240 Lack of power under hard acceleration

If I floor my 88 240, as it gets to high RPM, it cuts out a little bit. When I'm low on fuel, it's much worse.

The fuel filter, spark plugs, leads, dizzy caps and rotor are all ~12 months old.

Most likely to be the in tank fuel pump or something?


  • Could be the intank pump but also the main pump. Our 240 did that I remember and a new pump was fitted and fixed it and went as new again.

  • edited August 2019

    Test the tank pump first. The fact that it gets worse with low fuel level is a huge clue. The tank pump feed hose could be porous allowing the tank pump to suck air thus not able to deliver enough fuel

  • edited August 2019


    Fuse 4 is the in tank fuel pump

    Fuse 6 is the main fuel pump

    When I apply 12v to fuse 4, I can hear a pump running loud and clear, sounds like the main pump. However fuse 6 has 12v even while the car is off.

    I applied 12v directly to the in tank pump, and it sounded like someone sucking liquid through a straw, I couldn't hear a pump at all. I tested its connector, it was getting about 10v, I used a wire and connected this to the positive side of the pump, and it didn't make any sound.

    I pulled one fuse, then the other, and had both out of the car at the same time, and it still ran fine 🤔

    I'm guessing the in tank pump is on its way out, judging by the sound it makes with 12v applied to it, but why does my car still run with fuse 4 and 6 removed, and why is the pump only getting 10v?

  • Also, fuse number 4 has no voltage whether the car is running, or the key is turned to II

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