COBB PROTUNED for 11.5 AFR ECU Slowly leaning car out to dangerous AFR???? Help!!!

Clipse3GT · Sep 28, 2009, 05:47 PM

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.

LaXGSR · Sep 28, 2009, 05:57 PM

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.

GST Motorsports · Sep 28, 2009, 06:33 PM

sounds like it wasn't tuned for the intake and/or larger injectors properly and the trims are slowing changing your fueling.

- Bryan

CBRD · Sep 28, 2009, 07:11 PM

Quote:

Originally Posted by GST Motorsports

sounds like it wasn't tuned for the intake and/or larger injectors properly and the trims are slowing changing your fueling.

- Bryan

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

Clipse3GT · Sep 28, 2009, 08:02 PM

Quote:

Originally Posted by CBRD

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

Thanks Chad!!!

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.

GST Motorsports · Sep 28, 2009, 08:55 PM

Log the fuel trims with the AP (or just view in real time), that will be good information to post.

STFT and LTFT.

GST Motorsports · Sep 28, 2009, 08:56 PM

Quote:

Originally Posted by CBRD

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

I didn't even notice the CBRD tune in the sig. I would imagine something is amiss as Chad knows a thing or two about deez evoz.

- Bryan

gunzo · Sep 28, 2009, 11:57 PM

Quote:

Originally Posted by GST Motorsports

Log the fuel trims with the AP (or just view in real time), that will be good information to post.

STFT and LTFT.

These don't affect Open loop .. or do they ??

lean spool ??

GST Motorsports · Sep 29, 2009, 12:10 AM

Many people have posted cases of LTFT swings effecting OL fueling on the 10's

Clipse3GT · Sep 29, 2009, 10:17 PM

Working with Chad @ CBRD to figure out the issue.

Great Tuner! Definitely helps his customers out.

Clipse3GT · Sep 29, 2009, 10:17 PM

Quote:

Originally Posted by GST Motorsports

Many people have posted cases of LTFT swings effecting OL fueling on the 10's

Yes, I am thinking this is what is happening.

jondimellow · Sep 30, 2009, 12:05 AM

Quote:

Originally Posted by GST Motorsports

sounds like it wasn't tuned for the intake and/or larger injectors properly and the trims are slowing changing your fueling.

- Bryan

if I got a tune using Ralliart drop in filter, then changed to Cosworth filter, do you think that would matter?

ak47m203 · Sep 30, 2009, 07:28 AM

can you try asking kevin of NTEC here at evoM. it's local evo club or i will post it there.

Hiboost · Sep 30, 2009, 07:37 AM

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.

coevolve · Sep 30, 2009, 07:44 AM

Quote:

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.

Chad, do you suspect that this is the issue?

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