My 1988 244 wagon has been sitting for a few years because I ran out of time to work on a fuel and computer glitch. Now I am working on the problem again and to eliminate the possibility of a bad fuel pump/relay/engine sensor, I rigged a manual switch across terminals 87/1 and 87/2 of the Fuel Pump Relay. In other words, bypassing the relay coils and sending +12v directly to the Fuel Control Unit.

This does indeed put 12v at the terminals of the main fuel pump, but the pump does not make any noise or vibration to the touch. Does this indicate a bad pump, or do these pumps run silent?

Also, the car is stranded with its nose uphill on a 5% grade. If the in-tank pump is also inoperative, would the main pump deliver enough fuel to the injectors to run the engine? As it is, I don't even get a cough out of the engine when it turns over, even using the manual FPR by-pass switch.

See Thread:
"in-tank pump question"

- Sitting for a few years.
-- Could the gas have soaked up too much moisture from the air?
Pumps should run regardless.

- 87/1 and 87/2 of the Fuel Pump Relay
-- My '88 240 sedan jumps 30 and 87/2 to run the pumps. I do not know what 87/1 and 87/2 does.

- the (main) pump does not make any noise or vibration to the touch.
-- The pump is not silent. When I jump 30 to 87/2 my main pump can be heard standing by the car. The in-tank pump should be heard through the fuel filler pipe.
-- My understanding is that the injectors need a specified pressure and that is delivered by the main pump. The in-tank pump is only lifting the fuel up to the main pump.

- nose uphill on a 5% grade.
-- Not sure what 5% slope is. Slope typically is in degrees or rise/run. If you do not have a lot of gas in the tank it would be sitting in the back bottom and the pump is in the front. The pumps would still run.

- If the in-tank pump is also inoperative, would the main pump deliver enough fuel to the injectors to run the engine?
-- Yes if there is enough fuel in the tank. I have 1/2 tank and mine failed to start. It turned over but would not run. I am currently doing work to confirm failure of the in-tank pump.

-- If you do the correct jump to run the pumps and you do not hear anything you might test the power to the pumps to confirm the cables are intact. You said you had 12v at the main pump. There is a connector in the trunk(rear) that can check for voltage to the in-tank pump.
-- I am checking now for reports on electrical continuity of pumps.
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1988 244 DL; B230F; LH-2.2; Manual 5-speed (M47)

rise/run x 100 = percentage grade

For some reason, the list of new posts was showing that I'd had no responses ever since my original post. About to head out to do some more diagnostics on this warm 40 deg. Massachusetts day and tried reloading my browser. Whaddya know? thank you all for the suggestions and knowledge. I will digest it all and let you know who wins the next round, me or the unknown opponent!

If it were me, I’d disconnect wiring at the pumps and jumper 12v from a battery to them to see if they work. Then work backwards from the pumps. Keep in mind, if the short in-tank output hose has rotted through, the in tank pump can run but not provide fuel to the inline pump.
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82 242-6.2L; '17 Mazda3; '16 Crosstrek

The car can run with a bad intank pump or if the hose is rotted, symptoms appears with less that 1/4 of a tank. Especially in turns. Main pump will run harder and maybe nosier. Car won't run with a bad main pump.
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Post Back. That's whats makes this forum work.