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Discussion Starter #1
Car is a 92 TT. 100k miles im the second owner, it was garage kept car but had oil pressure issues so i got it cheap. I always loved these cars since my brother had an RT when he was 17. Trying to keep this short, the short block was butchered by the previous mechanic. Replaced it with a brand new OEM 93 forged one. Put all new OEM parts on it and had the heads rebuilt along with new turbo centers. Installed a chrome ecu and am having a MAF problem. Baro and no MAF reading. IAT is reading good. Im not shy of electrical stuff by any means so keep that in mind. I bough a reman MAF and still the same issues. Question one is can a bad ECU ruin a MAF, ran the original and the new one with the old one before the Chrome one. Its been raining so I havent been able to check the wiring back to the ECU yet really good. Car starts fine and runs but the MAF is non exisint to the ECU.
 

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How are you confirming no BARO and MAF signal but IAT? I am going to assume with EvoScan. I would first verify the pins in the MAF connector (+5v, +12v, ground, etc.) followed by the harness itself, as mentioned.

Any dash lights or DTC's?
 

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Yes dash CEL is on, this happened with the car running, with old ecu. Lost boost gauge, IAC (ohm read good but installed a new one anyway) and the check engine came one. Read the codes with an analog voltmeter. So I put a reman one on it because I just throw parts at my own car Haha. But that didnt make a change. Now with the chrome ecu in it I'm reading live data through a normal OBD2 scanner. I did have 12v a ground there and a few 5v reference signals. That is as far as I got when the rain came. I do have factory 92 service manuals which are a huge help. I'm just wondering if my old ecu could have fried the sensors. I'll probably get out today to see what kind of readings I'm getting back at the ecu itself.
 

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Ok so it stopped raining for long enough to get this info.

Car running and warmed up.
Pin 70 ecu, 5v at idle, same reading with the sensor unplugged. Should be 2.2v to 3.2v acording to the book.

Baro pin 65 was .03v should be 3.2v to 3.8v

Intake air pin 52 2.7v witch is correct, around the low 70s today.

All these reading were the same at the MAF while plugged in and unplugged, other than the air intake temp, but that is reading so that is what I would expect. Im guessing the old ECU wiped out both MAF sensors somehow. Any input from anyone would be greatly appreciated.

Also sensor plug has battery voltage and ground at it too.
 

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Yes I do. Even tried it unplugged just to cover everything. I do electrical work as a living on firetrucks and that might sound dumb but you never know when your working with some things that your not that familiar with. That wire looks like it comes right from the ECU so it should with it unplugged anyway.
 

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These problems happend all at once with the old ECU while the car was running ok. I replaced the caps in it but one of the MOSFETS that controls who knows what looked bad. It was repaired sometime in the past because a small wire was soldered in to fix a trace. Im just not sure a bad Ecu can ruin a MAF. If it can it ruined the orginal to the car and a reman one from autozone. Im gonna try to get there to exchange it under warranty. Ill just say it worked then I had a problem.
 

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Ok, so new reman MAF sensor installed.

Now everything is working except air flow sensor. Was 5v constantly to .35v at idle now. If i try to rev the engine its sputters kinda and the reading jumps from .35v to 2v or up to 5v. This isn't every time I do it also. Kinda at a loss here.

These readings are excatly the same at the sensor ant the computer by the way.
Any help is or suggestions are gladly welcome.
 
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