• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

No Fuel Pump buzzing when turning key

JeepXJ92

NAXJA Forum User
Location
Ogden, Utah
1992 XJ Sport, 4.0l, 5 speed.

When I was comin home from work about 2 weeks ago, I turned a corner and the engine died.
tried starting, no start. Towed it home.

playing around with it and realized I had no pressure at the rail. Then I realized it was not pressurizing when I turned the key on.
I checked the relays, swapped them around and still nothing.
Spent $110 on a new fuel pump and still nothing at the fuel rail.

Any thoughts? PCM? (god I hope not or it's for sale). isn't that weird ballast on the drivers side fender for the low pressure at the fuel pump?

Any ideas will help. I need to get her back on the road!

Thanks!
 
If the ballast resistor is bad, the fuel pump will still run while in the full-to-the-right "start" position. That is by design. But when you let off the key, the fuel pump will stop running if the ballast resistor is the issue. So usually, the engine will start and run for a short while until you let go of the key. The ballast resistor can be safely jumpered if you wonder about it. Have you tried swapping the ASD relay yet?
 
ballast.jpg
 
Yea, thats the thing but mine is higher up by the firewall.
Is that safe to put a jumper inbetween or will that send too much current to the pump?
I checked all my relays in the fuse box and they are all powered and nothing is burnt inside them.

I "jumpstarted" my old fuel pump and it is still strong so it's gotta be higher up between the relays and the pump. :bawl:

Is there a pressure sensor in the fuel line that may be tellin the system "hey! I don't need anymore pressure!"?
 
Absolutely safe to jumper the ballast resistor. Do it all the time for troubleshooting. Later models don't even have this. The only reason they were on there is to reduce "noise" to the fuel pump circuit. Jumper away.

But usually if the ballast is bad, the engine WILL start and run for a couple of seconds because as I mentioned, the ballast resistor is "bypassed" when the key is in the full start to the right position.
 
I would disconnect the connector at the fuel pump pigtail, and test the ground wire on the wiring harness side. Then with a buddy, test the 12 volt signal at the fuel pump wiring harness side, when you first turn it on.

Both my 87 and 89 acted like the fuel pump was bad, and it was just 30 year old dirty, loose, oxidized connectors at the male/female fuel pump pig tail connection to the wiring harness near the gas tank (and probably dirty relay male & female contacts, which I also cleaned). Both have run for 1-2 years now.
 
OK... Played around today. tried starting fluid and nothing. Got curious and checked for spark. I pulled the coil and tested it. It tested fine. replaced the pickup coil cause it was ugly but still nothing. so, no fuel pump, no spark, just turns and turns...
Is it pointing more towards the computer? is there any way I can test it with out the OBDII diagnostic stuff?
 
OK... Played around today. tried starting fluid and nothing. Got curious and checked for spark. I pulled the coil and tested it. It tested fine. replaced the pickup coil cause it was ugly but still nothing. so, no fuel pump, no spark, just turns and turns...
Is it pointing more towards the computer? is there any way I can test it with out the OBDII diagnostic stuff?


Pick up coil? Do you mean the CPS (CKP)?

No spark is usually a bad CPS on XJs. (CPS=Crankshaft Position Sensor)

Ignition switch may be bad? It may be engaging the starter and starter solenoid only, but not the ECU, fuel, spark, etc!!!!!!
 
Back
Top