LB7 removed Fleece Allilocker, no start now.

Awenta

Active member
Sep 28, 2014
4,090
2
38
CT
Tried a new ficm
New TCM
disconnected FRP Sensor Pigtail Plug, along with the dual fueler controller.
When disconnected those it killed all power to the truck basically just the headlights turned on but the fuel gauge (which has 3/4tank) indicated that the truck was empty.

But once those were plugged back in it was back to what it has been doing.

What that means I have no idea

Checked all fuses all grounds and wiring

Logs were sent rail pressure is exactly why its calling for.....


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Tried some clean fuel? Maybe it's simpler than we're thinking

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BlkMax

Member
Sep 1, 2008
743
4
18
Wasilla, AK
I hate to ask this, but did you check the ground wires below the stock FICM location? I have an extra FICM because those grounds were loose.
 

NRA223

New member
May 20, 2015
288
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We know this.
The Ali locker and TCC wire is a moot point at this time. The issue at hand now that the truck cranks but won't start. And we've gone over everything in this thread....if you read all Quinnells posts.


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Sorry. Looking at his last post before mine it appeared the brown wire was still in question.

So the brown pin 29 wire could cause this? I don't have a schematic off hand but that's the only wire from the trucks harness that was cut/spliced into.

So the brown wire must be for the engine rpm front what you're telling me?
 

NC-smokinlmm

<<<Future tuna killer
May 29, 2011
5,215
365
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At Da Beach
You could have broken a diffrent wire internally when removing the Ali locker. Ohm them out if possible, its extremely difficult to find one with the naked eye. Its got to be related some how...
 

NRA223

New member
May 20, 2015
288
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0
You could have broken a diffrent wire internally when removing the Ali locker. Ohm them out if possible, its extremely difficult to find one with the naked eye. Its got to be related some how...

This, or is it possible to break a pin off or pull the wire part way out of the connector on these trucks? I know I've seen this issue on other GM vehicles.
 

Lb7_Katie

Lb7 Duramax
Sep 8, 2013
851
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Pins are all fine and we've already thought of another broken wire. Haven't found anything.


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x MadMAX DIESEL

<<<< No Horsepower
Dec 30, 2008
7,535
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Lexington, Ky
Try new Ecm? Pull the crank sensor and see if the tone wheel is loose. Try a different crank sensor. Check resisitance on the engine speed signal wire. Clear codes and see if the 0374 comes back? All of that might cause the p0374 and your issue.


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Lb7_Katie

Lb7 Duramax
Sep 8, 2013
851
31
28
34
Try new Ecm? Pull the crank sensor and see if the tone wheel is loose. Try a different crank sensor. Check resisitance on the engine speed signal wire. Clear codes and see if the 0374 comes back? All of that might cause the p0374 and your issue.


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Will try sometime this week.


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Lb7_Katie

Lb7 Duramax
Sep 8, 2013
851
31
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34
Good news! Truck runs! Not only that but it shifts perfectly no more hesitation or issues!

The boyfriend found a ground wire that was bad. Had a solid connection but must have been a bad wire.

Lessons learned a bad TCM ground can cause issues with shifts, truck won't start with TCM hooked up but will start without it but runs like shit....

Thank you everyone for your input and advice! Especially Matt Quinnell who spent 3+hrs helping us look over the truck!
b708f7a76e3659b201c43ade253deaab.jpg



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Lb7_Katie

Lb7 Duramax
Sep 8, 2013
851
31
28
34
Glad you got it figured out. Crazy something to simple can cause so much grief

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Tell me about it! Lol I was ready to drop it off at Duramax tuner. Lol texted Nick this morning and asked him to let me know how busy the shop was


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ridindurtylb7

New member
Feb 22, 2016
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Glad you got that beauty up and going again! I know this is off subject but what's the specs on wheels and tires? This thing has the perfect set up!