Knock Retard

[kid]

I'm getting spotty KR under light load, and the car bucks a little. It's all mid range in the chart, and I don't want to just pull timing from the table seeing as it's only a few cells that show it. Not sure what's going on. I do have long tubes, and an MS3 cam, so maybe false KR?

[WS6FirebirdTA00]

Tune?

[kid]

Sorry, I thought I attached the config. I'll add that when I get home.

[kid]

Here's the tune.
It seems to stumble at about 20% throttle on a pretty regular basis.

[04colyZQ8]

I have very similar problems , when and if you figure it out let me know!!

It would be very helpful if someone, would make a how to to tuning spark? Or a program to build a new spark table based on cam and engine displacement.


I have a feeling that we need to change more then just the spark high and low tables. There are also idle tables, and modifieres that change things verses temp etc..

If I couldd just figure-out a safe way to zero them or set them a at a certain value. Then build a safe table like say 15 degrees across the board? Then if there is still spark knock cut the burst knock tables down till there isn't, then gradually increase timing to knock happens then set it back a few degrees?? I don't have a clue, without help, but something along these lines should maybe work??

I am begining to think I have false knock? I have taken out more then 18 degrees in spots and still get knock?

Will I damage anything by zeroing all tables, except idle and main spark high octane then setting them to 15 across the whole table?

Here is my thread http://www.hptuners.com/forum/showthread.php?t=35157

[kid]

A lot of threads I have read say to just pull that much timing from the effected cell. I would think that would defeat the purpose, because you want to keep that timing.
Mines going to the dyno tomorrow, so they'll hammer out that timing issue while it's there.

[04colyZQ8]

A lot of threads I have read say to just pull that much timing from the effected cell. I would think that would defeat the purpose, because you want to keep that timing.
Mines going to the dyno tomorrow, so they'll hammer out that timing issue while it's there.

OK sweet let me know how it goes and if it was false knock or real knock, It's not just a couple of effected cells for me.. more like 20!!

[kid]

Apparently it was false knock. As the exhaust heated up, it started contacting the body on acceleration. The sensors read this as knock, and went a full -10 degrees to compensate.

[04colyZQ8]

Apparently it was false knock. As the exhaust heated up, it started contacting the body on acceleration. The sensors read this as knock, and went a full -10 degrees to compensate.

so what did they do to fix it, and how exactly did they determine that was the cause? ,

[kid]

It was just a matter of adjusting the exhaust so it wouldn't touch anywhere. The vibration from the body contact would reverb all the way back to the motor and get picked up by the sensors as knock. No touch...no knock. I also had a small leak at one of my O2 bungs. It was a bad weld from the factory. It was pulling in some air and making the car run too rich intermittenly.

[04colyZQ8]

It was just a matter of adjusting the exhaust so it wouldn't touch anywhere. The vibration from the body contact would reverb all the way back to the motor and get picked up by the sensors as knock. No touch...no knock. I also had a small leak at one of my O2 bungs. It was a bad weld from the factory. It was pulling in some air and making the car run too rich intermittenly.

OK thanks. How did they find the O2 leak? was there water dripping from it?

[kid]

You could see small amounts of carbon coming out of the crack.

[04colyZQ8]

You could see small amounts of carbon coming out of the crack.

OK thanks