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L8T dead on the highway 92k miles

lundimpact1775

By lundimpact1775
in 6.6L Gas V8 (L8T)

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lundimpact1775 Enthusiast

lundimpact1775

Posted
Posted

Hi everyone. Heading home last Thursday from running some errands my 2020 L8T went into limp mode and then died while cruising 70mph. 

 

As I waited for a flatbed I attempted some starts, which resulted in crank crank Frank no start. 

 

Codes showing immediately at limp mode were p0089, p0304 and p228c. I'm hoping it's "just" the hpfp, but any input is appreciated and welcome. This is based on the p0089 and p228c faults, combined with the no start condition but I'm only guesstimating here.

 

Current shop status is that every light on the dash is now lit up and they were able to start it but it misfired badly. Hope to have a final diagnosis later today.

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lundimpact1775 Enthusiast

lundimpact1775

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  • Author
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Multiple stuck injectors and a failed high pressure fuel pump is the final verdict. 

 

I'm just astonished that those things could all fail spectacularly at once. Would have guessed one or the other. 

Pryme Senior Enthusiast

Pryme

Posted
Posted
25 minutes ago, lundimpact1775 said:

Multiple stuck injectors and a failed high pressure fuel pump is the final verdict. 

 

I'm just astonished that those things could all fail spectacularly at once. Would have guessed one or the other. 

Yeah that does seem odd. How many miles on your truck?

lundimpact1775 Enthusiast

lundimpact1775

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92k and some change on the clock.

 

Bought it at 89k from a known reputable dealer. Needed something reliable with a crew cab and the normal size box, and did not want to break the bank. Hence buying a pre-owned unit with higher miles. 

 

My favorite and most reliable truck I ever owned was my 2010 1500 with 6.2 I bought it with 120k on the clock in 2013 which is very high for its age. Drove it until 2019 and 265k miles without a single hiccup. 

lundimpact1775 Enthusiast

lundimpact1775

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I suppose that makes sense, hadn't considered it that way.

 

We are replacing all 8 injectors anyway, and plugs since it's coming due soon. Should be all taken care of this week. I hate paying shop prices... But at this stage in my life I guess I can afford it and I probably would not have caught the failed injectors until after it was all back together. I did guesstimate the hpfp correctly anyway so that was worth a grin.

64BAwagon Senior Enthusiast

64BAwagon

Posted
Posted

My sons 5.3 went at about the same miles. Had to drop the tank also and replace the pump in the tank as well as clean it and flush all the lines. One of the lines at the HPFP is one time use and must also be replaced. 

newdude Senior Enthusiast

newdude

Posted
Posted
18 hours ago, 64BAwagon said:

When the HPFP goes it spreads debris through the system much like when a CP4 grenades. 

 

 

Gas are returnless fuel system.  Diesel are still a return system which is why the entire fuel system on a diesel ends up with metal. 

 

Only place for the metal to go on a currnet gas truck is into the high pressure lines and the injectors.  

64BAwagon Senior Enthusiast

64BAwagon

Posted
Posted
1 hour ago, newdude said:

 

 

Gas are returnless fuel system.  Diesel are still a return system which is why the entire fuel system on a diesel ends up with metal. 

 

Only place for the metal to go on a currnet gas truck is into the high pressure lines and the injectors.  

 It was a 2014. I know he pulled the tank and pump also. Thanks for clarifying that. 

newdude Senior Enthusiast

newdude

Posted
Posted (edited)
18 minutes ago, 64BAwagon said:

 It was a 2014. I know he pulled the tank and pump also. Thanks for clarifying that. 

 

 

Gotcha.  GM went returnless back in 2004 on trucks so I should have clarified that lol.   

Edited by newdude
lundimpact1775 Enthusiast

lundimpact1775

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Well here's an update for anyone interested, picked up truck Thursday, 40 miles home. Drove it into town to gas up Friday morning, then headed out Saturday morning for a 250 mile road trip with a truck full of people. Stopped for lunch at mile 200, ate, hit the road. 55mpg cruising, same exact failure.

 

Towed back to the shop that fixed it (luckily, passenger had AAA with 200 miles range). 

 

They offered a free loaner which I declined as I have a car too. They dissected it first thing Monday morning and said the new hpfp they installed had an internal fault in the regulator, causing it to misbehave. Another new hpfp in and picking up again tomorrow. 

 

I've lost so much confidence in my "road trip" rig at this point... Idk what to even do though besides keep driving it since this work is all under full warranty for 2 yrs/ 24k miles. My only solace at this point is the shop in question has committed to ensuring it stays on the road under their warranty. 

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