A couple of weeks ago I was driving my girlfriends 1989 740 GLE to get gas when the car quit. Because the gauge was almost on empty, I assumed it was out of gas and just walked to get some. After I put the gas in the car it started up fine but when I put it in drive and started to go it was very sluggish of the start until it got up to speed then it cruised okay. I attempted to drive the car home but when I made the turn into my street the car quit and wouldn't start again. The next day I replaced the fuel filter and the car started but quit under load. Next I pulled the fuel pump relay and jumped terminals to test the pump and found the tank pump wasn't making any noise. I replaced the pump and it started but again quit under load and wouldn't start again for maybe 20 minutes. It would also start immediately after jumping pump relay but left at an idle would quit after a couple of minutes. Next, with the pump relay installed, I bridged the terminals and started the car and it runs fine with the fuel pumps running constantly but if I remove he bridge while running the car dies within a minute or two. I replaced the relay and still no luck. I forgot to mention that the whole time the relay was clicking very loud and there is a bit of a sporadic gurgle noise from the main pump.

Can anyone help me find the problem? Thanks in advance.

 

I'm not as well versed in the 700 series since I have only owned 240's. However, my understanding is that the fuel pump circuitry within the "pink label" ECUs is weak in the early LH 2.4 systems.

Take a look at the ECU. If it has a pink label on it, it could be the cause of your problems. I think around 1990, they replaced the ECU with one with the white label. These are improved over the pink label ones.

I wish I could provide part numbers but perhaps one of the experts here could provide.

Good Luck.

 

i'd think it's the main pump dying...

 

sorry, didn't see that you changed to pump already...