LLY new engine won’t start.

gmduramax

Shits broke
Jun 12, 2008
4,081
252
83
Nor cal
Smoke means its getting fuel from somewhere. timing is off. Check your sensors or swap with known good ones.

Swapped the crank sensor already. I believe the cam sensor would still let it start it would just be extended cranking. I’ll have to double check that but I’ll swap it out anyway.
 

dmaxfireman

'Can do' kind of guy
Apr 8, 2007
2,329
1
38
CT
Back to the basics..... did you pump the primer and bleed off the air? Does the primer stay hard or get soft?
 

torqued2dmax

Member
Mar 26, 2017
646
1
18
Brookville, PA
I would think that since it starts on starting fluid it is not a glow plug problem because it should keep running after it starts like all of my diesel equipment dose . I think you are on the right track gmduramax Good luck please let us know what you figure out !
 

gmduramax

Shits broke
Jun 12, 2008
4,081
252
83
Nor cal
Back to the basics..... did you pump the primer and bleed off the air? Does the primer stay hard or get soft?

The factory filter head it’s gone. It has a fass with a nicktane added. Air was bleed there and at the fuel pressure sensor because I forgot to tighten it :rofl:
 

juddski88

Freedom Diesel
Jul 1, 2008
4,657
120
63
Chesterfield, Mass.
Yes my LMM doesn’t have glow plugs but it’s 16.5:1 I’ll have to double check but I believe this motor is the same. I’m in California so it was around 70*

That's why I started with asking about compression....What does it pump? Especially when running a big injector, the lack of glows makes a big difference in combustion temp and therefore cylinder pressure. I had a stock engine but without the IAH lbz in during the winter that had a disconnected 12V feed to the gpcm who was complaining about it not running below 32deg ambient. Started an ran perfectly normal above 32. Plugged in the gpcm and tried it at 15 degrees the next day and it made all the difference.
 
Jun 27, 2017
49
0
6
Nebraska
Possibly one other thing to check, make sure a mouse didn’t make it under the fuse box while it was sitting and chew the insulation off your crank sensor wire. I have one in the garage right now that did the same thing and that was the cause. Probably a long shot but it is easy to check.
 

ikeG

Oughta Know Better
Apr 19, 2011
2,472
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Western PA
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Coolant temp sensor plugged in? When we went standalone harness & no coolant, we had to wire in a resistor to the ect circuit to make ecm think it wasn't -50 degrees

I know 60% injectors are not a huge jump but that is what I'm leaning towards, the tuning. Do you have access to the tuning? You didn't mention a retune for them?

Sent from my SM-G960U using Tapatalk
 

gmduramax

Shits broke
Jun 12, 2008
4,081
252
83
Nor cal
Coolant temp sensor plugged in? When we went standalone harness & no coolant, we had to wire in a resistor to the ect circuit to make ecm think it wasn't -50 degrees

I know 60% injectors are not a huge jump but that is what I'm leaning towards, the tuning. Do you have access to the tuning? You didn't mention a retune for them?

Sent from my SM-G960U using Tapatalk

The injectors have been in the previous motor and it’s tuned for them. Coolant temp sensor is plugged in and reading.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,750
5,920
113
Phoenix Az
Still got the old sensors? I say it’s a cam/crank sensor issue or a wiring ground issue.

Small ground on the pass lower side of the block in good shape?
 

gmduramax

Shits broke
Jun 12, 2008
4,081
252
83
Nor cal
Still got the old sensors? I say it’s a cam/crank sensor issue or a wiring ground issue.

Small ground on the pass lower side of the block in good shape?

I’m leaning towards that. Ground is good. Swapped in a working crank sensor. Going to swap the cam sensor.
 

gmduramax

Shits broke
Jun 12, 2008
4,081
252
83
Nor cal
Update....... still doesn’t run, it’s throwing crank sensor voltage and fuel pressure sensor voltage codes for no reason. Wiring, sensors, ecm, ficm everything checks out. Debating doing an LBZ swap. Dealer is stumped, which never happens I know the tech very well. We’re still trying to figure it out we haven’t gave up yet.
 

KyleC4

Tech
Dec 30, 2016
470
48
28
Bay Area
Who does the diesel work there? I’ve always heard them being the corvette guru’s. I don’t think it would be Jim. Maybe Chad ?
 

gmduramax

Shits broke
Jun 12, 2008
4,081
252
83
Nor cal
Who does the diesel work there? I’ve always heard them being the corvette guru’s. I don’t think it would be Jim. Maybe Chad ?

It’s Chad. I’m gonna bounce some ideas off him tomorrow and see if we can come up with anything