m1009 dies if you let off the gas too quickly, thoughts?

brokedown

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My new m1009

Hi guys,

I'm looking at picking up a CUCV M1009, I spent about 2 hours with it yesterday and overall I really like it. It starts up as easy as any new car, the engine sounds very very smooth, and it feels nice and powerful to drive. The issue that I have with it is that the engine frequently dies if you let off the gas too quickly. For example, if you're in park and you "rev it up" a few times, when you stop it just falls flat and dies. When driving, if you give it more than about 1/4 throttle and then lift your foot, it will die. I can keep it from dying by two-footing it and not letting it drop to 0% throttle, but obviously this is a bad practice.

I'm used to cars that die also running like crap, this thing seems to run really well. Just to be thorough, i noticed these things:

. The alternator belts both need to be replaced and occasionally squeal, they are already adjusted to their maximum stretch.
. The vehicle had been converted to a police use vehicle, and a police radio and lights were installed. They are all removed now. All the lights work as expected now.
. The odometer reads about 37k, there is no 100k place on it so it is possible that it is rolled. Again, I am very impressed with the smoothness and quietness of the engine when running, and it doesn't make any noises you wouldn't expect on a new TDI VW.
. It idles smoothly and starts without pushing the pedal. When it dies you can put it in Neutral and it fires right back up like nothing happened.
. This vehicle hasn't been driven much for a while, and I make no claim to the quality of the fuel in the tank. I can say that during my test I ran wide open throttle to test transmission slippage and general acceleration, and it performed great. In my mind its function under load makes me wary of calling it a fuel quality/water/etc issue, so please don't say SeaFoam.
. I am not a diesel mechanic. I'm an IT guy. In a previous life, I was an auto mechanic, but this would be my first real experience with a diesel. Keep this in mind when you read everything else in this post, I only "sort of" know what I'm talking about.

Thanks in advance ffor any advice/help, I really do like this truck and need to move on it pretty darn fast if I'm going to get it, and I may just get it anyway and dig in!
 
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M923driver

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Sounds like injector pump seals are starting to go. Fuel filter is a possibility as well, cheap and easy to change just to be sure, but I'd bet on the IP. If that's your only issue, it sounds like a good truck. Welcome to the site!
 

brokedown

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if it needs an IP replacement, thats a black mark against it.. From what I've seen I can expect to spend over $500 and as much as $1000, and a week of downtime... Although the FAQ says more like $300, but I haven't found the place that will rebuild one for $300.
 
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M923driver

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How much is the truck? I know some police/fire vehicles go pretty cheap. If the rest is in good shape you may still have a bargain and a new IP to boot. The pumps and kits are on ebay, not sure of the time involved. I'm going to do mine soon, it sometimes dies when revved up and allowed to idle. Not as serious as yours, but it's coming. These trucks are 26-28 yrs old, it the IP hasn't been changed it's probably going to need it sooner rather than later. Good luck
 

epitts

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Check the IP return line check valve for small black particles. This could indicate pump problems or valve could just need cleaned. Just one more item that is cheap to check.
 

brokedown

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The truck is about $3000, and the list off things I need to replace other than the stalling issue is pretty short. I still think the good is outweighing the bad.
 

stampy

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Have you changed the filter and the fuel pump? Start there and check the sock in the tank too before replacing the IP. as they may be cheaper fixes for your problem.
 

bigbird1

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Check the IP return line check valve for small black particles. This could indicate pump problems or valve could just need cleaned. Just one more item that is cheap to check.
Great call epitts, If they get plugged they won't run right, just take some brake clean to the valve and try to hold it open with a pick and spray it out good. any dirt will plug it up and cause it to act up .
 

combatmech

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Welcome aboard Brokedown. Welcome to the wonderful world of old Army truck ownership. I spent about a grand right off the bat with both of the M-1009's i've owned. No IP's, just a bunch of other things.
 

brokedown

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well off to a bad start. a soon as I handed over my money, it stopped running and won't start! put in two new batteries and fresh fuel, changing the flow plugs now...
 

Barrman

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I worked on a M1010 that would idle great, but if you reved it up and let off real fast sitting still or let off while going down the road at 55, it would turn off. Filter, return valve, tank sock and lines were all checked. A new IP fixed it all.

$500 is what Stanadyne people around here want for a new pump. That is if you take them a pump to rebuild. There are several places on line that will send you a new one for less than $400 if you send your core in later. I never looked up what the book says an IP replacement should take time wise. I just know my first one took about 3 hours. Most of which was learning what I was doing and being very careful. My second pump replacement was less than 2 hours. If you have a helper to turn the crank while you pull the gear bolts out and put them back in. I figure an easy hour if the bottom lines aren't difficult coming off or going back on.

Don't feel too bad about your new truck. You knew going in that it had a fuel problem. At least now you get to fix it before you get stranded somewhere. IP's have a 5-15 year life span depending on use, fuel and how good they were put together. Starting out with a new IP will make everything else on the truck cheap and easy.
 

brokedown

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Well, evidently these trucks are magic. Maybe just mine.

I spent 3 or 4 hours trying to diagnose it. First off, the deal was, we started it and drove it about 50 feet to the guy's garage so I could check and fill the tires. Shook hands and went to leave, it wouldn't start for anything. He had some crappy batteries in there so it wasn't long before it wasn't spinning, and my first trip to Autozone was to get a set of shiny new (big) batteries. Also got a 5 gallon can of fuel. We ran those new batteries down fairly quickly and started poking and prodding.. Eventually I decided glow plugs couldn't hurt so trip to Autozone #2 and got those replaced. It didn't seem to have any effect, so we started making plans to tow the truck home. Right as we were going to leave, my brother hit the starter just for giggles and it fires right up.

We idled it for 5 minutes, he drove it around the block a few times, and its running better than ever. The problem it had yesterday is gone, you can just drive it like any other vehicle now. We made sure we could shut it off and it would start again, no issues there., so we drove the hour and 10 minutes home also with no issues. Now its in my garage, tight fit.

Tomorrow I have a list of tasks to do. The reverse lights don't work, both alternator belts are fully adjusted and squeak (already bought replacements), one of the headlights is missing its adjuster, plus all the filters and hoses mentioned earlier in the thread. I did find a local shop that rebuilds the injection pumps, so i'll be calling them tomorrow.

Overall I'm feeling pretty good about the truck, 2500 to the seller, $400 to autozone, and $80 to the gas station..

My brother says "its pretty fast for a big ass truck", my girlfriend says she can't even see it (camouflage). She was not at all interested/impressed until I mentioned the roof comes off.
 

brokedown

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Spent the day working on the truck.. well a lot of that time was driving to the junkyard, tool store, parts store.. End of the day I've got a new fuel filter, air filter, fresh oil and filter (the oil and fuel filters were marked 2009), fixed the reverse lights, adjusted the headlights, replaced all 3 belts, and finally gave it a good scrubbing at the car wash. I've got a few items left on my list, but today it started and ran perfectly all day, and other than the power steering belt it was a pleasure to work on. Beyond the necessities, I picked up a full size spare (the one in the truck had a chunk missing fro the bead and was worthless), a "nicer" shift knob for the transfer case, and a transmission gear indicator,. On the negative, one of the wiper blades broke.

I feel like I deserve a frosty beverage, so I'm going to do that now.
 

ranchhopper

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I have the same problem with the shutting down after revving it but it starts better than most I have owned I believe it is a fuel supply problem to the IP. My truck will run without any problem with the accelerator depressed as long as I want it to so its not a clogged check valve on the return because the truck would run until back pressure builds up in the return line causing the truck to shut down if the check valve were clogging up. These trucks have an IP that stays full of fuel all the time mine dies after revving and probably emptying the top section of the pump because after holding it wide open and some cranking it starts again. Im going to replace the fuel filter and base with a spin on type and install an electric fuel pump and Im betting it will take care of the problem.
 

brokedown

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My truck no longer has that issue... I can't really pick a particular thing I did that made it better, but before the problem went away I bled/primed the fuel filter, put in fresh fuel, replaced both batteries, replaced the glow plugs, and just plain drove it. The problem seemed to get less pronounced quickly over time and now it is totally gone.
 

Keith_J

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Diesels regulate power AND engine speed by injected quantity. The injection pump has a governor which sets the RPM based on how far the accelerator pedal is depressed. Automotive diesels also vary the timing of the injection, adding to the complexity of the injection pump.

Governors balance the force of the throttle spring against centrifugal flyweights, push on the accelerator more and the spring is pulled further, resulting in greater force. But in worn pumps, the injected quantity can drop far further than the throttle spring can pull.

You can hear this happening if you are coasting from a stop as the vehicle's inertia causes the engine to spin though transmission back-feeding. Since the governed speed at zero throttle is much greater than what is required to spin the engine, no fuel is injected. You can hear this as there is no diesel clatter.

Old and worn injection pumps can hang in this zero injected quantity, resulting in a dead engine. You can try pumping the accelerator as changes in throttle spring tension can free up the injected quantity adjuster. Eventually, you will need an overhauled injection pump.
 
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