I have a 6-71 non turbo detroit diesel in a 1976 GMC 9500 dump truck. It was running great when I parked it just before winter in 08. Spring of 09 it had a flat tire and I did not have time to fix it until oct 09. After I got the tire fixed I tried to start it it fired right up and stalled fired up the second time and stalled. It has a either start but no bottle so my friend cranked it and I hit it with starting fluid but still would not run. The primary fuel filter looked like it had not been changed in a log time so I pulled it off. And it was plugged with algae so I changed both filters. Dumped Bio Blast in it. Pumped all the fuel out I could through a hand pump with a filter on it and then back into the tank. It cranked for a while and started up.

Now it runs great at a idle. But does not have any power and just blowes massive black smoke out above a idle.

My uncle thinks the injectors are not advancing. I think I hurt the injectors with either. Or there is air in the injector retarding the timing. But I am not a mechinic nor to I play one on tv. And I am just flat out guessing.

We are trying to have a pole barn built at the farm and I need to get it going so I can haul gravel. The truck it up in the woods 350 miles from where I live.

Billy

Remove the rocker cover and look at the long tube that all the injectors connect to. This tube MUST be free to travel back and forth. [assuming you have the shutdown in the running posistion. ALL the individual injector racks MUST move in and out. Gamblers bet you have 1 stuck injector that is stuck in a minor run posistion and not allowing the rest to travel to full fuel. NO FUEL is AWAY from the injectors, FULL fuel is against the injectors.
Again, the shafts MUST operate freely.

Thanks Gone Fishen

That sure sounds better than what I was afraid I was going to hear I won't be going to the farm until the next warm spell. Right now the high temps are around 11-15 deg f and the lows around -5 f. don't much care to work outside when its that cold.



Here is the old beast when I got it three years ago when it was at my house. We bought the dozer from a friend to build our roads and trails at the farm. While after we looked at the dozer he ask us if we wanted a dump truck. We ask if it was a diesel and he said yes and he only wanted $2000 for it so we ended up buying it too. We haven't used it much but when its down it makes it really hard to get anything done. We also have a old 80's case W 14 articulated loader that finishes out out construction equ. Since then its been bombing through the woods in Michigan's upper peninsula. Our property up north is off grid in the woods. For power we have a diesel generator and 5000 watt power inverter on a forklift battery. We had to build a road in 1/4 mile across my uncles property just to get to our 120 acres. And that starts at the end of a dead end seasonal county road.



We built this room on the trailer just before deer season with a wood stove to keep warm in the winter. It worked out great. We were there one nite that it went to -18 f but inside it was 80 F. Thats my dad infront of the mule.



Here's a trail that I just put in that goes to a sand and gravel knoll that I will be digging up to use for the pad on the pole barn. The deer were eating on that brush pile just past the logs on the right. Three weeks ago when I was up last the wolves had killed a deer right there. They ate it hide and all. The only thing left was some fur a lot of blood.

Thanks again for your time and advice. Before I posted I did a search on the engine. I was suprised to learn that the engine was not supercharged and that it only had 238 hp. When it was running right that truck would just rip through the woods!!!!!!!!!!!!

I will be sure to let you know how it worked out after I am able to get up there and work on it.

Billy

All two stroke Detroits are supercharged, some don't have a turbo. Is that what you meant? The supercharger is on the passenger side of the motor. I have a 1972 GMC with a 500 bushel grain box and an Allison auto, wish it was a gear grinder instead. Twogun

Yes, it definitely sounds like you have a problem related to boost. I would suggest checking all of the connections. If you can't find any issues then do a boost leak check with an air compressor to see where the leaks might be coming from. If there are no leaks then use a wide band 02 sensor to check your air fuel ratio to see why all that black smoke is coming out with no power, but my best guess would be a leak somewhere.

Hi TwoGun

It does have the supercharger. But from my reading here it is considered a blower. As the unit is not designed to build boost but just equal what is needed for a fresh air charge into the cylinder and push out the exhaust gasses. And you do not get a boost unless it is equipped with a turbo. But I could be wrong.

That was my first thought QuoteWarz

As it seemed to be getting fuel but not having enough air to burn it. And it runs fine at a idle. In fact I hauled six loads of stumps out of my building area 800 feet to where I have a wood dumping area. But anything above a 1/4 throttle it smoked and lost power.

I pulled the air pipe off of the blower and let it draw air directly into it. To see if the air cleaner was plugged but there was no change. I did not look to see if the vanes in the blower were turning. But I do not think it would run at all if it wasn't.

Billy

Sorry guys, all the DDA books refer to that as BLOWER. Usually a supercharger is in front of a turbo. No, not all 71's have the blower on the passenger side. That engine can be made in 8 different ways. 4 RH and 4 LH. The blower stays on 1 side of the block and the exhaust/camshaft is moved from side to side. Basically. What is fun is to have these new greenhorn parts guys ONLY able to go by a serial #. They never get it right.

Something I just thought of which I should have earlier. In all the flayling around, no chance someone pulled the emergency shutdown flap knob? If it's shut, that's about all they'll do is idle and smoke.
They don't have any connections, about the only way they can loose boost is through broken airbox gaskets or a broken blower gear drive shaft (which is doubtful). Can't remember if the inlines have a drive shaft like the V series or not.

Thanks LMJD

I think my friend pulled out the emergency stop and pushed pushed it back in. Where is the flap itself located at? I pulled the air tube off at the blower and ran it but it was still smoking bad above a idle with it off. If it has something to do with the linkages that Gone Fishen was talking about. Then maybe the cable broke or did not fully close the flap. I do know the knob was pushed in on the dash.

I am going to the farm this weekend. But do not know if I am going to have much time to look at the truck. As I have to shoot the pad and level it. Put the rebuilt starter back in the loader flush the cooling system and refill it. I had to drain the cooling system this fall as the as the coolant was only good to 5 deg f. And with the armature bad I could not start it to mix new coolant into it.

Howdy Gone Fishen. I did a search on the 6-71 here and much of what little I know I have learned from you posts. It really helps to understand what does what on the engine. Thanks again for your help.

It sure is a lot different than work where we have a mechanic on site and all I have to do is go get him and tell him to get it fixed!! For the past 9 years I have been running either a finish dozer or excavator digging new cells for landfills.

Billy

No, it's been a long while but I'm almost sure you can't open the flap by pushing the knob back in (on any of the older Detroits). You have to do it manually at the little lever that releases the shutdown flap after you push the dash knob back in. Pushing on the knob doesn't provide enough power to overcome the spring pressure and the detent to reset it to the open position. When you take a look you'll see what I mean if you have a guy pull and push the cable knob while you watch the lever operate. If I'm wrong hopefully GoneFishen will correct me.
If memory serves correctly on all the Detroits it's right at the intake side of the blower housing. Just find where the shutdown cable comes out of the firewall and follow it. I've accidently flipped the flap myself a time or two working on the Detroits, it's easy to do. Hopefully this turns out to be your problem. If so, it might be a bit embarrassing but you'll have to admit it'll be the cheapest and fastest repair you've ever done.

I got called today to the firehouse down the street from my house today because the new guy accidently hit the e-stop button.

Yea, I drove a 8V71 powered loboy years ago with a winch mounted behind the cab and every once in a while I'd yank on the emergency shutdown instead of the PTO knob.

Wow that would be awesome if it is that simple. I will find time this weekend to try to find and reset it. And put the batterys back in and give it a test run.

Its kinda funny in a way. We were not planing on getting a dump truck at all when we got it. Now that it's been broke down. I keep looking at all I have to do and have been scratching my head trying to figure out how to do it with out the truck. And I have been really bummed out thinking I destroyed it by spraying either in it when I was trying to get it going.

I also can't wait to start razing Scott for breaking my truck and telling him he get to fix it now!!! He's about four years younger than me and has been one of my best friends since I was 15 years old or so. He is also the go to guy up there. If you need welding done or a garden or deer plot put in go see Scott. Any weekend there will be 3-4 people running around looking for him to help them out. And I feel honored that he always finds time to come over and hang out when I am up. When I first got the truck up there and saw it and thought it was the greatest thing. Jumped up took it for a ride. Said the air breaks weren't right grabbed a wrench out of his back pocket crawled under the truck and adjusted them. If I am working moving stumps or gravel and am loading it he jumps right in the cab and starts hauling it. If I start to get out to talk to him he starts shaking his finger at me and tells me to get back to work.

Billy

Unless you went crazy with the ether you shouldn't have hurt it. Where I worked last we maintained lots of 6-71s in graders, etc. and they all had ether Hot Shot kits on them for cold starting and they never caused a engine problem. Let us know how it turns out. Glad you got a good helpful friend up there.

Just a update

While I made it Up north last weekend I did not get to work on the dump truck.

I started leveling the pad for the pole barn with the dozer and within 15 minutes I had blown the tilt cylinder hose. And it took me most of the day saturday to get it out. It goes from the front of the blade through the frame under the floor plates and into a side compartment. Then I didn't have the right size wernches to take the fittings off. And had to fight it with a crescent wrench. Then when my buddy came over he ask why I didn't tape a rope to the hose so I could pull the new one back in. Well I just never thought about it. When I told him about the emergency shutdown flap. He said dam its a 6-71 I knew that I just didn't think about it.

I got the loader put back together and running. And as far as sholveling the snow off of the hood of the dump truck and ran out of time. I am going back up next thrusday or friday for a week and plan on working on it then. after I get the hose back on the dozer.

Billy