LLY Ficm

[kidturbo]

Weekend Updates.

Finished tagging and bagging all the important sensor wires in the Kodiak LB7 harness. Checked, then triple checked, with volt meter, and ECM sensor pids using EFIlive. Everything powers up and relays respond as factory designed on the ECM side. Leaving the ECM in control of the FICM power relay.

Key on, everything powers up correctly. Key off, a few seconds later, ECM shuts off FICM relay, then powers itself off. Also have CANbus data connected and capturing between FICM and ECM. Added a turn signal bulb in place of the FPR, and connected 8 LMM Injector coils to the FICM harness.

Ran all the Injector Control and Crank Speed wires to a bread board, so we can breakout each signal between ECM, FICM, and emulator.

Harness would look a lot cleaner, but I tried to keep keep enough wire on lenght to make a nice stand alone engine setup for somehitng down the road. ECM still fits nice on a shelf under the workbench..







Also fixed the Fuel Temp for @1FastBrick

 

[kidturbo]

Next, I swapped in the LB7 ECM that @Cougar281 sent over. Powers up fine, and shows a good SN and VIN #, "masked some digits in photo.." However the APP issue remains, and it shows a Class 2 error. Yet responds fine to serial commands. The APP voltage on pedal out of a gasser must be different from the Duramax. I checked pinout, and going to verify each line one me time, then just swap in some set pots to make it happy at idle RPM.

Did note one other issue with this new ECM. Not showing Fuel Pressure, BARO and Calculated Fuel rate PID's in EFIlive logging. Anyone ever ran into this before? Almost like we are missing a 5V circuit or something. Besides that and the pedal, looks fine.

 

[DAVe3283]

The U1000 could just be the ECM not being able to talk to a BCM. Any slight glitch and most GMT800 modules will store a U1000. So much so that if I don't see a U1000 stored somewhere on a vehicle, I assume the batteries have been disconnected or codes cleared very recently.

The accelerator pedal is odd, because my LB7 Duraburb is using the original pedal from the 2003 6.0L gas motor without issue. Odd that this one appears different.

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[kidturbo]

Good to know on the pedal. I could possibly have 5v and low ref backwards, but checked it like 3 times now..

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[Cougar281]

I know on the LBZ the pedal is different from a gasser for sure. When I swapped my truck over to a LBZ, I had originally grabbed a pedal out of an 06 gasser I found in a local u-pull, and it didn't work. Any time I tried to give it throttle, it set DTCs and went dead pedal.

 

[kidturbo]

Think I found my problem, crankshaft is broken...

Source: https://youtube.com/shorts/B5qc5vHwPd4?si=AbNJm-sXeeyJEdN8


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[2004LB7]

Think I found my problem, crankshaft is broken...

Source: https://youtube.com/shorts/B5qc5vHwPd4?si=AbNJm-sXeeyJEdN8


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I wonder how many people will misunderstand what you have going on here

 

[PureHybrid]

99%. It's funny how many people don't realize how noisy those solenoids are

 

[TheBac]

Ok, that was pretty cool, Ken.

 

[1FastBrick]

Good to know on the pedal. I could possibly have 5v and low ref backwards, but checked it like 3 times now..

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That pedal sensor and pig tail harness I sent you came from a 2003 duramax LB7 truck, how ever it was in the junk yard...

I never tried to plug it in to my LLY. The Pedal portion is still sitting here under my desk...

 

[kidturbo]

That pedal sensor and pig tail harness I sent you came from a 2003 duramax LB7 truck, how ever it was in the junk yard...

I never tried to plug it in to my LLY. The Pedal portion is still sitting here under my desk...

Well I must have ref lines backwards then. Will check again when get home.

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[1FastBrick]

Here is the vin from the pedal doner. The engine was still in it, but they removed all the modules and cut up the engine wiring harness.

8th digit 1= LB7
10th digit 3=2003 model year

 

[kidturbo]

I just rechecked the pins at sensor, 3 5v Ref, 3 Low Ref, 3 APP Signals. I even used the exact same circuit #'s as the pinout diagram just to be sure. And all the wires match up color code from ECM to APPS. Leaving me to believe maybe the physical pedal has something to do with calibration settings. Sensor is spring loaded internally. Got me.. Am gonna run it one last time before calling it a night.

 

[1FastBrick]

I can send you the rest of the pedal if it helps...

 

[1FastBrick]

The gas variant looks similar but I am not sure abouts it's compatibility.

I see dork men list on specific for diesel and 1 specific for gas...

 

[kidturbo]

Today before hooking the FICM up to play musical file cabnet, then onto a 6" speaker, I learned a few things. First, my crank and cam signals were 180 out of phase on the pulses.. I stumbled onto some other Pico tool scope captures of an LLY and LBZ, then quickly noticed that my arduino emulated crank signal looks to be voltage swapped according to everyone else, including the snapon scope captures here back around page 6. When the sensor reads a gap, that's a + voltage.

While the LB7 ECM would show a valid RPM # in EFIlive from that reversed crank cam emulator, when I attempted to run the FICM off that same signal, it would not fire injectors above 600RPM. Soon as I inverted polarity, little sucker started humming right along, all the way up to 10k RPM. So as I've mentioned before, the Duramax ECM's really don't seem to care much about specific crank or cam pulses. Just a long as you feed it a rhythmic pattern, at somewhere around 58 pulses per revolution, these will fire to some extent...

Here is a truely clean [good tool] stock 60-3 crank / cam scope capture for all future build references. Should also help fine tune those sensor to reluctor ring holes.




After playing around with the emulator for a couple hours, replacing an injector solenoid with an old boat speaker, figured I'd better capture some valuable data before I find the breaking point of an LB7 FICM. So I attempted to get this little knock off bench scope to capture an actual injector output signal, to spot any timing or lag delays. After sever attempts, found sticking a piece of wire inside the center of the solenoid and connecting 1 end to the scope gave me least glitching. Then I spaced out the 3 pulses on injector control #1, and disabled all the other signals. What I found, looks to be a 90 Degree, 15 tooth delay from start of first control pulse, to start of actual injector pulse. So the data @1FastBrick stumbled across, seems to line up..

Will take some better captures with a spark plug inductive pickup, but I think we need to focus on this aspect to discover how the ECM and FICM determine "who's on first..."

 

[kidturbo]

I can send you the rest of the pedal if it helps...

View attachment 118220

Do you have another? Just see if it's spring loaded when the bolt holes line up?

 

[kidturbo]

I can send you the rest of the pedal if it helps...

View attachment 118220

Yes, that would have saved me 4-5hrs I'm never getting back... But I told you to take it apart, so this one is on me.

There is nothing wrong with wiring or the APP sensor, only we are using it outside of design specs. So I go digging back to page 26, where someone graciously listed our Rest 0% and WOT 100% scale, then pull up the EFIlive pids again, stick a flat head screwdriver into the spring loaded POTS mounted inside our APP unit, turn it about 10deg, and guess what matches up perfectly now....

asdfdflasdfw9eruorbnwejwu ....

So it seems some engineer thought it would be good idea to set the lowest POTS range on our sensor about 10% past where the physical pedal in a truck allows it to stop on the scale.. If the sensor falls off the actual pedal, the truck won't start.. I mean it has 3 APP values for ____ sake... Thankfully that engineer retired, was fired or reassigned, and I know this is so, because no other APPS in a GM vehicle after 2005 every used such goofy spring loaded offset. Reminds me of setting up a TPS on a early 90's throttle body. Today you can take pedal out of a 16 Camaro, strip all the hardware besides the APPS itself, and 15 minutes later, drive a 2007-2019 Duramax with it.. That same sensor scaling remains in use 2020 last I checked.

You guys are gonna drive me to drinking.

 

[kidturbo]

Quick Macgyver job, and a couple more DTC's are cleared. Will share the hack, and maybe take the old girl for a drive tomorrow.

 

[TheBac]

Well, I guess you did find the real reason a person needs the pedal assembly when doing an LB7/LLY to LBZ swap.....so theres that.