no fuel pump activation in ford taurus

GMC guy

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#1
I got a 1998 Ford Taurus. 150k 3.0 vulcan auto tranny. I just flipped a 3. 0 vulcan in this taurus and the fuel pump does not activate. The fuel pump did work before the flip, but does not after. I would like to find a wiring diagram for the fuel system as I do have one plug that does not go anywhere, after the flip. I am assuming that this might be the lead that powers the fuel pump. Any help would be appreciated. Thanks in advance.
 

tdark

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#3
A shot in the dark. Fuel System Inertia Switch? Just press down on the button to re-set it. It is always possible that the car got movied around the tripped the switch. Tom
 
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#4
Would start by applying 12V directly to the pump, recall on some of these Fords, ground for the pump was at a terminal under the front seat someplace.

God, I hate these pumps, about the size of a can of Contadina tomato paste, pull around 75 watts, and need a constant supply of gas running through them because they are made so cheap, until you have to buy one, or else they would burn up if operating in free air. Use only a three commutator motor with a permanent magnet with axially extra long brushes driving a cheap plastic impeller and using a rubber ball for a check valve in plastic. And that constant supply of gas requires another return fuel line that soon rusts away. But they saved that in newer vehicles by mounting the regulator in the tank.

Plus they are absolutely miserable to replace, but today, dey all do dat. Even this isn't bad enough, introduced ethanol in gas that literally swells up that plastic. Ethanol wasn't even heard of in this era.

For a couple of bucks more, could have made an external brushless motor fuel pump, but you still get this piece of crap in an $80,000.00 vehicle.

Surprised the public doesn't rebel against this POS. Would be more than happy to pay two bucks more.
 

GMC guy

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#5
Thank you fellas. I bypassed the pump at the inertia switch.no power to it. I guess there must be a fuse in the interior fuse box...im stumped. Why would there be no power to the pump? The inertia switch is not tripped. I cannot read that schematic. Cant even tell the colors of the wires...that would help when I try trace the wiring. I would sure hate to drop the tank and replace the pump.
 
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#6
DG/Y...PK/BLK...check the wire on one side and see if it has power coming in and then the other side going out..If you have power going in and not coming out the switch is either tripped or bad...Jim
 
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#7
Will the fuel pump run if you provide 12v battery power to pink wire (with black tracer) at the inertia switch?
 
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#8
No brush limiters on these things, I use a current limited supply with both a volt and ammeter on it directly to the fuel pump tank connector. Already found pumps shorted out beside ones that were complete open circuited.

Does anyone like to drop a tank unless they are absolutely sure the pump is bad? Then if this is a 15 year old car with 150K miles on it, with the original pump, more than likely its shot. A shorted pump can also cause other wiring damage. Can find problems with these multi-pole ignition switches, relay points, lack of good grounds. Makes a guy wish they stuck with engine driven pumps. Surely an engine is capable of handling 45 psi.
 

GMC guy

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#9
Yes, thank you. I tested the wires at the inertia switch and there is no power going to or coming from the pump at the inertia switch. Inertia switch is completely down not popped up. I applied power to the pink wire. No pump sound. Just a click. So it seems there are two problems. Dead pump and no power to pump. Going to try solve the lack of power first. no use changing pump if there is no power to it.
 
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#10
When you turn the key to "on" position, fuel pump relay should click on (with some other relays) but then should click off after about 2 seconds. Can you or a helper hear that happen?
 

billr

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#11
Before you condemn the pump, try powering it with both temporary power and ground wires, often the grounding is an issue. Gotta ask, is this a fancy "returnless" system?
 
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#12
Another not so much of a trick is to pop over the cover from the fuel pump relay and hold the contacts closed. by hanging a test lamp with longer leads on it, can see of the bulb lights up. Or just jumper where the closed contacts should be in the relay socket.

Don't recall seeing that pigtail lead on Fords like on GM cars, can just hit that with 12V to check out the pump. Also not good knowing the history of a pump, if I buy a used vehicle, just change it as a matter of course. They can go at anytime, and don't want to be millions of miles away from home. Next rule with these things is to pay for towing insurance.

Another failure with these older cars, no such thing as ethanol in gas, need an ethanol proof pump. On some vehicles was tempted to install a 300+ external pump, but just couldn't find a good spot to mount it.

Yes the Ford has a return line, pump runs all the time with the engine running and needs that recirculating gas to cool it. Another rule I have, a 1/4 full tank is treated like an empty tank.
 

Gus

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#13
First, I would have someone turn the key to on, while holding the fuel pump relay, to feel if it clicks.....if it does, check power into the inertia switch, while the vehicle is cranking.....if no power, try swapping a relay with the same number on it....
 

tdark

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#14
I own a car just like the one that is having problems. Here is what I would suggest you do. Ohm your crank sensor. Mine shows .703 with the meter on the 2k scale. That is what yours should show. If I remove the crank sensor connection I have no juice on the green wire with yellow stripe on the inertia switch when I start to crank. I also do not hear the fuel pump run . I plug the crank sensor wire back and the green wire on inertia switch has juice when I try to crank the car and now I hear the fuel pump. I am betting you have a bad crank sensor or the wire is not connected good. You said you swapped engines?? Did you use your original crank sensor or the one that is on the engine now?? . Tom