What is too cold for plugs?

[n0dih]

I swapped in TR6's in my 3800 L67 working on a pinging problem, not sure if I should leave them in, not having a problem, still have the pinging problem (I am beyond lost on that one), and not sure if I should just leave them or swap them for the TR5's I had in there.

Not seeing any obvious problems right now.

[IndeedSS]

I swapped in TR6's in my 3800 L67 working on a pinging problem, not sure if I should leave them in, not having a problem, still have the pinging problem (I am beyond lost on that one), and not sure if I should just leave them or swap them for the TR5's I had in there.

Not seeing any obvious problems right now.

Usually your mods will help determine what heat range plugs you will likely need. When you say pinging are you hearing the "ping" or are you seeing KR on a scanner?

[n0dih]

Just seeing 8-13 degrees KR, nothing audible. I would chock it up to false knock, but if I move the point where PE mode enters up to say 80% throttle, it moves with it. So real knock.

This is my post on the KR on another forum....

Ok, been fussing with this a while, and I just can't lick it. I have a 00 Park Ave Ultra (personal car) with a L67 3800 supercharged.

I get knock (KR) at the point of PE mode enter. PRECISELY, almost EVERYTIME. With stock tune, tuned tune, doesn't really matter. It pings when it goes into PE mode. SO, I raised the point where PE Mode is entered, it tracks. So it is NOT false knock, I get KR at 80% throttle if I set it there, if I set to 100% throttle, I get it there, if at set to stock 45% throttle, I get it there. I have pulled a lot of timing out, and although it helps some, performance suffers heavily and isn't the answer. Same with fuel, adding more PE mode fuel, doesn't cut it either. Performance suffers and it isn't worth it.

I have changed plugs from stock platinums (GM installed NGK platinums) to NGK TR5's (stock heat range), no change. I have changed to a 160 thermostat, no change. I have changed to TR6 plugs (colder, similar to Autolite 103's for heat range), no change. The constant, I get KR when I go into PE mode. I disabled EGR, no change. I went open loop, no change. I disabled the MAF, no change. Cat Converter calc temp stays pretty constant around 450C, it doesn't' dump fuel till 750C or so. No issues there.

I did find a bad injector and swapped, it fixed my P0304 fault, but no change in KR. I still get it at the point of PE mode entry. I was guessing a bad injector causing one cyl lean. I have 5 more (used, but were good takouts for a psychotic 3800 Rivi owner with a Intercooled Whipple on a highly modded 3800 with a 4T80E.

I am at wits end. I just don't know WHY. Everything to me screams something in PE mode makes it go lean momentarily. When I bought the car in May 08, it did not do this, some 23K miles later, it does.

I have not been able to check fuel pump pressure, not sure how to with the 2 speed fuel pump, but that is next, but being fuel trims are good, I don't expect a problem there.

I get the least (almost none) amount of KR when I set PE Mode to 100% and just give up on it. For a SC engine, that is concerning to me.

What am I missing? Gotta be something here. I would expect if FPR that I would not see the precision of the point I enter PE mode that I have this problem (I would expect to see it at many other times).

I attached my latest log file after the new injector and you can notice mid way through the datalog I did up the PE Mode entry point from 45%(ish) to 100%, so you see that heavy application of the throttle does NOT have KR.

Anyone?

[driftnpow]

Ok im not 100 percent with the OS in your vehicle but if you do have an injector multiplier table this may help. how ive gone about with my ride is play around with the placement of fuel within the injector multiplier table. asume how the air and fuel is entering the block, like if you got high air velocity due to high rpm and valve overlap u may want to prolong the majority of the fuel injection, or if ya got slower air velocities in the engine block a more gradual and less potent punch of fuel, i found toyin with that i was able to cancel out alot of spacko random kr readings and also help improve fuel economy without throwin out the fuel trims

[n0dih]

My OS is 12201866, PCM is a 09380717

I haven't seen anything like Injector Multiplier, as I have found too, is some programs like HPT tend to rename things and some keep the GM names, which often can be a tad cryptic if you aren't used to them. I'll look and see.

Mine is stone stock save 1 mod, gutted air box (SC cars have a pretty complex air box on the Park Ave's to keep SC noise waaaay down).

Edit: Yup, I have it.... I guess if I have a prone to ping cyl this might help, or cyl to cyl variation if needed (My LT1 used this to refine it factory)

[driftnpow]

yeah that on my os on hp is known as injector skew, the multiplier im referin to is actually correctly named as injector pulse multiplier, how that works basically multiplies the injector constant by rpm vs timescale (1-20ms) understanable that you may not have this particular table as im runnin a totally different engine to you but yeah the injector skew may help you out ironing out some kr, keep in mind it may also induce further kr - only one way to find out tho.

edit- just added a screen capture

[driftnpow]

ok ive managed to find on the depository a close relative to your OS, yeah very much a totally different kettle of fish, ill have to go quiet for a bit n have a think of it.