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Car not getting above 5.3k - MAF voltage?

Posted: Sun Aug 07, 2011 1:41 pm
by markoshust
Hi all,

Just getting everything straightened out... car is a 95 240sx with ka24de, pt5857 turbo, lightning mac, bc v3's, delphi 75#, nistune, walbro, aem fuel rail, etc.

Anyways, car idles great. Runs pretty good under 5k with slight stalling here and there (needs decel adjustments). Just threw in new ngk spark plugs gapped at .024.

Whether it be in neutral or during a pull, the car does not want to get above ~5.3k. Has great power down low, but hits a brick wall like its missing spark or hitting fuel cut.

I just took it for a little drive to log some data. Please let me know what you think. The first part is just idle and light cruise, and at about 1:40 i did a small pull in 2nd gear.

The only apparent thing I can point out as a non-tech and non-tuner guy is that the maf chart gives out before anything else -- and at almost exactly 4v.

Anyone have any ideas? I'm a little lost right now :(

Log: http://shust.com/240sx/log_2011-08-06_2158_23.csv
Nistune BIN: http://shust.com/240sx/new2.bin

Re: Car not getting above 5.3k - MAF voltage?

Posted: Sun Aug 07, 2011 2:19 pm
by Matt
Sounds like ROM incompatibility with the KA24DE engines

Basically the file in the Nistune board may not be matching your ECU hardware

How to tell? Let us know the ECU ID 23710-XXXXX reported inside Nistune and the part number on the case of your ECU

If there is a difference like using AT hardware on MT model it can cause this fake rev limit

Re: Car not getting above 5.3k - MAF voltage?

Posted: Sun Aug 07, 2011 11:49 pm
by markoshust
I am in fact using an AT ecu on an MT car. How can I fix this? I thought MT/AT ecu's are interchangeable.

Re: Car not getting above 5.3k - MAF voltage?

Posted: Sun Aug 07, 2011 11:59 pm
by Matt
the ECUs may be on the vehicle, but the ROM images for this particular vehicle are not. We have seen this before which is why I need to check what you currently have loaded. Also is the speed signal working on the ECU?

Re: Car not getting above 5.3k - MAF voltage?

Posted: Mon Aug 08, 2011 12:18 am
by markoshust
Yes speed sig is working

Re: Car not getting above 5.3k - MAF voltage?

Posted: Mon Aug 08, 2011 12:59 am
by markoshust
So, I feel lik e an idiot - apparently the rev limit 3 is what was controlling the rev limit - not rev limit 1. Maybe different on AT ecu's?

Anyways car runs great now - ty for your help.

Re: Car not getting above 5.3k - MAF voltage?

Posted: Mon Aug 08, 2011 12:00 pm
by Matt
Okay does your neutral switch work okay? Might be neutral rev limiter

Re: Car not getting above 5.3k - MAF voltage?

Posted: Tue Aug 09, 2011 3:34 pm
by markoshust
Neutral switch doesn't work... Can start the car without the clutch depressed. Not sure if this can be fixed or not.