The connections at the fuel pump are pretty solid. (10mm nuts, lockwashers over studs) Now, a frayed wire back there is possible but I've never run into that on either of my cars. The relay is also a posobility but a bad one probably wouldn't allow the car to run at all. But I have experienced intermittent stalling which I was able to trace to a bad connection at the temp sensor.

This sounds incredibly like the chunk-of-crud (rust/varnish/tar) in the fuel inlet (to pump) from the gas tank problem. A large chunk of this crap that builds up in a tank will clog the inlet in the gas tank due to the pump's suction. When the car dies, the suction is released and the crud floats away allowing you to re-start. It then proceeds to clog the inlet again a little while later. Never had the problem, but I've run across it doing research quite a few times. The fix is to drain your tank and look for the crud then have it boiled out by a local radiator shop. If you look for POR-15 on the web you can find a sealer (I've heard excellent thigs about it, but again never used it) to 'renew' your tank if it is indeed rusting out from the inside.

Oh, and you may want to check the AFM. The fuel pump cutoff switch that's in there may be activating when you hit something. This is very speculative but easily tested by jumping the two connections on it to see if the problem re-occurs. For some good pics of this unit and other 'tweaks' (that you'll no doubt not want to mess with) go here:

http://www.atlanticz.ca/zclub/techtips/

Let's have him check the things I mentioned first before we get to dropping the gas tank or tinkering with the AFM, which can quickly become a one way street. Start with the simplest. I have actually encountered this problem and solved it on my car by doing what I suggested above. Those connectors are usually pretty worn after almost thirty years. Simply replacing all of the connectors (fuel injector, thermotime switch, cold start, air reg, temp sensor,tps), with the sturdier, easier to work with, BMW connectors has turned my car that had those intermittent problems in to one that starts and runs under any circumstances with no problems, and gets up to 25.5 mpg. But you don't have to go to that extreme. Just check and clean the connectors, see how it runs then, and if the problem still exists we can move on to something else.

Just adding my 2c in case the sensors didn't turn out to be it. On my 280 draining the tank is relatively simple (to check for the contaminants) due to the drain plug located on the pass. side. I wasn't suggesting he should drop the tank right away. As for the AFM, I did say he probably wouldn't want to tinker, didn't I? Again, it's definetly not a first resort but I thought I'd throw it out there. Apologies for any confusion I may have caused.

BTW, are the BMW connectors similar to the GM and Audi types, or of a different construction entirely?

The BMW connectors are similar to the other types. I just thought that they were sturdier and easier to remove. You just pull the clips straight out and they come off, push the clips back in before you put the connector back on and it snaps tightly into place. And the moisture seal is better than the original ones.

Oooh, they come in colors too Thanks for the pics! The do look rather better that the salvaged (but brand new looking) originals I have right now.

I'm not about to immediately get carried away -- too damn old for that. So, I'll replace the fuel filter and work on the water temperature sensor and its connector and then I will let you know what happened.

By the way, not long ago I kept having problems with the air flow meter and finally took it off the car, took it to CarQuest, they sent it in for "rebuilding". That did wonders for the old car. Prior to that, the car would start and run as long as I did not touch the accelerator pedal. It went dead after even placing the slightlest pressure on the pedal. Also the car ran very rough when I get could get it to run at all.

I purchased a new AFM for my 810 earlier this year at OEM surplus. They sell surplus Nissan parts at about 25% of list. Give them a try if you need any parts. Remember these are new parts. I've purchased an a/c evaporator, compressor, window mouldings, dash pad, and a few other things from them over the last couple of years.

http://www.oem-surplus.com/nwp/index.htm

Going back to the Air Flow Meter, I took what I thought was the cheapest route but I might have screwed up. Old problems seem to arise again. For instance, just a few minutes ago I started the car with problems. It wanted to go dead when I pressed the accelerator, but finally got going. Maybe I should go the route suggested (or almost suggested) of buying another from the OEM site.

Not so experienced since, as I have said before, It's been a very dependable car but brain boggling at times -- BUT, income warrants ME to handle it's future.

If I wanted to replace the connector to the Air Flow Meter, are they available?

I've never tried to buy that connector but I doubt that Nissan would have them. I would find a good one at the junkyard and splice it in if I had to replace one. Not necessarily a Nissan one either since some of the European cars used the same type of connector.

Let's have him check the things I mentioned first before we get to dropping the gas tank or tinkering with the AFM, which can quickly become a one way street. Start with the simplest. I have actually encountered this problem and solved it on my car by doing what I suggested above. Those connectors are usually pretty worn after almost thirty years. Simply replacing all of the connectors (fuel injector, thermotime switch, cold start, air reg, temp sensor,tps), with the sturdier, easier to work with, BMW connectors has turned my car that had those intermittent problems in to one that starts and runs under any circumstances with no problems, and gets up to 25.5 mpg. But you don't have to go to that extreme. Just check and clean the connectors, see how it runs then, and if the problem still exists we can move on to something else.

Are the connectors mentioned identical?

Being as inexperienced with older cars as I am, I look under the hood and see wires and connectors and become afraid to touch them. Afraid since the connectors look brittle and the wires were bent to a certain position, remained that way for years, and my thoughts are if I move them they will either crumble, insulation will break, or short out. Is this paranoid thinking?

Being new to this web site, I'm probrably in the wrong place since my car is the 1978 Datsun 810. I just noticed that there's a forum dedicated to those "other" Datsuns. I'll post my headaches there in the future.