RKerss99GS said:

Please explain the difference in the ecu
the one I am holding in the pic is the same as in my 99gs, the other is half the size and the harness is different

Thanks

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Im not sure if youre implying that since your 99ecu is different from a 95 that it must be a turbo ecu. 95, 96-97 and 98-99 turbo models had different ECU's and they all looked nothing like that one, and the harness is completely different. Its not just plug in a 4g63 ecu into your 420a and youre turbo ready. Your car running like shit is do to something else.

My mechanic did not say it was a turbo. The previous owner said it was and got swiched back. I was told by a computer shop that it was a turbo ecu and harness. I purchased the right ecu and tried to connect it but the harness adapters don't fit. When I drive it I can feel a hesitation like gas to air mix is wrong. But mostly around 55-60 mph. My mechainc said the wiring is a nightmare. So I guess we will just change the whole ecu and wiring system.

You will need to see what is what from. It is possible that you have a 99' stock ECU, but someone changed it to a 95'-96' ECU for what reason. This is where another car, book, ALLDATA comes into play and you will have to try to fix the mix and match....

Wow man I'm sorry I got no opinion on this for you. But good luck to and maybe think about getting a new mechanic cause if mine told me he would redo all that for some beer I'm running away

Maybe all you need is a tune up. Start with the basics. Why do you think the ecu is the problem?

RKerss99GS said:

Please explain the difference in the ecu
the one I am holding in the pic is the same as in my 99gs, the other is half the size and the harness is different

Thanks

Click to expand...

I believe the early year 420a have a different ECU and connector with a single connection the later years had a larger ecu with 2 connectors if your car is a 95 it has the correct harness its not a turbo or 4g64 harness or ecu just an early model 420a. Your harness does not look to be in the best shape though and its possible some sensors aren't connected etc.. that could be whats causing your performance issues. Does your check engine light work? O2 sensor working?

I have a few unused N\T ECUs from part outs if you need any

I'll try to dig up my 420A ECU wiring diagrams. Do you know what year the ECU is as well as the sensors with which your engine is running? You ALWAYS need to match the sensors to the ECU in engine swap scenarios or else you run into trouble.


Chris

Honestly, if it were my car, I would have the entire engine harness and ecu swapped from a car that isn't a hacked up mess. Then I would check over the rest of the wiring system for more ghetto-rigging. Idiots working on wiring is a potential fire hazard. I swapped my entire engine harness for far less than what you have there.

According to the Hollander interchange, every 420a manual transmission engine computer has a different interchange number, this means there was some difference from year to year to not make them 100% interchangeable with another model year.
Good luck with your endeavors..you're going to need it!

I would part the car out myself with that wiring nightmare. Good luck with it man looks like a lot of money and time will only be your best bet to get that car from having another problem.

Wow. If you really don't want to deal with this, google a company called 'painless wiring'. Tell them what you want, what you have, and they pretty much do the rest. Last I remember they were pretty reasonable too. That might be a big help for you.

the wiring cant be too bad if it runs and drives, just clean it up. what does it do at 60mph?

From all of this and what you have said, you need a tuneup. not a ecu. if you don't know anything about an ecu, don't touch your ecu.

Also, you need a new radiator hose and one hell of an engine cleanup :0

The radiator hose looks like it has a protective sleeve over it from being close to the exhaust manifold and that the protective sleeve is dry rotted and cracked not the hose

SpiderGST said:

I would part the car out myself with that wiring nightmare. Good luck with it man looks like a lot of money and time will only be your best bet to get that car from having another problem.

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Seriously, that is not that bad. Put some wire loom over it and tape it up and it will look good as new. That is what all harness's look like under the loom. You would shit your self if you saw some of the electrical things that i mess with.