problems!! knock for NO reason - experiments

[cjridert1]

severe tim retard problems b/c I am getting lots of knock. So I change the sensor, no different. I JB welded over the hole in the sensor (1g), no different. I then hooked up the new knock sensor, wrapped it in a papertowell/washcloth combo and didnt put it into the block (go figure). Knock is substantially reduced, but when free-revving, still get knock spikes of 9 (always nine) - The knock sensor is hanging statically and wrapped in cloth - what do you guys think the problem is? (fyi - the engine is not knocking @ all). WB O2 is good and this is done just free-revving in neutral.

logged a 3rd gear pull (11psi boost) with the knock sens out of block (attached to harness and wrapped in cloth).

RPM TIMA knock wbo2 (lambda)
2100 21 9 .86
2700 21 9 .78
3300 16 9 .75
4600 17 9 .72
5100 18 9 .72
5800 18 9 .72
6200 18 9 .72

Knock drops to 0 when I let off gas. Furthermore, any time there is load on the system (like lightly accelerating from 1k to 2k) knock count holds @ 9. Seems to only be 0 when maintaining load/rpm or in decel. Keep in mind the knock sensor isnt in the block and my car isnt very loud. Does everyone see this in their setups? My lifters are a little noisy now and then (noisiest @ idle), but other than that there isnt any noise/vibration I can find.

 

[cjridert1]

this is a 3rd gear pull with base timing @ 3* (I added 16% for you guys, assuming that is how you do it?). WB O2 values were good (~12:1) till redline. I just took the knock sensor out for that one pull to see how much better the car ran.

RPM---knock--Timadv--Airflow (Hz)--Airflow +16%
2100---18------18---------313----------363
2600---33------11---------520----------603
3300---30------10---------709----------822
4100---37------12---------884---------1025
4600---31------14--------1010---------1172
5200---30------12--------1223---------1419
5700---28------15--------1355---------1572
6200---26------17--------1405---------1630

 

[2gGSX]

You actually needed to log mass-airflow (lbs/min) instead of airflow in hertz, sorry

 

[cjridert1]

You actually needed to log mass-airflow (lbs/min) instead of airflow in hertz, sorry

I have MMCD, can I log this? I couldnt find it anywhere. Or can I convert hz to lbs/min?

 

[2gGSX]

After looking at their web page, apparently not.

You could try seeing if it's real knock via some other method. Do you have access to race gas or at least E85 somewhere? If it's an option, try running some race gas and see if it still behaves the same way.

 

[terminaltsi]

are you going wot, full boost for your log in post 26?

 

[cjridert1]

Race gas, that is a good idea - Ill call around and see if I can dig up a couple gallons. Thanks!

are you going wot, full boost for your log in post 26?

This is WOT, but only @ 6psi.

 

[terminaltsi]

it just occured to me that maybe because you are running less than stock (12psi) boost, the ecu is advancing timing farther than it should be at wot because it's seeing wot, but not the correct amount of airflow for that throttle position.
i don't know the ecu code that well, but it kinda makes sense to me....

 

[cjridert1]

it just occured to me that maybe because you are running less than stock (12psi) boost, the ecu is advancing timing farther than it should be at wot because it's seeing wot, but not the correct amount of airflow for that throttle position.
i don't know the ecu code that well, but it kinda makes sense to me....

It runs equally bad @ 12psi (but I like this idea). Thanks!