cat D4 2T 7884 wont start after died mid push (fuel related)

bingles · May 28, 2015

I have an old D4 2T 7884 cat crawler with a pony motor.

It was the first time it had been started in about 8months, so my buddy bought some diesel additive stuff and dumped it in the tank just incase the diesel was a little old.
I pushed dirt on hill and mostly flat ground for about 4 hours, the old girl was doing good and even felt like it had more power then before. However I waas pushing a full blade load of dirt and the tracror quickly lost power and died. My friend said herd some noises like a rattling. I didnt hear anything I had my hearing turned off.
I got the pony motor started and tried to get the diesel engine started, would not put out any smoke from the stack. Looks like its not getting fuel.

What I have checked so far:
Fuel Filters - pulled fuel flitters
Result: They still look new, I replaced them last fall, but there was alot of crap in the buttom of the fuel fliter housing. I cleaned the crap out. It almost seems like the fuel additive was cleaning out the tank and supply lines to get that much junk back in the housing because I cleaned that out last fall.

Bleed fuel lines - I followed the owners manual on how to bleed fuel system.
Result - I was able to get it bleed but it was bleeding like it did in the fall. its like there was just not enough pressure to bleed all the lines. I could get one or two of them to spray diesel but then it would just stop. or if I got it to where there was no air and it sprayed good I closed it and did the next one, and then the next, and then the next. When I would go back and double check them it was like starting over from the begining. I also would only randomly get fuel to come out of the top fuel vent.

Transfer pump- I am not an expert but it seems to that the transfer pump is what being used to bleed the fuel lines and injectors.
result - I pulled it apart and the gears looked good and the plates didnt show wear si put it all back together. tried bleed again. still doing same thing.

Then I notice if you are looking at the transfer pump towards the front of the tractor there is a steel line coming down and 90s into the fuel transfer pump. this 90 had a crack cause I could feel it wiggle, I tried to take it off but it broke, looks like it may have be leaking or sucking air. I dont know what this line does.

Does anyone know what I should check or had this same problem and know what most common issues are. its never done this, this old girl is very well kept and always starts. We have had a problem with the water pump but rebuilt and replaced it 2 years ago. We had proble with pony motor but by changing the govern spring in has been starting up great. this is first time this diesel engine has started.

Thanks for you time
millwrightbrian

Billy NY · May 28, 2015

I'd have to look in the serviceman's reference book to get familiar with the fuel system, so bear with me, I'll take a guess, the transfer pump or prior to the injector pump, its not bled. You can pressurize the fuel tank with a Schrader valve on a section of old tire tube with enough tubing to cover the fuel tank filler neck, and secure that with a large hose clamp, you will only need a couple of pounds or PSI for this, you don't want to go to far beyond that, you don't need much.

You have no white vapor like smoke when cranking the engine over with the throttle up correct ? Obviously you start with compression off, let it spin a bit, warm up things a little, then turn the compression lever to mid or run, then open the throttle a bit. That should indicate what you suspect, no fuel.

Someone will know the fuel system better than I, though its simple enough until you get to the transfer and injection pumps for service and bleeding etc. This may be of help to start though, if its air bound still and you need to clear it. On the other side of this, can the injectors be pulled or observed to make a fine mist or correct atomized spray pattern, no fuel or incorrect spray, not atomized etc. If there's been any chance of excess un-combusted fuel washing the cylinders, you may want to check the crankcase oil for fuel thinning/contamination, or at least monitor it for same, you don't want to run it if so, best to change it out. (just something to be aware, may not be an issue)

Do you have the serviceman's reference book for this tractor, one that corresponds to the serial number, that ought to help if you don't. I may have a military manual covering a 2T series in my collection, as I've tried to complete my hobby library for all military era Caterpillar tractors just no time to look at the moment.

I did find a book close by, 2T series and up, so this covers early tractors, not sure if there is changes in the production of this 2T series. It states to open the vent valves, both fuel filter vent valves and injection pump vent valve.

You are supposed to use the starting engine at an idle speed to spin the diesel, compression release in start position, throttle all the way forward, so the injection pumps are off. When you get steady fuel from the vents, no bubbles or intermittent stream or flow, close them. It states to open them "several times in succession" to be sure all of the air is bled. It does state by doing the above, it insures the transfer pump will force air and fuel through the filter housing vent(s) (early tractors have 2 vents) and the injection pump vent, which you should be able to observe.

I think the piece of tube with the valve on the tank filler neck may only be needed if you can't spin the diesel engine.

Hopefully a little more help, this part is relatively easy, theres a few sections on the fuel system on these, if you don't have the SRB, you should get one for that serial number range 2T series tractor.

I reread your post, take care of that cracked or faulty line, it does sound like you are taking in air, that line probably cause the whole thing. You probably don't have the reference book, given what you said, and that the intermittent flow of fuel out the vent, though i did not see where it says to open anything on the transfer pump. So this narrows it down a bit more.

I was just at my desk here and looked in the parts catalog for 2T1 and up, which is part of a complete set of books bound into one military technical manual TM5-3126 on page 41, diagram 19250 & 19388 is the Fuel Transfer Pump Group for early 2T's

I cannot discern what that line does either, from the diagram with the exception that there has to be at least one line for supply to the transfer pump and one supply line from the transfer pump to the filter housing, latter being pressurized, former being vacuum? In the Operator's Instructions manual, there is a photo on page 23, #7856, #5 is the transfer pump, and #6 is the "main fuel line" if that is what was cracked,then you know what the problem is now. You'll have to pardon my round about manner here. It must have an internal path to deliver fuel to the filter housing.

I'd have to suggest to repair this line, then bleed per the above, and discard any useless information I may have posted LOL! I'm familiar to a point with these old Caterpillar's, more so D7's, but it has the same kind of fuel system, so I took a stab at it here, I do stand to be corrected LOL !

PS: 3 most valuable books to have for these era Caterpillar tractors are the "Operator's Instructions" "Serviceman's Reference Book" and "Parts Catalog" Look on ebay, good used ones turn up usually for these tractors, reprints can be questionable unless you get them from CAT Legendary Literature, the current source for OEM reprints.

dozerbill66 · May 28, 2015

(quoted from post at 06:33:45 05/28/15) I have an old D4 2T 7884 cat crawler with a pony motor.

It was the first time it had been started in about 8months, so my buddy bought some diesel additive stuff and dumped it in the tank just incase the diesel was a little old.
I pushed dirt on hill and mostly flat ground for about 4 hours, the old girl was doing good and even felt like it had more power then before. However I waas pushing a full blade load of dirt and the tracror quickly lost power and died. My friend said herd some noises like a rattling. I didnt hear anything I had my hearing turned off.
I got the pony motor started and tried to get the diesel engine started, would not put out any smoke from the stack. Looks like its not getting fuel. Maybe blow the fuel lines out from the fuel tank to the fuel pump , is there a fuel screen in the bottom of fuel tank . I had a problem like you are having on a D7 17A.

What I have checked so far:
Fuel Filters - pulled fuel flitters
Result: They still look new, I replaced them last fall, but there was alot of crap in the buttom of the fuel fliter housing. I cleaned the crap out. It almost seems like the fuel additive was cleaning out the tank and supply lines to get that much junk back in the housing because I cleaned that out last fall.

Bleed fuel lines - I followed the owners manual on how to bleed fuel system.
Result - I was able to get it bleed but it was bleeding like it did in the fall. its like there was just not enough pressure to bleed all the lines. I could get one or two of them to spray diesel but then it would just stop. or if I got it to where there was no air and it sprayed good I closed it and did the next one, and then the next, and then the next. When I would go back and double check them it was like starting over from the begining. I also would only randomly get fuel to come out of the top fuel vent.

Transfer pump- I am not an expert but it seems to that the transfer pump is what being used to bleed the fuel lines and injectors.
result - I pulled it apart and the gears looked good and the plates didnt show wear si put it all back together. tried bleed again. still doing same thing.

Then I notice if you are looking at the transfer pump towards the front of the tractor there is a steel line coming down and 90s into the fuel transfer pump. this 90 had a crack cause I could feel it wiggle, I tried to take it off but it broke, looks like it may have be leaking or sucking air. I dont know what this line does.

Does anyone know what I should check or had this same problem and know what most common issues are. its never done this, this old girl is very well kept and always starts. We have had a problem with the water pump but rebuilt and replaced it 2 years ago. We had proble with pony motor but by changing the govern spring in has been starting up great. this is first time this diesel engine has started.

Thanks for you time
millwrightbrian

dpendzic · May 28, 2015

when your spinning the diesel over with the pony motor what kind of fuel pressure are you showing?

Jo Bird · May 29, 2015

Your description of "Then I notice if you are looking at the transfer pump towards the front of the tractor there is a steel line coming down and 90s into the fuel transfer pump. this 90 had a crack cause I could feel it wiggle, I tried to take it off but it broke, looks like it may have be leaking or sucking air. I dont know what this line does." That is an over flow line, runs from the top Lt back corner of the fuel filter housing, down behind it to the transfer pump and connects to the fuel line from the fuel tank. Replace it.. it's allowing air to enter the fuel supply causing your problems..

dozerbill66 · May 29, 2015

(quoted from post at 08:56:50 05/28/15)

(quoted from post at 06:33:45 05/28/15) I have an old D4 2T 7884 cat crawler with a pony motor.

It was the first time it had been started in about 8months, so my buddy bought some diesel additive stuff and dumped it in the tank just incase the diesel was a little old.
I pushed dirt on hill and mostly flat ground for about 4 hours, the old girl was doing good and even felt like it had more power then before. However I waas pushing a full blade load of dirt and the tracror quickly lost power and died. My friend said herd some noises like a rattling. I didnt hear anything I had my hearing turned off.
I got the pony motor started and tried to get the diesel engine started, would not put out any smoke from the stack. Looks like its not getting fuel. Maybe blow the fuel lines out from the fuel tank to the fuel pump , is there a fuel screen in the bottom of fuel tank . I had a problem like you are having on a D7 17A.

What I have checked so far:
Fuel Filters - pulled fuel flitters
Result: They still look new, I replaced them last fall, but there was alot of crap in the buttom of the fuel fliter housing. I cleaned the crap out. It almost seems like the fuel additive was cleaning out the tank and supply lines to get that much junk back in the housing because I cleaned that out last fall.

Bleed fuel lines - I followed the owners manual on how to bleed fuel system.
Result - I was able to get it bleed but it was bleeding like it did in the fall. its like there was just not enough pressure to bleed all the lines. I could get one or two of them to spray diesel but then it would just stop. or if I got it to where there was no air and it sprayed good I closed it and did the next one, and then the next, and then the next. When I would go back and double check them it was like starting over from the begining. I also would only randomly get fuel to come out of the top fuel vent.

Transfer pump- I am not an expert but it seems to that the transfer pump is what being used to bleed the fuel lines and injectors.
result - I pulled it apart and the gears looked good and the plates didnt show wear si put it all back together. tried bleed again. still doing same thing.

Then I notice if you are looking at the transfer pump towards the front of the tractor there is a steel line coming down and 90s into the fuel transfer pump. this 90 had a crack cause I could feel it wiggle, I tried to take it off but it broke, looks like it may have be leaking or sucking air. I dont know what this line does.

Does anyone know what I should check or had this same problem and know what most common issues are. its never done this, this old girl is very well kept and always starts. We have had a problem with the water pump but rebuilt and replaced it 2 years ago. We had proble with pony motor but by changing the govern spring in has been starting up great. this is first time this diesel engine has started.

Thanks for you time
millwrightbrian

Click to expand...

/quote] I will try this again . Did you blow air through the furl line from fuel pump to fuel tank , line could be clogged . Is there a screen in bottom fuel tank , does it have a glass bowl under fuel tank , if so it has a screen . Also when fuel tank sits it will rust on the inside, this will cause fuel line troubles . I had same problem with a D7 , 17A . Did all the above and tractor ran like new .

cat D4 2T 7884 wont start after died mid push (fuel related)

bingles

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Billy NY

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dozerbill66

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dpendzic

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Jo Bird

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dozerbill66

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