E78 '12 Silverado w/ Maggie and Cam

[FastEddy]

I've been playing with this thing all day. It's the first E78 I've done that's beyond a bolt on vehicle, so it's proving to be a bit challenging.

The truck's had a lean tip in problem all day that I finally seem to have fixed through PE enable parameters. Though in this last run I made, you will see in the data log file that it remained in CL during the WOT portion of my run. :-/

The truck has Deka 60# injectors w/ a Volant CAI that houses the factory maf in what appears to be about a 90-95mm housing.

Since everything on these E78's is torque based, I'm having a bit of a hard time figuring out the best method for getting 100% throttle. As you can see during the run, the throttle was fluctuating between 83-88% during the run. I was able to finally achieve this by adjusting the driver demand settings above 44%...

I'm afraid to adjust these tables too much though, because if you can see after second gear I let off (which shows as a decrease in MAF flow)... but the TPS remained in the 80+% range.

Anyways, I just need some second opinions and some help from anyone who has done more than a couple of these and knows what needs to be done. I know the tunes a mess, so don't be too critical... I will clean it up after I figure out the issues.

thanks in advance.

[FastEddy]

Updated tune and data log file... It's still not going into PE mode, still have throttle staying open after letting off the pedal, and I can't figure out WHY this thing would be part throttle detonating with less than 10 degree's of timing at part throttle. I know stock manifolds will hurt it a little bit, but w/ negative fuel trims I wouldn't think I'd be having that problem.

[FastEddy]

Fixed the PE enable problem... I forgot I had maxed out the peak torque table in effort to keep fix the throttle fluctuation under WOT problem. Changed that and PE now works.... but still getting throttle fluctuation under WOT. And it seems the truck is lean spiking all over the place, but fuel trims remain negative. I'm concerned the injector data for the Dekas could be part of that problem.

Still not sure about the timing having to be so low under 3000 RPM.

[Bill@HPTuners]

One of our customers ran into a similar issue previously and our head engineer gave this advice "Ok so the PE torque threshold is a % of maximum torque. In the maximum torque tables he has set these numbers to 8192, which is going to make the % torque very small and probably lower than the threshold he has set. Try either lowering the max torque tables to something realistic or lowering the PE torque % thresholds to 0."

[FastEddy]

I changed all the max torque numbers back to stock then added 10% to them. Figured that would be "realistic", but still had the same problem.

My fuel trims don't look THAT bad, but I'm leaning towards injector data possibly? Thinking about putting the stock 52's back on the truck. The Maggie came off a TBSS and already had these tall body Deka 60's on it. The data I used should be close, but I had to manually enter some of the stuff. I'm grasping at straws here...

Also, are there any idle timing tables for these? I'm having to control idle timing via the minimum spark, otherwise my idle timing is in the negative figures. Which I know would indicate a possible vacuum leak, but I think it's just because I had them drill a hole in the TB blade to help the truck idle since there aren't any base running airflow tables to adjust.

Another thing I noticed in my .722 is that there is a glitch when you copy the driver demand tables. It puts 0's in the low TPS% areas. See the attached screen shot...

[FastEddy]

Ok, starting to get a little better with my latest changes...

Still getting TPS fluctuation under WOT

Still having part throttle low speed lean popping

Not shifting 2-3... haven't spent much time trying to address this issue. However it seems to have started every since it started belt slipping at the top of 2nd gear. So I'm assuming that's probably why it doesn't want to shift.

It also keeps throwing P1516... I've disabled the code, but can't see anywhere that allows me to raise the airflow parameters for it?

[FastEddy]

Ignore the P1516 comments. I had it switched back on by accident.

[Chris@HPTuners]

ok so firstly you need to start logging some useful PIDs to find out where the ETC limit is occurring.

The ETC is controlled by the "predicted" torque, my guess is the Predicted Engine Torque Cmd is being limited by the Maximum Engine Torque.

Read the E78 Tuning guide in the help files to see more detail on the throttle calculations and limits.

You have a lot of the axle torque limits close to the stock level.

You also have the Driver Demand Torque set to stock. You will need to increase the 100% row to command more torque from the engine at WOT. Try increasing it at 10% increments and watch the PIDs in the scanner. Same with Peak Torque table.

The idle is all torque based, it is controlled by the Torque Reserve and the PID controllers for Immediate (spark) and Predicted (throttle) Torque. Basically the PCM opens the throttle to achieve the idle RPM using the torque reserve as the starting point. If your throttle is flowing too much air at idle its likely at the lower limit and timing is being pulled to achieve the idle (no different to any other idle control system).

[Ben Charles]

Ran into a 13 Truck today that wouldn't hit PE at all, These E78 computers are tricky b/c of the Tq based calculations. After doing some reading I think I have it figured out. Still learning