pcmhacking.net

Finally got my knock sensor sorted!!

Now I can finally give this tuning thing a proper go!

Finally getting around to tuning...

Decided I would start with the easy bit and get the idle right.

The issue that ive always seem to have is that the rev's fall quite sharply when I coast, and sometimes stall the car....(Real PITA)
After reading the basic's guide, I was able to get the AFR reading pretty much spot on, with that done I started bumping up the timing by 2Deg's at a time, watching for the KPA numbers to stop decreasing, but once I got to about 42Deg, the idle starting hunting....dropping the timing by about 4Deg made it stop.

The only issue now, is that during warm up the idle hunts....a lot......

A couple of questions....

A) Does 38 Deg timing, for such a small cam seem a hell of a lot to you guys ?
B) Is there anything within the warmup config that might stop the hunting ?

Thanks guys!

After editing the ADX to reflect Holden202's Spreadsheet, I went and did my first log and tuned from the histograms today. (ADX Attached if anyone wants it)

I sorted the RPM scale the other way around for the VE tables (xls attached with my numbers in them, for those that are interested)

Looks like things were out quite a bit. I haven't uploaded the new tune yet, because I noticed that the AFR numbers in the xls are different to those within the $12p A/F Ratio table. Im not sure which I should trust...I looks like the $12P table has things running a bit richer under full load. Im assuming that the std numbers are 'very' safe, so I can afford to use ones within the spreadsheet to gain a bit more HP ?

New tune also attached...

Ive also uploaded a Registry hack to allow the Aten USB to serial adapter to use 8192 baud. (Its a Prolific chipset, but slightly different registry entries)

you need to put the afr's into the spreadsheet to suit your tune.

v6 v's v8's and such all have different numbers in them, just make sure whatever is in your tune is the same as whats in the spreadsheet, otherwise your chasing a moving target and it will never be accurate. the whole idea is that once the ve table is right then you should be able to change a afr number in the afr table and the tune should adjust from the old setting to the new.

as far as idle timing, i probably wouldn't go over about 30 degrees at idle, maybe just try a few cold starts with different idle sparks and see if one is better than the other for cold hunting.

Started to tune the spark a bit now...

Is there anyway I can test the knock sensor / circuit to make sure its working ok ? Im pretty sure that im not getting any knock normally, but dam sure I can hear it rattle a bit if I change gears hard, but there isn't any knock count,etc....

I have the "Coolant Temp" enable set properly for the knock.

Hey Guys,

Im 'really' hoping someone can help me out...

I cant figure out why my knock sensor isn't working.

The CEL always shows 12 (which i believe means all clear)

I plugged in a multimeter into B11 and can see the multimeter jump when I tap around the sensor with a hammer...so im assuming at this stage that the sensor is working ok.

I tried running the engine and tapping near the filter hoping that 'might' work, but im guessing that its being filtered out.

Ive even tried setting the flags "Process code 43" and "CEL Enable code 43" (and a combo of either and both), and then watched the "DTC Knock Sensor Circut" Bitmask on the dash , but it never changes from "Clear"


If the knock sensor was enabled on a 'non' knock memcal would it error on the CEL ?

Does VL400's nvram board pass through the knock filter goodies ?

Thanks again guys!!!!!

Yep it passes the knock sensor filter board pins to the big memcal header.

When logging now you should see 0 knock counts - previously with no sensor or filter board on the memcal you would have seen over 200 counts all the time, but no retard due to cal settings. To test that you have the cal setup correctly now, unplug the memcal from the NVRAM board, set the jmp/mem jumper to 'jmp' and the cyl jumper to 8cyl and go for a drive. As soon as you reach the ESC operating temp it will pull a heap of timing as it will see ~200 counts. Another test for malfunction conditions is to just unplug the sensor - will then pull timing and give you a CEL.

Testing the sensor and filter is probably a bit harder if tapping it cant get the right frequency - if doing this at idle have you got min ESC RPM below idle RPM? You prob wont see knock counts logging, just the retard and then decay. Could do what the US ECMs do and actually cause it to ping by jamming in a whole heap of timing? They dont have the resistive test like we do for code 43, so gives varying levels of extra advance to cause knock - if it gets none it sets a code. It does this very briefly but could prob do the same in 12P by increasing a certain load point and driving through it or the map switch function to use the other spark table (with extra advance) briefly. Not great to induce knock but nice to know it works...

Ok, thanks very much, I will do those tests this afternoon, and keep my fingers crossed.

When I was testing as it was running I used the throttle stop to hold the engine at about 1400 rpm with the MIN ESC RPM set at 1000, I thought I heard it pull timing (the engine speed lowered slightly), but didn't see knock counts like you were saying. Do you happen to know the logic involved before it will log the knock ? Should I see the timing reduce on the TP5 dash ?

I will also try pumping some extra bad timing into MAP B and see what happens....the weird thing is thou, is that what lead me to this process, is that I'm pretty darn sure its pinging already, but its neither logging the knocks or pulling timing out....

Ok...

Did some testing...

I unplugged the Knock sensor and ran the car...no error codes at all. No timing differences etc.

I then removed the memcal from the nvram board like VL400 suggested and this produced symptoms expected, the knock counts went crazy and reving the car above the ESC min RPM showed timing being removed.

I then decided to removed the nvram module and plug the memcal straight into the ECU....the car runs but the CEL light stays on. Even when trying to read codes from it....

Sooo...Im guessing that the EEPROM part of the memcal is stuffed.

Im a little bit confused thou, because I would have thought that even if the eeprom is buggered, the nvram module still would have been able to use knock filter ?? Or am I completely wrong ?

If it turns out that this memcal is stuffed, whats the chances of me soldering the knock filter onto the nvram module and actually have it work ?

Thanks again for all your assistance guys!