M35a2 engine problem

[roadwarrior]

I'm new here, so be gentle.

I've looked at a M35a2 locally that is in pretty good shape, but the engine has an issue.
The owner said he ran it out of fuel, and ever since there has been a noise in the front of the engine. I drove it today and it is underpowered for sure, and the exhaust almost sounds like there is a "miss". There was a rattle at the front of the engine, but after a 5 minute drive, it was quieter. There did appear to be a fuel leak at the front of the engine, that was dripping onto the front 3rd member. Wouldn't get over 30mph.

Could this be a "bleed" issue, with air in the line somewhere? He said he bled the system up to the filters, but not the yop end or lines. My experience with diesels(tractors) is they don't start if there is air in the line. I am hoping it could be something simple like an air issue, but I just don't know.

Any thoughts on this problem?

Thanks.

 

[kc5mzd]

sounds kind of serious. I have 1 truck that makes a rattle from the front by the injector pump, turned out to be the air compressor. It still makes noise but runs fine. I willfix it someday.
Just curious will it do the same speed on level ground as it does up small hills? steep hills?

 

[Heavysteven]

Low power could be clogged filters, bad fuel, and I would suspect the in tank pump is not running. Your call could be a simple fix or maybe some thing else.

Was the transfer case in high? Could explain the 30 mph

 

[roadwarrior]

I thought it was in high. It will lug down under load. If it was a gas engine, I'd say it was down a cylinder.

 

[kc5mzd]

I have a friend that has one that won't go over 45. We replaced a bad in-tank pump and all the filters. It still won't go over 45. We decided it must be turned down or something. If you floor it with no load the engine sounds very strong but only revs to 2400 rpm.
Thats why I was wondering if it had power to pull a small hill but toped at the same speed as on level ground.

 

[Westex]

Taking a stab at it here, if this is in the realm of doing, replace the primary fuel filter (front passenger side forward), then turn on the accessory switch and wait about one minute, then fire it. Listen for the electric in tank feed pump to whine. If you don't hear a whine with the accessory switch up (and you have to go over to the fuel tank if you're deaf like me), then that could be an issue.

Failing this cheap resolution, it may be the injector pump. Check to make sure the kill handle wire, which comes through the dash and is 'covered' by the said accessory switch when the accessory switch is in the up position, is all the way IN on the injector pump. Sometimes the little shiny part gets partially stuck on the i.p., causing a low fuel condition.

This definitely sounds like a fuel problem; but I'm again, kind of guessing, here, and I really cannot fully answer until you describe this knocking sound more thoroughly.

 

[General Mcgregor]

Where was the leak? How bad? Sounds like she's starving.

 

[SSG Rock]

m35a2 engine problem

Roadwarrior,
Several months ago I had a very simular problem. After checking I found the #3 cyl intake push rod had come out from under its rocker arm. You might remove valve covers and check your valve train. I replaced my front rocker arm assy and the 6 push rods and set valve lash as TM described and all was wlll again.
SSG Rock

 

[91W350]

The in tank pumps have been known to come apart, yet still make motor noise. If the tank is less than half full, pull the strainer attached to the fuel cap and look inside. A good pump should really agitate the fuel. alternatively, open the drain on the primary filter, right front of the engine, below the alternator and have somebody turn the acc switch on. You should go from dripping fuel to spraying fuel instantly, use a large cup or prepare for a fuel shower... You can also do that at the secondary filters, to see if good fuel flow is coming through the primary.

 

[roadwarrior]

Thanks for the replys! The leak was obvious, but not squirting out, and it did appear to be fuel.
SSG ROCK, all my experience is with gas engines, and it did sound like it was at the front of the engine under the valve cover. The engine was so loud, it was hard to tell exactly what was going on! It was quieter after the test drive. The oil pressure stayed at 50 psi the entire time.

 

[treeguy]

I had a fuel leak in the front, it was a bad compression fitting on the primary fuel filter on the line that ran accross the front frame member.

When I first got my truck it couldn't get out of its own way (it was in high) lots of noise but now get up and go, I believe that the Gov. had the fuel turned down. This was after new filters, I turned the fuel up 1 1/4 turns, now she has more pep.

Noises - I have (I belive its one) a valve rod that ticks, and it sounds like the #6 injector tings, tinny clinking like some one pouring a lot of metal tacks into a large glass jar.

I don't know, I'm kind of nervious/parinoid but I drive it all over and she feels and sounds strong once up to temp.

Just my take on noises and leaks, Good luck

 

[Westex]

The in tank pumps have been known to come apart, yet still make motor noise. If the tank is less than half full, pull the strainer attached to the fuel cap and look inside. A good pump should really agitate the fuel. alternatively, open the drain on the primary filter, right front of the engine, below the alternator and have somebody turn the acc switch on. You should go from dripping fuel to spraying fuel instantly, use a large cup or prepare for a fuel shower... You can also do that at the secondary filters, to see if good fuel flow is coming through the primary.

Even better advice, and more advanced. Makes sense.

 

[gimpyrobb]

To answer your first question, no, I doubt it needs air bled out of the lines. I have run my truck out of fuel a few times. All I needed to do was fill it up, turn on the power switch to start the in tank pump, and bleed the air from the lines at the secondary filters. It has never failed to fire right back up. Even when doing IP swaps, I have never needed to bleed the injector lines.

 

[roadwarrior]

I should have mentioned, but I am pretty sure the in-tank pump was working. It sounds like the general feeling is the problem is more serious than air in the lines. I may have to pass on this one.

 

[gimpyrobb]

Or get it cheap and fix the issue. I bet we could help.

 

[rchalmers3]

RW,

If you believe there is a mechanical problem with the valve train, then your gas motor experience will serve you. You should be able to listen and determine if the engine noise is valve related because things on the top turn at 1/2 of crank speed.

The exhaust report can also be used for an indicator of a miss fire. You can identify a dropped cylinder by individually cracking open the injector lines, effectively "shorting out" each cylinder.

Don't give up on the truck. I suggest that you figure out an offer that makes it worth it to you to purchase it and straighten out the motor problems!

Rick

 

[roadwarrior]

Thanks for all the advice! I need to go take another look, and try to nail down the prob.

 

[onegmjack]

If you think you have a dead cylinder.Use a spray bottle,when engine is warm or hot,spray water on exhaust ports.One at a time.See if you have one that don't steam.

 

[Warren Lovell]

Deuce engines are strong, bleed your high pressure lines at the injectors. Do each one while engine is running.

 

[stancanpara]

Sounds like crudded up filters, looking forward to hearing more.