L5P will barely start, then die Please Help

[Mikey52]

VSE 2017-2024 GM L5P 6.6L V8 Duramax CCV Upgrade Kit - Platinum Diesel Parts

L5P CCV Upgrade system – keep your Turbo and intake air system clean! Install Instructions What is a CCV system ? CCV stands for “Crankcase Ventilation” On all diesels and especially the L5P the CCV is connected to a valve cover to extract the combustion gasses that have entered the crankcase...

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Might put this on instead of the factory part when it goes back together.

Diesel Parts - VSE Engineering - CCV Upgrade Kits - Vin Specific Enterprises

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[Rdomeck]

Mikey, I'll look in to getting one of those. All my parts will be in today to get this thing back together.... After a two year project, I'll want to drive this thing as soon as I can! I'll put that on the list of things to do with an upgraded fuel filter set up.

As for the color, I'll have to look and see what it is off of. I picked it out of one of my color books, mixed a sample and loved it. The orange is a bunch of orange I had laying around I just mixed together. The grey I think was a Land Rover color.

 

[NC-smokinlmm]

Looks like the blue from 2016. HD Dave has one so I see it all the time. Color looks killer…

 

[Rdomeck]

Ugh. This thing. Fired up. Had it idling while putting the inner fender liners back in. It quit. I can get it to start, but it won't idle unless I have the throttle open about 10%. I can see that I am not building any manifold pressure. Ambient is 15psi and manifold is 15psi. All of my intake hoses are connected.

No codes at all

Any ideas?

 

[Rdomeck]

Let it cool down and it fired up. Watching the oil pressure drop as it warms up is concerning. Could I have put so much fuel in the oil that the oil is now really thin? I'll change it tomorrow to make sure. I did have the oil cooler off of it but used new sealed going back together.

Seems I'm still idling a little low and my fuel rail pressure is still a little high.

Balance rates aren't above 3... for the most part.

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[PureHybrid]

At idle the manifold will be the same or close to baro, they won't make boost at idle. The fuel pressure you described before seems like a non issue, especially if the ecm is commanding it to be high, so don't just look at actual pressure but also desired pressure

Generally speaking, if an engine fires up easier after it cools off there's problems electronically, solenoids / sensors / capacitors/ coils etc.

 

[Rdomeck]

Wouldn't I be able to see some boost in pressure when I give it throttle?

 

[2004LB7]

Wouldn't I be able to see some boost in pressure when I give it throttle?

Without a load on the engine it won't really build much boost. Try a little power braking and see if you get more boost

 

[NC-smokinlmm]

Wouldn't I be able to see some boost in pressure when I give it throttle?

Not unless you brake boost it. If you’re worried about the oil I’d just change it, oil dilution is possible if you had leaking valves like you did.

 

[Chevy1925]

Ugh. This thing. Fired up. Had it idling while putting the inner fender liners back in. It quit. I can get it to start, but it won't idle unless I have the throttle open about 10%. I can see that I am not building any manifold pressure. Ambient is 15psi and manifold is 15psi. All of my intake hoses are connected.

No codes at all

Any ideas?

Take the exhaust back off again, see if it runs fine.

L5P uses an electronically controlled oil pressure pump. If you aren’t under 30psi at idle (I want to say they idle at 40-50psi), it’s a non issue

 

[Rdomeck]

I definitely have zero boost. The only code that finally came on was that the engine has low boost.

I changed the oil to make sure that wasn't the issue. The oil in it certainly had diesel mixed in. The new oil helped, but I'm only seeing 6-7 pounds at idle with it warm.

Might just have to cut my losses on this engine and drop a new one in.

Seems the only thing that would cause no boost is a big leak or the turbo is not spinning? I did another smoke test and everything is sealed up from the outlet of the turbo to the intake.

 

[Rdomeck]

I did not see anything electronic about the oil pump in this engine. Spins off of the gear on the crankshaft. The same gear for the water pump. I know these can have issue with that gear because they are not pinned. When I had this one apart, I pinned it so it would not spin.

I start out at 60psi cold, as it warms up, it keeps dropping. Once warm it will only make about 30 at 2500rpm

 

[Chevy1925]

Sorry, it’s controlled via a pressure relief valve, not the actual pump.

6psi ain’t good. Sounds like the valve may be stuck open

I’d suggest getting the oil pressure fixed before worrying about the rest

 

[Rdomeck]

I don't see that the valve could be sticking. It starts with 60 pounds and slowly falls as it gets warmed up.

Could it be a cracked oil pick up tube?

 

[2004LB7]

I'd put a mechanical gauge on it to verify the pressure. If it's dropping too low maybe the piston oil squirters. I've heard of them falling out before and messing with the oil pressure.

 

[Chevy1925]

I don't see that the valve could be sticking. It starts with 60 pounds and slowly falls as it gets warmed up.

Could it be a cracked oil pick up tube?

Well considering a cold start will be pushing over 100psi on my 2020, you have an issue even cold. Cold oil doesn’t flow so the regulator can’t bleed it all off. Once it heats up, it can bleed more and more.

I know one of our members had an issue with some kind of crap that went through a 2021 oil pump and he had to put a new pump in the truck to fix a starvation on initial start up. It would take 10-15 sec before it would show oil pressure.

If you had a pickup issue, it would show up like I stated above with the other member that had an issue.

 

[2004LB7]

Well considering a cold start will be pushing over 100psi on my 2020, you have an issue even cold. Cold oil doesn’t flow so the regulator can’t bleed it all off. Once it heats up, it can bleed more and more.

I know one of our members had an issue with some kind of crap that went through a 2021 oil pump and he had to put a new pump in the truck to fix a starvation on initial start up. It would take 10-15 sec before it would show oil pressure.

If you had a pickup issue, it would show up like I stated above with the other member that had an issue.

Wasn't that Ike? Had to pull the pan and redo the oil pickup. He tried new filters to rule out drain back valve issues first but didn't resolve it

 

[Ron Nielson]

https://www.duramaxdiesels.com/forum/threads/oil-prime.90198/#post-1237338 Last post

 

[Chevy1925]

Wasn't that Ike? Had to pull the pan and redo the oil pickup. He tried new filters to rule out drain back valve issues first but didn't resolve it

Yup

 

[Chevy1925]

So Josh was talking to me about the oil flow on these trucks. The old article I based my info off of is wrong. These trucks are still all mechanical as far as oil pressure control.