Removing Post Injection/Timing

[super_kev]

When removing the post injection in HPT, from what I can see (looking at a '07 5.9 ECM) I would want to zero out the Transient, High Air, High-Med Air, Med-Low Air and Low Air Density Tables in both Diesel Timing (Post Timing) and Diesel Fueling (Post Injection), correct? Or is there a simpler way to do it?

[jfreemanak]

Correct, though I think all you need to do is zero out the fueling and not the timing table.

[Jim P]

Yes only need to zero out post injection quantity, don?t expect to see any benefits/gains from it.

[super_kev]

Also, when I decrease pilot (say, turn pilot off at 2000rpm), from what I've read, it looks like it's: pilot + main = total timing BTDC if positive value, or ATDC if negative value on timing tables... right?

So if I go from 11.484 pilot timing (or ~11 degrees BTDC) at 2000rpm (I'm on a '07 5.9/48RE) at 10mm3 fuel qty - to 0 degrees pilot timing... if all else stays the same (and not saying it's the most efficient...), I would add the positive 11.484 pilot value to the 1.797 main timing at 2000rpm and 10.0mm3, making it 13.281 degrees BTDC - though that would be way too early for a main injection, and I would also need to adjust duration. So is there a calculation or rule of thumb for easing out a pilotless tune and adjusting duration?

[Jim P]

No calculation for building a ?12 valve? tune, its finding what the truck likes for main timing and main duration when there is no pilot. Without pilot main duration will need to increase to avoid the heavy ?diesel rattle? that will occur and you will have to increase main timing as well to get it running better. A 12 valve, depending on model year runs around 13*BTDC but also they have different injector spray angles, spray pressures and piston design than a VP truck or 03-04 or 04.5-07.5.

Reducing you pilot timing too much may cap off your main timing at lower timing than what you command so don?t zero out pilot timing. The ECM will still use pilot timing plus the minimum time between pilot and main to determine when to inject pilot no matter what, just work on zeroing out pilot quantity and increasing main duration and timing and listen to the what the engine tells you.

[Bamofo]

Also, when I decrease pilot (say, turn pilot off at 2000rpm), from what I've read, it looks like it's: pilot + main = total timing BTDC if positive value, or ATDC if negative value on timing tables... right?

So if I go from 11.484 pilot timing (or ~11 degrees BTDC) at 2000rpm (I'm on a '07 5.9/48RE) at 10mm3 fuel qty - to 0 degrees pilot timing... if all else stays the same (and not saying it's the most efficient...), I would add the positive 11.484 pilot value to the 1.797 main timing at 2000rpm and 10.0mm3, making it 13.281 degrees BTDC - though that would be way too early for a main injection, and I would also need to adjust duration. So is there a calculation or rule of thumb for easing out a pilotless tune and adjusting duration?

Im not sure thats right. My understanding was its Main injection BTDC + minimum pilot delay + Pilot Timing which is added to the main event... I could be wrong... but im pretty sure there is a writeup where i created a tool because i assumed what you did and a couple of the guys on here straightened me out quickly.

so if you do 7 degree's on your main event and 14 on your pilot... you would have 7+14+(whatever the minimum timing is after changed to degrees)

Im sure someone will chime in.

[sasdakota]

Pilot timing is based off main timing. So pilot is Main* + Pilot adv*(after factoring modifiers) = pilot timing. The min delay is a shut off, so if Pilot was set to happen too close to the main shot (within the min window) it would drop pilot off at the min time in order to prep for the main shot coming.