OT Dodge Cummins fuel system

We purchased a used Dodge 3/4 ton p/u about five years ago, powered by the Cummins engine. It provides 22 MPG and has been totally reliable. It is
the easiest engine to start I've ever owned, usually starting with just a tap of the key. Of late, it has, on occasion, been hard to start, as if it has lost prime in the injectors. It usually happens after it's been driven a while and then left to sit for a few days. It never does it if it is run daily, or routinely, and could be when the fuel tank is not more than half full. Haven't cleared up that issue as of yet, but I'm still watching.
There are times when it won't fire immediately, but starts within a couple seconds, then dies. When I start it again, it runs a little rough for a few moments, then smoothes out and runs fine afterwards. Other times it may take as much as 20 seconds of cranking with the starter to get it running. It does not always do this, but when it does I'm not a happy camper, needless to say. The only other symptom I might be able to report is that on occasion I can smell diesel fuel from under the hood, but I've yet to find a leak of any kind. I recently washed down the engine with solvent, and found the fuel filter somewhat oily, as if it may have the tiniest of leaks, but apparently not full time.
Any suggestions as to what may be going wrong? My thought is that the supply line is draining back to the tank. Does that make sense?
Harold
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Harold & Susan Vordos wrote:

Maybe air is getting in from a loose connection ? That would be first thing I would check followed be a cracked flare . Luck Ken Cutt
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I would look all your fuel supply and especially the injector lines over very carefully for a pinhole leak. It only takes a small drop of fuel to let all the pressure off of the injector lines. If you haven't changed the fuel filter in awhile now would be a good time to do it, or have it done. I would also check your shut off solenoid. Make sure it is functioning as it should, if it isn't actuating properly this could be why you are getting a start and die condition. My International truck has a DTA-466 in it and had been a plow truck for a few years. I went ahead and ordered all new injector lines and will just change them all at one time. I will experiece some slow starts from time to time but never a start and die. From experience I can tell you that you don't want to get out somewhere and then have to bleed your injector lines because they got air in them. Most diesels will not push much air out of the injector lines and will have to be bleed to get the injector to pop off.
tim
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Harold,
This situation happened to my brothers 1995 Dodge PU. It turns out Dodge made a few shortcuts when they wired the diesel. One of the small wires to the right side battery positive post (if your standing in front of the truck) is for the fuel solenoid relay. When you turn the key the selenoid must have power to kick open the fuel shutoff. In his case the corrosion in the wire provided just enough resistance that it would need some jarring (ie a long starting cycle) to finally trip the relay. Why Dodge didn't wire this to the fuse box located just a foot away from the battery is beyond me.
Also on a related note, there is a upgrade kit on EBAY for the starter solenoid. Large diameter copper contact ring to replace the cheesy one supplied by Dodge.
With both items fixed it starts and runs like a champ. The '95 has a mechnical fuel ramp instead of a electronic brain box so he put in a steeper ramp, wired the waste gate shut on the turbo and put 4" exhaust on all the way from the headers back. It runs great! In the Arizona mountains towing a 30' box trailer full of motorcycles it will climb the hills at 65mph at 30" of boost. Any more boost and the torque eats the transmission. (He has gone through 3 of those in 100K miles.)
Last thing I'd check would be leaky lines. We haven't run into those yet.
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Hey Bart,
The Dodge RAM owners manuals say that you must not tow in Overdrive. Eats transmissions.
Take care.
Brian Lawson, Bothwell, Ontario. XXXXXXXXXXXXXXXXXXXX On Sat, 06 Nov 2004 14:52:23 -0700, "Bart D. Hull"

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Brian,
The "stock" diesel is limited to 11lbs of boost, we use 30lbs of boost on a aftermarket turbo gauge to know when to "let off" the gas pedal when towing. This was after we learned what the tranny would withstand from experience.
Oh well. It was always the tranny, not the Overdrive converter that was shot. Too much torque, too much heat for too long. We always did make sure to "ease" into the locking Overdrive so as not to beat up the lockup parts.
Next truck will have a standard tranny. Unfortunately all new trucks have electonic control of fuel and wastegate.
Bart
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OK, I got some serious questions for you. I have a Hummer with the 6.5 GM turbo diesel. Rated 200HP with 11 lb of boost and pulling an 8k lb truck. This vehicle does not come with a boast gauge or EGT, but I have added both (westach). On an extented grade the EGT will go to about 1300 F. There are numerous "chips" out there for more power but I feel that I'm already pushing it pretty hard based on the EGT. The GM 4L80E tranny also died at 26K miles. Torque converter went out!
So what is the Max safe EGT? Also No intercooler on this engine.
chuck
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The temperature limited component is the turbine. A banks turbo I installed on an '84 NA 6.2 GM diesel in a pickup was limited to 1200 degrees. F. That was a Garrett turbo. The 6.5 has, if I remember correctly, an IHI turbo. Ishikawajima Harima Industries. I'd do a search for them and ask what the max. sustained turb. temp is. You did put the thermocouple in front of the turbine inlet, right? That's the only correct place for it. If it's at the turbine outlet, it will cause the indicator to be approx. 200 degrees low. On my '93 3/4 ton Chevy pickup, with the same engine as your hummer, I drilled and tapped into the cast iron boss directly before the turbine for the thermocouple. I've seen the results of overheating turbines and the resultant destruction. I believe you're probably right at the limit at 1300 degrees.
Garrett Fulton
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wrote:

<snipped>
I have a 93 GMC with a 6.5 Turbo, please tell me thats not the same 6.5 as in the Hummer!
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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! -)
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the
computer.
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
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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:

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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
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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
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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
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snip----

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
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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:

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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! <g>
Harold
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On Sat, 06 Nov 2004 14:52:23 -0700, "Bart D. Hull"
<snip>

Sh*t! - I'd check with Cummins and make sure you aren't going to blow out the bottom end and/or launch the heads into LEO by running 30" of boost with the fuel turned up. I know they use the same engine in pretty heavy trucks, but there /is/ still a limit to how much abuse the block, crank and rods will take. And a rebuild can't be cheap.
If it's safe to run that much boost, I'd still get the wastegate recalibrated for the maximum safe pressure and hook it back up - if something goes wrong and the boost manages to get past 30" and up into "grenade" territory...
And the next time the transmission barfs, I'd see if you can get an Allison that fits. They'll take a lot more torque.
(Been there by proxy - My brother found out that a stock Powerglide might handle a stock 265 or 289 2bbl fine, but it won't live long behind a 327 4bbl Vette motor with a mild cam...)
--<< Bruce >>--
--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
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Bruce,
We LIKE boost! My brother also has a '59 Ford Stationwagon with twin T-4's, intercooled, EFI port injected Ford 460 that we "let off" at 20psi boost. He just ran a 12.8 at Firebird Intl Raceway last night with it. He was "pedaling" it out of the hole to keep traction.
I'm in the process of building a 200HP Subaru 2.2L with a T-3 turbo for a airplane motor. Have to "downrate" it as it will need 200HP continuous to pull 200mph not just for 13 seconds like a drag car.
We've done Nitrous on a '63 Scout drag truck (10.90's 1/4), Turbos on the Dodge PU, and '59 Ford. Now if we have some spare cash I'd love to try a supercharger but their hard to hide under a hood.
See http://www.ayetech.com/cars/scoutrageous.htm for the Scout and http://www.ayetech.com/cars/thford.htm for the '59 Ford.
Just "ate" the C-6 on the '59 and had it replaced (under warrantee!!) just this Monday. Same story, too much torque, fried clutch plates and shift bands. It's really tough to find people that can build a serious Ford tranny. Now its a manual automatic to reduce the slip between gears. (You must pull into 1st, 2nd or third like a manual, it does not shift between gears.)
Bart
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