Lack of power at speed.

Now that my brakes work on the farm fresh M1009, time to address the power issue.

I've noticed that going up hills in the area gets difficult at highway speeds (65mph)

Pedal to the floor, unloaded, the M1009 will top out at 53mph going up inclines like
she's towing an 18-wheeler.

* New fuel filter.
* New air filter.
* Engine warmed up before hills.
* Fresh diesel.
* 58k miles.
* No noticeable/audible engine troubles (stuck valves, etc)

I planned on trying to do a little light towing with the M1009, but with the issues above I'm
a little concerned about making it.

I might be just expecting too much out of her though.

It's the nature of the beast.

I think tow rating is 1200lbs...

98G said:

It's the nature of the beast.
I think tow rating is 1200lbs...

Click to expand...

Ah, ok. I was wondering if it was just because of gearing.

Only 1200lb with the pintle? wow

The M1008 runs out of gearing 55ish, but the M1009 will do 70.

And yeah, 1200lbs...

kallisti5 said:

Ah, ok. I was wondering if it was just because of gearing.

Only 1200lb with the pintle? wow

Click to expand...

Did you look at how the pintle is mounted ?
If so you will see why the low tow rating , then add the gutless 6.2 and 3.09 gear ratio .

I see you are in Texas...What size tires are you running?

Yes, a M1009 can tow, provided you have the correct hardware installed. I have a Class III hitch on my M1009. It's bead welded and bolted to the frame, and sits under my pintle. I installed a Tekonsha brake controller, pretty sure it's a Prodigy. I have an 18' double axle steel bed car hauler. It weighs about 1700 lbs, and the total length is 22'. I towed a 2700 lb MUTT from Orlando to southern Georgia a few years ago. It took a while to get it up to speed, but I was able to hold it at 60-65 MPH in the flat lands. Overpasses slowed me down considerably, buy I stayed in the right lane and let everyone pass me. I've also used my CUCV to tow my wife's Mighty Mite. It's light at 1700 lbs.


Your Injection Pump might be weak, but please don't take my word as gospel. My advice, for what it's worth: Get in touch with CUCVRUS and Recovry4x4. Those guys are absolutely amazing resources. Recovry4x4 lives in the mountains with a small herd of CUCVs. CUCVRUS has forgotten more about CUCVs than I've learned in the 11 years of ownership!

ODFever said:

Your Injection Pump might be weak, but please don't take my word as gospel. My advice, for what it's worth: Get in touch with CUCVRUS and Recovry4x4. Those guys are absolutely amazing resources. Recovry4x4 lives in the mountains with a small herd of CUCVs. CUCVRUS has forgotten more about CUCVs than I've learned in the 11 years of ownership!

Click to expand...

Hm.. I was kind of thinking in the same ballpark. This thing has done a lot of sitting, and I know has had some abuse.

I used to run Diesel Purge straight on my B100 VW TDI Diesels... it did wonders to smooth them out > 100k miles.
(I know some will bawk at "liquid solutions", but I have seen it make a world of difference in real practice)

No **** clue how to run it straight on the 6.2L... need to dig up a diagram of the fuel system.
https://products.liqui-moly.com/diesel-purge-3.html

You will have to change the fuel return hose to go back into your bottle of magic cleaner. Otherwise what people have done is fill the fuel filter, if you have a spin on, and just let the suction of the injection pump pull it from the bottle. Be sure to reroute the return line or it will just dump it all back into your tank.
Be sure to disable the mechanical fuel pump or you will have a huge mess with fuel still pumping. Whether it's by removing the supply hose or whatever.

Try a test drive with the air filter housing removed. You will feel a noticalbe increase in power. Yes is will be louder from the air intake. These engines are starving for air. It is a small intake hole for a 380 cubic inch engine. If you like the difference you can drill a few small holes in the air filter housing to allow more air in. You can also replace the exhaust with 3 inch pipe and stop before the rear axle. This will reduce back pressure. Now that you have more air getting in and more exhaust getting out you can increase the fuel rate in the injection pump. It will feel like a different truck.

The dual exhaust on the M1009 is pretty free flowing. Changing to a 3" pipe will likely accomplish nothing. Add a Turbo if you need power..

All of the above suggestions are good.

Since we are basically in the same area I wanted to pass on a few M1009 driving experiences of my own.

Stock M1009 with a receiver hitch and 33x12.50 BFG AT tires.

Pulling a 2,000 pound flat bed trailer with nothing on it I can go any speed I like. I don't like to go more than 65-70 with the trailer. Most hills around here don't affect it any.

I have pulled my M101a2 with at least 1,500 pounds of stuff in the back through the hill country to Camp Wood a few times. 62-68 mph happy speed and not really slowing down on the hills. I will note that going from Leakey to Vandiver on 337 had me down to 30 up hill with the trailer empty. There are some big long grades out there and without an EGT or coolant temp gauge. I adjust the throttle so no black smoke is coming out the pipes in the mirrors. I don't like making the TH400 downshift so going to 2nd gear at the bottom of a hill to me is nicer on the truck.

However, that same trailer empty but with the cargo cover installed to act like a parachute means in any head wind above .0001 knots. I can't get over 54 mph. Even down hill it might only get to 60.

If that is the kind of hills you are describing in the first post. Then you are getting all you can get out of the truck without a turbo. Which brings up the dark side of diesel engine ownership. A Banks kit is an easy weekend bolt on kit for a good bit of money. A GM turbo install will give similar performance but could take more than a weekend to install with all the custom fitting for exhaust needed. Either way you go, you will need a fresh IP to get all you can out of the engine. You will need good head gaskets, fresh injectors, gauges to monitor, probably a radiator professionally cleaned, maybe a new higher flow water pump and you will still find that in some situations you want more power.

Then you will look to a 6BT 12 valve. They do fit, kind of. There are even a few companies that make 6BT cross members for the square body trucks. Then fitting an intercooler will cross your mind, you will have to get a different transmission because the TH400 won't last behind a 6BT. Axles will need to be upgraded to handle the engine power and weight as well. Which means new rims and tires and probably a lift.

If you get that far down the power path, you probably would have been better off finding a 1997 D3500 single wheel from the start. Think about what you are going to use the M1009 for and see if it really does fit that mission before going down the above described path.

Hasdrubal said:

The dual exhaust on the M1009 is pretty free flowing. Changing to a 3" pipe will likely accomplish nothing. Add a Turbo if you need power..

Click to expand...

IMHO it is more restrictive then one would think. Although I didn't have it on a dyno before and after, a shorter 3 inch pipe improved the seat of the pants acceleration in my case.
I installed a Banks Sidewinder on my 82 Civi 6.2 with good results but not worth that kind on money.

Lots of good stuff here. I had access to the M1009 today, and took note of some light to moderate white smoke blow-by from oil-fill cap when running.
Since it is designed to re-coop exhaust from oil fill to intake, i'm assuming some is normal for the 6.2L?

As for money, I was lucky enough to get the M1009 as a gift... so trying to prioritize

kallisti5 said:

took note of some light to moderate white smoke blow-by from oil-fill cap when running.

Click to expand...

If crankcase ventilation system is working as it should, there should be a slight vacuum at oil fill cap. If the positive pressure gets too high, oil leaks start, and seals fail. Worn piston rings rings is another cause of blow by.

From my experience, CUCV's are under powered at all speeds. You only have 135 or so HP. The mid-80's civi Chevy pickup with the 350 gas motor is over 200HP.

It is what is. Short of turbo charging, you are not going to see a large HP gain. I would either not worry about it, or start looking for a CUCV II.

If you want to remain low buck, try this. The air cleaner housing was mentioned. If you add a second snorkel, it will really open that up. If 3" exhaust isn't in the budget, add a balance tube between both sides. It really makes a difference. Also consider a reman IP. I know it's a few bucks but assign it as a maintenance item.

I have (had) 3 combinations of exhaust on M1009's. My Mule M1009 had complete stock size pipes and ran great, fabulous. It had great throttle response and power every time I needed it. I have complete 3" on another M1009. That breaks the plumbing rule. The exit at each exhaust manifold is 2 1/4" - 2 1/2" at best. So that amount of flow is the best I can hope to exit the 3" pipe. I had it done as a suggestion. I notice no more power over the stock M1009 Mule truck. They both run well. I also have my Crown of Thorns M1009 with 2" exhaust front to back. It was a Stainless Steel exhaust system and was for a 350 gas K5 Blazer. It was brand new and free and I said why not. I needed an entire exhaust at the time. I have it on many years and I do the most work and trailer pulling with that M1009. As mentioned with 135 pony's out of the barn at one time hooked up to a car trailer with a tractor or pulling another M1009 up I 81 is not a fast trip. That runs fine over the road loaded by itself. But any trailer will bog the M1009 on hills and heavily loaded. I think the M416 trailer was a great combination and a perfect towing match for the M1009. I towed one many miles with mine. And if I hauled rocks or wood it towed great. I agree. it is 35+ year old technology and power. now we are getting 300hp out of 4 cylinder engines. So if you need more towing power look elsewhere. The 6.2 CUCV is NOT and never will be a power house with or with out a turbo. Newer pickups will run circles around them and get better fuel mileage and comfort. I love the CUCV for many years and had many uses for it. At this point it is fun to drive on occasion and cool to use as designed but after that it can be a disappointment and money pit to improve on it intended design. A utility vehicle. Merry Christmas. And a rebuilt injection pump does solve a lot of power/performance issues all at once. IMHO. Have a Great Day.

Might be the injection pump, lift pump or a combination of both.....

The engines aren't powerhouses to begin with, but they're decent when the fuel is working as it should. Mine was having issues with sputtering at speed. Put a fresh fuel filter on and it was a night and day difference.

cucvrus said:

I have (had) 3 combinations of exhaust on M1009's. My Mule M1009 had complete stock size pipes and ran great, fabulous. It had great throttle response and power every time I needed it. I have complete 3" on another M1009. That breaks the plumbing rule. The exit at each exhaust manifold is 2 1/4" - 2 1/2" at best. So that amount of flow is the best I can hope to exit the 3" pipe. I had it done as a suggestion. I notice no more power over the stock M1009 Mule truck. They both run well. I also have my Crown of Thorns M1009 with 2" exhaust front to back. It was a Stainless Steel exhaust system and was for a 350 gas K5 Blazer. It was brand new and free and I said why not. I needed an entire exhaust at the time. I have it on many years and I do the most work and trailer pulling with that M1009. As mentioned with 135 pony's out of the barn at one time hooked up to a car trailer with a tractor or pulling another M1009 up I 81 is not a fast trip. That runs fine over the road loaded by itself. But any trailer will bog the M1009 on hills and heavily loaded. I think the M416 trailer was a great combination and a perfect towing match for the M1009. I towed one many miles with mine. And if I hauled rocks or wood it towed great. I agree. it is 35+ year old technology and power. now we are getting 300hp out of 4 cylinder engines. So if you need more towing power look elsewhere. The 6.2 CUCV is NOT and never will be a power house with or with out a turbo. Newer pickups will run circles around them and get better fuel mileage and comfort. I love the CUCV for many years and had many uses for it. At this point it is fun to drive on occasion and cool to use as designed but after that it can be a disappointment and money pit to improve on it intended design. A utility vehicle. Merry Christmas. And a rebuilt injection pump does solve a lot of power/performance issues all at once. IMHO. Have a Great Day.

Click to expand...

Hi CucvRus,

I was just searching for experiences with exhaust pipe and various diameters.
My entire exhaust needs replacement, since it is a horrible DIY of various bits and pieces from one of the previous owners; it binds and rubs and just does not fit right.

Before looking into what size or diameter of pipe I need, I checked the current size and indeed from what I can see, the pipe size at the exhaust manifold is 2" and from there it does get larger to 2.5".

So I was thinking, no point in increasing beyond 2", as this is the most restrictive size along the exhaust path and thus I am opting for 2" pipe all along front to back.
I know, there are some comments saying that increasing exhaust diameter will reduce friction resistance by exhaust gases and is therefore better. On the other hand, as soon as exhaust gasses leave the manifold, the gases start to cool down as they travel towards the rear end, so the friction and restriction of flow decreases already and actually creates a slight suction effect thus pulling subsequent "puffs" of exhaust gas from each explosion towards the rear end of the truck.

Yes, I realize this is a simplified explanation, as there is still a little bit of fuel burning going on when the gases leave the cylinder and in the exhaust manifold and likely even as gases travel in part of the exhaust pipe [which explains why that is the hottest part of the exhaust system and which also explains why we still have so much harmful emissions and soot because of incomplete burning and which also explains why we consume as much fuel as we do as we very poorly burn just a little bit of the fuel in the cylinder {which can be resolved by injecting pre-heated diesel fuel to 400degrees Celcius and which then will warrant a complete, clean and most efficient burn}; but this leads into another topic where I am very happy to talk about freely and exchange ideas...] ).

Anyways, I read you post here: "...my Crown of Thorns M1009 with 2" exhaust front to back. It was a Stainless Steel exhaust system and was for a 350 gas K5 Blazer. It was brand new and free and I said why not. I needed an entire exhaust at the time. I have it on many years and I do the most work and trailer pulling with that M1009"

Did you notice any disadvantages with this 2" setup?
Loss of power, increased fuel consumption, noise,.... ?

Thanks,
Jake