2000 Crown Interceptor won't start fuel pump won't run

[chrisstag]

Nope it's not the fuel pump or cut out switch. I tested the relays which are fine, fuses are fine with full B+, not getting any voltage at the cutout switch, not even the 1 second initial B+. Tested conductivity about 2.7K to the front and about 70 ohms to the pump. I hotwired the disconnected pump line to B+(12 volts) and pump runs fine consuming about 5 amps which should be nominal, I can keep voltage on it and car starts and runs. Manual does not include a wiring diagram, help!
Thanks

[rhandwor]

If you have a logic probe check at the relays for a ground. Go to advance or auto zone and look at a haynes manual check for a wiring diagram. You could have a loose fuel pump ground. The 1997 was located at right cowl panel,near door sill. Other grounds rear of left front fender apron. Right fender apron right side of battery. Center rear of trunk on support.

[chrisstag]

Thanks for the tips. Center trunk ground is good, pump ground confirmed good due to my hotwire job would not have worked unless ground was ok (hotwire only applied to B+). I think both relays did operate (driver side did confirm) thus the coil ground would be ok. Wonder about the passenger side one.

[rhandwor]

Ford used to have an eec iv relay which supplied the voltage to the fuel pump relay. I think this relay feeds the fuel pump relay. This ground should be for this relay right side kick panel.They have a 10 amp fuse for the pump control voltage and a 40amp relay for the pump.
Push the button on the inertia fuel shut off switch see if this helps. Check voltage both sides. Left front of trunk.
My wiring diagram is for a 1997 if these tips don't help fix the problem. I have went to a small shop which has mitchell on demand and gave him a case of beer to print me a wiring diagram.
If these tips don't help you are going to need one.

[chrisstag]

Thanks for the help, I really appreciate it. It's 32 deg. outside so I think it will take me till Saturday to get the courage to do more.
The relay you refer to may be the one on the passenger side of the engine compartment which I was curious since it has 2 according to the owners manual. Also the heavy fuses are in the same box which all test full voltage.
The inertia switch I tested long ago which is closed and indeed disconnected the plug to do my power on tests as well as power off resistance tests I mentioned in my first log. It is at this location I injected my phantom 12 volts in order to test the pump and circuit from this point on proving wiring integrity from inertia switch to the pump and ground as well as the return wiring which indicates hi resistance of about 2.7k. About expected for a hi impedence circuit for purposes such as the monitoring circuit I read about in the manual. Power on voltage at the inertia switch is null including the first second of ignition power on as indicated in my first post.

[rhandwor]

I had a loose ground for this relay on a trip. The 1984 T-B 5.0L wouldn't start at a service area in Va. I got a triple A tow to a garage. They put it on a lift and found two pumps. The T-B had a small one in the tank and a big one outside back bt the gas tank. I said ok as long as they put a 12v test light and It had power. They checked and no power. I was in the front seat and they were under the car. I was aware about where the relay was and reached over and down as I pulled the glove box as I smacked the relay they said check it and it started. I paid them $5.00 or $10.00 and left. I didn't shut the car off until I got to Ohio. My mother had room in the garage and I called a dealer on monday who didn't have one. I went to a yard and got one for $3.00. When I pulled the side panel I found the loose ground. So I tightened it up and checked both relays were good.
Hopefully you will be as lucky.

[radioman2002]

If all else fails run power and ground to the leads comming up to the trunk, the fuel pump should run if not, looks like a bad pump.

[rivguy]

there is some wire problmes on these vehicles - the engine electronics harness runs behind the front bumper and breaks or rubs on the corners - if you find a loss of power and can't find where it's broke good place to start.

[chrisstag]

Thanks Dane that's the best idea yet. When I get time I will test the grounds and coil B+ lines at the relays, I have suspected for sometime that it is a failed wire, but without diagrams it has been my last activity.

[chrisstag]

Update:
I confirmed green/pink color for the B+ line at the driver side relay and at the supply fuse. Power at the fuse line but not at the relay. There is either a break in the line or the line goes elsewhere. Time to obtain a wiring diagram to confirm. I read in my manual that they monitor and duty cycle the pump.

[sparkslg]

Originally Posted by chrisstag

Update:
I confirmed green/pink color for the B+ line at the driver side relay and at the supply fuse. Power at the fuse line but not at the relay. There is either a break in the line or the line goes elsewhere. Time to obtain a wiring diagram to confirm. I read in my manual that they monitor and duty cycle the pump.

when you are checking power and ground to your fuel pump remove fuel pump relay and turn key on , you shoul have 12v at pin 30 and pin 86 ( look on relay for pin description) pin 30 comes from fuse #1 in battery junction box under hood , pin 86 is fed from a splice which comes from your pcm power relay ( located next to fuel pump relay) if there is power at both terminals then you need to be checking grounds. Keep in mind that the pcm controls the ground to excite the relay . Pin 85 at the fuel pump relay is the ground from the pcm.
Good luck

[garst2328]

dose your car have fire to the plugs please reply i might know what it is thanks shawn

[garst2328]

well you havent wrote me back want to let you know it sounds like a crank shaft position sensor wich is about 40 60 dollars ...... i had one go bad on my jeep and got no fire and the fuel pump would not kick on i put this part on and it started right up and ran good.................

[chrisstag]

I got a CD publication which has wiring in it and found that indeed B+ from the fuse goes directly to the relay. I started taking the harness apart to locate where the wires go, one harness the wire Ys off and goes to a test connector a foot away and the other disappears I think to a connector that is so low on the firewall I cannot even reach it. It's cold up here in Minnesota now so I strung another wire from the fuse to the test connector in effect hot wiring the break (maybe the unreachable connector) and the car runs with exception to cylinder number 4 which under torque has a misfire (I think a clogged injector caused by oxygenated fuel sitting for months without running I believe). So if I ever get the time to find the actual connection breakdown (and be able to reach it) it would be interesting to locate it and the reason thereof.
Thanks for everybodys postings!

[SCPDMechanic]

Originally Posted by rivguy

there is some wire problmes on these vehicles - the engine electronics harness runs behind the front bumper and breaks or rubs on the corners - if you find a loss of power and can't find where it's broke good place to start.

Before you go any farther, you might want to read this post again and heed his advice. Those bumper harnesses hang right over the metal bumper support and wear right through, sometimes breaking through more than one wire. If you're losing power or ground to the relay (and all fuses are good) this is the first place you should look.