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Need help! Can't get truck to start!

9K views 32 replies 6 participants last post by  mray 
#1 ·
I am at a loose here, I can't get truck to start. A lil info about the truck, it is a 2007.5 2500hd ccsb, originally had the LMM in it, bought truck with no motor, tranny or t case for cheap. Ended up putting a the drivetrain (Lml engine, trans, tcase, all electrical wiring and computers and components) in it. Did dpf/def delete, EGR delete, 5" exhaust, 3" DP, efi live by ridge runner. Went to fire it up and couldn't build rail pressure, ended up finding tip broken off #1 injector and tip broke of #1 glow plug, so I pulled engine back out and tore down to take heads off to check for damage. Everything turn out good, no scratches on cylinder wall no hole in piston! Figured since I was down that far I had all injectors tested and 7 out of 8 failed, so I got new stock Bosch injectors. Figured I might as well change out cp4 while I at! So I got the cp3 conversion kit from wehrli with sports cp3! I gasket matched the exhaust manifolds/heads, and exhaust manifolds/up pipes. Also gasket matched the exhaust intake side of turbo and cleaned it up nice and smooth, and did a lil on the exhaust down pipe of turbo. Ported and polished the intake side of turbo to and put on a wicked wheel 2 wheel!
So I got it all back together and put in truck, finally got rail pressure up to where it needs to be and pressure on return line for injectors! Truck cranks over, but never seems to fire. Doesn't seem like everyone is telling injectors to fire, I noticed on the scanner the ign 1 signal of always off, and on my dads duramax it is on when you crank engine. I have went thru wiring diagrams and it seems to be getting voltage where it needs to be, the gpcm show ign 1 signal on but ecm and bcm never do?!? I been messing with this for about a week and I am at a lose! Any input would be great! Thanks guys! Josh


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#2 ·
Have you checked for the wire rub problem by the hard aluminum a/c line usually a orange and black sticker ? What year is the lml. is it a 2011-2013 ?

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#4 ·
Have you changed the fuel filter since first tried it. with it sitting that long might be clogged or water in the fuel, also have you pressure checked the cylinders. How old is this lml? What's the story behind it??


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#6 ·
It's strange that #1 injector and GP were damaged with no apparent cause. Have you checked the cam sensor? Any codes?
 
#7 ·
Ya I dropped the tank cleaned it out took all fuel lines off and cleaned all of them, changed all filters when I did cp3 conversion and put engine back in truck for the second time! I haven't pressure checked the cylinders, when I tire engine down to check #1 for damage all cylinders looked good (walls and pistons) no scratches or anything out of the ordinary, new head gaskets and bolts. The engine, tranny and t case came out of 2011 2500 hd with 65,000 miles,truck was in a minor roller over. Guy took engine, tranny, t case and all wiring and electronics out to put it in a older truck, but ended up selling due to medical issues.
I not real for sure what happen to the #1 injector and glow plug that caused it to break off. Didn't look like anything went thru the turbo to get in there and knock them off, only thing I can think of is glow plug broke off and then knocked injector tip off. I checked the plug on the cam and crank sensor and they looked good, on the snap on scanner (verdict) the crank sensor show it is working good, revs go up every time it cranks over, the cam sensor show the revs going up to 5 then down to 3 or so, not sure if that is what it is supposed it do or not? The only other thing I see on scanner is that there is no ignition 1 signal at the ecm, but I got ignition 1 signal at gpcm? It shows a u1500 codes for bcm.




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#10 ·
I've seen cp3 overpressure on a vacuum locked system where it will grenade the first injector in the series, I don't think # 1 is the first on an lml is it??


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#8 ·
if you have another lml to test why don't you figure out the voltage at ignition 1 on off so on and then use a temporary jump wire to make it do the same. BTW you have tuning for the cp3 correct and not the cp4?

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#9 ·
I just got an LMM I was going off of, I figured the ignition voltage would be close to the same on the scanner, which everything was except the ign 1 signal, mine is always off. Replaced ignition switch, no change. Anyone else got an LML and a scanner they wouldn't mind hooking it up and checking to see what the ign 1 signal in with key on and while cranking?! Ya I got tunes for the cp3 loaded on it! I just checked and I am getting 12.3 volts on both ign 1 wires going into ecm. So there is either something else telling the truck not to fire injectors or ecm is bad are my only guesses, just hate to spend money on ecm if it ain't bad!


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#14 ·
I don't think so let me dig a little and see what I come up with...


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#19 ·
Are all your fuses and relays good ? Doesn't the ECM get more than one power feed ?

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#20 ·
Another thing that happened to me recently is that the fuel filter head was leaking down slowly because of the orings inside between that and the original starter still on the truck dragging, it wouldn't start. The new starter sounds like an impact gun. didn't realize how slow the starter had got, not turning over the cp4 fast enough to build pressure high enough to fire up.

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#28 ·
Good question there


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#31 ·
Finally got it started! I feel like a dumbass, I guess when I took the rails off and cleaned them out I didn't get the fuel regulator tight enough and it was letting to much fuel by, it built pressure just not enough to start I guess! Tighten it up and it fired within a couple seconds! Thanks for all the info guys!


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#33 ·
Cool!
 
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