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JD450B won't fire

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ADKJD450B

New Member
I have a 1971 JD 450 B crawler dozer which will not fire/start. A few days ago it began revving as if running out of fuel and then quit. I removed and replaced fuel filters, which were pretty full of sludge, bled the system and re-started easily. I then operated for another hour or so until it did the same thing again. This time there was a little sludge in the filters, though not so bad, but after cleaning and bleeding it will not fire.

I have fuel to the injector pump. I checked the fuel tank for contaminants,removed and blew out all injector lines, ensured the fuel shutoff solenoid is operating and checked solenoid reservoir and the timing window to see if there was any indication that the pump was coming apart (there wasn't).

I do have fuel to the pump but have no fuel to the injectors.

Any help would be appreciated.
 
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lantraxco

Senior Member
Take the cover off the timing window and roll the engine over to make sure the part that is supposed to rotate actually is. Reprime.

Blowing out the injector lines is fine, but in my experience it can take a long time to refill them with fuel when they're bone dry.

Check the fuel return line, make sure it isn't plugged with debris, some of these pumps had a fiber drive plate that liked to come apart.
 
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Garrie Denny

Senior Member
You have cracked the nuts on the injector fuel lines right ? When you crank the motor with these nuts cracked open you should get spurts of diesel,if not your injector pump has issues.
 
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Garrie Denny

Senior Member
Also check at the top of your fuel filter housing,does it have a bleed nipple at the top,try that if it does,but if youre getting fuel at the I-Pump, I think your pump may be blocked or worse,good luck.
 
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Karl Robbers

Well-Known Member
Does your injector pump have a fine mesh screen in the inlet and return lines? Check these are not blocked with sludge.
I have known people with equipment that doesn't like to bleed out, run them on aerostart until they bleed.
I will leave it up to you whether you choose to use this method or not.
 
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