First look at a meth tune

[Ghostnotes]

So I'm hanging a chandelier at a friends house yesterday and he has a C7. After hanging it, he asks me to take a look at his tune because he keeps going into limp mode( 416 with a YSi-v7, large VT cam, headers,meth) so I'm thinking P0068 which was one of the codes and needed to be set higher. Has a ton of other codes in it. Come to find out some of his wiring was damaged by a header install.

Anyways got that taken care of. Now I have never messed with or tuned a car on meth injection so I was curious to see what the tune looks like. Is it normal for your fuel trims, at idle to be a constant ~12+ with your LTFT's tuned out?
Sat there idling for 20 minutes and that's where they sat the whole entire time. His O2's are working but sluggish( location), he has all 4. His trims at idle never went below 10+.

[Ben Charles]

Nope, that’s just off some

[Ghostnotes]

Nope, that?s just off some

Kind of thought so.

This was from a very reputable organization. I only glanced at it to look for simple issues. What got me moreso was the LTFT's being turned off. The rest of his tune suggests closed loop since thats what his output read on the scanner. Did not look at the VT/VE etc.. tables yet to see if he is running MAF only or not.

I know he paid around 1k for the tune though....

[Ben Charles]

Nothing wrong with long terms being off, I Rarely use them myself!

Don’t get me started on most “pro tunes” usually far from it

[Ghostnotes]

Nothing wrong with long terms being off, I Rarely use them myself!

Don?t get me started on most ?pro tunes? usually far from it

I know you can run with LTFT off, just figured for who they claim to be and what he paid, it would be more polished.Looked.... and MAF only as suspected.Havent looked at anything else yet.

I'm by no means near a pro, but since i was able to figure out my zone boundary issues and tune my VE, I've done several friends and family GEN V, 10 or more and came out good enough. No surging, good idle, passes emissions etc, so in my mind as an amatuer i should have some AH HA moments and learn a few things looking at a pro tune Hopefully that will be the case when i have more time to look.

[malikib]

I know you can run with LTFT off, just figured for who they claim to be and what he paid, it would be more polished.Looked.... and MAF only as suspected.Havent looked at anything else yet.

I'm by no means near a pro, but since i was able to figure out my zone boundary issues and tune my VE, I've done several friends and family GEN V, 10 or more and came out good enough. No surging, good idle, passes emissions etc, so in my mind as an amatuer i should have some AH HA moments and learn a few things looking at a pro tune Hopefully that will be the case when i have more time to look.

well if you attach the tune we can help you more

[Ghostnotes]

Here it is.

I've only tuned a small handfull of GEN V, so it maybe its fine. Apparently its putting out 1000 or so hp

[Ghostnotes]

Thoughts?

[Lakegoat]

I guess that must be a maf only tune because the map sensor is still a one bar. ??? I would think that you would want the vve table correct. Is that something different in a Gen 5.

[Ghostnotes]

I guess that must be a maf only tune because the map sensor is still a one bar. ??? I would think that you would want the vve table correct. Is that something different in a Gen 5.

I did not see that but yes it's a MAF only but that doesn't matter if I understand it correctly, the MAP still should be replaced since he running boost anyway. His baro is not even broke out either.

Again I have never tuned a meth injection system. Dual injector yes, but not meth so I cant say for 100% certainty on some things.

[malikib]

I did not see that but yes it's a MAF only but that doesn't matter if I understand it correctly, the MAP still should be replaced since he running boost anyway. His baro is not even broke out either.

Again I have never tuned a meth injection system. Dual injector yes, but not meth so I cant say for 100% certainty on some things.

well you need to adjust the vve as well it's extremely important as the ecu relies on the vve as a sanity check and will revert to it if it sees huge discrepancies

[LSChev]

Pretty much everything you have mentioned here so far is not related to the fact that the car has meth injection.

[HeavyChevy305]

Calibrating with meth your MAF should still be dialed in correctly (+/-5% fuel trims). You want your air model to be as accurate as possible. People run meth to compensate for a lack of fuel system. Dial back the PE till your pulse width is at 6.0 or below and flood it with meth till you hit target lamba at WOT.

[Ghostnotes]

well you need to adjust the vve as well it's extremely important as the ecu relies on the vve as a sanity check and will revert to it if it sees huge discrepancies

I'm not adjusting anything on it. As i said, I just pulled it to take a look at it to maybe help me learn or understand.

[Ghostnotes]

Pretty much everything you have mentioned here so far is not related to the fact that the car has meth injection.

Care to elaborate?

Your right, it doesn't since I never have tuned meth or dealt with it. I'm talking about things that don't add up, but since I know almost nothing about meth, I don't know if because he is running meth what i see as suspect ends up being ok.

[Ghostnotes]

From my understanding, since I have the exact same FI setup minus the meth, you should have a 2-3 bar map installed with a baro breakout. It is also my understanding that the VVE and VT tables at this point should be modified since he is running a 416ci. To me that's not just tuning, that's just plain physics. Not to mention it seems common understanding that even though it's MAF only, it does still reference the VVE tables for other reasons.

I haven't taken a ride/scan yet but I plan to. He has no installed WB so all I would be able to look at is everything below PE. However he did tell me that it bucks pretty bad when idle cursing, say in 1st to 3rd gear (manual trans) with light throttle and tip in.