924 fuel issues

Cannonball996 · 08-11-2009, 01:29 PM

I am not getting any fuel pressure, I checked the pump and I am not getting any electrical power to the pump with the ignition on, does the motor need to be turning for power to get to the pump?
I also wired the pump directly off the battery and still could not get any fuel pressure, or anything to come out of the pump, but it did make a lot of noise so I know it was coming on. could the pump and the relay have failed at the same time? is there any sort of fuel safety cut off switch, if so where is it?

agfisher · 08-12-2009, 10:45 PM

From what I have heard when the fuel pump starts making a ton of racket, it's on its way out. The factory 924 should not have any fuel cut of switch. Are you getting fuel out of the tank before it gets to the fuel pump?

xarkon · 09-19-2009, 05:26 PM

What year is your 924?

About mid-79 on have two fuel pumps. One inside the fuel tank, and another one later down the line.
The pumps do tend to get noisy, and particularly at high ambient temps, but I don't recall whether this was a necessary indicator of impending doom.

So, you'll need both pumps to work to get fuel to the engine.

Sorry, I no longer have my 924 or my manuals, having sold both years ago - but I recall my mechanic having to fix this problem.

Dave

CorsePerVita · 10-09-2009, 11:33 PM

Keep in mind with the CIS system, the only way to get the fuel pump TO run is to have the metering plate move up, if it doesn't move up, the switch doesn't get pressed, and the relay doesn't kick (no power to pump). Unless your metering plate was UP at the time, there will be no power at the circuit you tested. The only way to test that is to pull the boot off the metering plate on your CIS system, lift it up manually, turn the key over, and test the circuit.

More than likely your metering plate wasn't lifted up when you tested it.

If you bench tested it and you are unable to reproduce any flow by putting any gas through it or anything then you've got a bad pump. I hooked up a long fuel line, dumped a tiny bit of gas and tested to see if it spit it out. Refrain from using water, you don't need that in your fuel system if it tests fine.

We know:

- Pump turns on
- Nothing coming out, depending on how you're testing it then it is likely working, or hooked up wrong, or it HAS failed. It should have a nice hum.

We don't know:

- if the metering plate was up and the circuit was complete when tested

Eliminate these through process of test and elimination, and we can safely point to a) bad pump b) bad relay or c) bad switch from the metering plate (or a stuck metering plate)

08-11-2009, 01:29 PM	#1
Cannonball996 User Join Date: Mar 2007 Posts: 5	924 fuel issues I am not getting any fuel pressure, I checked the pump and I am not getting any electrical power to the pump with the ignition on, does the motor need to be turning for power to get to the pump? I also wired the pump directly off the battery and still could not get any fuel pressure, or anything to come out of the pump, but it did make a lot of noise so I know it was coming on. could the pump and the relay have failed at the same time? is there any sort of fuel safety cut off switch, if so where is it?

08-12-2009, 10:45 PM	#2
agfisher New User Join Date: Aug 2007 Location: Medford, MA Posts: 1	From what I have heard when the fuel pump starts making a ton of racket, it's on its way out. The factory 924 should not have any fuel cut of switch. Are you getting fuel out of the tank before it gets to the fuel pump?

09-19-2009, 05:26 PM	#3
xarkon User Join Date: Sep 2009 Posts: 6	What year is your 924? About mid-79 on have two fuel pumps. One inside the fuel tank, and another one later down the line. The pumps do tend to get noisy, and particularly at high ambient temps, but I don't recall whether this was a necessary indicator of impending doom. So, you'll need both pumps to work to get fuel to the engine. Sorry, I no longer have my 924 or my manuals, having sold both years ago - but I recall my mechanic having to fix this problem. Dave

10-09-2009, 11:33 PM	#4
CorsePerVita User Join Date: Oct 2009 Location: Redmond, Oregon Posts: 35	Keep in mind with the CIS system, the only way to get the fuel pump TO run is to have the metering plate move up, if it doesn't move up, the switch doesn't get pressed, and the relay doesn't kick (no power to pump). Unless your metering plate was UP at the time, there will be no power at the circuit you tested. The only way to test that is to pull the boot off the metering plate on your CIS system, lift it up manually, turn the key over, and test the circuit. More than likely your metering plate wasn't lifted up when you tested it. If you bench tested it and you are unable to reproduce any flow by putting any gas through it or anything then you've got a bad pump. I hooked up a long fuel line, dumped a tiny bit of gas and tested to see if it spit it out. Refrain from using water, you don't need that in your fuel system if it tests fine. We know: - Pump turns on - Nothing coming out, depending on how you're testing it then it is likely working, or hooked up wrong, or it HAS failed. It should have a nice hum. We don't know: - if the metering plate was up and the circuit was complete when tested Eliminate these through process of test and elimination, and we can safely point to a) bad pump b) bad relay or c) bad switch from the metering plate (or a stuck metering plate)