02 chevy 3500 lb7 crank no start :/

216 Views 16 Replies 5 Participants Last post by mray, 4 d ago

markson96

Discussion Starter · 6 d ago

so I got this 02 chevy 3500 dually with 6.6 lb7! cranks no start! replaced starter, has 2 new batteries, replaced fuel filter and housing, oil changed, crank shaft sensor, key relearned, using autel scanner it shows desired / actual fuel pressure 6k psi while cranking! disconnected fuel feed to cp3 to make sure Im getting fuel to cp3 and it is! primed tons of time and no start! using the scanner I checked for the security system to see if it prevents truck from running and everything passed ok! only code showing is glow plug! unplugged fpr and scanner reads 24k psi! try to crank and nothing! replaced all rubber hoses on low pressure system ! primer housing gets solid but looses prime after crank! disconected both lines on rear driver side of the engine ( fuel feed and return lines ) got 2 hoses and put inside a 5gal tank with fresh diesel and no luck! sprayed some starting fluid but doesnt make any difference! doesnt even want to start! while cranking some smoke comes out! Im kinda lost here! I also inspected wiring harness and didnt see any damage!

here is a pic of the scanner while cranking! anyone got any idea whats going on?

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1 - 17 of 17 Posts

mray

· #2 · 6 d ago

Does it show any codes, sorta sounds like maybe the Fuel Injection Control Module.

Ottowood

· #3 · 6 d ago

If won't fire on starting fluid I would be checking compression..
Make sure it's not something mechanical..

Ron Nielson

· #4 · 6 d ago

You have fuel and fuel pressure just find. Now I wonder if the injectors are being activated. Leaning towards FICM problem along with MRAY

markson96

Discussion Starter · #5 · 6 d ago

mray said:
Does it show any codes, sorta sounds like maybe the Fuel Injection Control Module.

only code that shows up is related to shorted glow plug! my injectors balance are all 0! when I unplug the ficm harness, it throws a code! not sure how to test ficm!

markson96

Discussion Starter · #6 · 6 d ago

Ottowood said:
If won't fire on starting fluid I would be checking compression..
Make sure it's not something mechanical..

sounds normal while cranking! Im guessing ecm or ficm! not sure how to test them

Ottowood

· #7 · 6 d ago

markson96 said:
sounds normal while cranking! Im guessing ecm or ficm! not sure how to test them

You stated it does nothing with starting fluid.. Is this correct?

DMAXfirefighter

· #8 · 6 d ago

I’m with @Ottowood on this- if it’s not doing anything with starting fluid or similar, you need to check compression.

Do you have a signal from the crank sensor telling the scanner rpm?

mray

· #9 · 5 d ago

When the FICM went out on the 01 for some reason it wouldn’t fire on starting fluid.

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Ron Nielson

· #10 · 5 d ago

markson96 said:
my injectors balance are all 0!

Doesn't this indicate that the injectors are doing nothing?? they aren't firing??

markson96

Discussion Starter · #11 · 5 d ago

Ron Nielson said:
You have fuel and fuel pressure just find. Now I wonder if the injectors are being activated. Leaning towards FICM problem along with MRAY

Ottowood said:
You stated it does nothing with starting fluid.. Is this correct?

thats correct! doesnt do anything!

markson96

Discussion Starter · #12 · 5 d ago

DMAXfirefighter said:
I’m with @Ottowood on this- if it’s not doing anything with starting fluid or similar, you need to check compression.

Do you have a signal from the crank sensor telling the scanner rpm?

yes! it does show rpm! previous owner replaced the engine, it was running for 1 month! parked then never started again!

markson96

Discussion Starter · #13 · 5 d ago

mray said:
When the FICM went out on the 01 for some reason it wouldn’t fire on starting fluid.

did you get any codes when your ficm went out?

markson96

Discussion Starter · #14 · 5 d ago

Ron Nielson said:
Doesn't this indicate that the injectors are doing nothing?? they aren't firing??

not too sure! yesterday I hooked up the same scanner on a 6.6 duramax newer truck that runs, the balance rate was all different! every single injectors had different numbers! with the key on and engine not running! but the lb7 that Im working on and doesnt start shows all 0!

markson96

Discussion Starter · #15 · 5 d ago

2

this reading is while cranking!

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DMAXfirefighter

· #16 · 5 d ago

Ron Nielson said:
Doesn't this indicate that the injectors are doing nothing?? they aren't firing??

Very well could be….

markson96 said:
yes! it does show rpm! previous owner replaced the engine, it was running for 1 month! parked then never started again!

It does show rpm so that’s good. I’m questioning a bad ficm as well at this point

markson96 said:
did you get any codes when your ficm went out?

I’ve seen several ficms go bad with no codes show. Best way is to get one from an operational truck and plug it in to see if it will start. If it does, then that means the ficm is bad

mray

· #17 · 4 d ago (Edited)

markson96 said:
did you get any codes when your ficm went out?

I did get a code for lost comm. with FICM. Not trying to steer you in the wrong direction but also know of the FICM going out with no codes. Sometimes there’s no rhyme or reason for them going bad. I agree with DMaxFF if you have access to another one I would try it. They are plug and play on the LB7.

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