zoomzoom

I hope this makes sense to those who take the time to read it, I am at work so do not have megatune atm to remember exact terminology for gauges, menus etc. If there is any more info that will help, maps or logs please ask and I will post it from home later.

The car is a '90 na6 with gt2556r turbo approx 13psi, MSPNP with VTPS, mapdaddy, hires code, innovate LC-1, 265deg cams, big pwr intercooler, the IAT is mounted in the steel pipe which is approx 250mm long with silicone hose both ends, one is 90 deg into the throttle body. The car is white.

The car was tuned and started to ping particularly in cooler humid weather (rain), I figured it was just to do with the different intake/exhaust I had on it so I got it retuned. It started to ping againn less than a week after the tune so I have looked into it further.

I believe it is something to do with the IAT compensation and another unknown compensation. I found from a log done after the first tune that the Gair was up to 148%. This log was taken in the evening after the tune which was a fairly warm day, probably around 30deg C so the log would have been done at around 25degC. I took another log the other day when it was pinging in wet weather probably around 22-24degC and found it was lean as and the Gair was down to about 120%. I had to scale the whole fuel map by 20% just to stop it lean surging in cruise. The Correction factor is also very unpredictable it leans out significantly at times and looking at the logs there seems to be no correlation between that and the IAT or anything else.

A mate and I had a play around with it trying to do some troubleshooting, we found that if the menu under coolant correction was turned to not corrected the correction factor on the Genrich? gauge went down to 80%. Baro correction gauge stays at 99-100%.

What I need to know is where can I alter the values for IAT correction as I believe this must be way off and what other correction would be present causing the overall correction to be 80% when I disable the IAT correction.

Cheers,
Tim

hustler

iTrader: (6)

You need to run easy-therm and get back to us. I can't tell you how to do this because its both complex and I don't remember how I did it last time.

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Do I need to easytherm with even using MSPNP and the std GM sensor?

Matt Cramer

No, if you're using the stock CLT sensor and a GM IAT, the MSPNP no-AFM firmware is already EasyThermed for your sensors.

zoomzoom

Where do I access the table to alter the IAT based correction? And where is the other correction factor of -20% coming from when I disable the IAT based correction?

Thanks,

Tim

zoomzoom

I am assuming that even though it says coolant related air density at the top, that is the IAT correction table?

Has anyone got one of these that works well with a turbo as well?

Also why when I turned it to normal correction did the correction drop to 80%?

hustler

iTrader: (6)

oops

zoomzoom

Can anyone tell me why my correction gauge is at 80% with the IAT based turned off/100%?

zoomzoom

Here is a short log I took after the first tune. You can see the crazy enrichments. The Gair is high then the Gammae is even higher. The IAT correction table which comes on the MSPNP is crazy looking too. When I change the value for correction to 100 it has a Gammae of 80? What else can contribute to this?

What do other peoples IAT correction maps look like and do you have it switching off completely at low rpms like the factory MSPNP setup or do you leave it active?

Tim

Matt Cramer

Hello Tim,

I noticed in this data log you seem to have been activating a fuel cut occasionally - were you deliberately using launch control, or was there a chance that switch is acting up?

Air density correction isn't fully turned off, ever - you can only turn off the curve that lets you make adjustments. With no adjustments, you'd normally see a gair of 100 at around 18 degrees C - IF you are using the correct code version. Using the code for stock Miata sensors won't shift it THAT far, though. Could you post a copy of your MSQ file? I'd like to check your settings.

GammaE is the total effect of Gair, Gbaro, Gwarm, and Gego - air correction, baro correction, and EGO correction.

zoomzoom

I'll post it up tonight when I get home. I will also put my other files up for you to check out. I am running hires code too so maybe you could check it has been configured properly.

In that log I was using launch control, I had just got it back from the tuner and taking it for a short test.

Tim

zoomzoom

Hey,
Here is the map from that log along with my car folder from megatune. The IAT curve in that map is crazy which is how it comes on the MSPNP but I have since tried it with values at 100 across the board and had a gammae of 80 still.

Thanks,

Tim

Matt Cramer

Try reloading it with the '96-'97 MSPNP firmware. Your firmware may be corrupted.

zoomzoom

Hi,

I tried loading the code from the 9697 and it still shows 80 in gammae. There must be something marginally different with that code though because it would rev to 3k then hit fuel cut with exactly the same map. I then changed the IAT options to keep it active beyond 3k rpm (I changed it to 7500) and set all those values at 140 and it wouldn't stumble. I have now got it set at 120 across the board to keep the gammae at 100.

I have done a rough retune with MLV to get the fuel table setup to suit.

Now something I have noticed looking at the recent tunes is that the IAT temps are outrageous, always between 80-90 deg C so I think I may have a bung IAT sensor? Would that be a likely symptom? It normally ranges between 20 deg C cold to around 40 hot and 60 or so at idle. I am thinking this might be causing the 80% also. Would you have a graph of what the curve looks like that is built into the code?

Regards,

Tim

Matt Cramer

90 degrees C IAT readings really should give you 80% air density correction. See your airdenfactor.inc file for the curve - the entries look like this:

DB 80T ; 24 197.58

The 80T is 80% air density correction, 24 is the raw ADC reading from the chip's ADC converter, and the last number is the corresponding air temperature in Fahrenheit. You may have a bad IAT sensor, heat soak issues, or a really bad intercooler setup.