94-Z-28M6

Hey, I am new to the whole programming thing and I just have a few ?. All Data is at WOT.

1) What exactly is burst knock?
2) Are the O2 sensors still reading and displaying info at WOT? I
have logged a couple of runs and the Mv readings are all over
the place, and differ from side to side at the same time from
89 on the left and 662 on the right!
3) I am also having spark retard problems at every shift point, It
starts right at the first shift but then I start having it retard up
10* in the middle of all of the remaining gears! It is a stock
program and I am at a high elevation so something seems
to be wierd to me.
4) I am in Denver and am only seeing 78kpa Max and 180gm/sec
Max on the MAP and MAF. Does this seem normal or not??

I apologize if all this has been gone over before but I appreciate any help. I have the Data log files and if that would help just let me know and I will send them, The car has always felt slower than the other cars I have driven and ridden in...Hopefully if I can fix these problems it will be better

Thanks again,
-Nick

drop top steve

What logging software are you using?

Burstknock is from the MAF seeing a sudden increase in airflow.

It is normal for the O2 reading to be changing from high to low numbers at cruise, at wot they stay steady, mine stay around .850+

You might try a LT4 knock module, all m6 cars I've datalogged show retartd at high rpm shifts (clutch noise??) my a4 car shows 2-3 degrees at 6300 shift point

I'm sure altitude affects map reading and I would think it would effect the maf. Your maf does seem low, I'm 250+gps@5800
My maf reading vary log to log, so I'm thinks changes in density altitude effect it.

You can email me your datalogs if you want. I've tuned a few cars, but I'm still learing too.

94-Z-28M6

I am using the PCMComm software for logging,

Ok, would a sudden decrease in airflow cause burst knock also??

wow, my O2 readings are definately not steady at wot, they are everywhere

Where can I get the LT4 knock module and how much?

Yeah, I knew that it would change at altitude but I do think that it is probably still down from where it should be I wonder what could be the cause of the low MAF reading

yeah, you have email, if you could just look at it and give me any info on what is going on it would be greatly appreciated, I looked at it and went WTF!!

Anyways thanks a lot!
-Nick

Injuneer

Your MAP readings appear low, but most of it is accounted for by the reduced barometric pressure at high altitudes. What is the exact elevation where you are? At 5,000' standard barometer is about 24.9"Hg = ~85.7kPa. At 6,000', barometer is 24.0"Hg = ~82.6kPa. This compares to 29.9"Hg (103kPa) at sea level.

The barometer might have been "low" when you took your readings and that could reduce MAP below the "standard". You will also lose some pressure through the air intake system, so 78kPa doesn't seem totally unreasonable.

And, once you have a low MAP, you have low air density. The MAF sensor measures "mass air".... or the actual grams per second passing the sensor. If you have a 78kPa MAP, you have reduced the air density by 78 / 103 = 0.757..... so that the same volume of air that would produce 240gps at WOT at sea level, will only produce 75.7% of that same mass (in essence, weight - the volume is the same, but each cubic foot of air weighs less because of the reduced density)..... or 240gps X 0.757 = 181gps.

So, it all fits together, and it all results from the altitude. You are losing 25% HP compared to those of us at sea level!!!!!

Yes, the O2 sensors are always working and are always being read by the PCM. It's just at WOT, the PCM does not do anything with the data.... just display it. It is only at part throttle/part load that the PCM uses the feedback from the O2 sensors to correct for rich and lean conditions. That is why the values change rapidly at idle and low loads.... the PCM is making the corrections to the fuel flow calculations, based on the O2 sensor feedback nearly 10 times per second, and is constantly swinging back and forth between slightly richer than and slightly leaner than the 14.7:1 target A/F ratio. And the two banks of the engine are INDEPENDANTLY controlled, so that the O2 sensor readings will very seldom be the same at part throttle.

Appears you might want to read my online document:

SCANNER DATA