Thread: Weird observations through Consult logs

Check this out:


I'm running blow thru on my practically stock Avenir swap.
There are some really worrying things with this log:

1) MAF voltage is over 5v. Am I maxing it out on stock boost?
2) When MAF voltage hits 5v (which I'm pretty sure is near torque peak) the injector PW is almost 25m/s, which is 100% duty cycle. How am I maxing out the injectors?
3) Around 5k, where all this happens, the motor will have a slight dip in performance.

Also, it seems ECUTalk's datalog might be wrong because the injector PW goes down after 5k RPM but it still shows 100% duty cycle. Is this right?

Now, what I know is wrong with the car is it it throwing a knock sensor code, and the O2 sensor doesn't work. I just loaded the timing values and when this all happens it is at 0 deg of timing, in fact before that it is firing ATDC, WHY?!

I know on other cars, WOT shouldn't take the O2 sensor into account (open loop), and the knock sensing should also stop after a certain RPM. I think that might be around 5k RPM since it is pulling a lot of timing before then.

After this bog, the remaining gears can be run to redline with no dip in performance. I think this is because the timing isn't retarded for a little bit.

Any thoughts?

I'm going to try swapping out the knock sensor with a known good one soon.

Not sure what ECU your using etc, but would be interested to see if its knocking at 5K. I know the standard Nissan Pulsar ecu jumps into a knock map and pulls the timing when it detects knock (at any rpm). Dont know if thats standard on all Nissan ecus though.

The AFM curve looks a little funky as well, normally it rolls over at the top and goes flat long before the maximum (looks like the shape of the rpm curve), yours looks like it goes vertical and then hits a wall at 5.12 volts ?

Have you got an AFM thats standard for your ECU or are you using something bigger with a piggyback ecu ?

My guess would be your getting knock, or the knock sensor is broken and indicating false knock, and its pulling the map back.

Stock Avenir ECU with what I presume is an Avenir MAF. How do I check the MAF to make sure?

I'm pretty sure the timing issue is because of the knock sensor code. That still doesn't explain why the MAF is going to 5v so soon, and why my injectors are at 100%

No piggyback yet either. Thinking about going full standalone.

have you got another MAF you can swap out to try ? You could try testing it on its own to see if it looks ok. Switch the ignition on and measure the output pin of the MAF. Use a straw and blow on the hotwire of the MAF, the voltage should increase quite smoothly with you blowing. If its erratic and jumps up and down suddenly then it probably bust.

Could be your just using that much airflow and the MAF is maxing out, does anyone else with the same setup you know have the same problem ?

The injectors are only following the MAF, its indicating lots of air so the ECU is only pumping in the fuel to try and match it.

I have to say though it looks like you have a broken MAF as well as a broken det sensor

If you haven't got a spare det sensor then you could frig it using a 500K resistor in place of the sensor. Obviously it won't detect knock but it would stop going into the det map. Best get a new sensor though

I checked the part number on my other MAF and it's the same with the spare I have.
I've looked at more of my datalogs, and they look ok. The MAF voltage doesn't hit 5v til WOT at 5k RPMs.

Does anyone have any pictures of an Avenir MAF and a part number?

Could the Avenir MAF not like to be in blow-thru? I've been thinking and thinking about it, and it shouldn't matter. Sure the air is compressed, but if it was draw-through, it'd be flowing the same mass of air (just not compressed). Does that make any sense?

On the DET sensor, they are $160 for knock offs locally, so I got a genuine Nissan off ebay instead, waiting for delivery.

FYI:

click here