fuel trims

[mbagge01]

I have been running some logs with vagcom and when i tried to check my fuel trims under block 032, everything reads out at 0 which I know cannot be correct because there should be some value within +/- 10% in each block. I get real readings when I run it with my A6. I have a stage 1/2 eurocharged tune and the car runs fine and pulls hard but I was interested in checking what my fuel trims are like to see it anything would indicate a boost leak or vacuum leak. Has anyone else every had problems in vagcom like this for the rs6.

[G2]

Been working on a RS6 that is Eurocharged and noticed the same thing...but it was awhile back and i might be getting it mixed up with another car. I know with my Revo tune is shows fuel trims (being that revo doesn't change the fuel mapping).

Makes one wonder doesn't it? Have you looked at 02 sensor readings instead? Or boost (actual vs spec) or MAP values? If it was too lean the EGTs would skyrocket (same can be said for running too rich).

Hope that helps some.

[mbagge01]

I would assume that even if the fuel maps are changed with the tune, you should still be able to read fuel trims because don't they represent readings from the precat 02 sensors

[G2]

I may have been thinking about a new Mustang 5.0 I played with a couple years ago. It was catless, with a matched tune, and did not show 02' values, presumably to prevent the computer from correlating the differences, hence setting a P420 code. Or for emission testing to pass the visual CEL/MIL light test.

The only way the ECU will know what to do with the FT's is by referencing the 02's. Far as I know right now in my sleep deprived state....

[mbagge01]

Wouldn't that be a bag situation for the engine not being able to determine if the car is in a rich or lean state if it cannot determine O2 signals

[lswing]

You can log lambda/O2 values, but not accurate enough for precise tuning. You've also got EGT temps to reference. There is also injector duty if you want to confirm amount of fuel being dumped in. A well fueled map seems to hold timing better I believe.

Guessing the ecu doesn't log the block you want. Agreed, just look at specified vs actual boost for boost leaks, smoke test for vacuum.

[G2]

Additionally with a generic OBD scanner, cannot get FT's with the Eurocharged tune. Double checked it tonight to be sure.

[mbagge01]

I have been speaking with Jerry at eurocharged about this issue and waiting to hear back on what the issue could be. I also had problems trying to pass emissions because many the systems would not come up as active and I actually had to flash back to stock to get cleared

[mbagge01]

I just tried to 10secs4 tune which I am pleased with and this tune does display fuel trims in vagcom. There is something in the eurocharged tune causing problems with certain measurements

[G2]

Curious what his tune costs? I was headed in the Eurocharged direction, but then again anything has to be an improvement over REVO.

[mbagge01]

The 10secS4 tune is 500 dollars and I can say on having his tune and eurocharged, the 10secs4 tune on the butt dyno is faster and for the cost, it is a no brainer when compared to what other tunes are selling for. I have runfuel trims in vagcom as well and they are solid and very slightly on the rich side which is good.

[TMAC]

I am very pleased with the 10secS4 tune as well

[G2]

The 10secS4 tune is 500 dollars and I can say on having his tune and eurocharged, the 10secs4 tune on the butt dyno is faster and for the cost, it is a no brainer when compared to what other tunes are selling for. I have runfuel trims in vagcom as well and they are solid and very slightly on the rich side which is good.

Was this done in Portland? Be nice to see the logs if available.

[mbagge01]

I am in Portland but have not run any logs yet but the car definitely feels faster, but with the caveat that it is pulling more boost than my eurocharged tune

[lswing]

I am in Portland but have not run any logs yet but the car definitely feels faster, but with the caveat that it is pulling more boost than my eurocharged tune

Would be great to see a set of logs. Boost, timing, EGTs, injector duty, Lambda O2s.

G2, you can just send the ECU to Marc. I might get an extra ECU soon and try it out myself.