08 LMM wont start

[gmduramax]

My LMM wont start. I just put in a new engine, cut coated pistons and cam. 7000psi+ rail pressure while cranking. Fuel is new and the entire fuel system was cleaned out. All sensors are working. Showing 8-9 grams of air while cranking. 400+psi on compression check on a couple cylinders. Trying to start on the stock tune. It will try and start right when you turn the key but after a couple cylinders fire it will just turn over and will not try to start.

Is there anything im missing? Anybody have any ideas?

 

[othrgrl]

Crank and cam position sensors and reluctor wheels are all on right?

 

[gmduramax]

Yea and the ECM is getting the signal

 

[gmduramax]

Ttt

 

[Kat]

See if you have 2 of the injector wires swapped.

 

[gmduramax]

Still won't start

 

[paint94979]

are you sure the machine shop installed all 8 pistons?... i heard the shop used a ruler, level, and file to machine and balance your engine.

 

[gmduramax]

If he didnt it would at least try to start.:rofl:

 

[Fingers]

From what I have read and experienced myself:

Anti-theft gets turned on some how. You need to rematch it sometimes.

Grounds grounds grounds. There are several grounds on the engine and the all have to be hooked up.

If the exhaust smells like fuel, you have a control problem. For instance, I know of at least two engines that sheared the crank reluctor wheel pin because something was wrong with the oil pump.

 

[gmduramax]

Already rematched the ECM to the truck.
All grounds are good.
Exhaust pours white smoke.
Ive got good oil pressure. Turned the crank and inspected all the teeth on the reluctor wheel and it seemed fine

 

[Fingers]

Cam reluctor is 180 out?

 

[RPM Motorsports]

Anthony, is this the first attempt to fire it?

 

[paint94979]

Anthony, is this the first attempt to fire it?

yes, its at the dealership

 

[skintback]

Cam reluctor is 180 out?

Good to know I thought the wheel would only bolt on one way

Thanks

 

[McRat]

High injection pressure makes it harder to start, not easier.

Triple check that crank and cam sensors aren't switched.

Triple check that two injectors are not swapped.

Triple check it's a 58 tooth wheel, not a 57.

If white smoke comes out, it wants to start, but the fuel is not being injected in the right amount at the right time, or the engine is not mechanically sound.

If you disable glowplugs, then start it with ether, it will prove the engine is mechanically correct.

 

[TrentNell]

Good to know I thought the wheel would only bolt on one way

Thanks

X2 , I didnt see any special alignment instructions in the GM specs , and it seems on a lb7 the alignment pins are off to one side on the cam gear , so you would have to flip over and turn 180 , I dont think it would work , not shure on the crank sensor , cant remember . other than i marked it for alignment before i pulled it off. Good luck Anthony , I agree with others you are getting fuel but at the wrong time some how ?

 

[gmduramax]

Cam reluctor is 180 out?

I talked to Guy and he said it would only go on one way

Anthony, is this the first attempt to fire it?

yup

High injection pressure makes it harder to start, not easier.

Triple check that crank and cam sensors aren't switched.

Triple check that two injectors are not swapped.

Triple check it's a 58 tooth wheel, not a 57.

If white smoke comes out, it wants to start,
but the fuel is not being injected in the right amount at the right time, or the engine is not mechanically sound.

If you disable glowplugs, then start it with ether, it will prove the engine is mechanically correct.

I will check that on the monday. I believe the engine is mechanically sound, injected some diesel in the intake and it ran a little bit. For a second IIRC. Do you think I should still try it with ether?

 

[skintback]

Check the oil pressure sensor and low oil sensor wireing on the lower driver side that runs up behind the A/C power steering pump bracket up front to the top of the engine harness make sure they were not pinched behind that bracket

Also make sure you have enough oil in it

 

[gmduramax]

Plenty of oil and good oil pressure.
I'll make sure they didn't pinch any wires

 

[Fingers]

Exhaust pours white smoke.
Ive got good oil pressure. Turned the crank and inspected all the teeth on the reluctor wheel and it seemed fine

I'm thinking the gear slipped that the reluctor wheel is attached to. Sheared pin?

Remove the crank position sensor.

Turn the crank till the missing tooth gap shows up in the window. Now count 25 whole teeth as you turn the crank clockwise looking from the front.

How does the timing mark on the Dampener line up with the mark on the front cover?