want to hardwire the MAF straight into the car. Has this been done before? I know ECMLink sells an adaptor harness but I'd rather have a cleaner install than that.

There is no cleaner way that the ECMTuning cable. There is special circuitry in it to interface the GM MAF. You can't just wire it to the ECU.

3.) The resistor pack for the injectors... forgive me but it's been forever. What does it look like?

Silver box bolted to the firewall behind the intake manifold.

4.) All the "hot" red wires are essentially identical, correct? Or are some 12V and some 5V? The factory harness is confusingly connected, to say the least.

Most of the red wires are 12v MPI circuit power but I don't have my 90 FSM handy so I can't be sure I didn't miss something. The +5v are all sensor power and usually something like green/red. The 12v for the ignition circuit is strangely black/white. The grounds typically are all black. You have to be careful with the white wire and very careful with the shielded ones.

There are some things not shown in the FSM. It's doesn't usually have pin 13 on the ECU connected to the fuel pump power from the MPI relay as is required.

 

[4g63Powered]

Sounds like there should be a list attached but I don't see it.

-Wastegate solenoid valve
-Ignition timing adjustment connector
-Fuel pump check connector
-Dual pressure switch
-Brake fluid level sensor
-Engine speed adjustment connector
-Anything associated with the AC system and emissions systems is removed/getting removed as well

I might have missed a couple as well. My goal is to get it as lean as possible.

There is no cleaner way that the ECMTuning cable. There is special circuitry in it to interface the GM MAF. You can't just wire it to the ECU.

I had a thought that this might be the case, but it never hurts to ask.

Silver box bolted to the firewall behind the intake manifold.

Awesome. Thanks

Most of the red wires are 12v MPI circuit power but I don't have my 90 FSM handy so I can't be sure I didn't miss something. The +5v are all sensor power and usually something like green/red. The 12v for the ignition circuit is strangely black/white. The grounds typically are all black. You have to be careful with the white wire and very careful with the shielded ones.

There are some things not shown in the FSM. It's doesn't usually have pin 13 on the ECU connected to the fuel pump power from the MPI relay as is required.

Care to expound on the comment on shielded wires? The only two I found were the O2 and the knock sensor. Since I'll be running an UEGO with narrowband simulation, I removed the O2 sensor. The knock sensor line is untouched but very long; it is one I would like to shorten.

I found the link to the FSM's this weekend, but I haven't been able to digest those monsters yet.