Need ECU for my evo x gt35r

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Nov 23, 2009 | 10:17 AM

#16

stokEd

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From: Denver, CO

Quote:

Originally Posted by SilverEvoX

If you got a "dead" o2 sensor code but were getting the p1235 code and the o2 code it's probably not actually dead, it triggers the o2 code sometimes with the overboost code. I know this from experience.

Yeah, I'm wondering about this too, what prompted the conclusion that the MAF and MAP were dead? Did he follow the tests prescribed in the service manual to determine this or was it based on P1235/P1238.. codes popping up for "MAF sensor plausibility"... ?

Nov 23, 2009 | 10:15 PM

#17

UAE_EVOX

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From: DENVER,CO

Quote:

Originally Posted by UT_EvoX

I've seen way over 29 psi output from EvoScan... and the size of the turbo obviously doesn't matter for reading manifold pressure, not sure how that was relevant.

Do you mean outflowing the MAF?

yes also the o2 ...yah based on p1235/1238

Last edited by UAE_EVOX; Nov 23, 2009 at 11:00 PM.

Nov 23, 2009 | 11:46 PM

#18

UT_EvoX

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From: SL, UT

Quote:

Originally Posted by stokEd

The stock MAP is a 3-bar sensor (44.1 psi) so when you subtract out barometric pressure (44.1 - 14.7 = 29.4 psi) you're left with room for another ~29psi before the sensor is maxed out.

However the barometric in Denver is ~12.5 psi so the OP should have room for ~31 psi of boost.

I've seen over 33 psi at sea level... with EvoScan properly adjusted. I'm pretty sure the stock MAP is more like a 3.5-bar sensor.

Nov 24, 2009 | 03:25 PM

#19

stokEd

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From: Denver, CO

@UAE_EVOX

Who replaced the MAP and O2 sensors for you? Dealership? Harvey? Do you still have the *old* sensors? If they were replaced based solely on P1235/P1238 codes then you may just replaced perfectly good sensors.

Get in touch with DG Motors/GST Motorsports/HBSpeed..., they spend a lot of time on here helping people with tuning issues and should be able to help you out as well.

Here's a thread that will be of some use: https://www.evolutionm.net/forums/ev...p1238-etc.html

Quote:

Originally Posted by UT_EvoX

I've seen over 33 psi at sea level... with EvoScan properly adjusted. I'm pretty sure the stock MAP is more like a 3.5-bar sensor.

You're right, the nominal rating of the sensor is 3-bar, but if you consider that its a 5V sensor calibrated to read 45.6psi (3.1 bar) at 4.6V, that means if you could actually max out the sensor you could go as high 49.6psi (3.37 bar.) I'm not sure if that qualifies it as 3.5 bar sensor or somewhere in between, but the sensor isn't necessarily accurate the closer you get to its 5V operating threshold. This doesn't mean that your 33 psi (~47.7 psia or 4.8V) isn't accurate, but going much beyond that might be questionable. I'm glad you brought that up, made me look into it a little deeper.