84 fuel pump issue

Topic: 84 fuel pump issue (Read 2645 times) previous topic - next topic

84 fuel pump issue

August 16, 2008, 10:10:36 PM

I have a few question on a cfi(I think) fuel system...it has 2 fuel pumps..the low pressure in tank and the frame mounted one..anyone have a schematic? Or...does anyone know how they get there power...I found the fuel pump relay in the trunk which I guess is for the in tank pump, but where does the frame mounted pump get power? Is there a fuse for these pumps, did not see one in the fuse box.. thanks...

84 fuel pump issue

Reply #1 – August 17, 2008, 01:35:06 AM

this topic has been covered but very rarely. Softtouch would be the man on this one. I think he has the "pusher pump" on his car and possibly a diagram.

pm him.

also, use the search feature and use "pusher pump" as the search word or phrase.

84 fuel pump issue

Reply #2 – August 17, 2008, 01:54:50 AM

Here you go.
3.8 and 5.0 are the same in this area.

The BK/Y D wire #175 and the R wire #361 are tied together on the next page.

84 fuel pump issue

Reply #3 – August 17, 2008, 02:21:50 AM

so i have a question softtouch,,,
why couldnt the exterior pump be deleted and a high presure on put in the tank.

the wiring events are pretty much identical to those with only one pump.

84 fuel pump issue

Reply #4 – August 17, 2008, 07:11:59 AM

Quote from: jcassity;232346

so i have a question softtouch,,,
why couldnt the exterior pump be deleted and a high presure on put in the tank.

the wiring events are pretty much identical to those with only one pump.

It can be and it is done all the time. I did the same thing on my '83.

The only thing is that on most of them, the intank pump has a reistor wire on the ground to reduce the voltage to the intank pump. Replace that wire with a "normal" ground wire so that the new HP intank pump will see full voltage.

84 fuel pump issue

Reply #5 – August 17, 2008, 11:08:21 AM

Thanks...that is what I needed...ok...so any clue as to where the eec power relay is located?

84 fuel pump issue

Reply #6 – August 17, 2008, 01:25:11 PM

Pass kickpanel above the ECU.

84 fuel pump issue

Reply #7 – August 17, 2008, 02:21:02 PM

Quote from: Chuck W;232364

It can be and it is done all the time. I did the same thing on my '83.

The only thing is that on most of them, the intank pump has a reistor wire on the ground to reduce the voltage to the intank pump. Replace that wire with a "normal" ground wire so that the new HP intank pump will see full voltage.

resistor,?
Ford missed that on the evtm then correct?

84 fuel pump issue

Reply #8 – August 17, 2008, 02:58:14 PM

Quote from: Chuck W;232385

Pass kickpanel above the ECU.

On the 3.8 & 5.0 it's right of center behind the dash, near left side of glove compartment.

If you are in a quiet place you can hear it click when it drops.

Turn the key to run (don't start), the fuel pumps should run for a second then shut off.
Turn the key off and after a five second delay you should hear the EEC power relay drop.

84 fuel pump issue

Reply #9 – August 17, 2008, 03:44:56 PM

Quote from: jcassity;232392

resistor,?
Ford missed that on the evtm then correct?

Yes, but it is shown in the shop manual. It drops the pump voltage to 11v. The high pressure pump runs at full voltage.

Since you got me reading the shop manual.
The 84 TC, CV and GM Have the one pump in the tank system. It runs at the reduced voltage all the time except when cranking.
They have a resister wire in the yellow wire input to the pump relay that is bypassed by a side switch in the starter relay while cranking.

And more trivia: The EEC will deenergize the fuel pump relay if the engine stops or drops below 120 RPM.

84 fuel pump issue

Reply #10 – August 17, 2008, 04:15:14 PM

Quote from: softtouch;232401

Yes, but it is shown in the shop manual. It drops the pump voltage to 11v. The high pressure pump runs at full voltage.

Since you got me reading the shop manual.
The 84 TC, CV and GM Have the one pump in the tank system. It runs at the reduced voltage all the time except when cranking.
They have a resister wire in the yellow wire input to the pump relay that is bypassed by a side switch in the starter relay while cranking.

And more trivia: The EEC will deenergize the fuel pump relay if the engine stops or drops below 120 RPM.

I'm guessing you mean TownCar and not TC?

84 fuel pump issue

Reply #11 – August 17, 2008, 05:14:31 PM

ok...this car has never ran for me (unless I put gas right down the throttle body) both fuel pumps were bad...pulled them out and put power to them...nothing. Now bot will run if I bypass the fuel pump relay...but wont run...I am guessing its because the injectors are not getting power too...guess my next move is find the eec relay and check for power there...what else I should check?

84 fuel pump issue

Reply #12 – August 17, 2008, 05:25:49 PM

Quote from: Chuck W;232402

I'm guessing you mean TownCar and not TC?

Correct, TownCar. Sorry for the confusion.

84 fuel pump issue

Reply #13 – August 17, 2008, 06:16:59 PM

Quote from: Pigpen52;232407

ok...this car has never ran for me (unless I put gas right down the throttle body) both fuel pumps were bad...pulled them out and put power to them...nothing. Now bot will run if I bypass the fuel pump relay...but wont run...I am guessing its because the injectors are not getting power too...guess my next move is find the eec relay and check for power there...what else I should check?

Lets troubleshoot one symptom at a time. The fuel pumps.

Put the pump relay wiring back to normal.

Put the ignition switch in RUN and listen for the pumps to prime. They only run for a second so listen close.

If no prime leave the ignition in RUN and;

Ground the Tan wire at the self test connector. If you look at it with the four terminals on the bottom, it's the one on the right end of the four.
This is the same wire the EEC grounds to run the pumps.

If the pumps run, the EEC power relay , the fuel pump relay and the inertia switch are good. This means the EEC is not grounding the pump relay coil.

If the pumps don't run check for voltage on the yellow and red wires at the pump relay. (ignition still in RUN)

Let us know what you find.

84 fuel pump issue

Reply #14 – August 17, 2008, 07:41:08 PM

The pumps do not run...so what would the test connector look like..I am guessing it is just an unconnected connector close to the eec... thanks for the help so far...