OT Dodge Cummins fuel system

I'm not a fan of GM diesels. Made LOTS of money in the early to mid 80's on the 5.7 and 6.2 diesels. I don't think they have come out with a redesigned engine so I imagine they would share the same weaknesses. Cranks broke frequently (most into multiple pieces.), blown head gaskets were so common we could do one in and out of the shop in 2 hours, injection pumps were also commonly destroyed, (had a dozen rebuilds hanging on the walls and sometimes we ran out of stock.) This was with STOCK engines, not somebody horsing around with them.

EGT of 1300 is getting quite warm! Only towing 8K and your getting this kind of temps? No intercooler? YUK! Careful as "quite warm" to melted could be only 1/2" away on the gas pedal.

Ford used a International designed diesel and it proved to be a good sound design, we rarely got these in, most were in for somebody putting gas in the diesel tank. Dodge buys the Cummins direct and it is STRONG!

Just my 2 cents.

Bart

Charles A. Sherwood wrote:

Reply to
Bart D. Hull
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No, I haven't, nor did I think of it, or know about it, but it certainly makes sense. Thanks for the tip, which I will explore. At this point I have no link, so I'd appreciate one if you have it.

Two very kind individuals contacted me on the side and provided some good information, including information on the supply pump of which you spoke. I'm up to my eyeballs working on the house and don't drive the truck much, even though it's our primary transportation. It often sits in the garage for a week and doesn't get driven. When my schedule is somewhat lighter, I fully intend to explore the problem until I get it resolved. I don't much like having it not start like it is capable of doing.

Will do. What I discover could very well be common to all of them, so others might benefit as well.

Thanks, Orrin.

Harold

Reply to
Harold & Susan Vordos

I've had nothing but good luck with GM diesels. I'm talking about true diesels designed to be a diesel from the ground up. The 5.7 was based on the gasoline 350 block. Yeah, a lot of broken cranks. From what I know of it, the third main bearing web in the crankcase would crack, allowing the crankshaft to flex. Expensive problems, sure enough. The '85 6.2 that I turbocharged lasted 234,000 miles with nearly no problems at all. My oldest son killed it in a rollover that he was lucky enough to walk away from without a scratch. The '93 3/4 ton pickup has 194,000 on it now and has been the best truck I've ever owned. Nothing wrong with GM diesels, in my opinion. Good engines. Of course, I am pretty good about maintaining them. Sure would like to have one of those Duramax's though. Now_there's_an engine.

Garrett Fulton

Reply to
gfulton

Very nice engine pix on your web site, Bart! Thanks. One question though. Is this an experimental aircraft and licensible as such? You made the comment the FAA is pretty picky about airframe/engine combinations.

Bob Swinney

PS: I take it back about the wrench wranglers, at least as far as you're concerned.

Reply to
Robert Swinney

It does sound like the lift pump is a possibility. One thing to keep in mind is that if the lift pump is weak then it could mess up the injection pump at least on the 98 1/2 and later models for sure. I believe you stated yours is a 94 which means it has the mechanical lift pump and injection pump. These are not known the go out like the newer electric pumps but do go out from time to time with symptoms similar to yours.

However I'm more concerned about the slight leak at the filter you mentioned. I don't know when was the last time you changed that filter but I ran into one which had rusted through the side do to water in the bottom. This wasn't so bad but when I cleaned it up I learned that it had rusted through inside as well and wasn't filtering!

Wayne Cook Shamrock, TX

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Reply to
Wayne Cook

Yep, its licensed as an experimental and I get the repairmans certificate so I can do my own maintainance and annuals. I can also update parts as I see fit. (My stainless AN hoses and fittings would NOT be acceptable on a certified aircraft as they were not original equipment is a perfect example.) We know that things have improved in the 50 years since WWII, why use the same old stuff?

Funny thing, if you import a Russian MIG or a AN-2 they get licensed as an experimental. 600mph or 14,500lbs of foriegn certificated airplane and it's "experimental". But hey, its the FAA! You just need a private pilot certificate for the AN-2 beast (the 14,500lb one) but you do need a letter of authorization from a "examiner" (the first guy with nuts enough to fly a MIG in the USA and lived though it)

Don't get me wrong I'd love to fly the AN-2 (I'm thinking one real ugly flying Winnebago) or any MIG. (Like a old Mini or MG and the motor and electrics are just as cranky) I got to fly once in a L-39 (Czech military trainer) and loved every minute of it. Oh, yea that's an "experimental" as well.

If we could only remove the paperwork and lawyers from this hobby. It definitely doesn't make it any safer.

Bart

Reply to
Bart D. Hull

Garrett,

Your one lucky dude. I was making $800 take home pay per week in the mid

80's due to the 5.7 and 6.2. (Just out of high school before I decided I could get paid more and work less after graduating from college.) Early 6.2's were just big block versions of the 5.7 and suffered just as badly. We went from repairing lots of "Luxury cars" to repairing lots of pickup trucks with the 6.2. Same problems as mentioned. Big thing was head gaskets, Arizona is not nice to anything that even thinks about overheating.

One thing GM learned and put to use on the 6.2 was to use 4 bolt mains. In retrospect they were nuts with the original 5.7's using two bolt mains with so much compression. (High compression for a gas motor, low for a diesel, that's why they needed so much preheat with the glow plugs and block heaters.)

I drive a Toyota Tacoma I bought in 1997 new. Enough of that repair stuff on all my previous domestic cars and trucks and 25 mpg is a real bonus nowadays. If a need a big clanky pickup, I can always borrow my brothers Dodge diesel and get a loan for fuel. (SMILE!)

Bart

Reply to
Bart D. Hull

No, I'm not lucky, Bart. You've been away from it too long. GM has been building good pickup diesel engines now for a lot of years. They use the NA GM 6.2 in our pushback tugs on the flight line at work. They're worked very hard, run for many hours without shutdown, and the drivetrains grenade before those GM engines. Only complaint I've heard from the fellows over in the ground support equip. shop, who maintain them, is that the glow plugs will curl sometimes and they have to pull the cyl. heads to get them out. I get 21 mpg with my '93 diesel pickup with that 194,000 on it. Only repair I've done is the oil pressure switch that controlled the electric lift pump. $14.00 and 30 minutes. GM diesels have treated me very well. I always take up for good reliable friends.

Garrett

Reply to
Garrett Fulton

Interesting comment. While our '99 1 ton Dodge w/Cummins gets around 15 MPG, the trusty old '94 yields right at 22 MPG. Considering the weight of the truck (3/4 ton Dodge w/Cummins) I'd say that it gets exceptional mileage. Certainly better, pound for pound, than the Toyota. Of course, right now anyway, diesel is the priciest of all fuels where we live. Still, considering I used to drive an '86 GMC with a 454, the 22 MPG leaves me almost speechless.

Harold

Reply to
Harold & Susan Vordos

Blush! Changed the filter?

This truck, under the hood, looks almost new. It has barely over 90,000 miles on it. I'm almost embarrassed to say I've never changed the filter, but it has been garaged since we've owned it and has run like a top. The likelihood of water condensing in the tank is small, especially when you consider that we run a dehumidifier in the garage. As I see it, only at a station would we pick up any water, and so far we've never found the slightest indication that we have.

The only problem we've had with the truck was a leaking boot on the front right wheel cylinder (piston froze up due to rust), which I rebuilt, turning the rotors and replacing the pads, plus about a year ago it started having trouble with the starter. Turns out one of the contacts was burned almost completely away. I made a new one from some copper stock I had on hand an installed it. End of problem.

Back to the filter, it has been bled, and nothing but clean fuel comes out, so water isn't an issue. The likelihood of any internal rust is non-existent as far as I can see, especially considering how well the truck has run until this small problem reared its head. If water had been getting past the filter, I couldn't help but think that it would have missed some, and it hasn't. Still, I appreciate your comments. Who knows what the real problem may be!

Mind you, the amount of oil I mentioned on the filter was nothing more than a thin film, hardly even dusty, and represents a few years of service. It's just that the engine is cleaner than that in general, so I couldn't help but wonder if I didn't have a slight air leak, which might have accounted for the fuel problem.

Tonight, on the side, I received this email from Mike. (Thanks, Mike!)

"94 to early 98 inline Bosch pumps have an overflow valve on the back side of the pump on the return line. The spring is prone to breaking and letting the fuel drain back to the tank."

I can't help but wonder if it might be the problem. It describes, exactly, what the symptoms appear to be.

When I finally get to the bottom of the problem, I'll post what I learned. Could be useful for others.

Thanks for the comments.

Harold

Reply to
Harold & Susan Vordos

Actually the AN-2 is quite a safe airplane to fly. For one thing it's built like a tank. For another it was designed to take all kinds of abuse, like hard landings. Also the Kuznetsov radial is extremely reliable. Just be sure to take a pair of ear protectors. The Russians didn't believe in wasting weight on sound proofing and those puppies are LOUD!

Regulation of private aircraft is certianly out of hand and the concepts behind the way it is being done are out of date. Modifying the system is ridiculously difficult (look at how long it took/has taken to get the 'sport flying' category approved -- and I'm not sure they're certifying or issuing licenses yet.)

--RC

That which does not kill us makes us stronger. --Friedrich Nietzsche Never get your philosophy from some guy who ended up in the looney bin. -- Wiz Zumwalt

Reply to
rcook5

I'd recommend changing the filter then.

There's not telling but I would definitely change the filter. There was very few signs of anything wrong till this one just started leaking out the side.

All possibilities.

That's possible. I'm not as familiar with those year models as I am with the earlier and later models.

Definitely.

You're welcome.

Wayne Cook Shamrock, TX

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Reply to
Wayne Cook

The hard start problem is a common known issue. Caused by deterioration of the rubber fuel hoses between the metal lines coming and going to the tank and the engine. Air gets into the system while sitting especially in an uphill position. They are a pain to change. They need replacement probably every 5 yrs or so. Use high quality marine grade diesel hose. Go look at

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for details. Email if you need further.

Reply to
Al

I have a 93 GMC with a 6.5 Turbo, please tell me thats not the same

6.5 as in the Hummer!
Reply to
Forger

Note, I am not pulling a trailer, the 8k pounds is the vehicle all by itself!

Yes, it before the turbo but on one side of the engine so its close to the head. EGT will sit at 800 on the expressway. Will hit 1000 with just a mild accell. Will hit 1300 if I let it, but I usually back it off.

could be. I though GM made the 6.2 back in those years though. Turbo is located differently to make it fit. Probably reprogrammed computer. I know one guy with a 93 hummer with a 6.2L Normally Asperiated Diesel with 270K miles on the engine! Not bad for a GM engine! -)

Reply to
Charles A. Sherwood

Yeah, I believe it's the same engine. But the '93's were the last year for the mechanical injection pump. No computer input. They started that in '94.

Garrett Fulton

Reply to
Garrett Fulton

Yep,

Diesel is pricy here in Arizona as well. The stations don't list the taxes like they do in some states but I wonder if diesel is taxed a bunch more. After all we have the expensive special EPA mix gas in the Phoenix metro area and diesel is only one blend (not counting summer or winter blends.)

Most of the time I'm just commuting to work so a small pickup is great. Expecially when Davis metal salvage is on the way home and is open after 5pm. (Metal working content.) ;-)

Bart

Harold & Susan Vordos wrote:

Reply to
Bart D. Hull

The price on diesel here was lower than regular until the recent price hikes. Now it's a dime higher than premium. I can't help but wonder if heating oil has placed a huge demand on it, raising the price (surely there isn't any gouging, is there?). Many don't understand that the difference between #2 diesel and #2 heating oil can be nothing more than the name. Unless you can buy low sulfur heating oil, which my supplier doesn't sell, offroad diesel and heating oil (dyed red)come from the same storage tank (theoretically no road tax).

Way to go, Bart. We want to keep this thing legitimate!

Harold

Reply to
Harold & Susan Vordos

Snip

I'm not sure if this is the resource my son used, but it is a start:

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And another:

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Good luck,

Orrin

Reply to
Orrin Iseminger

look here

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here on how to fix yer truck,
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the contest is still open, my guess is the transfer pump is failing. joe

Reply to
joe

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