97gst_spyder

I have a 97 gst with an Evo 8 ecu installed. I'm running an Omnipower 4 bar map sensor, just bought 11-16-10. I have it logged with Evoscan, all values are correct. It will read correct randomly with my mech Apexi boost gauge. Once it starts mis-reading, it shoots to 4x.xx PSI and just fludders around up there. No CEL's, seems to run fine when its doing this also.

Rom: 96532706
Log:

*** I cant post the rom and log itself, so heres a screenshot. ***

joseph143

iTrader: (8)

are you using the 4bar to log boost or to run an SD system? are you certain that you modified the ROM definitions in the ecu and scaled the definition in Evoscan properly

and you are certain that you installed a legit omni 4bar... if you scaled the definition and everything correctly but still have a 1bar then when teh sensor reads 4v+ for 14ish psi it would make evoscan think your running 40psi

joseph143

iTrader: (8)

also a poor ground would cause stray voltage at higher rpms and that would also make evoscan read higher voltage and show a higher psi...

97gst_spyder

I have the settings in Evoscan all correct. I checked the wiring at least 3 times now ( I built the harness ). I am using the map currently for a boost only sensor. Once I get the tune and this issue taken care of, I will be going SD.

You mentoned that all the settings need to be correct in the ROM, is there a spot for it in ROM 96530706 v7. I could not find any info on how to add my Omni map to it.

Thanks!!

06RedRalli

iTrader: (49)

It's already integrated into the v7 roms..

97gst_spyder

Under what section? I'm looking through it right now.

06RedRalli

iTrader: (49)

Should be under MAP sensor section.

97gst_spyder

I do not have that in my rom. Is there a way to add it? I could not find the how-to for my rom.

donour

iTrader: (6)

96530706 doesn't need any changes because it doesn't have a factory MAP sensor.

Assuming your are reading the correct MUT channel, the value is just an integer 0-255 which is 8bit indicator of voltage 0-5v. If it is fluctuating wildly, then either

a) the voltage of the sensor is flucating
b) the sensor is wired incorrectly (and probably (a))

or
c) the DAC is broken.

Have you plugged in a multimeter to see what voltage your getting from the sensor? Checked to see whether it matches the values from MUT (take out the scaling, just print the raw value)

Voltage = 5 * MUT_VALUE / 255

Once that works, its just a matter of scaling to match psi or kPa. Use the Omni 4bar thread to find it...

d

97gst_spyder

I'm 99% sure that the wiring is good, it does read vacuum like a pro. It will read boost correct when it feels like. The voltage coming out of the harness should be 12v, 5v, and ground? I will check that in the morning.

On a side note here are the two roms w/logs I have tried and seem to fail with...

This is the rom I drive to work everyday with:

Rom: 96532706 http://www.mediafire.com/file/gmpkai...h/96532706.zip

Log: 96532706 Log http://www.mediafire.com/file/zn06ri...2706%20Log.zip

Here is what I just tried and had a fuel/rpm limiter issue anytime I went near boost:

Rom: 94170715 http://www.mediafire.com/file/ho71s5...-v7_Edited.zip

Log: 94170715 Log http://www.mediafire.com/file/wjdwmf...0715%20Log.zip

Any help would be appreciated!!

** I cannot figure out how to get these files uploaded to this forum, that why there are links ***

JohnBradley

iTrader: (30)

97,

If you have it in the stock location in the stock harness?

aaron

97gst_spyder

Yes, on both.

JohnBradley

iTrader: (30)

Hmmmm I got confused when we got to the stock harness that you built...if its rebuilt then I wonder if something is bare somewhere. If it is 100% stock then I would presume the sensor is done.

If you built the harness though, looking at the sensor with the closest to the firewall being top wire, that is 12v / 5v / ground?

97gst_spyder

The harness was built, but I kept most of the wiring on the top of the engine stock, and made the rest for the trans/fans/coolant/etc. Ihave checked and double checked for shorts/bare wire from the ecu to this sensor, nothing. I'm running this in a 2g dsm, just so everyone knows. For the numbers, I haven't tested it yet but asking if thats basically what it should come out to.

JohnBradley

iTrader: (30)

We have done a number of Evo ECU to 2G swaps. Never ran into this issue. I will put a multimeter on my car in the morning and doublecheck for you.

aaron