Low Performance 6.7

[anarchydiesel]

Moved duration, timing, pressure below 90mm3. Rescaled axis's to give more control between 0-90. The truck still never ran to potential and I have not talked to Richard in quite a while.

[anarchydiesel]

Likely, but not sure. We really need to track down the load based limiter, that would change all 6.7 tuning completely not just the conversion trucks.

[2007 5.9]

Makes it such a SMALL window for tuning....

[anarchydiesel]

Yes, very hard to get a good smooth tune built. The 5.9s can be similar but usually the limit to around 115 not 90.

[ScarabEpic22]

Good info, Ive heard the 6.7s have a load based limiter but havent heard if it's been found yet or not. Guess this confirms it hasnt yet.

If you can only get 90-94mm3 of fuel, yea that's going to seriously limit potential. Since Im still getting into the diesel stuff, is there any way you could fudge the ECM into giving more fuel even if it only commanded 90mm3? Like gas guys do with fudging injector flow rates or fuel pressure (probably not applicable on a diesel)?

[KhakiCummins]

Eric, I think this goes back to what Zach told us in class, the mm3 in the diesel tuning is just a value...

Assuming that what the load limited does is limit you to say 90 mm3, then I think that if you were to re-scale your tables from say 0-90 instead of 0-150, you may be able to get around it. This is all just theory though...

I suppose I could always try to build a tune like that and run is and see what it does.... With not having to deal with the limiter though, I don't know if I would really be able to tell if it worked.

[WetMtnCrd]

Ill look at it in the morning with fresh eyes, do you happen to have a log of it not fueling past 94mm3?

And you just do not have a VSS feed into the ECM correct? All other sensors except VGT and VATS/security are there?

What are your goals with this, how many RPMs do you want/can you run? Mods on the motor?

The sensors to the ECM I have are: RPM, ECT, MPA, IAT/Baro, MAP, MAF. No VGT, no emissions of any kind, and no VSS. As far as a data log what would you like to see. I have so many right now I'd have to look through them all and see if I have something you want. Or just get a new one. Either way it'll have to wait till the weekend when I have more time to look through stuff. I sent a few to Les, he might be able to answer some questions too. He worked on this a bit without much success either. I'll look at and try the tune anarchy redid this weekend also. Sounds like finding the load limiting may be the answer though. Also I've been trying to get the fuel pressure up and haven't had any luck at all with it. I've adjusted the fuel pressure tabel, the duty cycle table, and the FCAC table. None of them made any significant difference. But I have developed a fuel pressure oscilliation under moderate acceleration when empty or towing. It's pretty noticeable seat of the pants and on the data log. Light cruise it can't be felt but there is a slight oscillation that can be seen at times on the logs. I'll try to find one that shows it and post it. The oscillation problem is almost a bigger issue for me right now. I don't think it's good for the engine and fuel system for this to be happening. Thanks to everyone for your input. We'll get this figured out.
Doug

[WetMtnCrd]

Les, I would say that it is the load based limiter that is killing it. We have a fummins w/6.7 that should be running in the next couple of days and I imagine I will be fighting the same thing. When Zach and I were tag teaming Richard Madsen's truck it reacted the same way.

Keep us posted on your fummins project. I'd like to know if you have the same tuning issues. The question I still have is how did Smarty do it. I had Smarty on here when we first got it running and it ran pretty good. I didn't log anything so I don't know if it fully fueled or not. But it ran ok. Has anyone ever logged a Smarty tuned 6.7 to see what it's doing with the mm3. Or are they just doing a work around with pw and timing.

[2007 5.9]

Two logs from this truck...crude tuning with high pulse, but I was to get it to do something....
Log_0007 (1).efi
Log_0008 (1).efi

[2007 5.9]

No DTC's in any logs...