Now a question on detonation

**AKIRA** · 03-20-2007, 10:20 AM

Today we installed the LS6 intake manifold. We took it for a drive and everything ran fine. SES light came on cuz of the EGR shit, but I predicted that.

Anyway, when I took off from a light, at the top of 3rd gear (4000-5500), you can hear a clear sound of detonation. Now, this did NOT come from the installation of the LS6. This detonation had always been there, but Ive just ...well....drove like an old lady for about a year. I hardly ever floored it from a dead stop for so long, I just kinda forgot about it.

My mods are in the sig...
I use 93 octane and the car does smell kinda rich.

This problem has been occurring for years. My compadre who helped me install the intake is actually a mechanic and he said it could be caused by bad gas or carbon build up.

This is not a nice problem, so what do I do? Get it tuned? I dont know of ANYONE in south florida (I am on the east coast, 45 min N of west palm beach.)

**0rion** · 03-20-2007, 11:15 PM

You have a diablo listed in your mods, have you tried adjusting your spark curve? I'm assuming you have the performance tune installed? As for carbon buildup you could use seafoam on it found at most parts stores. Directions are on the can. Have you logged it to see how much knock you're getting?

**AKIRA** · 03-21-2007, 09:50 AM

Umm..Ive installed the Diablo's stock performance tune. As far as adjusting spark, I know how to on the tuner, but I dont know which way to go.

Logged? No I havent..

SeaFoam...I remember reading about that shit on here. I didnt know it was still useful.

**0rion** · 03-22-2007, 12:42 AM

First off set the diablo up to monitor real time data and have someone ride with you to watch it or have them drive and you watch it since the diablo won't let you record. DON'T TRY TO DO IT BY YOURSELF. You'll kill either yourself or someone else. I've never used mine to monitor so I'm not entirely sure what parameters it'll let you look at. At a minimum look at your fuel trims and knock/spark retard and WOT O2 voltages. Try to hit a few different scenarios such as accelerating from a stop, accel from ~30 mph, and a WOT run. Post back up what numbers you're seeing and I'll try to help you. I'm interested in the amount of knock you're getting and what your fuel trims and O2's are doing. They'll fluctuate around quite a bit so try to get a decent average of what everything is doing. Have you thought about buying autotap or some other type of logging software? Good investment if you plan on modding your car.

**tblu92** · 03-26-2007, 08:14 PM

There is a table in your spark file that adds timing at certain points of your RPM band to make the EGR work more efficiently--Table # B5907---It must be
"0" ed out other wise you will be adding timing and the EGR isn't there so it will ping like crazy--It is adding the timing from 800-4400 RPM's and at .006- .023 oz. per cylinder.On my tunes--I typically "0" out this table even if the EGR is still in the car-Doing so eliminates that PT ping especially on higher mileaged cars

**99Firehawk** · 05-13-2007, 05:59 PM

Sounds like I have the exact same problem. I had the ping start about a month after i started playing with the PE and timing on the diablo tuner. I reset it and uninstalled the tune back to stock tune and problem still persists.
I have tried bringing back the timing 2% and even adding 2 % PE, and no change. Either way I still get 3.75% knock retard under WOT above 4700 RPM.
Sometimes i will get a knock code. or rarely MAF code.

**0rion** · 05-13-2007, 07:01 PM

do you know how much timing you're actually getting at WOT? If I remember correctly 99's were 26 degrees WOT. 2% of that is a shade over .5 degrees. Not enough. I would maybe try 10% and see how many degrees of knock you're getting then. Actually, I would start by making sure it's real knock. I just saw where you're getting knock sensor codes. Might want to make sure your knock sensors are straight before doing much. I would also put some high octane gas in and see if the knock goes away. If it does go away then it was real knock. I know the 98 knock sensors were replaced in 99. Not sure of when though. Might want to look and see what your build date is and whether you have the newer sensors. I have 98 sensors and until the heads/cam never really had much issues with knock but since then I'm getting all kinds of weird knock but I'm still working on the tune so once I'm sure my fueling is good I'll take care of my knock sensors.

edit:
Another thing I just noticed after re-reading your post. You say you're adjusting pe and timing. What are you using to verify AFR? Narrowband O2's, what's your voltages if you are? Might want to find someone or buy a wideband to verify AFR and make sure you're not lean up top

**99Firehawk** · 05-14-2007, 07:20 AM

Originally Posted by 0rion

do you know how much timing you're actually getting at WOT? If I remember correctly 99's were 26 degrees WOT. 2% of that is a shade over .5 degrees. Not enough. I would maybe try 10% and see how many degrees of knock you're getting then. Actually, I would start by making sure it's real knock. I just saw where you're getting knock sensor codes. Might want to make sure your knock sensors are straight before doing much. I would also put some high octane gas in and see if the knock goes away. If it does go away then it was real knock. I know the 98 knock sensors were replaced in 99. Not sure of when though. Might want to look and see what your build date is and whether you have the newer sensors. I have 98 sensors and until the heads/cam never really had much issues with knock but since then I'm getting all kinds of weird knock but I'm still working on the tune so once I'm sure my fueling is good I'll take care of my knock sensors.

edit:
Another thing I just noticed after re-reading your post. You say you're adjusting pe and timing. What are you using to verify AFR? Narrowband O2's, what's your voltages if you are? Might want to find someone or buy a wideband to verify AFR and make sure you're not lean up top

I cant remember how much timing it was running at WOT, ill have to re-check sometime. But because of the consistant knock code i will get (even after resetting the codes more than twice), I am going to replace both knock sensors and pig tails with the 99-2001 sensor type. That should solve the problem im hoping.
I always run 91 pump gas -always, unless 93 is available.
Its just odd that the code came up just shortly after i played with the settings on the tuner. I never had increased the timing more than 2.5% though. (im actually going to put it down to -2.5% and see what that does, my PE is now at stock setting (0%) (though it smells rich at WOT with the tops off) and the computer is at stock tune otherwise.
I might be getting a wideband after i do the new knock sensors and ls6 intake...
Do you think if I add PE that would help any?

**rbob93** · 05-14-2007, 08:40 AM

A rich condition should actually help in the case of ping as would a colder plug type ( on the condition the incorrect plug heat range is the cause )

**99Firehawk** · 05-14-2007, 01:17 PM

Ok, So I tried 93 gas, and added .5% PE and took out -6.5% spark, and still I will get a 3.97% spark retard over 5000RPM in 4th gear (wot), and the car will buck a little bit too. It doesnt seem to matter at all what i do, the computer will always retard the timing, im going to blame the knock sensors being bad.
The timing is at 22.8 deg @ 5100 rpm wot.

A new issue that my baby is doing is at a low RPM (under 1400 especially) it will buck and kick when you push on the gas. !?