Duramax L5P rough idle fixed with Power Service Kleen Diesel additive

wwillson

Staff member
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Aug 20, 2003
Messages
5,361
Location
Naperville, IL
Our Duramax L5P has 19,000 miles on it now, mostly pulling our 5th wheel trailer. Since about 10,000 miles I have noticed a small lope in the idle, which progressed to what I would call a slight miss in what felt like one cylinder. I noticed no difference in power or fuel economy while pulling. The miss was much more noticeable at a cold idle than it was after pulling. Almost all fuel was purchased at either TA or Petro truck stops.

I haven't run an fuel additives in this truck, but decided to try a fuel injector cleaner to see if it made any difference. We just pulled the trailer 1,300 miles and within the first 500 miles the rough idle was much better. At the end of the 1,300 miles, the idle was completely smooth, just like it was when the truck was new. I have read that the common rail injectors are prone to clogging, not through coking, but through internal deposits of sodium salts of alkenyl succinic acids. These salts are insoluble in fuel and come from contamination at the refinery all the way through the delivery system.

The Power Service Kleen Diesel did the job of cleaning the injector(s) that had deposits and returned the idle back to creamy smooth. There are probably several other products that will do the same, but when I find something that works, I stick with it. I'll be running a maintenance dose of Kleen Diesel continuously. My opinion is that everyone who has a common rail diesel should consider doing the same.
 
Joined
May 25, 2020
Messages
2,260
Our Duramax L5P has 19,000 miles on it now, mostly pulling our 5th wheel trailer. Since about 10,000 miles I have noticed a small lope in the idle, which progressed to what I would call a slight miss in what felt like one cylinder. I noticed no difference in power or fuel economy while pulling. The miss was much more noticeable at a cold idle than it was after pulling. Almost all fuel was purchased at either TA or Petro truck stops.
The quality of Diesel fuel leaves something to be desired. One of the mistakes truck drivers make is that they don't carry extra fuel filters with them. Sometimes they fill up with dirt and water pretty fast. I seriously question the quality of Diesel fuel sold across the US today.
 
Joined
Dec 19, 2018
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Vancouver
The quality of Diesel fuel leaves something to be desired. One of the mistakes truck drivers make is that they don't carry extra fuel filters with them. Sometimes they fill up with dirt and water pretty fast. I seriously question the quality of Diesel fuel sold across the US today.

It is garbage. Common rail stuff lasts at least twice as long in other markets and the sole reason for that is fuel quality. Bosch has a slang term for our diesel - “dishwater diesel.”
 
Joined
Jul 11, 2014
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Location
Paradise of Florida
My previous diesels all ran a fuel additive at every fill up. Make it a habit.

PowerService, Howes, .... available at the local walmart. Autopart stores... Napa, Carquest, Oreilly, Advance, Pepboys, Autozone.... have various other brands like Pri-D, Stanadyne, Hotshots, Amsoil... Don't get hung up on brand loyalty.

Keep the fuel side lubed and cleaned always, and antigel'd when needed. Consider an upgrade fuel filter kit too.
 
Joined
Jul 11, 2014
Messages
3,455
Location
Paradise of Florida
Cat, Donaldson, Fass, Airdog, Fleece.... check with the Duramax forums to see what owners have been installing. Kits are available at dmaxstore, sinister, underdog, xtremediesel, blackmarketperformance..... so do your research.
 
Joined
Nov 8, 2017
Messages
645
Location
California
Costco B5 diesel is excellent and has deposit control additives blended in their “Top Tier” formula. I’ve been using it for a few months because lately it’s about $0.50/gal cheaper than my old favorite Chevron D2. I filled up yesterday @ $6.49/gal.

I add TDR-FL additive to both brands and the Costco B5 gives me +1-2 MPGs avg per tank better than Chevron. It also has a stronger combustion odor which is the only other difference I’ve noticed. I Always use fuel additive for the last 5 years never any issues with deposits, water, contamination or lubricity. It’s a hassle adding the 9.5 mL/gal of fuel at each fill up but it’s totally worth it IMO.
 
Joined
Jun 19, 2020
Messages
1,439
Location
Iowa
@wwillson I saw the Farm & Fleet add today and thought of this chain... FYI F&F has this Power Service on sale for $11.99 for reward members, buy 2 and get a $10 rebate. Turns out to be $6.99 for a 64 oz container. Not a bad deal IMO. I'm not sure I need that much injector cleaner but it is a darn good price.

F&F Flyer and the rebate form

just my $0.02
 
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