LB7: Died on the road and won't fire?!

Jules1525

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Jun 15, 2016
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-Sorry for the novel, the truck is a pain-

Hi all, back again. So, the backstory on this truck first- she came from auction for a pretty good steal at $1500. Was running but had intermittent security no start issues, no prndl, no trans cooler hooked up and a blown brake line. Snapped a tie rod backing off the trailer. Oh, and the front end was a bit banana like from what looked to be a good hit (air bags didn't deploy).
Fixed the security issue with a toothpick, changed all the brake lines, soldered my cluster, did the tie rod etc etc.. plated it and started driving to work out the kinks I knew I'd find at this price.

Since driving- new NSBU switch and rear calipers, blower motor resistor, power steering line to keep her going. Then my g80 blew and I can't get one right now so it's disengaged to avoid any problems until I can... all of this has the body work coming along nicely haha!

Since I got it I've been pretty sure I'd need injectors (hard long starts and she was smokey at idle). The longer I've been running it with new fuel and stanadyne the better it's gotten. Almost no smoke now and a nice smooth idle but the long crank persisted. Seemed like a good time to install the lift pump I bought last year. While that was going on I rebuilt the filter head and changed the filter. Immediately a line leak appeared. But it was running better than ever and I had an hour long round trip I had to make. Didn't make it. At all.

Out of nowhere, dead on the road. Lost throttle response and maybe a second later it shut down and wouldn't fire. Assumed the line leak had gotten worse, so changed the line. Still no start. While changing the line, the fuel drained off had a lot of debris in it. I'm assuming the tank does as well and will be dropping it and cleaning it.

But now it will not fire at all. I even gave in and tried a bit of either in the air filter (I know, but was out of wd40).

I'm trying to get it to fire running a line from a fresh can of fuel to avoid the tank so I can get it the last fifty feet to my driveway. Ideas?

Could the filter head have a problem even after it ran probably 6 hours after the rebuild? Could junk be in my cp3 and it's not pulling? What do I check next? Help!



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Jules1525

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02b90c30bfb496fa7feac247d2c567ab.jpg


This is what came out...


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Jules1525

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4a6e0bbf01de92b0dbffa14243458c49.jpg


The jar on the right is what came out when the pump went in and the filter head was done...


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Jules1525

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I don't think I have a pressure tester. There was fuel at the Schrader valve when I was trying to prime it though


02 Silverado 2500HD 4x4 ECSB LB7
99 Silverado 1500 ECLB 5.3L
02 Silverado 1500HD CCSB 6.0L
 

Jules1525

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The tank is definitely a concern. The tow truck couldn't get near my driveway and I'm hoping to not have to drop the tank on the street.. or push that beast uphill and into my driveway (shared and tight fit on a good day)


02 Silverado 2500HD 4x4 ECSB LB7
99 Silverado 1500 ECLB 5.3L
02 Silverado 1500HD CCSB 6.0L
 

Jules1525

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It's also not throwing any new codes at all. Not even when it first died. Two hours to wait for the tow truck so I had time to pull out the reader. All I have is glow plug module A (I think) still, which has been there since I got it and a short code for my abs pump- looks like the ground wire is dirty.

I'm tempted badly to bypass the filter head and use a diesel primer bulb (I have one that came on it where the lift pump was removed before me) to run it from the can and see if it will fire but the idea of unfiltered fuel even fresh worries me


02 Silverado 2500HD 4x4 ECSB LB7
99 Silverado 1500 ECLB 5.3L
02 Silverado 1500HD CCSB 6.0L
 

DAVe3283

Heavy & Slow
Sep 3, 2009
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To really diagnose a no-start on a Duramax, you really do need a good scan tool that can log (or at least display) desired and actual rail pressure during cranking. If it isn't building pressure, then a mechanical fix is in order. However, if it is building pressure, then something else is preventing the start.

Until you know if it is building pressure, you are just wasting time working on the fuel system when it may be fine.

If you don't have a scan tool, you can do a bottle test to see how much fuel is being returned. It is possible that your CP3 or injectors are just done.

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Jules1525

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The bottle test is just removing the return line at the top/back of the engine and replacing it with a length into a bottle crank for 15 seconds and check to see how much fuel is in the bottle correct?

I'm hoping it's not the cp3 or injectors, if it is that means I'm going to have to push it up the hill and then do a three point turn. Nothing about that sounds fun. The day it quit it was running smoother and quieter than ever before right until the moment it shut down. That and the lack of any codes is giving me enough hope to hold onto that this isn't a tear down condition. If so, I'm still ahead of the game for what I've put into this truck so far.


02 Silverado 2500HD 4x4 ECSB LB7
99 Silverado 1500 ECLB 5.3L
02 Silverado 1500HD CCSB 6.0L
 

DAVe3283

Heavy & Slow
Sep 3, 2009
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Normally the bottle test is just testing the FPRV, but in your case, yeah, you want to know the total return rate. During cranking, it should be very small, since it isn't building enough pressure to start.

If you find a lot of fuel getting returned, you can make an adapter to measure the return fuel from each bank and the CP3 all independently, which should point the finger at the guilty component.
 

Jules1525

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The fprv was something I was suspecting before the leaky line made itself known. As I had mentioned, the longer I was actually using the truck the less I was thinking injectors. The last week it ran there was barely any lopes or smoking. I just saw a video where they just unhooked the return line and powered the lift pump without cranking to see if fuel passed through, is that a valid test? It would be the easiest the way it's sitting now. I'm probably going to go buy a pressure test gauge. Seems like a good investment when parts are adding up so a good scanner isn't happening soon


02 Silverado 2500HD 4x4 ECSB LB7
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Jules1525

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Well, air in the fuel. More accurately there's some fuel in the air coming through the schrader. Since it's new line from supply to the filter, it's not there. The lines from the filter head look rough. Guess I'll replace them. Nobody local has them in stock, so do they use any special fittings or can I replace them with the same rubber line I'm using everywhere else?


02 Silverado 2500HD 4x4 ECSB LB7
99 Silverado 1500 ECLB 5.3L
02 Silverado 1500HD CCSB 6.0L
 

Awenta

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Sep 28, 2014
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If that much shit came out the pickup in the tank could be clogged


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Jules1525

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The tank is getting taken out and cleaned inside and out. I doubt there's anything good in there after seeing that. But- since it came back on the tow truck I've been bypassing the tank and using fresh fuel from a jerry can.

Anything from the filter back (with the exception of the return line which is still running to the tank) is at this point new.


02 Silverado 2500HD 4x4 ECSB LB7
99 Silverado 1500 ECLB 5.3L
02 Silverado 1500HD CCSB 6.0L
 

Jules1525

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Update-

All lines from the cp3 to the fuel supply have been replaced now. Filter is holding prime. Schrader valve is getting nice clean fuel.
Still no start. Not even with wd40.
Checked codes again (have never had any lights illuminate but bulbs could be missing from the cluster) my glow plug code and abs ground code disappeared ? Pulled the ecm1 fuse and reinstalled it, got the glow plug code back. No start. Cleared and read the codes and they are gone again.

This is reminding me now of when the security was acting up except there's no security light this time.

My code reader is pretty basic, so I could be missing codes? Thoughts?


02 Silverado 2500HD 4x4 ECSB LB7
99 Silverado 1500 ECLB 5.3L
02 Silverado 1500HD CCSB 6.0L
 

zakkb787

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Sep 29, 2014
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If you have access to a scan tool you really need one for these trucks. You can get one at Autozone for a decent price. We really need to see what your actual vs desired rail pressure is. Not sure if someone suggested that already. You may can even rent the tool.