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00 JDM v5 STI
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8 Posts
Discussion Starter #1
Whats up everyone.....

I know there are a lot of different threads out there about MAF problems and I have scoured each and every one trying to figure out the problem to no avail.

I recently did a JDM STI Version 5 swap into a '00 RS. I had the harness merged by ECS Performance in Windsor Ct and they did a great job. Everything went together great and it started up on the first crank. I know that it needs to get tuned for running on 93 octane and stuff so I found an EcuTek tuner that has the ability to flash and tune the V5 ECU. I met with him to confirm that he was able to communicate with the ECU before attempting to tune the car. and he discovered something.

The car is running pretty rough and once its at operating temp it stalls at idle. When we looked at the ECU readout the intake air temp was reading at -40C. Thats a problem. Cant tune it like that. So first thought was a bad MAF. After some research and conversations with ECS we located a 22794-aa010 as the part number for the new MAF. Ordered it and installed it and it was still reading at -40C. So the next thing was wiring. I just pulled the ECU plugs and located the MAF wiring and checked continuity between the ecu plug and MAF plug and I have continuity on all 4 wires.

What the heck is going on?!?!?!? :bonk::bonk::bonk::bonk:

any help/ideas would be a HUGE help!! thank you to all!
 

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Registered
99RS 207 V9 AW
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1,285 Posts
Swap the wires, possibly wrong polarity so ecu read negative value. MAF has a thermistor to send voltages to ecu to convert to temp. If wires backward, u might get negative value.
 

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2000 RS Sedan SRP
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180 Posts
Do you have the IAT sensor plugged in?. The car will run real rough of you don't plug it in. I had the same problem with my car.

Sent from my HTC One XL using Tapatalk
 

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Baby❤Daddy
98L Wagon
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27,848 Posts
i don't have anything constructive to add, but it seems to me that the harness is the issue here. i've not heard (read) good things about ECS's ability to merge harnesses. i would get in touch with brian at iwire. he's a god with this stuff.
 

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2000 RS Sedan SRP
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180 Posts
ECS did my harness and it turned out great, and I have the same exact swap as he does V5 STi swap into a 2000 RS.

Sent from my HTC One XL using Tapatalk
 

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Turbo, LS swapped Impreza RS
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5,172 Posts
I'm sure you've checked this but is the maf in backwards?
 

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00 JDM v5 STI
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8 Posts
Discussion Starter #8
Thank you to all who replied and had suggestions! So I'm basically an idiot. Might even be more dumb then putting in the MAF backwards. Hopefully my stupidity will save someone else in the future.

So heres the concrete answer:

After finishing the whole swap I had a few "extra" plugs from the harness that when to nowhere. JDM version 5 had a water spray system that I am not running at the moment so I was expecting this. After some suggestions from John at Visconti Tuning who will be tuning the car and Spf-ii with some research I found that the JDM versions 3-6 all had a separate air intake temp sensor. One of those pesky "extra" plugs was for that!! :curse:

For those who have a similar problem the actual part number is: 22634-KA071 and I have attached a diagram showing the sensor.

Luckily Subaru used the same part for a 2000 Legacy Outback so I called up my local autozone and they had one in stock. Plugged right in and is working perfectly.

Amazing how a $50 plastic part can make you look like a total fool lol :facepalm:
 

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2000 RS Sedan SRP
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180 Posts
Don't be embarrassed by it, it took me a while to figure out what that little black plug does to.

Sent from my HTC One XL using Tapatalk
 

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ECS *****
500hp Unicorn #142
Joined
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298 Posts
Whats up everyone.....

I know there are a lot of different threads out there about MAF problems and I have scoured each and every one trying to figure out the problem to no avail.

I recently did a JDM STI Version 5 swap into a '00 RS. I had the harness merged by ECS Performance in Windsor Ct and they did a great job. Everything went together great and it started up on the first crank. I know that it needs to get tuned for running on 93 octane and stuff so I found an EcuTek tuner that has the ability to flash and tune the V5 ECU. I met with him to confirm that he was able to communicate with the ECU before attempting to tune the car. and he discovered something.

The car is running pretty rough and once its at operating temp it stalls at idle. When we looked at the ECU readout the intake air temp was reading at -40C. Thats a problem. Cant tune it like that. So first thought was a bad MAF. After some research and conversations with ECS we located a 22794-aa010 as the part number for the new MAF. Ordered it and installed it and it was still reading at -40C. So the next thing was wiring. I just pulled the ECU plugs and located the MAF wiring and checked continuity between the ecu plug and MAF plug and I have continuity on all 4 wires.

What the heck is going on?!?!?!? :bonk::bonk::bonk::bonk:

any help/ideas would be a HUGE help!! thank you to all!


Hey Guys,

The Version. 5&6 WRX/STi has an 2 wire IAT Sensor that was separate from the MAF sensor. Do you have that plugged in, Its a small black sensor, the 2001 2.5RS would have the same sensor in the intake track if you needed to replace it. Hope this helps.




-Paul
 

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ECS *****
500hp Unicorn #142
Joined
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298 Posts
i don't have anything constructive to add, but it seems to me that the harness is the issue here. i've not heard (read) good things about ECS's ability to merge harnesses. i would get in touch with brian at iwire. he's a god with this stuff.
George,

Other than my turn around time suffering in 2008/9 when we moved into the new facility, what else is wrong with my ability to merge harnesses?

Ive completed over 1000 of them to date with less than 6 warranty claims. And in those cases, they were all related to the quality of the donor harness, sometimes gremlins like to hide deep. A recent issue, poor guys harness was setup for a JDM o2 sensor and someone had swapped the pins, Hard to figure out, and certainly something i would have never thought to check on the bench, I helped him figure it out, hes a happy guy!

-Paul
 

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Baby❤Daddy
98L Wagon
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27,848 Posts
just sharing what i've heard. being the messenger of sorts. obviously in this case, i was wrong about the root cause which had nothing to do with your harness. the clues he was giving did not preclude your harness from NOT being done wrong.
 

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ECS *****
500hp Unicorn #142
Joined
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298 Posts
just sharing what i've heard. being the messenger of sorts. obviously in this case, i was wrong about the root cause which had nothing to do with your harness. the clues he was giving did not preclude your harness from NOT being done wrong.
In that same regard, he certainly did preclude it as not being the harness when he said the harness was not the issue and it was done as expected in the first few sentences of the post.
 
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