3400 w/ Milzy Stage 2 (was Stage 1) tuning

[moonwell]

So here's the scoop. I've been running a 2001 3400 in my 94 Cavalier since last spring. Running the Multec 2 injectors on a custom tuned chip and after a lot of work, all was good.

I just got done installing the Milzy Stage 1 cam now. I also ported the heads & got a 3-angle valve job & LS6 springs while it was apart.

So now comes the fun of tuning. The car idles rough, but steady (it's only pulling 12hg of vacuum), which is expected. I raised the idle 100rpm to smooth it out some & modified the code so it would still use the idle fuel table at 60kpa.

The main problem is that I am getting tons of knock retard at part throttle. WOT is actually good. The BLM's are all showing rich, which seems like it should be the other way around. I tried backing off the timing quite a bit w/o much affect.

Here are a few freescan datalogs from today, if anybody has some insight.

Idle
Drive 1
Drive 2 (Timing at 80% previous values)

[onefastV6]

First off what tuning software do you have? I have the DHP Powr Tuner.

You scan look similar to my 2001 Grand am when it was stock, I have since upgraded to the 3500 top end so I am in the process of learning the tuning myself.

Are you running a MAF sensor and if so have you changed any of the MAF tables?

If you are only running a MAP sensor then I would look into changing the VE (Volumetric Efficiency) tables.

[moonwell]

Thanks for the reply.

I'm running the stock 94 computer, so it's OBD1. It's a MAP system, not MAF. I had been using GMPCM, but trying to get going with TunerPro now that GMPCM is no more...

I know that the VE tables need adjusted, but it just wasn't making sense to me that it would be knocking with it running rich, since a lean condition or too advanced timing would cause that.

I'm going to siphon the gas today & fillup w/ premium. The car was put away for the winter, so it's been sitting since November. Maybe stale gas is causing the knock.

[ryan.hess]

I know that the VE tables need adjusted, but it just wasn't making sense to me that it would be knocking with it running rich, since a lean condition or too advanced timing would cause that.

A lot of different things can cause that. Especially if someone inexperienced or not knowledgeable ported your heads, you could have a very stratified charge, causing a rich misfire. I haven't looked at your logs, but do you have any wideband data from when the knocking occurs? Do you see it shoot real lean indicative of a misfire?

[moonwell]

Well, I took it out & topped off the tank with premuim. So much for wishfull thinking...

I don't have a WBO2. When the knock registers at cruise, it definately feels like it is missing, though.

I did the head porting myself. I didn't do anything radical, though. Just gasket matched, smoothed the short side radius & ground down the valve guide boss's. Everything was smooth, no rough transitions.

From my latest log, just holding it steady at 35mph, 1700 RPM's, 65kpa MAP, it is registering a pretty consistant 10* of retard with BLM's at 112!

Push the pedal to the floor, it pulls like a mofo and the knock disappears!

A couple pics of the port work

[moonwell]

Re: 3400 w/ Milzy Stage 1 tuning

Here's a new log

http://www.v6z24.com/misc/datalogs/3400cam/3400_04.02.06-07-Drive.csv

[onefastV6]

Have you increased the AE table any?

[moonwell]

Have you increased the AE table any?

I've adjusted the VE tables, but that last log shows knock w/ up to 12* of retard even where the BLM is 127 & the Integrator is 128.

It just baffles me when at WOT the knock goes away.

I'm not sure if its all the retard that is making it feel like a miss, or a miss causing the retard... I need to pull the plugs tonight and see if they tell me anything.

[moonwell]

So, it the little amount of time I had to mess with the car tonight, I first changed out the plugs for some cheap Autolites. Idle improved a little & no more stalling when coming to a stop. But that's all that improved. Still massive retard

So, as per burns suggestion on V6Z24.com, I cut the timing in half. Of course the motor really runs like crap without the timing advance. But guess what!? Still the same amount of knock retard! WTF!?

So it must be something else in with the ignition, even though the car was running perfectly when taken off the road for the winter in December.

I've also been seeing random cells in my logs where the spark advance jumps up to 23000+. This isn't corrolated with the knock, and I was just brushing it off as freescan glitching. I'll datalog my '92 Z on my way to work tomorrow & see if it does the same thing.

This is the log where the timing was halfed.

http://www.v6z24.com/misc/datalogs/3400cam/3400_04.03.06-08-Half_timing.csv

[blackbombshell95]

Did you block off your EGR?

[moonwell]

EGR is completely removed & disabled in the chip. CCP is disabled as well.

[bszopi]

Are you running the 94 KS or the 01 KS? If you have the 01 KS in there, well there is your problem right there. The KS needs to match the ECM, no matter what. If you have the 94 in there, you might look at replacing it anyway in case it is bad.

[moonwell]

I'm actually running the knock sensor from a 94 Camaro 3.4. I've been running this setup for a while now before the cam with no problems.

I switched to the F-body sensor since it's OBD1 and tuned for the frequencies of this motor. Before that I was running the 94 3.1 sensor. I switched when trying to diagnose some WOT knock when I was tuning the stock motor. Saw no change between the sensors. Not sure if I have the old sensor laying around still or not...

[ryan.hess]

Do you trust your o2 sensor?

One way to rule out fueling is to up the BPC and see if the problem lessens or goes away.

[bszopi]

According to ACDelco, the PNs of the KS's are the same for the 3.1 and 3.4, so you should be ok. Just wanted to make sure...