No start 03" LB7 Please Help!

[turbogmc]

Rebuilt motor just installed but will not fire. Motor is all stock besides arp head studs and lbz inj pump (I know this will need to be changed in the tune but it should still start).

Heres what we know and have tested:
-Makes desired rail PSI while cranking (6000+ PSI)
-No codes in any of the 12 modules on truck
-Tried another known good ficm with no luck
-Has 400+ psi compression
-Tried multiple stock tunes
-Injectors were bought from reputable injection shop and were cleaned, tested on stand
-Has rpm on scanner while cranking and tech 2 shows inj pw
-Drained all fuel and put in brand new fuel
-Checked ecm pins and engine harness pins
-Tested power at glowplugs with test light
-Checked CMP and CKP conectors for correct placement
-Checked all fuses on underhood fusebox and dash fusebox
-With glowplugs/intake heater disconnected it ran on a couple sprays of ether but wouldnt stay running
-Injectors all ohm out at 0.4-0.5 ohms
-switched out engine harness with no change

Any input would be greatly appreciated.
thanks in advance
Bret

 

[custom8726]

Put the LB7 Reg on the LBZ pump.

 

[dirty_max]

it should still run with the lbz regulator though? all grounds are hooked up in the proper location correct? also seems silly but ive been burnt by it before, all fuses good?

 

[custom8726]

it should still run with the lbz regulator though? all grounds are hooked up in the proper location correct? also seems silly but ive been burnt by it before, all fuses good?

I have seen one lb7 with a LBZ pump & Reg start with factory tuning but started ruff and sounded horrible. And then just a few days ago a guy I know tried it and it would not even start. I went over with EFI and made ajustments for the LBZ reg on a LB7 but it still would not fire. Changed the reg back to a LB7 and it runs perfect. I'm sure if I was more EFI savy I could have made the LBZ reg work as I've read many have. I copied notes off DP from a respected tuner and still could not get the truck to start with the modified tables

 

[Aaron@LDS]

It really should fire with the LBZ fpr, I installed mine and didnt have tunes adjusted for it yet. Rob was a day behind, but he told me that I can drive it home from the shop if I needed to. I did... And she loped hard at idle, but ran consistently. Only difference it might be is that my FPRV was shimmed, which may have allowed it to stay shut under the extra pressure?.

It sounds like the injectors aren't opening. Have you pulled the glowplug and checked for fuel while cranking?

 

[turbogmc]

Not yet, but thanks for the recommendation. We will have to check for that right away. We had bought tunes from idaho rob and hopefully we have our tunes soon as we were told he is pretty backed up at the moment. We ordered 5 tunes for the dsp 5 but currently the dsp 5 is bypassed and it is returned to a single stock tune. Idaho Rob has been made aware of all the modifications in mind (modded lbz cp3, air dog 150, etc) and maybe having a little more of a custom tune will help too.

 

[turbogmc]

Now we have it tuned for the dsp 5, modded lbz pump, and the other mods. It was tuned by a another reputable tuner since rob was backed up and still no difference. Anybody else have any other ideas? Thanks, Bret

 

[bluecollar]

Im with aaron on ur injectors not opening.

 

[turbogmc]

If the injector is firing perfectly normal, will we actually see fuel coming out of the glowplug hole or will that only happen of the injector is bad and being hung open dumping a ton of fuel in?

 

[bullfrogjohnson]

If the injector is firing perfectly normal, will we actually see fuel coming out of the glowplug hole or will that only happen of the injector is bad and being hung open dumping a ton of fuel in?

With the ficm plugged in and the glow plugs out you will see fuel coming out every time the injector fires. Sounds like something is disabling your injection.

 

[turbogmc]

Okay, well pull the plugs and check for fuel when we get a chance. Thanks alot for the replies, Bret

 

[Aaron@LDS]

Wear eye protection if you get close!

 

[turbogmc]

Cant really tell on fuel as it gets foggy in the room and looks like fuel is coming out sort of but nothing definite. We double checked compression on all 8 cylinders and had 440-450 psi on all of them. Also bypassed factory filter head (since we already had an air dog) and bled fuel lines and no change. Still stumped. Any help appreciated, Bret

 

[dansdieselp]

Be nice to see a datalog of the truck while its cranking.

 

[turbogmc]

We will try and get a log of it and sent it to you. Thanks, Bret