LMM and LBZ DSP5 Desired boost tables not looking up correctly

[vortecfcar]

Surging, loss of throttle response - smoking.

[bballer182]

Bballer,

Thanks for your testing, but I need to verify with EGR on as well. That's why I left EGR function untouched. This has to work on Bosch trucks without the blocker installed. I've had drivability problems on Bosch trucks with the EGR function disabled and no plate installed.

Nick

What kind of problems? I've never noticed any problems.

Surging, loss of throttle response - smoking.

Up until recently i've had mine shut off but not blocked for a couple of years and have had none of those issues.

If i were to guess i would say those symptoms are from the ECM switching back and forth between EGR ON and OFF tables in the DSP folders.

[vortecfcar]

I see these symptoms routinely on trucks with single tunes and trucks with DSP5 tunes. I get about 5 calls a week from customers who attempt to shut the EGR off in the code and get the symptoms I describe (smoking, surging, dead pedal). I tell them to put blocker plates in or put the EGR operation back to stock. This fixes the problem every time.

I've tried disabling the EGR in the software a number of different ways without success. If you want to share your EGR off parameters I'll try them on a few trucks and see if I get consistent performance.

Nick

[bballer182]

This is how i've always done it.

[vortecfcar]

Your script sets all EGR function to stock.

[bballer182]

HAHA, whoops. got the scripting backwards.

[rcr1978]

Here is mine, I also zero al 3 flow tables

[JoshH]

I see these symptoms routinely on trucks with single tunes and trucks with DSP5 tunes. I get about 5 calls a week from customers who attempt to shut the EGR off in the code and get the symptoms I describe (smoking, surging, dead pedal). I tell them to put blocker plates in or put the EGR operation back to stock. This fixes the problem every time.

I've tried disabling the EGR in the software a number of different ways without success. If you want to share your EGR off parameters I'll try them on a few trucks and see if I get consistent performance.

Nick

I don't think a big time pro tuner like yourself needs any help from me, but I have NEVER had any kind of those problems from disabling the EGR without a blocker plate. I have recently put a stock motor back in my truck that is running without a blocker plate and the EGR shut off. I've also had a disabled EGR tune in my dad's LMM for about 60k miles with none of those issues. I've also tuned a few trucks locally with the EGR shut off and no blocker plate. No problems here.

[Dozerboy]

I can't say that I did neither, but that was a while ago. I don't think I changed much other then the speedo and EGR until after I had the plate and transgo though.

[killerbee]

Also, I do seem to recall that messing with the EGR flow tables led to the issues you report. EGR is best disabled without touching them. I don't know why, however.

These ECM's are like drug interactions sometimes.