Help me diagnose my 2006 z06...

[Thacker]

Please note I am a HPtuners nooby... I had Vengeance attempt to tune this car but they were unable to do so... which has me troubleshooting now.

Hey guys.

I've been fighting a nightmare with this car. The car has 10,500 miles on it. I first got it and it was bone stock. I put on a halltech mf103 and took it out one night with my friends. Ran it hard on the highway a few times and I could feel it lay over in the upper RPM range... but nothing too serious.

I didn't worry about it much.

The next week I swapped the heads to AHP heads that were milled .020 and added a ported TB and ported LS7 intake manifold.


I sent the car to vengeance racing to get tuned, and they were unable to tune it. Massive KR in the upper rpms.

I got the car back and began looking for causes.

I've replaced:
MAF
Alernator (old one fan was dinging teh housing)
Plug wires.
Ran some 100 octane with the original gas that was in it for the tune and then filled up with Quik Trip 93.
Ran Mopar combustion chamber cleaner to remove carbon from pistons

I am still getting massive knock retard.

Here is a screen cap from my log session tonight.



When I first nailed the gas, it didn't get any KR but the car was spinning so the car wasn't under heavy load.... I backed out and nailed it again. Immediately it tacked up to like 12 KR and I could hear audible detonation :leaving::leaving::leaving:.


I am at a loss on how to fix this. It seems like something is majorly wrong with the car.

Mike @ vengeance told me the AFR looked great on the dyno when the detonation started, but I didn't get a print out.

I've attached a log that includes the Knock retard...its quite large though and the knock is in the middle somewhere.

EDIT, here is the tune as well.


badknock.hpl



z06aftertune.hpt

[5FDP]

Post the tune aswell.

[Thacker]

Post the tune aswell.

I've added the tune to the original post.


I am at this point starting to consider mechanical problems. Did I install the head gaskets wrong? I've lost 0 coolant in 500 miles... car gets NO kr at anything but WOT at 5k+ rpms.

Fueling issue? Spark?

[5FDP]

Ideally the car should be tuned for the heads/intake and throttle body swap first. Like a new MAF tune and VE table work done.

And it looks like you are nearly maxing out the MAF sensor too, you are like 300-400hz from it being maxed out. Looks like they also set it up to be a MAF only tune really, it uses the MAF only after 300 rpm and has long term trim disabled.

You should also log commaned air fuel ratio in the table display and a wideband is a must at this point with those mods. I wish I knew more to help you here but I don't know enough about those cars and hopefully someone else has a better opinion for you.

[Thacker]

Ideally the car should be tuned for the heads/intake and throttle body swap first. Like a new MAF tune and VE table work done.

And it looks like you are nearly maxing out the MAF sensor too, you are like 300-400hz from it being maxed out. Looks like they also set it up to be a MAF only tune really, it uses the MAF only after 300 rpm and has long term trim disabled.

You should also log commaned air fuel ratio in the table display and a wideband is a must at this point with those mods. I wish I knew more to help you here but I don't know enough about those cars and hopefully someone else has a better opinion for you.

I was hoping Vengeance racing would have done this... the tuner told me he started with a base tune that he loads on these cars and goes from there.

They put out cars that make great power all the time so I have a feeling they know what they are doing.. I just dont know why mine is so far off.

[Nick@Newtech]

First thing you need to do is verify you AFR, by no means should you use narrow bands to determine AFR but to me .8xx might be a few hairs lean. if you are hearing audible knock, when and where exactly? I will tell you also once you have a real AFR reading and you are sure you are safe there you can continue tuning until then add some fuel for safety if you insist in beating on the car. I will also mention that 9 times out of 10 burst knock has to be turned off in E38 cars but only when you are using the proper tools. make sure your plugs are a little colder than stock I recommend a TR6 open the gap up to 40-45 thou. DO NOT disable burst KR until you have a wideband and have the Proper heat range plugs in, and you know your setup is correct. I also don't see you mentioning a cam in your post? if true your SCR went up as well as your DCR, your part throttle timing rolling in to WOT might give you a tip in knock also. I could go on and on, first things first GET A WIDEBAND.

[Nick@Newtech]

Ideally the car should be tuned for the heads/intake and throttle body swap first. Like a new MAF tune and VE table work done.

And it looks like you are nearly maxing out the MAF sensor too, you are like 300-400hz from it being maxed out. Looks like they also set it up to be a MAF only tune really, it uses the MAF only after 300 rpm and has long term trim disabled.

You should also log commaned air fuel ratio in the table display and a wideband is a must at this point with those mods. I wish I knew more to help you here but I don't know enough about those cars and hopefully someone else has a better opinion for you.

A lot of tuners do this because they dont wanna deal with VVE stuff im guessing. I go the extra mile for my customers and make sure their cars have an excellent VVE tune as well as MAF tune. I have invested a lot of time in perfected maps and coeff values for most setups, including 3 bar ZR1s and I always verify on my dyno.

if you look at his PE commanded its 1.143 = 12.86 commanded, his PE delay is 5000, which I like to lower myself. Also his map readings are odd, which makes me wonder if hes at high elevation as well.

[Thacker]

A lot of tuners do this because they dont wanna deal with VVE stuff im guessing. I go the extra mile for my customers and make sure their cars have an excellent VVE tune as well as MAF tune. I have invested a lot of time in perfected maps and coeff values for most setups, including 3 bar ZR1s and I always verify on my dyno.

if you look at his PE commanded its 1.143 = 12.86 commanded, his PE delay is 5000, which I like to lower myself. Also his map readings are odd, which makes me wonder if hes at high elevation as well.

I am in Atlanta, so close to sea level.


I feel like the car is running lean. I pulled my plugs yesterday and they were really white..... but I figured that might be from the mopar combustion cleaner I had ran through it the day before.

Is a vacuum leak possible?

I am scheduled to take the car back to vengeance on tuesday.... but if I can't get this sorted I don't know if I need to do that or not.

[Nick@Newtech]

A vacuum leak could cause the car to run lean yes, it's unmetered air. Showing 94-95 kpa means you have some restriction and slight vac while at WOT or your map sensor is reporting in accurate data it should read 105 engine off and typically at wot 99-100 with decent intake parts on the car. Set your pe to 1.167 maf hz 7000 and up add 5%. See if that helps with kR. Also refer to my first post. What plugs? Also set pe delay to 2000.

I am in Atlanta, so close to sea level.


I feel like the car is running lean. I pulled my plugs yesterday and they were really white..... but I figured that might be from the mopar combustion cleaner I had ran through it the day before.

Is a vacuum leak possible?

I am scheduled to take the car back to vengeance on tuesday.... but if I can't get this sorted I don't know if I need to do that or not.

[mowton]

Check for plugged cats as well. Your injector pulse width kind of flat lines at 14.x ms? ....Add commanded AFR, MAF Hz and Dynamic Airflow to your log. And as said above, a wide band is a must. Did anyone check the knock sensors? Do you hear actual pinging? How about any exhaust or engine noises as you accelerate hard which can develop false knock.

Add those pids, hook up a wideband and carefully log events up to the start of knock...and check the cats.

Ed M

[Thacker]

A vacuum leak could cause the car to run lean yes, it's unmetered air. Showing 94-95 kpa means you have some restriction and slight vac while at WOT or your map sensor is reporting in accurate data it should read 105 engine off and typically at wot 99-100 with decent intake parts on the car. Set your pe to 1.167 maf hz 7000 and up add 5%. See if that helps with kR. Also refer to my first post. What plugs? Also set pe delay to 2000.

As far as intake goes, I have a Halltech MF103, ported LS7 TB and Ported LS7 Intake Manifold.

The plugs are NGK TR6iX @ .038

[Thacker]

Check for plugged cats as well. Your injector pulse width kind of flat lines at 14.x ms? ....Add commanded AFR, MAF Hz and Dynamic Airflow to your log. And as said above, a wide band is a must. Did anyone check the knock sensors? Do you hear actual pinging? How about any exhaust or engine noises as you accelerate hard which can develop false knock.

Add those pids, hook up a wideband and carefully log events up to the start of knock...and check the cats.

Ed M

This is all above me. I paid 590$ to have vengeance tune the car and this is how it was given back. They said it must be a plug problem or bad gas. He had never seen a LS7 do this before. As far as plugged cats, is there anyway I can tell without pulling them off the car? The car only has 10,300 miles on it.

[realcanuk]

Agree with checking cats on this...best way is to pull them and check. Also how much compression increase do those milled heads give you ?

[Nick@Newtech]

This flat out ridiculous a professional tuner just says "I can't tune it" gives a a vague diagnosis of what the issues are charges 600 bucks and gives you the boot.

[mowton]

Could also be electrical pickup from the ignition on the knock wiring. Double check wires aren't "leaking electrically" and the wiring to and from the knock sensors. Ls7 are known to knock but 18-19 degrees should be fine.

Ed M

[schpenxel]

When my power steering pump was going out I had a ton of KR from the noise it was making... though, it wasn't just at high RPM's

It probably isn't the answer in this case, but I figured I'd throw it out there just in case.

[Thacker]

When my power steering pump was going out I had a ton of KR from the noise it was making... though, it wasn't just at high RPM's

It probably isn't the answer in this case, but I figured I'd throw it out there just in case.

I can hear audible knock along with the KR and the car gets 0 KR even under WOT situations until about 5300 rpm.

[schpenxel]

Ah, gotcha. Never mind on that one then!

[mowton]

so looks like we have to wait for the wideband and wot fueling results....

Ed M

[schpenxel]

This flat out ridiculous a professional tuner just says "I can't tune it" gives a a vague diagnosis of what the issues are charges 600 bucks and gives you the boot.

Agree. With the kinds of cars Vengeance puts out I'm surprised to hear this story though..

so looks like we have to wait for the wideband and wot fueling results....

Ed M

Agree... check cats, install wideband..