lly long cranking times

[jpatt]

Ok so as the title says my lly has a very long crank before fire.
Already replaced fuel filter housing and a new filter. Had the whole system tested.
This happens all the time. Hot, cold Temps and engin running hot or cold. Sometimes it's a 5 second crank. I watched some videos and seen where the factory guage will stay low a bit after its started cause of glow plugs. Mine does not do this. It shoots right up to pay 14 after it fires. I also just went out and put a volt meter on my driver side battery and it showed 11.8 volts with truck not been running for 12 has and 35 degrees outside. Truck cranked for 3-4 seconds and fired up. Which I would feel is normal in cold weather. So that told me the glow plugs seemed to work. Could my batteries be weak and that's why I have a long crank. It cranks fast, just struggling to fire. I hate this truck for this reason. And need it fixed. I have more info about issues I have had with the truck but wanted to get the battery question out 1st

 

[mechman3]

Do you have any codes or messages in the DIC?

 

[jpatt]

No codes at all.
Truck has a ppe lift pump. I unhooked it a bleed the fuel system and the long crank I thought went away. But then it seemed to be right back so I think it was just a fluke. I had to use starting fluid last yr to get it to start when it was having a fuel issue last yr. Just a small amount though, thought maybe that hurt glow plugs but it has a long crank even when it's hot out. So I'm wondering about the battery. I read that they r very picky about them

 

[WVRigrat05]

You'll need a tech 2 to get glow plug codes on the LLY.

Have you had your injector returns tested? Mine cranked hard before starting when my injectors were bad

 

[jpatt]

Here's the story with it.
Truck just shut off one cold day. Would not start for nothing without starting fluid. Had it towed and took it to a duramax guy that is highly recommended. He had it over a month, cause he was dragging his feet. He said my sending unit was bad. He replaced it and said it starts fine now but has a long crank. Sending unit made no sense to me since it would run fine after it got started but I said ok. I seen the old sending unit when I picked truck up and it was a rusty mess. He said number 5 injector had a high return rate so he changed it out. He said everything else tested good. I had 10k and told him fix everything and I didn't care what it needed So im sure he checked it all. It has had a long crank ever since. Battery went dead a few times in cold weather which is why I'm question about them now. Truck tows my enclosed race trailer with no issues and had plenty of power. Doesn't not smoke at all at idle or driving unless u really hammer it and it will blow a little black smoke. Glow plug light only stays on for maybe 1-2 seconds when it's cold.

 

[WVRigrat05]

The light won't stay on long. IIRC when my glow plugs were bad my light stayed on for a good while but I could be wrong. I just know it didn't show any codes until it was hooked up to a tech 2.

And weak batteries will make it start a little slower. Usually if they go dead more than twice it's time to change them. I had to replace mine every 2-3 years. Already put one set in my LMM and they were two years old

 

[Burn Down]

You need to ck rail pressure while cranking. Also need to see if it will make full rail pressure once running. Do you have any way to read rail pressure?

 

[jpatt]

Going in now to have my batteries load tested. Anyone ever see a truck have a long crank from a lift pump installed

 

[jpatt]

No way to check pressure. He told me that it went straight to like 13000 or something when it cranked. That's crazy hight but I swear that's what he said unless I misunderstood completely

 

[jpatt]

Just had batteries tested. Both are 850 CCA batteries. 1 came back 12.13 volts and 586 cca.
Other came back 12.11 volts and 618 cca.
Said both needed charged, but they should have been fine in that they are always in truck right. Didn't buy new ones, he told me to charge them and bring them back to be checked again

 

[Burn Down]

Just had batteries tested. Both are 850 CCA batteries. 1 came back 12.13 volts and 586 cca.
Other came back 12.11 volts and 618 cca.
Said both needed charged, but they should have been fine in that they are always in truck right. Didn't buy new ones, he told me to charge them and bring them back to be checked again

I would say they are both shot unless your alternator isn't putting out enough voltage... My battery tester flat out tells you they are bad or good.

 

[jpatt]

Well my battery guage on dash goes up above 14 volts as soon as the truck fires. It doesn't even stay low for a min like glow plugs are running. Hate to dump 300 bucks into batteries if that's not my issue

 

[Burn Down]

Well, then have them tested somewhere else... Cables all clean and connections on the batts good?

 

[jpatt]

I'm gonna check cables tomorrow. But I'll probably buy battery to I guess so at least I know

 

[jpatt]

Any other ideas as to why I could be having this issue. I'll try to get a video of it

 

[jpatt]

So I unhooked lift pump and put a fitting to connect the two n lines back together. Had a hard time getting it to fire after bleeding system. With truck running my stock filter housing plunger has tension on it it but with a little pressure I can slowly pushbutton down ones. It's not super easy but it does move. Is this normal. With my lift pump it was rock hard

 

[jpatt]

I had truck tested today and they told me it won't hold fuel pressure at idle. And fuel Temps were high. Said I need injectors. It hols pressure just above idle, they commanded max pressure and it would build 18k of the 23k it demanded. Low on cash I asked which ones do I need to replace. He said it's not worth it. Replace them all. Looks like it's gonna be a while

 

[Burn Down]

How many miles on the truck?

 

[jpatt]

219339... It's my tow vehicle to pull the enclosed trailer to the race track. We don't out alot of miles on it. Full of power and doesn't smoke at all. Having balance rates checked friday at a different buddy's house.

 

[Burn Down]

That's a lot of miles on injectors... Your going to have to have a return rate test done to know which one/ones are bad. You could get away with changing just the bad ones but it's a matter of time before the others crap out.