Need help with a LB7 / LBZ conversion truck in SW NY state.

[036.6turbo]

Worst case pull the module and send it to me. If he wants to save the VIN license send the flashing device as well.

I can attempt a bench flash via SPS and then put his file into it.

Thank you but we were able to get it to flash.

Unhooked the batteries overnight.

Started with the stock tune the next day. First attempt failed with a $0101 EFILive error.

Tried stock tune again, it loaded.

Then flashed in the DSP5 tune from Rob, back in 16 when I did the conversion.

The DSP5 tune loaded as well.

No effect on functionality of the truck. It's still dead.

Replaced Cam position sensor.

Crank position sensor ohms out fine.

Currently looking at replacing the ECM as the injectors are not getting any signal.

He's in communication with a ECM repair place, they're telling him it sounds like the theft deterrent in the BCM, not ECM.

No codes, nothing. I hate just throwing parts, but I'm six hours away from the truck and at a loss to really help him.

 

[2004LB7]

What about trying the Vats relearn?

 

[036.6turbo]

What about trying the Vats relearn?

Rob disabled VATS in the tune.


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[2004LB7]

Rob disabled VATS in the tune.


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I don't think that does anything for the BCM. Shouldn't prevent the truck from starting though. Do you have the security light on?

 

[Cougar281]

If VATS is disabled in the tune, it's not a security issue... The truck would run regardless of any security mismatches, and with it disabled in the tune, I doubt you'd get any DTCs

 

[036.6turbo]

I don't think that does anything for the BCM. Shouldn't prevent the truck from starting though. Do you have the security light on?

No, no security light.

If VATS is disabled in the tune, it's not a security issue... The truck would run regardless of any security mismatches, and with it disabled in the tune, I doubt you'd get any DTCs

No DTCs.

When we got the ECM to flash, I took that as a sign it is was functional. My perception of an ECM failure is that it, just goes dark, no communication.

This instance appears to disprove my perception. It's communicating, just not sending any pulse signals to fire the injectors.

When the FICM functions of the earlier platforms (LB7 / LLY) got baked into the E35A ECM for the LBZ, it must still be its own little island of misfit toys, not playing nice with the rest of the group.

(I obviously have NO IDEA of the circuitry of the ECM. I just know the LB7 had a separate FICM and the LBZ does not.)

 

[Cougar281]

Have him remove the ECM and shake it. If there's something rattling inside, it's probably got blown caps.

 

[036.6turbo]

Have him remove the ECM and shake it. If there's something rattling inside, it's probably got blown caps.

That's really a thing?

 

[2004LB7]

That's really a thing?

Yes. I think there is some discussion and photos in the LLY FUCM thread. The solder joints for some of the high voltage capacitors break and the caps fall off the board. You might get lucky and can solder them back in. Or it shorts out something and damages the ECM

 

[2004LB7]

No, no security light.

No DTCs.

When we got the ECM to flash, I took that as a sign it is was functional. My perception of an ECM failure is that it, just goes dark, no communication.

This instance appears to disprove my perception. It's communicating, just not sending any pulse signals to fire the injectors.

When the FICM functions of the earlier platforms (LB7 / LLY) got baked into the E35A ECM for the LBZ, it must still be its own little island of misfit toys, not playing nice with the rest of the group.

(I obviously have NO IDEA of the circuitry of the ECM. I just know the LB7 had a separate FICM and the LBZ does not.)

Off the top of my head, the ECM needs to see a good crank and cam signal that is in sync. It also needs to see a good park/neutral signal to crank. And if VATs is enabled, a good can bus signal from the BCM that it is ok to fire the injectors.

As far as I know there is nothing else that would keep the ECM from firing the injectors unless there is physical damage like cougar mentioned

 

[Cougar281]

With vats disabled in the tune, about all that would prevent the engine from starting, other than no fuel, would be a cam AND crank issue (like swapping the cam and crank connectors, which sadly/stupidly can be done), or a bad ECM. I believe they will start with a good crank signal, but no cam, but won't start without a crank signal.

 

[DAVe3283]

Hang on, is the throttle position always reading 100%? On the gassers, and I seem to recall this also on my LB7, if the throttle is held at 100% during cranking it won't fire the injectors.

With the key on, have him observe throttle position with EFILive vs the pedal. Should be able to get it to sweep cleanly between 0 & 100%. Then try cranking with 0% throttle, as the screenshot above showed it at 100% the whole time.

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[TheBac]

Yeah, looks as if the TPS failed to 100%

 

[036.6turbo]

Hang on, is the throttle position always reading 100%? On the gassers, and I seem to recall this also on my LB7, if the throttle is held at 100% during cranking it won't fire the injectors.

With the key on, have him observe throttle position with EFILive vs the pedal. Should be able to get it to sweep cleanly between 0 & 100%. Then try cranking with 0% throttle, as the screenshot above showed it at 100% the whole time.

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TP shows 0%
TP_A shows 100%

Pretty sure one of those PIDS is from the "generic ECM" list and one is from the ECM Enhanced" list.

Really not clear of the difference or which one to look at?

 

[DAVe3283]

As long as one of them tracks the actual pedal position, then I think you're good. I just saw it pegged at 100% and thought it might be your problem if so.

Otherwise I'm out of ideas, sorry.

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[036.6turbo]

As long as one of them tracks the actual pedal position, then I think you're good. I just saw it pegged at 100% and thought it might be your problem if so.

Otherwise I'm out of ideas, sorry.

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Appreciate the input. Not much about this is making sense.

 

[2004LB7]

I always have trouble finding a reliable pid for peddle position in the ECM. But the one in the TCM always seems to work for me. See what it shows if you can

 

[1FastBrick]

Yes. I think there is some discussion and photos in the LLY FUCM thread. The solder joints for some of the high voltage capacitors break and the caps fall off the board. You might get lucky and can solder them back in. Or it shorts out something and damages the ECM

The BBQ Special LBZ ECU I purchased for our experiment... post #980

LLY Ficm

I'd like to see how they integrated the injector driver circuit into the LBZ/LMM ECM

www.duramaxdiesels.com

 

[Bdsankey]

If you need an ECM I have mine here out oif my personal LBZ that I can VIN change and sell him if needed to help get him back on the road. My LBZ isn't going anywhere soon.

 

[036.6turbo]

If you need an ECM I have mine here out oif my personal LBZ that I can VIN change and sell him if needed to help get him back on the road. My LBZ isn't going anywhere soon.

Thank you, we may still need some help from you.

He bought an ECM from a local salvage yard. (it was ordered before the whole discussion about the throttle position sensor.)

He installed it, tried to flash it, EFI live wants a vin license.

I totally missed that aspect of replacing it.

So now he's left in a spot trying to find someone to flash the replacement back to the VIN of the donor truck I used. The tune Rob wrote for the LB7 / LBZ swap I did, will only flash to an ECM with that VIN.

If he has it towed to a dealership, they're going to look at the VIN on the firewall and try to flash it to an LB7 file.

He has actually been looking at just bailing out and buying a different truck.