Hello all,
Criteria:
240 DL wagon. Not turbo. Automatic transmission.

The scenario:
I'm on vacation. The compartment above the tank was filled with tools and stuff. Previously, nothing has ever been in this area. It was possible that the wires to the sender (in-tank fuel pump or "pre-pump") pump can be bumped and pushed by the stuff in the compartment. The car is loaded enough to cause it to sag a bit in the back.

So, I was going up a steep climb outside of Ellensburg, Washington. Just as I topped the incline, it started to choke. It was as if I had lost half the power of the engine.

I got a tow into Ellensburg and began to fiddle with stuff. Entirely by chance, the thing started working well enough to drive again. From there, every 300 miles or so (I was making my way back home to Iowa), it would get to the same condition.

Eventually it became apparent that the sender pump was responsible. When it was acting up one particular time, I removed the fuse for this pump. It had no effect. So, in other words, the thing wasn't running before I pulled the fuse. Fiddling with the fuse would almost immediately cause the engine to go right back to full power. This was not true every time, but just about. I even got it to go back to normal while driving once by fiddling.

I eventually got some petroleum jelly on the fuse and took a wire brush to them. So it was no longer necessary to fiddle with the fuses. The problem still came around a couple more times.

When I got into some rain, it became more frequent. I guessed that it was a short which was exacerbated by moisture or any change in environmental conditions.

EVERY TIME it went out, I could get it going within 5 minutes.

So, obviously, I am looking to solve the problem. Looking through the archives I see some possibilities:

Fuel Pump Relay: could be this. The intermittency definitely makes it possible. Would the fuse fiddling have any effect with a bad relay?

Corroded ground or connections at top of tank: this is what I favor since it seemed that there was a narrow threshold of tolerated electrical current that, once crossed, meant trouble. Of course, the same symptoms lead me to think it's the relay.

Bad pump: would it act intermittently? Would it respond at all to the fiddling with the fuses? Was it not the fiddling but the fact that the pump got a chance to rest, if even for 5 minutes? I figure a bad pump would likely fade. There were no indications that it was out before this started happening. HOWEVER, there WAS relatively bad gas mileage: not chronic, but not very god either.

Bad in-tank hose on pump: the fuel level had no influence. This seems to rule this out.

I have been told to just replace the in-tank pump. I can find one at a fair price, but I'd like to avoid it if it's not necessary.

There is evidence that someone has been at the sender pump, OR perhaps the fuel guage unit. The top plate has mismatched screws. That's the real question: should I replace the pump? I will clean up the wires and resolder the fuel pump relay, Don Foster style. Should I save $100 and some of my precious time and skip the pump?

I suppose I will just try the electrical and see if it comes back. I'm just curious to hear what others think. I still have not witnessed enough trouble in these LH systems to know my way around very well. I am really book-smart only. So I seek the advice of the veterans.

Regards,
-JSBB

P.S. I dealt with this from Ellensburg, WA to Iowa City, IA. My stomach hurts a bit still from the stress.


--
'Beware of the man who works hard to learn something, learns it, and finds himself no wiser than before... He is full of murderous resentment of people who are ignorant without having come by their ignorance the hard way.' -- Kurt Vonnegut