What would not switching pins 6 and 14 cause the motor to do? I have 2 ecu's for my car one is a 90 ecu and one is a 91 ecu. How can i tell the diffrence between them?

One is the signal from the IPS to the ECU telling it that the throttle is closed so it should manage the idle speed or perform dash pot emulation. The other signal is from the ECU to the MAF to reset the airflow counting circuit. These signals run to different pins on the ECU connector between the 90 and 91+ 1G ECUs.

The ECU part number, if correct for what's inside, would indicated which is which. Checking the circuit board is the only way is the ECU's have been molested. The 90 ECU will have three vertical circuit boards near the capacitors in the center where the 91+ ECUs have only two.

These are the 2 boards. I dont see a diffrence really. These are my issues with the ecu. The one will turn fuel pump on and off with key but will not start the motor it has no spark. The other ecu when key is turned on runs the fuel pump runs comstantly it does have spark and runs the motor. It idles good once warm but if you try to give it gas it goes to 4krpm and acts like its hitting a rev limiter. Driving the car or sitting still does same thing. Almost like a fuel cut or something. Ive spent alot of time and money trying to make this issue go away with no success

so that's 2 different ecu's with the same e2t number ? (the 6578 part)

which means they're both 91-92 ecu's, not 90s, according to this: http://simon.chi.il.us/ECU/ECUID.html

Yes all same numbers. Except the 4 digit number under the 2 long numbers.. i took the car for a couple mile ride. It runs great until it starts to build boost it is alright until it builds more than 3 to 5 pounds. Then it starts chugging and sputtering and wont run right till you let off the throttle. I did notice at idle it shakes the motor alil not sure what that would mean. Also i noticed the sensor for waist gate gets extremely hot even when car is cold and only ran for a min or 2.. When i take off in first gear if i dont let it build any boost it will run all the way threw the rpms. I just dont get it.. as i am new to turbo applications any input would be greatly appreciated

well is your car a 90 or 91-94?

My car is a 91 but came with spare motor i belive came from a 90. Has the diffrent coil pack and diffrenct cas and other diffrnt parts including a spare ecu

the 90 motor, is that in the car now with its "different parts", or does the car have its original 91 stuff ? help us help you out, provide ALL the pertinent information plz.

My car has original motor back in it now. Ive checked the mechanical timing.. it is good. I set the iginirion timing to 5deg btc. Brand new plugs. Brand new tps installed. Installed adjustable fuel pressure regulator to ensure no pressure loss. I drove the car yesterday close to 40 miles. It runs good as long as your really easy on gas peddle. As soon as you go over 1/4 throttle or it builds more than 3or so lbs of boost the car acts like its on a rev limiter or something. If i start out in first gear and go really gentle on gas building no boost i can run it all the way threw the rpms. As soon as you try to get on it at all or its building boost i get maybe 3500 rpms and it goes into "goofy" mode

Well here is something weird or not idk.. driving my car this morning and all the sudden my boost gage stops working the cel came on and the car died. Pulled over to check stuff. Unhooked battery for couple min. Hooked it back up and the car started. Boost gage in working order. Went to try to move the car all the sudden boost gage stops working again cel came on and car died. Checked codes and the needle pegs out and doesnt move. Would that be the constant code for ecu problem? Is there anything else that could cause this?

Sounds like a huge boost leak after the maf, or maf not hooked up to the intake piping, or its just a dead maf/wiring problem.

Ya know ive had a few people now say its the maf. I hate to do it but this car is killing me. I cant afford to keep buying parts for it. I am going to put this car back in the garage as a project car like it was suppose to be in the first place. Then i can save for and buy all the goodies i want for it. Aem computer for starters and all new sonsors and so on. I greatly appreciate all your help and comments. Im sure ill be picking your brains more in the near future.... if you have any further info on what my problem might be please help. I need all the info on this car i can get.. thanks again

Don't give up, just keep plugging away a little at a time and you will be having fun again soon. They can get expensive!

I know they are fun and not giving up. Just gonna take my time and build the way i want. Need transportation to work to afford these parts i want for the car. Just gonna be awhile to save up some cash. Dont wanna spend money on parts im gonna end up changing later anyway (ecu,maf,etc) if im spending the cash on something its gonna be what i want not just something to get by. This car is ment to be my street/drag car and ive always wanted one.. so its back to the garage for her. Till new parts can be bought and installed

Sounds to me like the ecu, have you tried the other?

When the ECU is powering up it turns the CEL on and 5 seconds later turns it off. You don't even have to start the car just turn the ignition on. If the boost gauge doesn't move to zero and the CEL turn on and off, coupled with not getting a heartbeat from the diag connector (on, off, repeating) would point at it. Like I said earlier in your other thread, both looked like they had original caps and should be replaced and any corrosion damage repaired.

I'd begin there before replacing any more parts.

Yes i tried the other. It doesnt have spark when that one is hooked up. When i get it back home im gonna look more into things. I know after it throws the cel and diesnit will not restart and the boost gage doesnt move. Not sure bout the cel goin on and off. I know if i unhook the neg side of battery for a couple min and then hook it back up it will work and run for about 1 or 2 min. And when i check the codes the meter just pegs and stays there. Will keep posted on what i find when she is home

Got the car in the garage today. Started it and it ran and kept running no problems. When i shut the motor off. i started looking around under the hood. There is what is listed as a fuel injector resistor pack. It is making kind of a sizzling noise. What is this part and how would it affect my car?

The injector resistor pack limits the current to the low impedance injectors used on the turbo cars to keep the ECU injector drivers from burning up. The metal housing is a heatsink for the resistors inside.

Could it be going bad? Why would it sound like its melting or something? Is it possible that it gets to hot and screws up injectors and that might be why the car died the other day?

Each resister is about 6 ohms. There are fed from a common power feed an then run to each injector. Check the resistance of each to make sure none have shorted or broken.

Ok thank you. I will check them. Is there a link or anything on here that might help in the process so i know what pins on the connector are what?

Injector resistor pack testing is shown here under "Verify Spark at All (4) Cylinders": How To Diagnose A No-Start

Yes don't give up I had to do the pin swap when I had a 90 ecu http://vfaq.com/index-main.html