Thoughts on this tune?
Thread Starter
Joined: Jun 2014
Posts: 1,238
Likes: 47
From: Noblesville, IN
Thoughts on this tune? This is a buddy's truck. He bought it modified and asked me to take a look and see if there was a reason why he was only getting 8MPG when he was driving normally.
It's a 2006 Silverado 6.0 LQ4. From what I was told it is bone stock save the turbo, and was tuned by a professional shop out of Oklahoma. I'm not super familiar with speed density (or turbo tuning) so I don't want to pass judgment on anything I see here yet, but, there are some things that are standing out to me as odd.
1. The O2's have been turned off entirely. I expected to see the MAF deleted but I'd never heard of a speed density tune that also deleted the O2 sensors. In the log you can see some very odd reading from the O2 sensors (you can see them in the log), is it possible there was an issue with the O2 sensors and the shop just deleted them as a bandaid or is this a standard thing to do?
2. The Electronic Throttle tables have changed. Given that the throttle is still stock, again is this standard practice with a turbo? (I was told by my friend that P.O. added a TAC module "for tuning", whatever that means)
3. I see a lot of changes to the idle table. Since the motor is completely stock (and the turbo isn't doing anything at idle) I didn't think there'd need to be any reason to change much, except for possibly making off-idle acceleration better. Is that the case or is there something else?
I also attached a log with some basic PIDs on it (was just trying to get a sense of how the truck was running). If anyone sees anything else out of the ordinary please let me know.
Thanks all!
It's a 2006 Silverado 6.0 LQ4. From what I was told it is bone stock save the turbo, and was tuned by a professional shop out of Oklahoma. I'm not super familiar with speed density (or turbo tuning) so I don't want to pass judgment on anything I see here yet, but, there are some things that are standing out to me as odd.
1. The O2's have been turned off entirely. I expected to see the MAF deleted but I'd never heard of a speed density tune that also deleted the O2 sensors. In the log you can see some very odd reading from the O2 sensors (you can see them in the log), is it possible there was an issue with the O2 sensors and the shop just deleted them as a bandaid or is this a standard thing to do?
2. The Electronic Throttle tables have changed. Given that the throttle is still stock, again is this standard practice with a turbo? (I was told by my friend that P.O. added a TAC module "for tuning", whatever that means)
3. I see a lot of changes to the idle table. Since the motor is completely stock (and the turbo isn't doing anything at idle) I didn't think there'd need to be any reason to change much, except for possibly making off-idle acceleration better. Is that the case or is there something else?
I also attached a log with some basic PIDs on it (was just trying to get a sense of how the truck was running). If anyone sees anything else out of the ordinary please let me know.
Thanks all!
1. The O2 codes have been turned off, but the O2s are still setup to function in closed loop... even though they are not working. That tells me there is a wiring problem.
2. It looks like they tried to make it more responsive to throttle input, not out of the ordinary but can cause other problems in these controllers so most people leave that stock or it can cause reduced engine power sometimes.
3. There is no reason to change those tables on a stock engine.
There are LOTS of problems with that tune, but I'm seeing mechanical/electrical issues that are probably causing the bad gas mileage with dead O2s, etc. Without knowing what injectors were used, etc I don't know if the data is correct so the current VE table could be very inaccurate because it looks like ****. I mean everything in that tune looks like **** IMO.
2. It looks like they tried to make it more responsive to throttle input, not out of the ordinary but can cause other problems in these controllers so most people leave that stock or it can cause reduced engine power sometimes.
3. There is no reason to change those tables on a stock engine.
There are LOTS of problems with that tune, but I'm seeing mechanical/electrical issues that are probably causing the bad gas mileage with dead O2s, etc. Without knowing what injectors were used, etc I don't know if the data is correct so the current VE table could be very inaccurate because it looks like ****. I mean everything in that tune looks like **** IMO.
Thread Starter
Joined: Jun 2014
Posts: 1,238
Likes: 47
From: Noblesville, IN
That's kind of the feeling I got from it, but I'm not master tuning so I didn't want to pass judgment on anything until I spoke with those more knowledgeable.
Spoke with the owner and he said that the manifold bolts had all backed themselves out and he had a pretty huge exhaust leak at both heads. Also, the drivers side O2 sensor is completely disconnected and the bung in the manifold has been capped, and the passenger side had an O2 sensor that looked new. We've got new manifold gaskets and new O2's on the way (as well as a quality wideband so we can do some actual tuning).
I don't think he's run into any reduced engine power or throttle issues, so I'll leave those alone. I'll double verify the motor is stock before i touch the idle tables. I know internally it is, but with the awful tune/mechanical work I've seen so far I think this needs to be double-checked everywhere.
Spoke with the owner and he said that the manifold bolts had all backed themselves out and he had a pretty huge exhaust leak at both heads. Also, the drivers side O2 sensor is completely disconnected and the bung in the manifold has been capped, and the passenger side had an O2 sensor that looked new. We've got new manifold gaskets and new O2's on the way (as well as a quality wideband so we can do some actual tuning).
I don't think he's run into any reduced engine power or throttle issues, so I'll leave those alone. I'll double verify the motor is stock before i touch the idle tables. I know internally it is, but with the awful tune/mechanical work I've seen so far I think this needs to be double-checked everywhere.
That is definitely a case of "professional" in the sense that they got paid for doing it. Certainly not professional in the sense of deserving to get paid for that garbage tune.
Thread Starter
Joined: Jun 2014
Posts: 1,238
Likes: 47
From: Noblesville, IN
Alright. I've been working on cleaning up the tune, and i'm running into an odd issue. Whenever i lift off the throttle, it is pegging super rich. Like I've seen as low as 9:1 AFR. Pulling air out of the bottom of the VE table doesn't seem to make a difference, and it doesn't matter at what rpm. Any ideas what's causing this? Posted a log snippet of what I'm talking about.
Other issue is this truck does not want to start when cold (and sometimes when warm). First thing in the morning it will crank, backfire, and continue to not start unless I let go of the key. Will fire up immediately after that however. Posted a log of that as well. I tried reverting the idle and startup tables back to stock to see if it made a difference, but it's doing the same thing. Also posted a log of that.
Appreciate any/all help!
Other issue is this truck does not want to start when cold (and sometimes when warm). First thing in the morning it will crank, backfire, and continue to not start unless I let go of the key. Will fire up immediately after that however. Posted a log of that as well. I tried reverting the idle and startup tables back to stock to see if it made a difference, but it's doing the same thing. Also posted a log of that.
Appreciate any/all help!