my 450E Dozer just started slowing down. Engine rpm drop

Handyman Steve · Jun 27, 2013

Ben using my dozer about 30 minutes and just started noticing a drop in rpm,s and of course power which got worse in the following 5 minutes. I think a fuel restricting problem? Just don,t know where to look. It has about 4 or 5 running hrs on I since a changed the square fuel filter. Filter looks like it stays full when I start it. It will start but at not much more than a idle.I did crack the feedline to the injectorpump and saw a brief increase in rpms then right back. I hear no other noises every thing seems fine temps wise. any ideas Guys??

dirtdobber1 · Jun 29, 2013

Handyman,

I don't know specifically about your machine, but start with fuel flow from the tank to the filter. There could be rust or debris in the tank blocking the outlet. Fuel line could be stopped up. If it has banjo fittings take them out and check for obstructions. Check for inline screens that may be stopped up. They can be very small and imbedded into a fitting or the body of the priming pump. If you do find the fuel system to be trashy, you will need to change those square fuel filters again.

Also, check to see that the fuel return is not obstructed. typically, this will be the line that connects to each injector and then makes its way back to the tank or fuel supply line.

I don't know how modern this machine is -- whether there could be an electronics issue cutting power to the engine. Just my 2cents.

Handyman Steve · Jun 29, 2013

Thanks for the advice if it ever stops raining here I,ll try the fuel line. By the way, it dosen't have any electronics so I would be safe in saying an older machine. I haven,t had it to long. A year, first real problem. Thanks again.

Handyman Steve · Jun 29, 2013

One other thing. What does a banjo fitting look like? hear and read here the term just trying to comprehend what they are.

wilko · Jun 29, 2013

I could describe it, but just type "banjo fitting" into google and you'll get pictures. They're just a common way to attach fluid lines to housings, an alternate to flare fittings.

Handyman Steve · Jul 1, 2013

I have checked the fuel lines both feed and return and don't seam to have any blockage at all flow seems good. There is a screen or filter of some kind in the bottom of the tank. I tried to fish it out of the supply port couldn't get it to move. tried unscrewing it no luck. I did take a piece of wire and worked it around seamed to increase the flow but flow wasn't bad before. Put back together and same result. At full thro just idles. One thing I did do that seamed to have a reaction. Took the return fuel line off the top of the injector pump took a small wire and stuck it in the return port and the rpm's picked right up. Not back to operating rpms but enough to move the machine. Now I 'm wondering if the injector pump is coming apart. Also I was wondering about the fuel shutoff not working properly. It is electrical not manual. and I did have a problem with the machine shutting itself down right after I pulled it out of storage found some wires chewed behind the dash and the problem went away after I taped them up. Didn't think it was related but now I wonder. Any Ideas?

Coondog · Jul 1, 2013

Steve, one time we had 773f haul truck that was slowing and losing power. I went about checking pressures as the book says to and all came out good. It would idle fine but as soon as you tried to GO, it would stumble and die. I looked and looked and looked, for about a day and a half. I was just about to give up and call someone in to help. I was checking flow from the tank again, which was full, an it was flowing great. I had the feed hose off of th tank. And went to pu I back on when I seen something that was nt quite right up in the fitting to the tank. When I removed it I found a piec of plastic, very small, that was lodge in behind th check valve fitting. It was such a perfect size that it only restricted flow when the pump asked for more fuel. I'm guessing it would turn sideways under suction and shut flow off. I'm not saying this is your problem but my point is look again. I had taken all these line off numerous times and blew with compressed air and cleaned and changed filters and everything possible. Just go back over it a couple times, take ever fitting off, especially on corners, check it ALL again.

TOM V · Jul 1, 2013

If fuel flow is ok, most likely the governor flex ring is coming apart plugging the fuel return valve. If so the injection pump should come off and get reonditioned.
Good luck.

Handyman Steve · Jul 1, 2013

Thanks both of u! I'll recheck ONE MORE TIME! Mabeye missed something.

Any one know where the best prices are for JD dozer parts?

Coondog said:
Steve, one time we had 773f haul truck that was slowing and losing power. I went about checking pressures as the book says to and all came out good. It would idle fine but as soon as you tried to GO, it would stumble and die. I looked and looked and looked, for about a day and a half. I was just about to give up and call someone in to help. I was checking flow from the tank again, which was full, an it was flowing great. I had the feed hose off of th tank. And went to pu I back on when I seen something that was nt quite right up in the fitting to the tank. When I removed it I found a piec of plastic, very small, that was lodge in behind th check valve fitting. It was such a perfect size that it only restricted flow when the pump asked for more fuel. I'm guessing it would turn sideways under suction and shut flow off. I'm not saying this is your problem but my point is look again. I had taken all these line off numerous times and blew with compressed air and cleaned and changed filters and everything possible. Just go back over it a couple times, take ever fitting off, especially on corners, check it ALL again.

Handyman Steve · Jul 1, 2013

Than one last request? Where might I get parts for above machine (450E mid 70's JD dozer) I know prices seem to range quite a bit on the web. Thanks again! And it's raining here again!!!

Handyman Steve · Jul 3, 2013

I now think that the next course of action is getting the injector pump rebuilt. I have been online loking for info on removal and as I have done some work of this kind I havn't pulled this particular pump and am scared to death of screwing it up. the main concern is timing issues. Any help in that area would greatly be appreciated. I have a company that will do the rebuild with guarantee I just need to get it off and reinstall. When it comes back. Thanks Steve

Handyman Steve · Jul 3, 2013

I now think that the next course of action is getting the injector pump rebuilt. I have been online loking for info on removal and as I have done some work of this kind I havn't pulled this particular pump and am scared to death of screwing it up. the main concern is timing issues. Any help in that area would greatly be appreciated. I have a company that will do the rebuild with guarantee I just need to get it off and reinstall. When it comes back. Thanks Steve Ho by the way this is a older Stanadyne pump model DB2 4490

Delmer · Jul 3, 2013

I'd tee in a pressure gauge at the injection pump supply and see what it does when it runs and dies. And then figure out the return valve. You'd hate to send it off, get it all back together right, and have it do the same thing.

Handyman Steve · Jul 4, 2013

Thanks, I'll try that!

thepumpguysc · Jul 4, 2013

Pump is EASY to remove.
Shut the fuel off at the tank.
Remove the small side window on the pump.
Rotate the engine in the proper direction of rotation until a line appears and line it up with the stationary line already in the window.
Remove the throttle linkage, injector lines, inlet and outlet fuel lines.
Remove the 3 nuts holding the pump to the engine and pull straight back..the drive shaft will stay in the engine.
As long as you don't move the engine from its "pump removal position" you wont have to worry about a thing..just line up the lines on your remaned pump and slide it back on, being careful not to roll the new drive shaft seals..
DO YOURSELF A BIG FAVOR and ask your rebuilder for an EID weight retainer..it takes the place of the old "flex ring" and you'll never have to worry about this problem again..
It drives the cost up about 70.00 but WELL WORTH THE MONEY..

Goatfix · Jul 5, 2013

Re the pump removal instructions, you will have to remove the small rectangular cover on the front of the timing case and remove the nut in the centre of the pump drive gear before you can move the pump back one the nut is loose give it a rap with a copper drift. Don't loose the woodruff key when removing or installing, it should face up from memory. I would definitely check the fuel pressure at the injector pump before you go to the difficulty of removing the injector pump, I have frequently found that lift pumps failed, the valve which are little el cheapo press in valves that fail or even fall out and the pump can become blocked with emulsion, dirt rust or alloy corrosion or as frequently happened in this part of the world in cold weather, wax precipitate. If the machine has been in storage you may also have a growth of algae in the fuel tank which can coat the filter paper and restrict flow..

Handyman Steve · Jul 5, 2013

I appreicate all the very helpfull suggestions and instructions. I don't think I could have gotten to this point without you guys! And at this point I've pulled the injector pump Thanks pump guys the instructions were dead on!!!!

Handyman Steve · Jul 5, 2013

The info I got online for inlet line to the injector needs to be at least 2 - 3 psi my inlet at a little more than an idle which was all i could muster was almost 4. again, pumpguysc I am going to check on a EID from the rebuilder , which I had already comitted too Before your offer Thanks again I'll sleep better tonight!!

thepumpguysc · Jul 5, 2013

KOOL, Glad to help..TPG

Handyman Steve · Jul 6, 2013

By the way, talked to the pump builder and they don't carry the EID weight retainer. If possible, I will order one from you. Let me know what you need from me. Thanks Steve

my 450E Dozer just started slowing down. Engine rpm drop

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