Running close to 0.75V does seem high, but with the funky exhaust port these engines have maybe it's how it is on them, I'm not sure.
Ah yeah, this ain't Diesel direct injection.
Running close to 0.75V does seem high, but with the funky exhaust port these engines have maybe it's how it is on them, I'm not sure.
Ah yeah, this ain't Diesel direct injection.
I no longer monitor the forum, please either post your question or create a support ticket.
I found a service bulletin on gm site about MAF causing fuel trims to be out of wack. Where they cast the plastic housing it was casuing a disturbance in the air flow. I cleaned up the casting flaw and thought I would try that but I doubt that did it. These engines run pretty low vacuum too. I put a vacuum gauge on it and it is running somewhere around 15 inchs. I had a local tune shop owner drive it this week and he said the computer was constantly taking fuel out. He said the MAF could be adjusted to compensate. He didn't have the software to mess with it. I bought EFI from a diesel shop who was too intimidated by the whole thing a gave it up. I am starting to understand his frustrations.
There really isn't a whole lot you can do with these ecms without adding boost is there? Nice to have that capability but not on a daily driver for wife.
Ahh, yes... I missed the E39 bit thereOriginally Posted by GMPX
Some logs of the car would help, it would help shown the longer term details of what the fueling is doing, if it included wide-band O2 data it would be even better. Also, a copy of the tune file to see what may be possible.
The MAF its self does not make any "adjustments" to any thing. The MAF is just a sensor, it measures air flow / density and reports that back to the ECM. If it's faulty (broken or even just dirty) it will report the wrong values and the ECM will try and correct when in Closed Loop (CL) mode. If the ECM can't correct, it should throw and error code.
STFT's should not remain negative, they should oscillate +ve and -Ve. LTFT's can remain either +ve or -ve though. If the NB O2's are stuck at 750mV and do not oscillate at all, then I'd say the closed loop function is just not working, and the car is always running rich. So it's probably worth doing the following...
- checking for any error codes before trying anything else.
- Log the car ensuring STFT's, LTFT's and O2 mV are being logged. Also the Fuel Mode (OL vs CL) should be logged as well as ECT.
- Clean the MAF, use a "carby cleaner" to rinse off the sensor elements inside the MAF.
It sounds like it's stuck in OL mode and simply running too rich. This might be due to a faulty O2 sensor or even a stuck thermostat not letting the car warm up correctly.
Simon
The o2 are oscillating along with the stft"s the Ltft are staying pretty much in positive. It is going into closed loop. I cleaned the casting flaws from the MAF sensor and watched the trims and it seemed to help . I went back to a custom tune I purchased from another vendor also. He was able to play with the throttle response and a few more things I can't or don't know how to do in EFI.
I wish I could read his file with EFI so I could see what he has done but it won't read his cal. He didn't change the Final drive ratio in the ECM. I don't know what that will effect. The transmission controller seems to work the speedometer. I have it calibrated to the 3.39 and the engine is programmed to the 2.77. His files are trt files instead of tun or bin files.
you wont be able to open the file directly in EFILive but you might be able to flash the trt into your ECM then read it out with EFILive
I think i tried but it says the ecm isn't supported I may try again
Gives an error code and says file not formatted
I take it you can read it out with a stock tune? Try EFILive v8 Pass thru (Use the software interface) instead of BBR
I have to read it with V8 with the stock tune. I tried with the pass thru that doesn't work either. What does the ecm use the final drive calculation for if the speedo doesn't need it?
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