I have 1995 m998 that continues to have fuel delivery issues. It’s had 3 mechanical pumps replaced on the side of the passenger side engine block. The last “fix” was to blank off the mechanical pump and replace it with an electric fuel pump. The truck runs for a few weeks then dies. I checked the glow plugs and they all ohm out around 1.7-1.9 ohms. I pulled the top off the fuel filter/ Water separator and it’s empty. Is there a lift pump/fuel pump inside the fuel tank that could be my issue?
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Rough idle/no start
- Thread starter Gcrash
- Start date
Dock Rocker
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Have you checked the filter sock on the pickup in the tank? They have a history of degrading and coming apart and clogging the fuel pick up. That sounds like what your problem is.
There is no pump in the tank. I bet when you drop the tank you will find pieces of cheese cloth looking stuff at the fuel intake.
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There is no pump in the tank. I bet when you drop the tank you will find pieces of cheese cloth looking stuff at the fuel intake.
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Use that new electric pump to drain the tank.
Action
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That won't work if the line is plugged between the tank and pump, or the sock is plugged up.
Dock Rocker
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Short term fix to help drain the tank. Take an air gun and blow back into the tank from where you cut into the line to add the fuel pump to dislodge the pieces that are hindering the flow.
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Disconnect the pump from wherever it's mounted, connect a hose to the suction and run a hose down thru the filler spout, temporary power and should be good to go.
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Doesn't look like my fuel pump. 12 volt ? Is this a HMMWV ?
HMMWV... Normal pressure 4 PSI low to 8 high. At least 1 pint in thirty seconds at cranking speeds of 150 RPM minimum. 77 F. degrees.
Anything more is a little better, CAMO
HMMWV... Normal pressure 4 PSI low to 8 high. At least 1 pint in thirty seconds at cranking speeds of 150 RPM minimum. 77 F. degrees.
Anything more is a little better, CAMO
papakb
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There is no electric fuel pump on an M998 vehicle, it's a mechanical pump driven by the camshaft off the right front of the engine. If someone wired this pump into the system I'd advise removing it and reinstalling an original. They're available for under $20 but they are a PITA to install. There are plenty of threads here on the SS site with information on replacing the pumps.
Usually when someone installs a 12 volt pump in a 24v vehicle they tap off o one battery which if done incorrectly can cause battery failures or fires. If they wired it directly to 24v it might have run for a while until it rolled over and died. Either way, you should stick to the original system. It's been working in thousands of trucks for over 30 years. That's a pretty good track record isn't it?
Usually when someone installs a 12 volt pump in a 24v vehicle they tap off o one battery which if done incorrectly can cause battery failures or fires. If they wired it directly to 24v it might have run for a while until it rolled over and died. Either way, you should stick to the original system. It's been working in thousands of trucks for over 30 years. That's a pretty good track record isn't it?