I have a 1986 240DL wagon with 300,000 miles.

It refused to start a few days ago and, looking under the hood, I observed the ground cable from battery to engine block had parted. Thinking that must be the problem I replaced the cable but failed to solve the starting problem.

I can hear the fuel pump running for a moment after I shut off the key, and I've checked the fuse between the battery positive and the electric system.

Suggestions, anyone?

Thanks in advance for your advice.

If you are having this problem with < 1/2 tank of gas, then likely your pre-pump is not running or the hose to the pre-pump is torn (these are both in the tank, accesible from the sending unit opening).

If this is a problem, other simptoms would also have been difficulty to start with a not-full tank.

In this case, it is the job of the main pump (under the rear seat area) to pull all the gas out of the tank. This destroys the main pump and overheats the fuel pump relay (pack of 2 in 1).

While diagnosing the fuel delivery system ( always a problem on these older cars), you would want to replace the fpr (fuel pressure regulator ) under the hood attached to the fuel rail at the injectors. This though would not cause a no-start scenario.

Good luck.

Greg Mustang

First place to look, always always always: Fuel pump relay.
Replace it, resolder it, whichever- if it's turning but not starting 9 times out of ten it's that.
The engine bay fuseholder is next, you've covered that.
Check fuse #1 in the fusebox too.
If you've got spark and still not firing up, you could have lost the main fuel pump. Good luck with it!
--
Rob Bareiss, New London CT ::: 86 244DL, 87 244DL, 88 744GLE, 91 244: 808K total

Thanks for the suggestions. All were helpful, but the winner is Aye Roll with the No. 1 fuse.

I removed the fusebox cover and got set to wiggle fuse 1 when I began cranking, but when I turned the key, bingo! it started. Just removing the cover must have jiggled the fuse enough to make contact again.

I cleaned the ends of the fuse and the holder ears.

Now I'm good for the fourth hundred thousand.

Divadad

Probably the best advice is to check the 700/900 FAQ for Diagnostic directions on no-starts, ie checking for spark and fuel. But before resorting to "reading the instructions," make sure all fuses have a good connection (and are in all-right shape). This includes the waterlogged blade fuse and its socket under the hood. Try giving it just a touch of gas while she's cranking, it works on my '88 at least. Finally, try disconnecting the Air Mass Meter to see if something happens. If nothing else, you'll feel like progress is being made. Best of luck.