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View Full Version : gas mileage problems - ran a/f logs



a4cefed
02-07-2007, 06:57 PM
ok guys i posted about my gas mileage problems before. 170 miles on a full tank, finally go to run some logs
car has 88k on it, with new plugs(bkr6e), maf,o2 sensor,throttle body,sea foam done to gas tank and vac lines. fuel filter
here are the logs:

UPDATED LOGS = SCOLL DOWN

http://www.audizine.com/gallery/data/500/0af_trim_2-med.JPG

mike-2ptzero
02-07-2007, 10:15 PM
Any 02 sensor(block 031) logs. Just seems very odd that your injectors are already at max duty cycle(16.32) starting at 3800 rpm and maf reading at 111 g/s. Injector duty cycle readings are way too high even at 2500 rpm and everything above that. My guess would be there is a huge boost leak or the 02 readings are way off.

a4cefed
02-08-2007, 06:29 AM
i did not log block 031 but i can, should i look for boost leaks ? or is there somethng else causing this ? thanks

badassbaldie
02-08-2007, 07:39 AM
Any 02 sensor(block 031) logs. Just seems very odd that your injectors are already at max duty cycle(16.32) starting at 3800 rpm and maf reading at 111 g/s. Injector duty cycle readings are way too high even at 2500 rpm and everything above that. My guess would be there is a huge boost leak or the 02 readings are way off.

Unfortunately Mike, we didn't run block 031 for the 02 sensor logs. I am kind of new to the logging aspect of our cars so I ran the blocks that the Ross-Tech site recommended.

I noticed that his multiplicative trim (-9.4) was JUST below the 10% margin of error which indicates that he is running rich, correct? I guess we already knew that seeing that he is getting such crappy gas mileage with no evidence of fuel leaks.

Two things that should be noted. First, there is a slight "whistling" sound while the vehicle is in load. This could support your huge boost leak theory. However, the car seems to pull pretty hard. Honestly, I didn't even hear it until Mike (a4cefed) pointed it out.

Second, would a clogged cat have any affect on his gas mileage? That's about the only thing that he hasn't replaced.

Thanks for your help.

Poopie
02-08-2007, 07:45 AM
maybe a sludge issue? Did you check compression on the cylinders?

a4cefed
02-08-2007, 07:58 AM
did not check compression.

bass_lover1
02-08-2007, 08:30 AM
I agree with mike, you're hitting the max injector duty cycle wayyyyy too early especially with those MAF readings.

What K04 software do you have?

onemoremile
02-08-2007, 08:36 AM
I agree with mike, you're hitting the max injector duty cycle wayyyyy too early especially with those MAF readings.

What K04 software do you have?

99.5 A4 1.8TQ Laser Red
K04 / GIAC / Borla / Forge 007

Daft
02-08-2007, 08:48 AM
Just and Mike said, as 031 log would be fairly useful here. As far a injector duty cycle numbers, 16.32ms @ 3800rpm is a 51% duty cycle. That doesn't seem too high to me. Even at 5840 it's showing a 16.32ms pw. This is only a 79% duty cycle.

a4cefed
02-08-2007, 08:54 AM
the crazy thing is the maf and o2 sensor are less than 2 weeks. i will log block 031

bass_lover1
02-08-2007, 08:55 AM
99.5 A4 1.8TQ Laser Red
K04 / GIAC / Borla / Forge 007


I'm not stupid, I can read...FYI GIAC Makes two k04 programs...thus why I asked.

bass_lover1
02-08-2007, 08:59 AM
Just and Mike said, as 031 log would be fairly useful here. As far a injector duty cycle numbers, 16.32ms @ 3800rpm is a 51% duty cycle. That doesn't seem too high to me. Even at 5840 it's showing a 16.32ms pw. This is only a 79% duty cycle.


16.32 is the hard coded limit of the ECU, he shouldn't be hitting that at 3800 RPMS at 111g/s. Now, at 5800rpms, it seems a bit more logical especially w/ 169g/s maf reading. Something isn't right, he shouldn't hit 16.32 ms that early in the RPM band.

a4cefed
02-08-2007, 09:01 AM
im running the standard giac k04 program with 5 bar fpr

Daft
02-08-2007, 10:53 AM
Just stumbled upon this: http://www.passatworld.com/forums/showthread.php?t=170625

He was having the same issues with the 16.32ms limit like you were: http://home.houston.rr.com/vwturbo/WOT.xls

He was using the PC-16 with a 3bar FPR and 310cc injectors @ 44psi. He seemed to make better use of his fuel @ WOT once he increased his fuel pressure to 48psi. Only downside was that he was slowly approaching the negative limit of the long term fuel trim.

a4cefed
02-08-2007, 05:11 PM
http://www.audizine.com/gallery/data/500/5716thursday_runs-med.JPG

Poopie
02-08-2007, 05:20 PM
if anything you are running lean. Very very lean

mike-2ptzero
02-08-2007, 08:16 PM
The +1.6 and -10 readings tend to point at a leak between the turbo and throttle body. Might want to do a pressure test to look for leaks.


Hard to figure out where you are at WOT vs part throttle and the engine load readings on your log isn't helping. Any chance you could post a log with block 003 and 031 together? You dont really have to log block 032 since it wont change during WOT runs, you can look at that block after running the car at idle/part throttle to see what the reading looks like.

a4cefed
02-09-2007, 05:12 AM
thanks mike, i will run those logs this weekend and also do a pressure test.