97 GST ECU from MAF issue

[greydelta38]

Hey guys,

I removed SAFC2 from my ECU in a 1997 GST and accidentally split the pinout 90 which is the 'volume air sensor' I think. I'm guessing that is related to the MAF. Anyway, I took another large guage wire and attached the 2 split ends with it.

I assumed it would work fine, the connections looked good. But I started the motor and it runs awful, and won't rev over 1500 which is no doubt a maf issue.

I want to get some ideas as to what the issue may be before I dive into it and start replacing wires and sensors. I'm guessing I just didn't use the right wire or get a good connection on it? It's the blue wire with yellow stripe going into the top connector on the ecu.

Thanks

 

[greydelta38]

discovered only 1 o2 sensor is connected, could that cause the car not to start? I checked the fuel pump and fuel system, it all checks out.

 

[greydelta38]

bump, someone reply

 

[Dsmkauai]

Did you solder the wires together or use a butt connector? Are you sure the maf is plugged in all the way? You may need to reset the ecu (disconnect battery for a few minutes) then take the car for a drive so it can relearn what's going on. You had the safc in place fooling the ecu pretty much so now it's gone and the ecu might be alittle confused. May need alittle drive time to smooth out again, just go for a nice cruise and don't really get on it to much. So wait your car won't start now? How come you removed the safc? And you want to sell it? Let me know

 

[greydelta38]

Did you solder the wires together or use a butt connector? Are you sure the maf is plugged in all the way? You may need to reset the ecu (disconnect battery for a few minutes) then take the car for a drive so it can relearn what's going on. You had the safc in place fooling the ecu pretty much so now it's gone and the ecu might be alittle confused. May need alittle drive time to smooth out again, just go for a nice cruise and don't really get on it to much. So wait your car won't start now? How come you removed the safc? And you want to sell it? Let me know

Yes, car is already gone, but it's my girlfriend's now. She wanted a cheap, stock dsm. She didn't like the SAFC unit on it, so I took it off, along with my wideband. The car ran like crap for a few days, so I just assumed it was MAF readjusting. I drove it around the neighborhood, real easy, waiting for it to adjust. But a few days later, it wouldn't start at all. Crank, spark, but no fire.

I wonder if something in my fuel system isn't screwed up. I have a spare Walbro, so I'll install it and see if the stock pump didn't go out; unlikely, but worth a shot.

I just hard wired the MAF sensor wire back connecting, no solder.

 

[Dsmkauai]

Ya I would solder that connection or any that's that important. Those crimp connectors don't always work the best and can wiggle loose easy. I would double check that and make sure you wired them right. If it ran good before you removed the safc then you must have missed something! What are the no start conditions? Does it crank? Does the battery have voltage?

 

[greydelta38]

Ya I would solder that connection or any that's that important. Those crimp connectors don't always work the best and can wiggle loose easy. I would double check that and make sure you wired them right. If it ran good before you removed the safc then you must have missed something! What are the no start conditions? Does it crank? Does the battery have voltage?

Yes it cranks. Yes the battery has voltage, it sparks fine.

On the ecu, the guage wire I used is bigger than the original wire. the original blue and yellow wire wouldn't reach from the harness to the pinout, so I put a new wire in. Is it possible the new wire is too big to carry the correct current from the MAF?

 

[bryanwheat]

Yes it cranks. Yes the battery has voltage, it sparks fine.

On the ecu, the guage wire I used is bigger than the original wire. the original blue and yellow wire wouldn't reach from the harness to the pinout, so I put a new wire in. Is it possible the new wire is too big to carry the correct current from the MAF?

You can use what ever size wire you want. It still sounds like something isn't quite right with how you did it. Do you have a scanner or anything to moniter the ecu with. This would be very easy to diagnose with a live feed scanner. Hook it up, start the car and watch for maf data.

 

[Dsmkauai]

Where did you run the wire through? Maybe it got snagged or cut open.

 

[97_4g63t]

Which wire? Check this with your wiring. 2G Turbo ECU Pinouts
what kind of upgrades are on the car? Stock injectors? The car ran fine before this? Any more splices?

 

[greydelta38]

Which wire? Check this with your wiring. 2G Turbo ECU Pinouts
what kind of upgrades are on the car? Stock injectors? The car ran fine before this? Any more splices?

I said in OP, pinout is "90- volume air sensor". Stock injectors. I removed safc2 and it ran like sh**- to be expected after a large MAF read change. I gave it a few days for maf to adjust, and then all of a sudden the car wouldn't start. Full gas tank.

Where did you run the wire through? Maybe it got snagged or cut open.

The wire was spliced very close to the ecu, so I didn't actually split the harness. As far as I can tell all of the wires are good to go.

You can use what ever size wire you want. It still sounds like something isn't quite right with how you did it. Do you have a scanner or anything to moniter the ecu with. This would be very easy to diagnose with a live feed scanner. Hook it up, start the car and watch for maf data.

I'll have to get a live scanner, all I have is a code reader. The car isn't throwing any codes though.

Is it possible that somehow a fuel system part HAPPENED to go out when I removed safc, and now it's not getting fuel?