GOLFMK8
GOLFMK7
GOLFMK6
GOLFMKV

Am I running rich?

grambles423

grambles423

Automotive Engineer
Timing...just Slipped? How does that happen?
 
Modshack1

Modshack1

Go Kart Champion
Look at Lambda and multiply values x 14.7 to get actual Air Fuel ratios... at .72 in the upper RPM's that's 10.6 A/R. Slightly rich for best power, but better to be rich at RPM's and boost than lean. I'd be more concerned with the timing pull.

Check your fuel trims (Block 32 I believe). You can do that in the driveway...Key on, not running. Idle trims and partial throttle ideally should be within +/-5%. A minus number is a rich correction, Plus is lean. Remember, these are correction factors based on your sensor (02) input. Usually a function of the programming if all systems are in good shape.
 
Last edited:
thedude4bides

thedude4bides

Go Kart Champion
Anyway, the temporary solution is for me to run this gas to E and fill up with Sunoco. When that tank runs to 1/2 full, I should repeat my logs.

EDIT: I will not run the gas to E. Instead, I will siphon as much as I can and gracefully hand it back to the terrorists that put it in my car.

Disclaimer: my use of the term "terrorist" in this post does not refer to any specific creed, race, or religion. But rather, applies to any degenerate responsible for the degredation or attempted degredation of my beloved VW, performance-wise, cosmetically, or otherwise.
 
Last edited:
T

TRUboost

Go Kart Champion
Bad gas is always a scapegoat for something else.

Bad gas would cause knock which would cause your car to pull timing. Octane, not enough fuel or too much fuel can cause knock.

Depending on what kind of timing your map is achieving a 10.5 AFR isn't necessarily bad, also remember that your tune isn't specific to your vehicle so the tuning company more than likely makes the maps conservative in timing and fueling to allow for many different variables such as altitude and climate.

I know that Cobbs OTS maps run in the low 10's under boost.

slackin via taptalk
 
thedude4bides

thedude4bides

Go Kart Champion
Modshack said:
Look at Lambda and multiply values x 14.7 to get actual Air Fuel ratios... at .72 in the upper RPM's that's 10.6 A/R. Slightly rich for best power, but better to be rich at RPM's and boost than lean. I'd be more concerned with the timing pull.

Check your fuel trims (Block 32 I believe). You can do that in the driveway...Key on, not running. Idle trims and partial throttle ideally should be within +/-5%. A minus number is a rich correction, Plus is lean. Remember, these are correction factors based on your sensor (02) input. Usually a function of the programming if all systems are in good shape.
Click to expand...

Thanks, Modshack!

Does the timing pull depend on the fuel trim values? Or are they simply related to the "richness"? I'm trying to figure out how all this ties. For example, if my ECU detects shitty gas is it going to run rich to be on the safe side (meaning less chance of running lean at higher rpms, which is worse)? Is the fact that timing is off a result of running rich? Unrelated?

Thanks for schooling me!
 
Modshack1

Modshack1

Go Kart Champion
thedude4bides said:
Thanks, Modshack!

Does the timing pull depend on the fuel trim values? Or are they simply related to the "richness"? I'm trying to figure out how all this ties. For example, if my ECU detects shitty gas is it going to run rich to be on the safe side (meaning less chance of running lean at higher rpms, which is worse)? Is the fact that timing is off a result of running rich? Unrelated?

Thanks for schooling me!
Click to expand...


No problem!
Typically bad gas and a triggering of the knock sensors will pull timing back.
As to the trims, It may enrichen the mix as well, as a protective measure, but I don't know the specifics of the Uni tune..
 
thedude4bides

thedude4bides

Go Kart Champion
Just reflecting on my symptoms...

First thing I noticed: shifting felt much "lighter" than normal. Not sure if "lighter" the best term, but it's all i got... it definitely felt odd.

Second thing I noticed: mpg's dipped. Not by much, maybe 2-3 mpg's below normal.

Third thing I noticed: power drop. I assumed it was heatsoak. Seemed odd because I never felt it this before, even on hotter days.

Fourth thing I noticed, shifting lost a lot of smoothness between 1&2, and 2&3.

I was real easy to blame the CTS intake I just installed because the symptoms occured simultaneously. Anyway, I will be siphoning out as much gas as I can tonight and filling up with Sunoco 93. After 1/2 tank, I will post new logs.

I have mixed feelings about the potential results... say it was bad gas, then how much harm did I do my engine with the WOT runs to get the logs? Say it's not bad fuel... then wtf is it? Tune? Intake? Karma?
 
G

gkamenov

New member
thedude4bides said:
I have mixed feelings about the potential results... say it was bad gas, then how much harm did I do my engine with the WOT runs to get the logs? Say it's not bad fuel... then wtf is it? Tune? Intake? Karma?
Click to expand...

If it is bad gas, you didn't harmed your engine at all (according to logs). If you drive too long with bad gas, eventulay ECU will enter into limp mode and you may have "Check Engine" light. Replace the fuel, log again block 020 and check values. They sould be greater than -3 for example. In ideal case all values across the rev range will be "0". -2, -3 at some revs is OK.

In your situation I woluld also do a reset of the ECU - with VCDS (ignition on,engine off) -> Basic Setings -> Chanel 0 -> Save. This clears all adaptations ECU have made and resolves the issue with gears shift smoothness as well.
 
You must log in or register to reply here.
Top