spark retard???

[97blackformula]

Here's what I came up with today. First off I talked to Bryan from pcmforless and he said that knock burst is programmed out. I went up to my buddies shop and used his snap on scanner for some testing.

First we had my lt4 km in, and at idle it showed between 5-9 degees of spark retard. Cruising it was almost always showing several degrees of spark retard. WOT it had 5-9 degrees of spark retard through the entire rpm range. Mostly stayed between 7-9 though.

Next, we put in another lt4 km and had basically the same results as above except we had a few peaks of 10 degrees of spark retard. Also the entire time the "knock on/off", the knock was showing off at wot, and only came on a few times the rest of the time.

Next, the lt1 km, at idle it was showing up to 4 degrees of spark retard, but for the most part it was none. Cruising it had none to 2 degrees of spark retard. At WOT, it had .1 spark retard until I hit 5300 rpms then the "knock on/off" changed to "on" and it pulled 7-9 degrees of timing. We did another run and at 5300 again it showed knock "on" and pulled 7-9 degrees of timing. Below that no timing was pulled though.

Bryan from pcmforless thinks it the knock sensor, but I'm still not sure. I do have the obdI conversion from him. (thus I still have the obdII knock sensor) I know I'm definitely down on power with it retarding the timing and all. Any ideas guys before I change the knock sensor?

[Red96SS]

Use a second spare knock sensor and plug it in to the harness in place of the one that's on your engine block. With the new sensor not physically attached (just dangling) to anything you should see 0 knock.

If you don't then this shows clearly that your knock sensor has gone bad.

Hope this helps...

[97blackformula]

Originally posted by Red96SS
Use a second spare knock sensor and plug it in to the harness in place of the one that's on your engine block. With the new sensor not physically attached (just dangling) to anything you should see 0 knock.

If you don't then this shows clearly that your knock sensor has gone bad.

Hope this helps...

:sillyme: I should've thought of that. Good idea. I'll borrow the one from a local shop and try that today. Thanks.

[Red96SS]

No problems... glad to be of some help :)

[XXV ANN]

What was the result of your test?

[97blackformula]

Sorry, I didn't get time to try it yesterday. I'll find out probably Monday and let everyone know. Thanks.

[97blackformula]

OK, I plugged in another knock sensor and zip tied it up and it showed no knock at idle/part throttle/wot, which was good. Put in a new knock sensor and it showed the same timing retard as before. Even tried not tightening it down as much. So, now I'm not sure exactly what it is. I did put it on the dyno and air/fuel was dead flat at 13.6. Datamaster showed it pulling 5 degrees of timing at wot, then slowly dropping off to 1.5-2 degress. Now I'm really clueless as to what is causing the problem.

[Red96SS]

Then it's something mechanical or electrical:

- check plugs, wires and ignition coil
- make sure nothing is rattling near the motor (ie. loose motor mount)
- loose rocker (you should be able to hear it)
- really really bad gas

Can you actually hear the motor knock?

[97blackformula]

Nope, you can't hear it knock at all, and nothing is rattling. Rockers are tight, and plugs/wires/ignition look good. I've put in a lot of gas so it shouldn't be that.