fuel pump sounds strange-engine dies

[madkaw]

You have probably noticed from the other thread that I have fuel pump issues and i have ordered another fuel pump. I wanted to relay my experience to see if anyone else has had the same issue.

My daughter told me the car was dying on her, but it always happened on the other side of town and I couldn't duplicate the problem. Well it did it again and I went to rescue her and I drove her car home this time and the car died on me 15 times in 10 miles.

You could always here the constant hum of the fuel pump in this car-I guess that's normal(81 280zxt)- and I noticed that before the car would die ,the pitch of that hum would get higher ,as if the pump was straining or something, and then the hum would about disappear as the car died. The car would not immediately restart, but within 30 seconds it would run again. This only seemed to happen when the car was slowing down to approach a stop. The car never dies at a full cruise. Sometimes when I got the car going again after dying, it would be very sluggish. It almost acted like the fuel line was clogging and whatever clogged the line would break loose after the car stopped. I have been in side the tank and it is very clean. I replaced the fuel sending unit with an extra clean one I had laying around-the symptoms happened with both sending units. The old one had a good amount of rust in the pick up tubes.

I removed the fuel pump to see if the inlet was clogged. The small screen was not clogged, but when i pulled it out I noticed shiny metal shavings on the back side of the screen. I figured the tolerances on the pump were going away and it was spitting metal from the gears. It wasn't a lot of metal, but it was there.

So I have ordered a Walbro to replace the fuel pump because honestly I am HOPING this is the issue. I don't feel good about the stock pump because of the shavings, but I may be way off on this analysis. The car has 91k original miles. I have replaced the fuel filter, checked the fuel tank and replaced the fuel pick-up assembly. I would think if this was an electrical issue(relay) then the pump would be more of an instant on/off issue. The fact that I hear the pump acting differently tells me that it is not electrical, unless the pump is locking up or getting hot and kicking the relay.

 

Any thoughts?

[madkaw]

Thanks for all the replies guys , but I figured it out. Obstruction in the return pipe in the fuel sending unit. There was no reason to suspect this earlier since the sending unit looked new with NO visible rust at any of the orifices. It's just one of those deals where the car says--gotcha:-o

 

Now I can concentrate on getting the car to run smoother!

 

By the way, a fuel pressure guage is an essential tool to have when troubleshooting these cars-and their cheap. I paid 150$ for a walbro install before I bought a 35$ fuel pressure test kit-dumb.