1977 Mack CF600 Crank but No Start

[rjmcfarland]

Bit of a long story here so I apologize.

I've owned my 1977 CF600 for about a year now. ENDT-675 motor.

Admittedly after driving it about 4 hours on the highway to get it home last May, I parked it and drove it maybe a couple more times before letting it sit for a few months, including over the winter. Priorities.

I came back around two weeks ago to a truck that wouldn't start. Two dead batteries which is an easy fix. I should have removed them for the winter but didn't even think about it. Replaced one of them and still couldn't get it to start. Cranks like it wants to start but just won't.

Now I'm thinking fuel issue because it sat all winter. Replaced the fuel filter and added some diesel 911 + some fresh diesel. This is the first diesel motor of this size I have dealt with so I'm really shooting in the dark just hoping something will work. Still no start.

I then read a post where a gentleman says he puts his foot to the floor to start his rig and cranks for 15 - 20 seconds, so I try this. Fires up after maybe 10 seconds, tons of white smoke, but all seems fine. I then drove the rig around for a little over an hour, came back and parked it. Everything seemed normal.

Couple days later (today) it cranks but doesn't start again. Open the drivers door and it smells incredibly strong like diesel fuel. I go to look in the doghouse and see white smoke coming from the exhaust in multiple different places. Not a lot, but a noticeable amount coming from the muffler and some holes in the exhaust pipe. I've read that white smoke when trying to start isn't an unusual thing but it made me nervous so I stopped.

 

So a few questions: 

What am I missing?

Why did the rig start the other day but today it cranks and won't start?

Should I get another battery and see if it just needs both to start?

Is the white smoke just a sign that I'm getting fuel, or something to be worried about?

What about the strong diesel fuel smell?

 

Also:

I noticed this peculiarity happening to one of my oil filters when I checked the doghouse. Something to be worried about, or should I just replace the effected filter and build a heat shield in front of it? I'm guessing it's coming from the incredibly hot exhaust coming off the turbo. I could also wrap the exhaust with heat shield in hopes of stopping whatever is happening (I assume just too much heat).

 

Thank you to anyone with any insight. Much appreciated.

 

Edited March 18 by rjmcfarland

[CF-Firefighter]

Are you sure those are oil filters? 
 

mine has an 865 but they are on the side of the block like most motors. 
 

Could be fuel filters or trans filters. From the sounds of what you describe, it could be loosing prime when sitting. If it ran fine before a doesn’t after this winter I’d suspect air in the system. If those are fuel filters, it would make sense. 
id change them either way. 

[rjmcfarland]

3 minutes ago, CF-Firefighter said:

Are you sure those are oil filters? 
 

mine has an 865 but they are on the side of the block like most motors. 
 

Could be fuel filters or trans filters. From the sounds of what you describe, it could be loosing prime when sitting. If it ran fine before a doesn’t after this winter I’d suspect air in the system. If those are fuel filters, it would make sense. 
id change them either way. 

They are Donaldson lube filters, P551807. Well, at least the one that is affected is. I can't see the text on the one next to it.

The fuel filter is in a pain in the rear spot next to the passenger front wheel. Took me forever to even find it.

I think most of the filter locations were moved at some point and have spin ons.

 

As for losing prime, any idea where to start on what could be causing that?

[CF-Firefighter]

Ok that makes sense could be like a filter relocation. 
Does it crank right up after you have had it running and shut it off?

Does it have an electric lift pump or just the mechanical? 
 

If electric, turn it on and check for leaks. But places I’ve noticed, hand primer and old braided fuel lines. Just follow the line from the tank, to the filters, to the injection pump. Then check the return lines.  Check lines tightness and wetness. Sometimes it’s an air leak and it won’t leak fuel but will suck air. 
 

that’s my very limited experience with these trucks I’m still learning. 
 

can be a pain to track down

[rjmcfarland]

3 hours ago, CF-Firefighter said:

Ok that makes sense could be like a filter relocation. 
Does it crank right up after you have had it running and shut it off?

Does it have an electric lift pump or just the mechanical? 
 

If electric, turn it on and check for leaks. But places I’ve noticed, hand primer and old braided fuel lines. Just follow the line from the tank, to the filters, to the injection pump. Then check the return lines.  Check lines tightness and wetness. Sometimes it’s an air leak and it won’t leak fuel but will suck air. 
 

that’s my very limited experience with these trucks I’m still learning. 
 

can be a pain to track down

It did when I drove it the other day. Fired right up a couple different times after turning it off.

I believe its just the mechanical pump, nothing electric. Can't say for certain though as this kind of motor is way out of my wheelhouse.

I'll have to take a look tomorrow at it and see what I can find. Unfortunately the hand primer and many associated fuel lines are located in a spot that is incredibly hard to reach so it's going to be time consuming no doubt.

Thanks for all your help so far.

[Geoff Weeks]

Old truck= old fuel hoses. I have chased my tail looking for a problem only to find the hose was porous and would allow air in but not fuel out. When in doubt, I would replace the suction hoses from the tank to the lift pump before going further. 

 Funny thing is they can leak air and not show a drop of fuel from the outside.

[rjmcfarland]

20 minutes ago, Geoff Weeks said:

Old truck= old fuel hoses. I have chased my tail looking for a problem only to find the hose was porous and would allow air in but not fuel out. When in doubt, I would replace the suction hoses from the tank to the lift pump before going further. 

 Funny thing is they can leak air and not show a drop of fuel from the outside.

I have a record from the previous owner that says a fuel line was repaired, along with some seals and gaskets. That being said, I don’t know what exactly was replaced/repaired so I will take a look and see what looks new and what looks old.

Thanks for your help across multiple threads.

[CaptainCrutch]

It sounds to me like it’s losing prime in the fuel system. I’d try pumping that hand primer a bunch and if it starts with ease doing that then you have the answer to your problem.

Alternatively it could be something up with your shut down linkage, either the linkage itself or the part inside that actually shuts off the injectors. But my money is on the fact it’s losing prime, I had a similar issue at one point on my CF, and that was it.

[mrsmackpaul]

If your losing prime when it's not running you have air leak in the return to tank side

White smoke means air in the fuel

Grey smoke is burnt oil

Black smoke is unburnt fuel

So you have white smoke and no fuel, takes a lotta cranking

 

So get some rubber inner tube and a tyre valve, a big hose clamp

Tyre valve thru the inner tube (might need a large over size washer on the valve to stop it popping thru the inner tube

Hook up some shop air and crank the regulator air pressure diwn as low as 15 psi

Crawl about underneath looking for leaks

 

Paul 

[mowerman]

The CF does have a tilt cab??????? Bob

[mechohaulic]

it had TWO dead batteries and you replaced ONE, this indicate you charged one didn't replace ?? with one new and one "used" battery;; is it spinning fast enough for a proper start? fire equipment usually had ? have  dual start systems  . only two batteries in this unit ?? 

[Geoff Weeks]

7 hours ago, mrsmackpaul said:

If your losing prime when it's not running you have air leak in the return to tank side

 

 

Paul 

As far as I know Detroit two strokes are the only common diesel that returns to below fuel level. It done so because the Detroit system is just a loop with a restriction. Cat and Cummins and I assume Mack (I don't remember looking at a Mack tank) all return to the top of the fuel tank and  are open to air so are an "air leak". There is no check or other valve that keeps air out of the return.

 Air in the suction line will make its way to the highest point in the fuel system and can cause a no start. the return line is always open to air (except Detroit 2 strokes)

Edited March 20 by Geoff Weeks

[CaptainCrutch]

6 hours ago, mowerman said:

The CF does have a tilt cab??????? Bob

CFs don’t have tilt cabs, just a doghouse rear of the cab (unless it’s a 4 door in which case it’s just in the cab). The whole drivetrain is located entirely between the axels.

[mrsmackpaul]

2 hours ago, Geoff Weeks said:

As far as I know Detroit two strokes are the only common diesel that returns to below fuel level. It done so because the Detroit system is just a loop with a restriction. Cat and Cummins and I assume Mack (I don't remember looking at a Mack tank) all return to the top of the fuel tank and  are open to air so are an "air leak". There is no check or other valve that keeps air out of the return.

 Air in the suction line will make its way to the highest point in the fuel system and can cause a no start. the return line is always open to air (except Detroit 2 strokes)

The only diesels I have seen that don't return to the bottom of the tank are Cat

 

Most have a pipe inside the tank that returns the fuel to the bottom of the tank

In rough going this pipe can crack and when the tank gets down a bit the motor looses prime when not running 

The rubber hoses between injectors are a common leak point on the return to tank side on a Mack 

But as they say "wadda I know"

 

 

Paul 

[Geoff Weeks]

Cat and Cummins both return above fuel (just an open dump in the top of the tank) I can't say for sure on Mack. At least on the older mechanical engine like we are dealing with here.

Edited March 20 by Geoff Weeks

[mowerman]

8 hours ago, CaptainCrutch said:

CFs don’t have tilt cabs, just a doghouse rear of the cab (unless it’s a 4 door in which case it’s just in the cab). The whole drivetrain is located entirely between the axels.

OK, thanks for that. I was wondering why he mentioned a couple of times about everything is hard to get it.

[rjmcfarland]

On 3/20/2024 at 8:33 AM, mechohaulic said:

it had TWO dead batteries and you replaced ONE, this indicate you charged one didn't replace ?? with one new and one "used" battery;; is it spinning fast enough for a proper start? fire equipment usually had ? have  dual start systems  . only two batteries in this unit ?? 

Sadly enough on my part, this seems to have been the issue. At this point that's what I'm going to say at least. Charged up a battery and threw it in there with the other one, seems to start no problem now. Maybe just needed more cranking power.

As for the fuel leak, I think it is a small leak around the injector pump. Not the leak that I thought it was originally, I think I was just telling myself it was new because I had never noticed it.

I was told originally it only needed one battery to start, which is probably true in the right conditions.

[mechohaulic]

8 hours ago, rjmcfarland said:

Sadly enough on my part, this seems to have been the issue. At this point that's what I'm going to say at least. Charged up a battery and threw it in there with the other one, seems to start no problem now. Maybe just needed more cranking power.

As for the fuel leak, I think it is a small leak around the injector pump. Not the leak that I thought it was originally, I think I was just telling myself it was new because I had never noticed it.

I was told originally it only needed one battery to start, which is probably true in the right conditions.

may have been told "it only needs one to start" BUT it sure would start  alot better with two(or more) goood batteries. gas engine relies on spark to fire. a diesel needs combustion.  good grade of fuel and spinning fast enough to combust.  AND I KNOW  there are those diesels that turn slow and fire right up. based on experience older= less combust== takes a lot of spark to get the "cylinder  " hot🤣😱