4 dead fuel pumps? WTF
 

How is this possible? I don't know...started off with a Walbro 190hp that I have been using for about 4 years. Eah, shit happens, fuel pumps die. So throw in the stock one. Well that one lasted about an hour. Out of fuel pumps so ordered a new Walbro 190. It also died almost immediately. Guess it was a bad pump? Got a dw200. Plugged it in and the battery was more or less dead so it came on and built about 60psi (had about 2 ohms of resistance before install). So I threw the charger on and left it for about a week. Now it too is dead reading in at 3k ohms. The other pumps are in the 100-300 ohm region. None of the pumps have actual run time (because the car refuses to start but is impossible to figure out if I can't get a fuel pump to work long enough to troubleshoot).

For the detail oriented it is a 90 chassis with 6an lines, duel feed rail and an aeromotive fpr. Also running ms1. The car shows 12v at the plug when the key is turned to the on position and there is almost no resistance in the tank wiring (.2 ohm for each wire and 40M ohm between each wire). Does anybody have any ideas?

Yes, clogged filter, it happened to a car I was tuning about 2 weeks ago. Ate 3 Aeromotive pumps like there was no tomorrow.

Note to self, replace fuel filter.

I can change the fuel filter. It is about 4 years old...maybe one of my fuel lines is crimped causing excess back pressure?

After reading this I think I may fit a new fuel filter before I fit my new pump.

Another theory is some shitty fuel that has been sitting in my tank for the past years has seperated and is killing the fuel pumps. I think it is a long shot but I am going to change that as well.

Shit, all of this applies to me. Got a 255 lbh walbro ready to go in, cars been sitting for almost three years. Guess it wouldn't hurt to drain the tank as well.

Check the fuel pressure, maybe the pump is dead-heading against the regulator and going to maximum head pressure on the pump at zero flow. That would kill a pump very fast.

I once worked at a shop wher me it was standard procedure to replace fuse and or relay (along with filter) anytime we did a fuel pump. The theory behind it is that anything causing higher amperage than what it's designed for will kill it.

You could always do a voltage drop across the relay to check. Or measure amperage in the circuit and see what you get. Although I couldn't tell you how much the aftermarket pump should be pulling.

I know this is an old thread but the miata project is back on and this caper is solved. It is like patsmx5 said, my fpr wasn't letting any fuel by so the pump was continuously pumping to a dead head. Rebuilt the fpr and the system is good to go at a solid 60psi...now to get the car to start.