COBB PROTUNED for 11.5 AFR ECU Slowly leaning car out to dangerous AFR???? Help!!!
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COBB PROTUNED for 11.5 AFR ECU Slowly leaning car out to dangerous AFR???? Help!!!
Well I cannot figure something out.
I was PROTUNED with the COBB AP for 12 AFR then to 11.5 AFR under WOT. I am running a AEM UEGO to monitor my AFR under boost etc...
However, this is the issue. If I unmarry the COBB AP, unplug the battery, and let the ECU reset. Then I go and re-install the COBB AP on the car, and reinstall my COBB AP PROTUNE map. The car will run 11.5 AFR at WOT and 12's under light partial boost (i.e. 5 psi and under). After about 50 miles or less. The ECU will start to retune the car for leaner settings. Therefore the car will begin to lean out to 12.2-12.8 AFR under WOT, which is dangerous because of the knock. I got about 7CA of knock with that, which is dangerous and I do not want to grenade my motor.
Once it starts doing this, for me to drive the car hard. I have to either reset the ECU (with COBB AP) or I have to remap the COBB AP by reinstalling my PROTUNE map from CBRD.
I tried to switch relays, I tried 3 relays. Stock BLACK, Stock Green, and BOSCH 30A relay wired in. It has the same effect with all three. The computer starts to revert to original tune or tries to tune for leaner settings.
I am not sure what is going on, anyone can help with this issue. I am trying to get a hold of CBRD to switch me to ECUFLASH.
I was PROTUNED with the COBB AP for 12 AFR then to 11.5 AFR under WOT. I am running a AEM UEGO to monitor my AFR under boost etc...
However, this is the issue. If I unmarry the COBB AP, unplug the battery, and let the ECU reset. Then I go and re-install the COBB AP on the car, and reinstall my COBB AP PROTUNE map. The car will run 11.5 AFR at WOT and 12's under light partial boost (i.e. 5 psi and under). After about 50 miles or less. The ECU will start to retune the car for leaner settings. Therefore the car will begin to lean out to 12.2-12.8 AFR under WOT, which is dangerous because of the knock. I got about 7CA of knock with that, which is dangerous and I do not want to grenade my motor.
Once it starts doing this, for me to drive the car hard. I have to either reset the ECU (with COBB AP) or I have to remap the COBB AP by reinstalling my PROTUNE map from CBRD.
I tried to switch relays, I tried 3 relays. Stock BLACK, Stock Green, and BOSCH 30A relay wired in. It has the same effect with all three. The computer starts to revert to original tune or tries to tune for leaner settings.
I am not sure what is going on, anyone can help with this issue. I am trying to get a hold of CBRD to switch me to ECUFLASH.
Have you logged your long term fuel trims? One guess would be that over time, it is becoming negative, causing the car to give less fuel than necessary during WOT. This could be adjusted through injector scaling/latency I believe.
Bryan,
I would normally agree, but if I recall the long/short were both within 2-3%. I can't remember what intake it was, but I've seen the return hose into the inlet pipe post maf leak and cause similar issues.
Cb
Kris I'll call u tomorrow
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I am not sure what is going on with this damn COBB AP.
I thought it was my relay's going out at first, that's when I switched out the original relay with a green one, but the problem persisted. I even tried a BOSCH relay, and that did not help the cause either. I then started doing various tests with unmarrying and remarrying the COBB AP and relfashing maps.I have CBRD MAP, CBRD 2, and CBRD 5 maps. I tried all of them, and it keeps happening with all of the maps. I am really clueless what is going on, the best I came up with is that it is adjusting the long term fuel trims over the course of a few trips. It is fine for a cruise or low boost. Since the AFR's a still in the 12's put I cannot do any WOT pulls without fear.
I mean the car runs about 14.3-14.9 cruising in 5th on the highway at 70mph. But then in 5th if I try to give it a bit of boost it goes to low 12's and then mid to high 12's.
Ontop of it will throw a p1241 with a STOCK EVO X DV valve. I switched to stock ever since that time we had issues with the FORGE RS throwing that code.
Now I am not sure if its the lean conditions that cause it throw the code. On top it the car will throw either a p0172 (system too rich) or p0139 (rear O2 circuit slow response) whenever the car feels like it.
P.S. I have the COBB AP intake and COBB Turbo Inlet pipe. We used the MAF scaling from OTS maps from COBB.
Last edited by Clipse3GT; Sep 28, 2009 at 07:41 PM.

- Bryan
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My car is doing something similar but only swinging from +5 to -5. I bet yours is going to -5 or even -10 LTFT which really pulls out fuel when that happens. If I reset my ECU everything is fine at 11.5 AFR but it's almost random where the LTFT will settle and there are no other variables besides day to day weather changes. I'm using the same gas every week for fillups and checked the intake connections from the filter to the turbo and all seems fine.
I know that Tephra is working on a Fuel trim disable code but at the same time I want to figure out why it was hovering around +-2 before and now all of a sudden it's swinging +-5 day to day.
I know that Tephra is working on a Fuel trim disable code but at the same time I want to figure out why it was hovering around +-2 before and now all of a sudden it's swinging +-5 day to day.
I know that Tephra is working on a Fuel trim disable code but at the same time I want to figure out why it was hovering around +-2 before and now all of a sudden it's swinging +-5 day to day.
Over time I'm sure that we will arrive at definitive answers regarding the structure/logic of the X ecu. However, it would be so nice to have our own EvoM Mitsubishi engineer that could affirm or deny theories...
I'd pass a hat and put in a large bill myself to encourage Tephra to accomplish this
Last edited by coevolve; Sep 30, 2009 at 06:47 AM.


