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Fuel pump wont turn off


Jimmmy
02-18-2006, 12:13 PM
It just got really really cold here (below zero) and now my 93 jimmy wont start. Yesterday it worked fine in warmer weather and has been for 2 years. This past summer i replaced the cpi. Now when i go to start it, it cranks but won't fire. When i take the key out, the fuel pump wont stop priming until a minute later when it finally turns off. I tried using starting fluid, but no luck. I then moved on to ignition and the coil is putting out spark. So i'm stumped?

maxwedge
02-18-2006, 01:19 PM
Spark at the plugs, nice blue streak?

Jimmmy
02-18-2006, 02:22 PM
Yea, removed the spark plug wire and it's arcing. I let the car sit for a couple of hours and it almost sounded like it was going to fire up, but didn't.

maxwedge
02-18-2006, 03:17 PM
Unless you have an internal engine problem spark and fuel should do it, pull some plugs see if they are wet. Again, sometimes you can have spark but not enough to fire the engine.

horse482
02-18-2006, 04:11 PM
The fuel pressure regulator could be causing both problems, no fire from not enough fuel, fuel pump keeps running because it is letting fuel back in to the tank and not reaching the primed pressure.

Jimmmy
02-18-2006, 05:00 PM
I'll try and pull the spark plugs tommorw when its a little warmer. I hate working in the cold becuase and can't even feel my hands. Horse482, I thought the fuel pressure regulator was part of the cpi, which i replaced. Shouldn't the fuel pump stop when i turn off the car?

Jimmmy
02-18-2006, 05:15 PM
I take it back, there is NO spark from the spark plug wire but a spark from the coil to the distributor.

maxwedge
02-18-2006, 06:56 PM
Now you are track look at the cap and rotor of course.

Jimmmy
02-19-2006, 12:27 PM
took off the cap and rotor. The cap looks fine, but i'm not sure how the rotor is supposed to look? I'm used to ford rotors that are bent upwards that act like a spring. This metal part of the gm rotor is flat. There is also black residue and a circular pit where it revolves around.

The only thing i can think of is if the ignition module failed?

Jimmmy
02-19-2006, 02:31 PM
Replaced ignition module and it still doesn't start. I noticed that while i'm cranking it, the spark plug wire only ignites once or not even at all.

old_master
02-19-2006, 08:37 PM
Replace the distributor cap and rotor. Then find out why the fuel pump is staying on. The contacts in the fuel pump relay may be partially fused together and/or pitted and not releasing when the current is shut off to the trigger. The relay should only supply current to the fuel pump for 2 to 3 seconds after the ignition is shut off.

Jimmmy
02-19-2006, 09:26 PM
It got a little warmer today and she finally started! I think it was just so damn cold that it could'nt start. Now the fuel pump turns off too. Go figure. When the fuel pump didnt turn off, i disconnected both the relays on the driver side firewall (didn't know which one it was) and it still didn't turn off? When i disconected the relay, should'nt that have killed the power to the fuel pump?

But like i said, everything is ok.

old_master
02-19-2006, 10:20 PM
The fuel pump should shut off immediately when you remove the relay. If it continues to run, you’ll need to locate and repair a short circuit from battery positive to the fuel pump feed circuit. It would have to be somewhere between the relay socket and the fuel pump. I’m not certain, but I believe it’s a grey wire. You might want to have an assistant turn the key off while you're down listening very closely to the pump, to make sure it shuts off after 2 to 3 seconds. Tracing wires can be very time consuming.

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