LLY hesitation

[LarryJewell]

here's a log from a while back, pulse width is hunting in the later part, mm3 jumps around a little too. I'll try and get a log of the throttle heistation this weekend.

[Big D]

here is some wierd LLY stuff.

It always seems to occur at ~3100rpm. Whats with the defuels.

SOmetimes it does it, sometimes it doesnt. Sometimes its a violent on/off/on/off defuel, as if im taking my foot off the pedal quickly, then mashing it again, then other times, it just lays down.

stupid LLY electronics.

ben

I think you may have to log different pids to get a better picture of what is really happening. Your current pids work good for a LB7 but dont tell us the whole story for your LLY.

log
GM.ENGTQRREF_DMA
SAE.TP
GM.MAIN1Q_DMA
SAE.BARO
If available, GM.TRQ_FACT_DMA

This should reference your tables better and then you will be able to see what is being desired vs. commanded.
I find your pulsewidth interesting, frames 3246-3289. It does not seem to be consistent with rpm, TP or VSS.
If you could post up another log with the 3 additional parameters with some wot runs at various speeds showing down shift and "rolling" in one gear. I would like to see you tune to correctly reference the tables and give you a different set of eyes if something can be enhanced.

[DURAtotheMAX]

Ive logged "driver demanded torque" a couple times and it was ALLLLL over the place! Definetly the root of the problem/what the ECM is referring to when it does screwy things with the main rate.

Ill have to find the logs though.

ben

[LarryJewell]

here is a log from a buddies truck "05 LLY", near stock tune, stock transmission, this shows a classic up & down mm3 fuel shot at 100% throttle. The only mods this truck has is a Volant intake, pcv reroute, Opies turbo inlet and 4" exhaust. The truck holds rail pressure good, but notice the mm3 hunting throughout the run.

Actually attached is a before and after log of installing Opies turbo inlet and the pcv re-route.

Opies turbo inlet is actually the part used in some MPI twin turbo kits.

[killerbee]

Larry, the problems with your logs (defuel) is torque table settings.

Ben, I was surprised to see you didn't log "maximum engine torque". Looks like the dips you are referring to are colocated with shifts.

[LarryJewell]

bumpty

Ross, please see this thread

http://www.duramaxdiesels.com/forum/...018#post207018

[cmitchell17]

I always though this was just bad turbo lag with my LLY. It looks like it from my logs seeing how slow boost comes in. I have maf limiting on but its still slow with no maf limiting. I don't have another truck to compare it with so it might not be slow.

[GMPX]

Please see here for some testing to try to track down this problem -
http://forum.efilive.com/showthread.php?t=10732

Cheers,
Ross

[DURAtotheMAX]

here is a log from a buddies truck "05 LLY", near stock tune, stock transmission, this shows a classic up & down mm3 fuel shot at 100% throttle. The only mods this truck has is a Volant intake, pcv reroute, Opies turbo inlet and 4" exhaust. The truck holds rail pressure good, but notice the mm3 hunting throughout the run.

Actually attached is a before and after log of installing Opies turbo inlet and the pcv re-route.

Opies turbo inlet is actually the part used in some MPI twin turbo kits.

Larry thats interesting that after the mouthpiece install it started to drop off mm3 more rapidly... hmm

ben

[abkimble]

I always though this was just bad turbo lag with my LLY. It looks like it from my logs seeing how slow boost comes in. I have maf limiting on but its still slow with no maf limiting. I don't have another truck to compare it with so it might not be slow.

I see six things happening in a 1.5 second time frame. Pilot going off, engine rpm climbing faster than mph in scale, throttle based injection quantity dropping due to rpm, torque limited injection quantity changing due to anticipated shift, rail pressure way below desired and a gradual increase back up to mm3/commanded pw... All of these symptoms compound to create one huge problem. Even with a vvt it's hard to get boost from fuel that will not burn. I say you have a bunch to fix before you can pick on the poor turbo.

I'm referring to 1496 to 1504