Odd fuel pump failure

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My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Odd fuel pump failure

Post by Petros » Fri Jan 11, 2019 12:23 am

I had an unusally fuel pump failure yesterday I thought I would share, it might save someone someone else some trouble in the future.

after months of slowly, little at a time, getting my engine rebuilt, and a few other unrelated issues on the car fixed, I got my engine installed and running on Wedesday of this week.

It refused to start after much cranking. I had not changed the timing setting since I did not remove the distributor from the head when I took it apart. IT was running when I pulled the engine, so if I had spark it was not the timing. I squirted some starting fluid down the carb, and it momentarily started and died. looks like fuel starvation.

After inspecting the fuel lines in the engine compartment, I pulled the fuel line to the pump and sucked on it until fuel came to the line (yetch!), and plugged it back into the pump. I then plugged the outlet to the carb, and sucked on the return line to fill and prime the pump with fuel (double yetch- I have a hand held vacuum pump but I could not find where I misplaced it, gave up looking and used manual suction). It started right away and ran on its own. It was running off the 9 month old fuel in the tank.

I got out and inspected the running engine for leaks: a small coolant leak appeared to be from the by pass tube (typical place to leak), and the fuel pump was leaking fuel like a sieve.

It appeared to be leaking around the seam where the metal cover is swagged onto the cast lower housing, I pushed on it and twisted the top, and it changed the way it was dribbling out at that seam.

That is a way I had never seen any fuel pump leak before. my pump is at least 10 years old, likely much older. I think I got it on the original Tercel I first bought about 18 years ago or so, as I recall. It has never given me any trouble, it still pumped fuel, but this leak would be a big hazard and not help my fuel economy.

I thought I had a spare pump somewhere, spend perhaps an hour going through half a dozen boxes of old car parts and spares (really need to organize my inventory of spares). I found one, but it appeared to be frozen solid, the lever would not move much at all. After some lubricant squired inside and over the lever pivot, and forcing it to move in a vise, it was till too stiff to trust. I put it in the trash so I do not mistake for a good pump.

I really needed my tercel to run this week, that, and other car trouble with our extra cars I had been driving, put my regular work behind several weeks. I thought I might be able to fix it without having to find a new pump, it was late in the day and not in a mood to drive to town and check all the autoparts stores before they close. I removed the pump, put it in a vice up-side down, and used a punch and hammer around the joint between the sheet metal top and the cast housing so it would tighten this seam. I thought if I tighten this joint it might hold fuel, there should be some kind of rubber seal or gasket in that joint. IF I can tighten it, it should stop the leak.

I suspect that when I had the head off, and I was cleaning and resurfacing the gasket face, the fuel pump (which I left installed on the head to save time) must have gotten bumped or knocked around and perhaps rotated and broke the seal round that joint.

I put it back on (what a PIA to line up the bolts--you have to push the spring loaded lever against cam shaft, hold it steady, align the pump, and install the bolts), and started it to check for leaks. It appeared to work, pump and heat shield stayed dry. I drove it today for about 150 miles, still looks good, no fuel smell and no noticeable leaks.

I ordered a new fuel pump from the local Autozone store (they do not cost too much, worth having on hand in case it leaks again).

Picture below looks like my old fuel pump, I show where I tightened the leaky joint between the upper housing and the cast base by using a punch around the joint.
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'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

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