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6.5 stuttering from stand still. Smooth otherwise

K

KennyB

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OK my 6.5 has a new Injection pump (about 2 years old), New tank sock (about 2 years old), New PMD (a few days old Heath & new backup with same results), Fuel filter (about a month old looks new). New PCM about 2.5 years ago. New air filter (about a month ago) Was doing well for months, started the "bite the shark", so contacted Heath (pmd was about 2 years old at that point). Put backup on (a cheap Dorman but works fine) It solved that problem, got replacement Heath and all was well for a couple of weeks. Then it started sputtering when coming from a stop or low rpm. It seemed to do fine once you got through it until I stop or slow down again. Changing to the backup PMD had the same results. No codes. I always use Diesel Kleen when filling up.

Fuel pressure from the filter 4psi when running, almost 6psi with just Key on (its a 2000 k3500 diesel). 4.5psi from T valve when running idling. Got 4 to 5 when revving the engine. Ironically I could not make it sputter while I had the gauge on it. The LP is loud and working. All the fuel lines appear in good condition. The ones behind the FFM looks fairly new and in good shape. Did not see any air bubbles when checking with clear tubing (I have clear tubing for my gauge)

Just for the record I'm not a mechanic (I'm a You Tube mechanic lol). But in the past the great minds of this site have helped me to fix things.

Another thing, it seems to be worse if the AC is on. I appreciate any help you can give me. I only have 180,000 miles on it and hope to get 300,000 before retiring it!.
 
The clear line- you need to have it on the 1/4” ip return line coming out of the ip to the metal return.
You need to interrupt the 5/16 fuel line just before it gets to ip with a “T” fitting and read pressure there while driving. 8–4 pei is what you should have.

Working somewhat but not in required spec is not good enough. Factory style lift pumps are pretty much junk for ds4. If you get ine to stay in the 5-8 range it can work a while but expect to replace it soon. But understand 8-14 is how to get longest life from the ip.
 
Will L. said:
The clear line- you need to have it on the 1/4” ip return line coming out of the ip to the metal return.
You need to interrupt the 5/16 fuel line just before it gets to ip with a “T” fitting and read pressure there while driving. 8–4 pei is what you should have.

Working somewhat but not in required spec is not good enough. Factory style lift pumps are pretty much junk for ds4. If you get ine to stay in the 5-8 range it can work a while but expect to replace it soon. But understand 8-14 is how to get longest life from the ip.
Click to expand...
Thanks Will I’ll try it as soon as I get a chance. What lift pump would you recommend?
 
The reason he brought up the tank sock is because there is a difference between the gas and diesel ones. Most 6.5 owners that replace their tank sock replaced it with a gas sock not realizing there is a difference. The diesel sock has a bypass built into it.
 
I truly don’t know about the sock. my fuel gauge didn’t work, I had him fix it and put a new sock in too. It worked good for a coupl of years, wou it take that long to clog a gas sock? It is my daily driver, i also have taken a few trips towing my fifth wheel rv since then without any problems. I would have to drop the tank to find out I guess. I might could find the invoice from the shop.

thanks for the help!
 
Wait until the tank is next to empty before You drop it.
Remove the sock and put the tank back together and install it.
Then install a 3/8ths inline fuel filter between the tank and he lift pump.
 
One of these motorcycle lifts works mighty fine for dropping tanks, lifting them back into position too. Even if they are loaded with fuel.

Motorcycle & ATV Lifts - Harbor Freight Tools

Easily lift your motorcycle or small recreational vehicle for servicing with a Motorcycle & ATV Lift from Harbor Freight. Easily lifts up to 1500 lbs.
www.harborfreight.com www.harborfreight.com

It dont necessarily have to be a chinesium unit, just the pic for reference.
 
KennyB said:
Then it started sputtering when coming from a stop or low rpm.
Click to expand...


Do a video of it "sputtering". That's a pretty vague description and only combined with "fishbite" can we ASSume what is going on. Can you describe it better without a video?

From experience you pull over and shut it off when acting up. Then pop the hood and check the "clear return line" off the IP for air bubbles. I had a hose behind the Fuel Filter Manager, FFM, that would randomly kink shut and "vapor lock" my 1995. Took way too long to find it although a 250 GPH race Mallory pump (Yes, Alcohol/Methanol due to Meth leftovers in Biodiesel production) would push through it most of the time. Short brush life though... The air bubbles told me it was a fuel problem not a PMD problem... I kept the 1993 with the DB2 NOT the 1995 DS4 PMD mess.

Pictures are of the DIESEL sock with the gelled fuel bypass valve in it. Gas socks do not have this. The silver strips clogging the works up are the lining of the tank coming off due to Biodiesel ALL of our diesel is now spiked with.

DSCN0569.jpg

DSCN0570.jpg
 
Hey Will, I'm thinking of going ahead and changing the lift pump. It's been on it for at least 4 years and was a cheap autoparts store one. Probably delphi. I looked at the fass, but I think that's out of my league (best I could tell requires redoing parts of the fuel line). Expensive too. Does Fass have a bolt on replacement? (simple idiot proof, so I can do it lol) Would the AC Delco pump work. If so which one? I saw ep158 was popular but my truck is a 2000 model Vin F. AC Delco's site said ep1000. Is this unit OK or should I get the ep158? I really appreciate all your expertise. I can't afford much more into this this truck. On the verge of selling it, if I keep having problems. Thanks so much man!
 
My original raptor was almost a bolt on, didn't modify the fuel lines any, but I did have to order fittings. The newer one I have now I had to make an adapter fitting
 
KennyB said:
(simple idiot proof, so I can do it lol) Would the AC Delco pump work. If so which one? I saw ep158 was popular but my truck is a 2000 model Vin F. AC Delco's site said ep1000. Is this unit OK or should I get the ep158? I really appreciate all your expertise. I can't afford much more into this this truck. On the verge of selling it, if I keep having problems.
Click to expand...

Easy button for better lift pump.


🤪 You expect a 21 year old pickup with 2x it's design life miles to not have problems? Don't look for an excuse: Just. Get. Rid. Of. It. FWIW the gas engines are less trouble, but, at this age good luck on em too. My NEW pickup payment is less than the monthly average I spent at the parts store.
 
My suggestion is evaluate what it will cost to make this truck viable long term.
Examine the cost of what you would replace it with and whatever it costs to make it viable long term.

Get out of it and replace it, or invest in it. This old of a truck- it is best to know right away.
 
On the pump- don’t do anything until you can decide economics of it.
any of the stock style pumps is a waste of time with the ds4.
 
I dont know why I always take the painful path of keep and fix.
I look at different trucks, all Chevy of course, and then I look at the miles on said new to me unit. Thay always seem to be hitting over 150,000 and thats the break off point of needing a bunch of work. Oil pump and timing chain/sprocket set for starters, then whatever else breaks along the way.
I think, crap, get thaat and start all over again or, keep what I have and continue down this lonely path.
Big vehicle payments plus parts bills is just not a doooable thing for Me. This one is paid for so guess I’ll continue that trail.
 
Well I hope you enjoy laughing at my expense. I’ve put a lot into this truck and truly like it. I just want a dependable truck. I can’t afford a new truck. Great for you if can. I was looking for help and advice. I saw on another forum where the AC delco was great for a stock truck. Like mine. I guess I’ll look for help elsewhere. God Bless
 
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