Good battery, starter, alternator. Why won't it start?

My wife and I are students and have been fortunate enough to own a workhorse 240. In the three years that we have owned it, what little work it has needed I have been able to do myself. But recently it has come down with a mysterious and intermitent problem, it simply won't start and I don't understand why. If anyone has seen this problem before or can offer some advice we woule greatly appreciate it.

This problem first showed up about a month ago. For a while now the shifter hes been a little off and has to be jiggled sometimes in order to get the car started. But one day it simply wouldn't start at all. No jiggling would get anything out of it. The lights, radio, and fan all work but the engine does not turn over, Nor is there a click from the solonoid.

The first thing I did was to jump start the car. This worked fine but the engine cut the second I disconnected the cables. We tried it again and this time let the two cars remain connected with the engines running for a few minutes. But again the engine cut off.

Thinking this meant a weak battery, I took my old battery to the parts store to be tested, But it checked out just fine. So I hotwired the car to test the starter solonoid. The starter turned just fine. Thinking it must somehow be the alternator, I pulled that part and took it to the store to be tested. It tested just fine.So I went home and replaced the alternator, reconnected the battery, and the car started.

Now the problem is back again. I suppose there could be a bad electrical connection somewhere, but I can't find it. The only other things I can think of are that either the fuel pump is going out or the computer is broken and for some reason the car believes that it has been in a collision and is cutting off the fuel. But I don't know enough about fuel systems or computers to test either hypothesis.

I do know that my wife and I are struggling students and the last thing we need is to have to spend hundreds on repairs. While we could probably scrape together enough to replace a fuel pump, and we could probably get an old computer from a junkyard. I don't want to have the car towed to a shop until I can be fairly certain that I know what the problem is. The reputable shops around here have a long wait and high hourly rates. And I don't even want to think about what the other shops would do with this sort of problem.

The only thing that could be worse would be having to replace the car altogether.

[Peter Milnes]

Let me guess, your 240 has an automatic gearbox. You will find that the starter inhibitor switch has become disconnected or has become unserviceable. It may even have suffered it's attachment screws becoming so loose that the switch is not moved by the gear lever anymore. I would have a good look at the component and it's wiring connector, the fault should be quite obvious and fairly easy (and reasonably cheap) to remedy. Make sure that it is lined up correctly so that the starter operates in Park and Neutral only.

All the best, Peter

http://pic7.picturetrail.com/VOL188/...8/23744414.jpg


I think you have two problems here, the failure to crank unless the shift is moved is as Peter says.

Once jump started it should keep running, not cut out when the jump leads are removed regardless of the gearbox switch.

My guess would be a bad connection, the simplest to check being the battery terminals. Click on the link below for more ideas, most of the info relates to the 200 series as well.

http://www.brickboard.com/FAQ/700-90...alStarting.htm

Colin.

1990 740SE B200E/M47, remote C/Locking.