LLY crank no start

[Yellow Jacket]

Alright, I'm pulling my hair out...

My daily driver hasn't seen the road in 14 months. I put a donor lly shortblock in it from a burned truck... Shortblock is only thing different, I used my heads, harness, injectors, and other parts.

My Tech 2 is showing cranking rpm, shows crank signal and cam signal, shorts calculated and fuel rate, rail pressure goes high while cranking (but it is a modded lbz pump and I didn't change tune yet), and it shows a duration/pulse width on the scan tool...but still only chugs/smokes a little after cranking 10-15 seconds...

What am I missing? One code is usually not active at time, but keeps coming back is Generator circuit no voltage or something (p0622 I believe)... But I have a battery charger on it and cranking the piss out of it.

 

[02ilduramax]

I had a similar issue with mine and Ithe turned out I forgot to tighten the wire on the back of the alternator

 

[Yellow Jacket]

That wire is tight...

It's not starting, acts like it isn't firing all of the injectors or something... Actually acts likes it isn't firing them for first 10+ seconds of trying, then it does some chugging with grey puffs of smoke coming from exhaust, until starter solenoid times out...

I tried unplugging the FPR/FCV to peg rail pressure, still similar results, and I tried swapping rail pressure sensor from another engine because I know that can cause some funky stuff, no difference there either...

 

[Yellow Jacket]

Is there anything that can stop or hinder injectors firing even if the ECU is commanding a pulsewidth? That wouldn't leave any codes? Like power to the FICM? Or something along those lines? The cab was up in the air, so maybe a pin or wire in the bottom of the distribution block?

 

[NC-smokinlmm]

Sounds like an ficm issuse. You tried swapping it yet? Maybe ground is bad on it...

 

[Yellow Jacket]

Gonna try swapping the FICM tonight...

 

[Yellow Jacket]

Swapped FICM, same results...

Checked voltage on bottom of all pink wires(ignition) on bottom of fuse block....also checked for 12 volts on all orange wires...

Pulled all 8 brand new glowplugs... All are dry as can be, crank it with all 8 glow plugs out and zero anything coming from holes...

Still seeing crank and cam signal with no faults, theft deterrent says inactive and all no's on scanner, so that's good.

BUT, PTO Engine Shutdown Signal (if equipped) = Yes. Is that keeping it from starting? Anyone able to verify this against another LLY? It still shows rail pressure and injector pulse width command?!?

 

[dirtydmax]

Could it be a vats prob?Had a simular issue with a crank and no start.edit...just saw the inactive part.fuel at injectors?

 

[gmc502]

are you sure theres not air in the system.I had to bleed out the air from my truck when I swapped FICM's.My lift pump is dead so bleeding was done by pulling fuel out the return line.

 

[04BlackSmoker]

:hug:Light it on fire

 

[messejme]

Air its not bled out fully or more likely it is getting in from somewhere. Bleed screw, connectors from plastic fuel lines to engine metal lines, etc.

 

[JoshH]

Strangely enough, I had an LBZ brought in that died in a parking lot. Symptoms were identical to what you are describing. I verified injectors were firing with a lab scope. It turned out all 8 injectors were bad. Don't ask me how or why, but 8 new injectors fixed it right up.

 

[RPM Motorsports]

Sure it has the correct reluctor wheel on the short block? Check the grounds on the side of the block. Had an Lly doing all kinds of funky tricks like described plus running funky. Ended up being one of the small ground wires on the pass side of the block.

 

[Yellow Jacket]

Sure it has the correct reluctor wheel on the short block? Check the grounds on the side of the block. Had an Lly doing all kinds of funky tricks like described plus running funky. Ended up being one of the small ground wires on the pass side of the block.

Headed to a pull today... I'll clean up grounds on the passenger side...I swear I put the correct reluctor wheel in and I'm not getting any correlation faults, but I can pull the crank sensor and count teeth...

 

[Yellow Jacket]

Could it be a vats prob?Had a simular issue with a crank and no start.edit...just saw the inactive part.fuel at injectors?

It's not VAT's according to scan tool, plenty of Fuel at injectors

are you sure theres not air in the system.I had to bleed out the air from my truck when I swapped FICM's.My lift pump is dead so bleeding was done by pulling fuel out the return line.

Air its not bled out fully or more likely it is getting in from somewhere. Bleed screw, connectors from plastic fuel lines to engine metal lines, etc.

I can unplug FPR/Inlet metering valve and rail goes to over 20,000psi cranking... I bled it and cranked it a lot, injectors just aren't "firing" or opening...


I hooked up to a 2003 lb7 and all the PTO parameters are just Asterisks, because it's not equipped.... I'm still wondering if my problem is related to the PTO thing...

 

[dirtydmax]

Could it be an 06 lly short block with the lbz reluctor?

 

[NC-smokinlmm]

Maybe try a diffrent tcm if you have one to swap. That PTO signal comes from it I believe...

 

[Yellow Jacket]

Pulled the crank sensor, has 57 tooth reluctor wheel on crank...

Wire wheeled the ground points on passenger side of block for FICM grounds, no change there either...

Will an Amp Clamp around the individual injector pigtails pick up if the injectors are getting power to fire?

 

[Yellow Jacket]

Oh, and I hooked up to a LBZ truck and all PTO options are the same as my LLY and it starts, so it's not that I guess...

Maybe all 8 injectors are bad...

 

[RPM Motorsports]

Edit: missed that you had good rail, NVM the post below.
Check the return rates? I've had them not fire when only two had a higher return than the rest.