Urgent: No fuel pump

[CharlesS]

Gage sending unit out should be 8.6 to .8 volts depending on fuel level. Input should still be 12 V. (Info for a 2000)

According to the 98 FSM; the fuel gauge resistance will vary between 20 ohms in the FULL up position and the 220 ohms in the EMPTY down position.

When the ignition switch is first switched to ON the PCM will close the ground side of the Fuel Pump Relay which provides 12VDC for 3 seconds until the fuel rail is pressurized...

IF you are only getting 6VDC to the fuel pump..; there is something wrong....

 

[97XJ2]

I had left the key on for a couple minutes, while I checked everything, and checked the power to the pump last, and running a direct line didn't do anything. But I ordered the pump, and hopefully all's okay. :dunno:

 

[CharlesS]

Verify the pump had a good ground available while you are running the positive lead direct from the battery to determine whether the pump is good or bad....

 

[97XJ2]

I did what I could for that, my pump, being a 97+, sits on top of the tank rather than in front. We'll see what happens tomorrow

 

[Spoony]

Re: Related question... how do fuel pumps die? slowly, all at once, etc?

I have a 97 with 150K and sometimes when I'm accelerating the engine bogs. If I stay on the gas the engine continues to bog, but if I let off the gas and then press the pedal a few seconds later I have the "normal" really good acceleration.

I've hooked up a fuel pressure meter to my fuel rail and it reads 49lbs at idle.

Is this a sign of impending failure?

not to threadjack, but what's the pressure do, when you rev it? I've got the same issue, and mine idles at 43, but drops to mid 30psi range when off-idle.. I'm pulling the pump saturday, to check/replace the pump and/or sock..

 

[winterbeater]

Re: Related question... how do fuel pumps die? slowly, all at once, etc?

not to threadjack, but what's the pressure do, when you rev it? I've got the same issue, and mine idles at 43, but drops to mid 30psi range when off-idle.. I'm pulling the pump saturday, to check/replace the pump and/or sock..

Please let us know what you get with the new pump in both conditions. Your idle pressure is OK, but shows that you should do a capacity test to pump at least 1/4 liter in 7 seconds. Failure of test would indicate kinked line or dirty filter or fuel pressure regulator failure.

 

[Spoony]

where's the regulator? Mine is a '96, and appears to be a returnless system?

 

[winterbeater]

Not sure on '96, on 2000, it's part of the "fuel pump module". The older ones with the fuel return from the rail had it on the rail (I think).

 

[97XJ2]

new fuel pump runs fine when plugged into the factory harness, just need to install it now

 

[winterbeater]

Try not to run pump dry. That can cause motor bearing damage from over-revving.

 

[97XJ2]

i know, it was just half a second to prove that it was the motor and not wiring, it didn't even spool all the way up.

 

[winterbeater]

I would have done the same thing. Good luck with the installation.

 

[97XJ2]

Ok so, new pump, it runs, builds pressure in the line, I have spark. But no start. Or will it crank for a while if the line was dry?

 

[Spoony]

mine took 3 or 4 times before starting, last saturday, after i replaced the pump..

 

[97XJ2]

Anything else it could be now?

 

[Spoony]

so it'll crank now, and has spark?
what's the fuel pressure at the rail?

 

[97XJ2]

Cranks like a champ, lot of pressure at the rail, I dont have a gauge but it sprays out good, not just a trickle. And it had spark when I checked that a couple of days ago.

 

[Spoony]

check your plugs - they may be wet. if they are NOT, then I'd suggest next, to check compression..

If you still have spark, and the plugs are wet, clean 'em up good, reinstall, and retry.

 

[winterbeater]

But if the plugs are totally dry, the injectors must not be working.

 

[Spoony]

correct, WB.. I forgot to write that in my previous post