Fuel cutout issue (possible free beer inside)

[rover346]

Hello,

I new to tuning things but not new to building engines and how engines work. I have a problem with what i think is the calibration on my computer where I'm having fuel cut out when the motor is being progressively loaded around 4k but I've seen it as low as 2500. This is while going down the free at speeds around 50-65. If I press the gas more during the cut out to downshift then fuel comes back. I'm including the tune so someone with more experienced eyes than I might be able to spot an simple oops that i'm not catching. I'm more than willing to buy someone a case of beer if they can help me get this figured out and I have no problem data logging if need be.

Thank you

[Jetmech442]

Hello,

I new to tuning things but not new to building engines and how engines work. I have a problem with what i think is the calibration on my computer where I'm having fuel cut out when the motor is being progressively loaded around 4k but I've seen it as low as 2500. This is while going down the free at speeds around 50-65. If I press the gas more during the cut out to downshift then fuel comes back. I'm including the tune so someone with more experienced eyes than I might be able to spot an simple oops that i'm not catching. I'm more than willing to buy someone a case of beer if they can help me get this figured out and I have no problem data logging if need be.

Thank you

I'm not a pro either, but I'd be happy to look over the tune when I get home to see if anything might cause that. (unless someone gets to it before I do)

Sent from my Nexus 6P using Tapatalk

[rover346]

That would be much appreciated, and if anything needs to be logged let me know what pids need to be recorded. It might be abuse or torque management but I don't know what i'm looking at to be sure

[ScarabEpic22]

A0001 and A0002 are out of range, change these to 99, save the file, close V7, reopen and change back to 100.

Need to work on your VE tables, both Main and Boost. They are far too spikey. Spark looks a bit high in the High octane table as well.

For your fuel cutout issue, I bet it's because you have 64 in one cell and 92 in the next going from 4000 -> 4400rpm. Your fueling in row 3200rpm is way lower than 2800 or 3600, likely causing the PCM to think it's fueling properly, then over-fueling, then proper again.

I'd start by smoothing your VE tables out a bit, then logging again.

[rover346]

A0001 and A0002 are out of range, change these to 99, save the file, close V7, reopen and change back to 100.

Need to work on your VE tables, both Main and Boost. They are far too spikey. Spark looks a bit high in the High octane table as well.

For your fuel cutout issue, I bet it's because you have 64 in one cell and 92 in the next going from 4000 -> 4400rpm. Your fueling in row 3200rpm is way lower than 2800 or 3600, likely causing the PCM to think it's fueling properly, then over-fueling, then proper again.

I'd start by smoothing your VE tables out a bit, then logging again.

I did that which helped the weird spots but for some reason if I'm doing a WOT pull from zero, second gear hits about 70 which is around 4,200 and the ecm cuts fuel completely, like a governor fuel cut, its baffling me. The governor is set for 95.

Thank you for the help, hopefully my truck runs decent and someone gets a cold one. win win

[rover346]

I wanted to add that this is not in before a shift as it normally will go into third at 85, its just power then no power

[Jetmech442]

A0001 and A0002 are out of range, change these to 99, save the file, close V7, reopen and change back to 100.

Need to work on your VE tables, both Main and Boost. They are far too spikey. Spark looks a bit high in the High octane table as well.

For your fuel cutout issue, I bet it's because you have 64 in one cell and 92 in the next going from 4000 -> 4400rpm. Your fueling in row 3200rpm is way lower than 2800 or 3600, likely causing the PCM to think it's fueling properly, then over-fueling, then proper again.

I'd start by smoothing your VE tables out a bit, then logging again.

Beat me to it Scarab,lol.

Rover, how certain are you that it pulls fuel and not timing or throttle blade?I'll poke around now ans see what I see. Perhaps you should post the trans tune as well, and a description of mods to the car.

[rover346]

Beat me to it Scarab,lol.

Rover, how certain are you that it pulls fuel and not timing or throttle blade?I'll poke around now ans see what I see. Perhaps you should post the trans tune as well, and a description of mods to the car.

OK the truck is a 2002 silverado

Cable actuated Throttle
Iron block LS6 (5.3 bored to 3.898)
317 Heads
ZR1 Camshaft
Whipple
blower pushes right around 9 pounds at 3600 rpm and drops to 6 at 5600
I built the motor for longevity so if you guys have any suggestion as to make life easier on this motor through the tune, that would be much appreciated
I raised the amount of timing being pulled by psi based on scarabs suggestion

I was data logging injector duty cycle and it drops to almost nothing when it happens and my lambda value sky rockets, If I keep my foot on it when it cuts, you can hear the blower pulling air as rpm drops but no ignition.

Watching timing on the data log timing stays at 17 when the power disappears.


I've included my updated tune which has smoothed out VE tables

guys your help is much appreciated

[Jetmech442]

nm, trans tune already attached...

just some quick thoughts... 4000 RPPM is the threshold set to transition from the dynamic mode to pure MAF. Have you altered the stock MAF in any way?

Cat protection is still Enabled. Maybe a contributor?

Can you confirm you are running a 4 speed auto with 3.73 gears, and make sure your tire diameters are correct.

Last observation is that the max speed H0109, is set to 95 kph. thats really close (~60 mph) to your 70 mph issue. maybe if tires are off a bit, or converter is flashing higher...I dunno, but maybe worth looking into.

Other observations which will help for a better tune: Your Base spark in gear and PN need to match in the idle area for your High/Low octane tables. You have a large jump from 800 - 1000 rpm and different values in each one. matching them up will reduce surging off idle.

[rover346]

nm, trans tune already attached...

just some quick thoughts... 4000 RPPM is the threshold set to transition from the dynamic mode to pure MAF. Have you altered the stock MAF in any way?

Cat protection is still Enabled. Maybe a contributor?

Can you confirm you are running a 4 speed auto with 3.73 gears, and make sure your tire diameters are correct.

Last observation is that the max speed H0109, is set to 95 kph. thats really close (~60 mph) to your 70 mph issue. maybe if tires are off a bit, or converter is flashing higher...I dunno, but maybe worth looking into.

Other observations which will help for a better tune: Your Base spark in gear and PN need to match in the idle area for your High/Low octane tables. You have a large jump from 800 - 1000 rpm and different values in each one. matching them up will reduce surging off idle.

Jettmech if you have paypal pm me so I can send you a case of beer!!!!

Same for you scarab.


I paid for someone to do this for me and the guy gave me a base tune and walked. I paid in full to establish some sort of trust with the guy ��

Applying those changes now and will report