Mechanical fuel pump brand recommendations?

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Red Truck
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Location: Vader, WA

Mechanical fuel pump brand recommendations?

Postby Red Truck » Mon Oct 09, 2017 2:06 pm

I've sifted through the forum, couldn't find a good answer: Does anyone have a recommendation for a mechanical fuel pump brand? Short of switching over to an electric conversion (no pun intended), I haven't had much luck in getting one to last very long. It's for a 4ZD1. It's doing the typical leak down the starboard side of the block, from the pump. No, it's not the flange. The current one is a NAPA M1400 (Carter? Airtex product?), and it lasted about 6000 miles. Sadly, that's the first NAPA product I've ever had trouble with. The one prior to that (brand unknown) lasted about a year. I'm at the point of using wing-nuts on the mounting studs.....
'87 Isuzu pickup 2.3 gas, 5spd, 4WD

oldestisuzuist
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Re: Mechanical fuel pump brand recommendations?

Postby oldestisuzuist » Mon Oct 09, 2017 3:02 pm

Questions:
-Is the leaking fluid gasoline or oil?
-Are you sure it's the pump? If the pump it should be leaking out the drain hose on the 4th pump connection, either gasoline or oil. The pump has failed internally if leaking from this connection. Delphi claims to be OE equipment, but who knows? The fuel pump is normally not failure prone no matter the brand. Someplace like Autozone usually has a lifetime replacement warranty on mechanical parts, a pump bought from them would be the last you had to pay for. If the leak is not from the drain hose & is gasoline check the three fuel line connections to the pump, they all have pressure & a loose clamp or hole can readily cause a fuel leak. There is also a connection or two at the fuel pulse regulator between the supply line from the tank & the pump, check those also.
-Is the leak oil running down the block? If so it's probably the gasket(s), there are two pump gaskets, one between the intake & pump spacer, the other between the spacer & the pump, then the intake gasket makes the final seal to the port in the head where the oil is. Many replacement pump kits only have one pump gasket, the second must be purchased separately, both need replaced along with a new pump. Also check the spacer for flat sealing surfaces or a crack.
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Red Truck
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Location: Vader, WA

Re: Mechanical fuel pump brand recommendations?

Postby Red Truck » Mon Oct 09, 2017 4:44 pm

It's oil, no doubt. Plus, if it were gas, it would stink up too much. I've become well-used to this symptom, and is most likely an internal failure. The gasket/spacer placement is acknowledged, and was previously applied. The only cure I've found has been a new pump; now if I can only find one that will last. DelphI? I think R-Auto sells those. Thanks for the input.
'87 Isuzu pickup 2.3 gas, 5spd, 4WD

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Quahlity
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Isuzu vehicle(s): 1992 Isuzu pickup 2.3 carb

Re: Mechanical fuel pump brand recommendations?

Postby Quahlity » Tue Oct 17, 2017 7:33 pm

I just replaced my fuel pump, and hope to never have to do it again. I just brought the cheapest one.

It seemed odd to me you've had this problem more than once and made me wonder what's causing it. The only thing I could think of is internal pressure, and the fuel pump was the path of least resistance. I think the only way you get pressure inside the crankcase would be if the PCV valve was clogged and the intake (which normally is connected to your air cleaner) is also blocked. Like if you installed a Holley and plugged all the lines. Just a thought.

Red Truck
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Location: Vader, WA

Re: Mechanical fuel pump brand recommendations?

Postby Red Truck » Wed Oct 18, 2017 12:50 pm

Thanks for the comment. I believe you're correct, something like an aftermarket carb improperly installed could cause this symptom, as well as a plugged PCV, wrong part application, and lots of other possibilities.
This fuel pump issue is well documented throughout this forum, and has been addressed several times. All that was absent, and what I sought, were brand name recommendations. I've got a Delphi on order, we'll see what happens with that.
'87 Isuzu pickup 2.3 gas, 5spd, 4WD


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