PontiacBonnevilleClub.com

Now that I have my Scangauge, I'm watching KR like a hawk.
I've noticed the KR has hit 3, 4, 5 on a cool night at WOT about between 2-3K rpms.
Today, it was 88 degrees and humid! I saw it hit 10!!

I did some research on KR and found several causes:

Increased compression, high temperatures, lean fuel/air mixture, advanced ignition timing, and lower octane fuels are all factors that PROMOTE detonation conditions.
Because lean condition (fuel starvation) also contributes to detonation, it is important to make sure that the fuel system (pump, injectors, etc.) is capable of delivering the increased fuel requirements of the supercharged engine.

I now know that having my WOT timing advanced 3 degrees is promoting KR without the supporting exhaust headers and more aggressive cam.

I also know that I have yet to replace the factory fuel sending unit, which reads levels until 1/2 a tank then move back to full as miles are put on. (fills up every 280 miles)

However, I'm wondering if this might be the culprit...
A buddy of mine who had a 12 second GTP gave me an adapter for the IAT that fooled the computer into thinking it's always 42 degrees.
I wonder if this in-line adapter is working against the computer in reading appropriate air temps.
Any thoughts?

I'm taking the car to the track on the 19th of July and need to resolve this before race day.

Your KR is 10!!!! STOP DRIVING BEFORE YOU POP A PISTON!!

The fuel LEVEL has no effect whatsoever and never will.

The IAT 'spoof' resistor is a short-term (track only) trick that the PCM is smart enough to overcome.



KR is a mechanical problem. Fix it mechanically and not through electronics or tuning FIRST. You can TUNE out the last degree or two, but yours is severe enough to warrant IMMEDIATE removal of the 3.5" pulley. And you'll still have KR after that (very likely).

Your advanced timing on stock exhaust/valvetrain is also a contributor.

Go back to the stock pulley and PCM and see what you have to start with on a hot/humid day. We'll go from there.

(remember that for the scangauge to SEE knock, it's ALREADY happened, and has done damage to the motor in small steps. This builds up over time.......KR is always slowly damaging your engine, as every one of us that have popped pistons will tell you).

KR is an indication of what has ALREADY happened.

DE-MOD THE CAR NOW!

Will putting on the SLP header exhaust elevate the KR?
I've been putting it off because it's so expensive, but I'd rather add than take away.
If I have to, I will put it on the credit card.

Always cheaper in the long run to take the time to figure out what is causing the problem before introducing more variables. Adding a header would be another variable you'd need to figure out.

Take it back to stock and see what you have going on. If it's bad in the stock configuration, then fix it. Save the header money for fixing the car.

It's not the answer you want to hear. It's the answer that will fix the problem.

I've removed the IAT spoof resistor and ordered the SLP headers.
Hopefully, I can get them on this weekend. I'm taking it real easy with the car until then.
If that doesn't work, I'll order the tuner and bring down my advanced WOT timing.

99ssei wrote:I've removed the IAT spoof resistor and ordered the SLP headers.
Hopefully, I can get them on this weekend. I'm taking it real easy with the car until then.
If that doesn't work, I'll order the tuner and bring down my advanced WOT timing.

You neglected to take sound advice from the above posts on NOT ordering SLP headers. You MUST use that money to fix the car. It could be a handful of things. Try best you can to demod the car one part a time until you see the KR decline. If you reach 100% stock with lots of KR then something it clanking around pretty hard or maybe (hopefully) its a bad KR sensor.

When he pops a piston then he will be able to start from scratch.... with a new engine. think positive!

I agree with Allmachtige, take the car back to stock and make sure it isn't one of your mods that made it knock in the first place.

At least there will be the necessary parts to make one quick SSEi left over from the wreckage that will be his engine...

It will be a bit daunting to take the car back to stock considering...

a) Don't have the original pulley
b) Don't have the original PCM
c) Don't have the original intake
d) Don't have the original...you get the point.

Since this issue is isolated to only WOT conditions, I suspect the advanced timing is the problem.

Ok fair enough, but think about purchasing a 3.8 pulley for the hub.

As for your PCM I'm not sure why you have it configured for a 160stat and 3^ timing increase at WOT. I'm going off your sig, but this could be a problem in your case.

When I bought the PCM, this option looked like a good idea:

"Increase WOT ignition timing tables by up to 3 degrees - ideal for naturally aspirated vehicles with any premium fuel, or supercharged vehicles with stock camshaft where 93 or 94 octane fuel is readily available."

As for the 160, I like to keep things cool. I'm running a 160 stat and the PCM setting is only to turn the fans on at 165.

1st thing you do is get out the resistor that makes your car think it's always 42 out.
#1 it's a hack
#2 it's useless
#3 even honda owners will laugh at you...

edit: nm i saw you took it out. good job!

I would also do some Seafoam through the intake. Some of that KR might be due to carbon buildup.

How are your plugs? Fuel pressure? What temp was your IAT indicating?

We need to know what your engine is doing - What are your fuel trims? You could just have KR from over fueling?

Whether lean or rich try running some race gas and see if it goes away.

Worst comes to worst I'm sure if you try someone has a tuner around you that can take some timing away until you get some exhaust mods.

I see you have a Scanguage...what are you LTFTs locking in at when you go WOT? What are your O2s like at WOT? Below 900, between 930 - 940?

Problem with having a Bonneville and finding someone with a tuner nearby is the tuner probably (99% of the time) won't have the proper year Bonneville file. I found this out the hard way, but recovered -I was seeing 9* KR with a 3.35" pulley. I backed up to a 3.8" until I put PEM's on, an adjustable Fuel Pressure Regulator (bumped WOT FP up to 52 psi) and then put a 3.5" on. A scan the other day revealed 3* KR with a weakening FP only able to achieve 44 psi at WOT, on a day with temps in the mid-80's.
My next mod will be a replacement fuel pump.
I'd suggest you find a local mechanic who'll lend you his fuel pressure guage for a couple WOT runs -do this with under 1/3 tank of gas if you can so can see how bad your fuel pump is under load with low fuel and on a hot day.

Still need to get trims that will tell us were to go from there...

Also: [cough] I have a mechanical fuel gauge with 6' of stainless line that I have for sale - $55. [/cough] if you want to check fuel pressure.

sandrock wrote:I would also do some Seafoam through the intake. Some of that KR might be due to carbon buildup.

How are your plugs? Fuel pressure? What temp was your IAT indicating?

- Plugs were replaced in March along with a complete and thorough TB cleaning.
- Fuel pressure: not sure under WOT. I'll watch it tomorrow morning on the way to work, however, with it hitting 4-5 KR, I don't want to push it too hard.
- Pre-resistor = always 42 degrees. Now it's reading actual temps (seen it as cold as 80 and as high as 111).

TommyGloves wrote:I see you have a Scanguage...what are you LTFTs locking in at when you go WOT? What are your O2s like at WOT? Below 900, between 930 - 940?

- LTFT - have to check tomorrow morning
- 02s - have to check tomorrow morning