tylerwerrin

As the title says, my fuel pump died, so I replaced it with a new one. The engine will start but won't stay running for more than a couple seconds. My father in law thinks that it could be a problem with air in the fuel lines since I swapped in the new pump... but I have some pressure at the Schroeder valve on the fuel rail.

When i turn the key, I get the BZZZT of the fuel pump priming... so I'm not sure what else I could do. Is my new pump bad? Did my regulator go bad?

Injuneer

You need to put a fuel pressure test gauge on it. “some pressure” may not be the right pressure. How did you determine the old pump failed?

tylerwerrin

Figured it out, I think:

When I lifted up the spare tire, i noticed that the fuel line had gotten kinked, which I believe had starved the pump and prevented the rail from reaching full pressure. I also believe that this is why my other pump started squealing the way it did. After priming the pump a few times, the engine turned on and idled as it should.

The new pump is still making some noise - it's one of those Walbro 255 external style pumps, which supposedly are notoriously loud... although this seems especially loud.

Injuneer

Are you sure the Walbro is genuine? There are many Chinese rip-offs on the market.

tylerwerrin

The old pump was a Walbro, i got it off JEGS a number of years ago. The new one is most definitely a chinese knock off, which is probably why it's so loud. It's an odd whine - instead of a continuous WHEEEEE like the old pump developed, this one "undulates" - WEEEEoooooWEEEEoooooWEEEooo... very obnoxious... but it was only 13 bucks off ebay, so...

Injuneer

You really need to check the fuel pressure, to insure it can supply your engine's need at max power/WOT. You don’t want it to lean out and cause detonation, beyond the knock retard system's ability to eliminate it.

tylerwerrin

Wow, yeah - so just to cap off this thread - tested the fuel pressure, and it came up at like 10~, obviously not good. It was JUST enough to keep the engine running at idle, anything else and it would start to struggle and die.

I checked around to see what the issue could be - tested the fuel pressure regulator, which appeared fine. Then checked the hoses, which also were fine. Finally I checked the XJ6 "changeover" valve, which is a small electrically operated valve to switch between the two gas tanks. Sure enough, inside the valve, there was some varnish/bits of crap clogging the valve, which was causing the obstructed fuel flow.

I decided to just pull the change over valve and run from the left tank, which is the only one i run from anyways.

Car is back up and running, although the knock off Walbro is still louder than i wish it was... although way quieter than what it was doing previously. Still need to check the fuel pressure now that the obstruction is gone. Once I do, I will post.