zz17iroc

iTrader: (4)

I switched from 165 to 730 6 months ago and I have yet found the time to hit the dyno. I have a few questions concerning knock retard and PE.

Just after switching to SD the ecm pick up knock counts like crazy and plenty of retard to go along with it, but with the MAF set up I experienced no knock what so ever. Why, is the 730 KS that sensative? With further programing I de-tuned the knock sensor ( I know you cannot nessesirally de-tune the knock sensor through TC tuning) by zeroing out the LOW OCTAIN RETARD table and I was able to eleminate the retard, but the knock counts remained. Does that mean I need to use a higher octain level than 93 or adjust my timing?

The engine machanics is in perfect running condition.

PE tuning, what tables do I use to tune for PE ( I know it's a dumb question) but not to me remember I'm new to the game.

Like I said I've only been tuning for 6 months. And I also have learned alot, but there is a few things I do not understand. I am constantly reading threads and responses to other members posts so I can learn how to fix my own problems because that is the soul purpose of this board right!!!!!!


I also read alot of post about patch work and file editing. I'm really interested in file editing. How can I get started? And I'll also need some help on that aswell. I know there is more to tuning than tunercat because thats all I've been reading about file editing.

TRAXION

Hey Craig ...

Couple quick questions for you.

1) You did go with the 730 KS correct?
2) How tight did you tighten it into the block?
3) Do you know if you are experiencing real knock or false knock?
4) Which MemCal are you using piggybacked on the adapter? Is it an AUJP? Remember that the knock module is contained on the MemCal. You want to make sure that you are at least using a 350 MemCal.
5) When are you experiencing this knock?

In situations like this you want to make sure that the knock you are experiencing is real knock. Overtightening the KS can cause a situation just like this.

Tim

zz17iroc

iTrader: (4)

Hey Tim,

I have the 730 KS and also a 350 memcal with the blue zif socket soldered in place of the factory prom for the use of flash proms.

I may have screwed the KS in to tight, but why would I pick up knock counts with SD and not MAF? I've always made pretty sure that I never screw in the KS to tight. I've Known that one for a long time.

It always happens between 1000 to 2500 rpms, but when I took out low octain retard, I had no spark retard. Why?

zz17iroc

iTrader: (4)

Also when I had BJ laptop with me I took some scans using Craig Moats software and it said that I was run at 14.69 on A/F ratio during the knock counts if that can help.

TRAXION

To keep this short ... the Low Octane Knock routines kick in when knock is detected consistently. GM implemented this routine so that if you get a bad batch of gas then the computer won't have to consistently use the standard knock routines. So - given the fact that you are getting knock consistently, the Low Octane routines kick in. When you removed the knock from the Low Octane Routines then you don't get knock anymore. Clear as mud?

Do you hear ANY audible pinging?
What does your pump shot table look like (AE vs. TPS)? Do you have a bog when you first open the throttle?

My instinct tells me that it's probably one of two things:
1) KS too tight.
2) Something to do with fueling when you first crack the throttle at lower RPMs. You can work with this one by adding/subtracting fuel. But, if you had a Wide Band then we would know for sure. The ECM displayed A/F that you mentioned doesn't really matter too much. The ECM could display that it is shooting for 14.7 AFR but really spitting out 12.0 You can never be sure unless you have a wide band.

Tim

zz17iroc

iTrader: (4)

Basically the AE vs. TPS is the has been the same since you e-mailed that bin to me when I got started. I never touched that table.

I have no audible pinging of any kind, but there is a slight little bog very slight when I crack the blades.

TRAXION

If it were me I would do a couple of things ...

1) Verify that you have no exhaust rattling/banging etc. I had false knock awhile ago when my exhaust would tweak up into the floor on engine torque. It would only do it on a hard takeoff.
2) Pull the KS and wrap it with 2-3 turns of teflon tape. Reinstall. This is how I have to do the KS on my car. We all know its hard to get a torque wrench on this thing so most of us just tighten it down ... but not too hard. I add the tape because I tend to overtighten.
3) Play with the AE/TPS table. Try various settings A LOT richer and A LOT leaner and see if the knock changes. If it doesn't change no matter what you do then it most likely is some type of false knock (due to what you said about it happening at really low RPMs when you crack the throttle on a WOT takeoff). Notice I said most likely. If you do get no change in the knock retard then try changing the spark curve in the locations where you are getting the knock. If the knock doesn't change then change the VE tables in this location. If everything changing all three of these variables still gives you no change in the knock retard then I would REALLY think it's false knock either from an overtightened KS or from something banging around.

Tim

LETHALRACER

Traxion. I have basicly the same problem as Craig. My knock just started one day. I ended up having bad wires and injectors. I replaced the KS to no avail. I still have K counts and a slight retard at the initial blast. I richend up the Accel vs. TPS and that took care of it on the half throttle low end. Today I adjusted my valves and left one loose. The KS went crazy. I fixed that problem and it went back to normal(slow count). When I hammer it I don't get any more counts. It is only when I am sitting or cruising. My question is, is there any way to desensatise the KS through the computer? My plugs look great and there is no pinging. Does K attack rate have any thing to do with it? I am almost positive I over tightend the KS. I will change that and run some tape on it. I am just worried because it never did this before. I could turn the initial up to 14* and still get no K. I have run this basic program for a long time. Any ideas.

TRAXION

Lethal,

GREAT points about the plugs, wires, and injectors. I was ASSuming the car to be in a good state of tune mechanically. But, never ASSume. Bad plugs/wires/injectors can easily cause knock retard. Also, anything that can yield knocking sounds is suspect to producing knock retard. Although the Knock Filter on the MemCal filters based on frequency, false knock could still easily creep in through clanging sounds in and/or around the engine/chassis.

Now, on to your question - yes, you can desensitize the knock sensor electronically via using the Knock Attack rate. However, personally, I wouldn't do this. I leave the knock attack rate stock. Definitely change the knock recovery rate to allow your advance to come back in quicker but, changing the knock attack rate could have bad affects if you are experiencing real knock and your motor does need the reduction in timing.

Tim

LETHALRACER

I took off the AC unit and rerouted the belts. The tensioner click and knocks because I am basicly running it backwards. It pulls up on the belt instead of pushing down on it. This may be another source. I will do the tape thing and loosen the KS a little. I will also check the recovery rate against the stock bin. I guess it is running all right. I ran a 12.31@126 on the G-Tech, on street tires. The normal times are 12.6+@124. I didn't get the scanner on it though. Thanks for the help.