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Technical => Electrical Tech => Topic started by: Pigpen52 on August 16, 2008, 10:10:36 PM

Title: 84 fuel pump issue
Post by: Pigpen52 on 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...
Title: 84 fuel pump issue
Post by: jcassity on 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.
Title: 84 fuel pump issue
Post by: softtouch on 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.
(http://mysite.verizon.net/vzetk5cc/sitebuildercontent/sitebuilderpictures/EEC38L1.JPG)
Title: 84 fuel pump issue
Post by: jcassity on 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.
Title: 84 fuel pump issue
Post by: Chuck W on 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.
Title: 84 fuel pump issue
Post by: Pigpen52 on 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?
Title: 84 fuel pump issue
Post by: Chuck W on August 17, 2008, 01:25:11 PM
Pass kickpanel above the ECU.
Title: 84 fuel pump issue
Post by: jcassity on 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?
Title: 84 fuel pump issue
Post by: softtouch on 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.
Title: 84 fuel pump issue
Post by: softtouch on 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.
Title: 84 fuel pump issue
Post by: Chuck W on 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?
Title: 84 fuel pump issue
Post by: Pigpen52 on 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?
Title: 84 fuel pump issue
Post by: softtouch on 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.
Title: 84 fuel pump issue
Post by: softtouch on 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.
Title: 84 fuel pump issue
Post by: Pigpen52 on 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...
Title: 84 fuel pump issue
Post by: softtouch on August 17, 2008, 09:00:07 PM
Quote from: Pigpen52;232431
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...


It is a six pin connector with one row of two and one row of four.
On the 3.8 it is under the hood near the driver's side strut tower.
Title: 84 fuel pump issue
Post by: MasterBlaster on August 18, 2008, 05:13:54 AM
(http://www3.telus.net/neat/pics1/eec_test_plugs.jpg)
Title: 84 fuel pump issue
Post by: Pigpen52 on August 18, 2008, 07:13:52 PM
Ok...I grounded that out. and the pumps ran...sooo...what now?...thanks for the pics...it helped..now if I could just get a pic of the car running...thanks for the help so far...
Title: 84 fuel pump issue
Post by: jcassity on August 18, 2008, 10:37:46 PM
good,,
now the next step (hope you dont mind softtouch)


Key off Engin off

remove the jumer wire you have at the eec self test connector.
find the same color wire on your fuel pump relay.
probe the wire with a stick pin
use a jumper wire to go from fhe stick pin to a good frame ground on your car.

Turn on your key

does the pump run now?

If it does,, fess up to whos been back there tinkering, they have shorted your EEC out and the computer can no longer deliver a ground to your fuel pump relay.


The fix

with the tan / light green wire grounded out **ALL THE TIME*** had no adverse effects on my pervious 3.8.

the only differences were, :
I turn on my key and the pump runs full time.
I run my car and the pump still runs like normal
I turn off my car and the pump runs for about 10sec then shuts off.

basically, the pump was waiting for the eec relay to shut off to kill power to the pump.
Title: 84 fuel pump issue
Post by: softtouch on August 19, 2008, 01:24:10 AM
jcassity, I think he already tried what you are suggesting when he bypassed the pump relay to keep pump running and the car still wouldn't start.

pigpen, jcassity is right, the EEC is not providing the ground for the pump relay. The EEC is probably bad. Any chance the under dash wiring has been haywired or is it still virgin?

Try pulling computer codes. This will tell us if that part of the computer is still alive.
Post #2 in this thread shows how to do it. KOEO means key on engine off.

http://www.foxtbirdcougarforums.com/showthread.php?t=8897&highlight=pull+codes

The EEC is behind the passenger side kick panel.
Title: 84 fuel pump issue
Post by: Pigpen52 on August 19, 2008, 08:35:58 AM
Ok...will try that when I get home...just one more question (for now) why would it not start when I bypass the relay and force the pumps to run?
Title: 84 fuel pump issue
Post by: softtouch on August 19, 2008, 02:08:27 PM
It could be because the EEC is bad. It controls the fuel injectors.
If you have a test light you could probe the tan wires at the injectors and see if it blinks while cranking. If the EEC is not working the light should stay on solid.
What engine do you have? 3.8 V6 or 5.0 V8
Title: 84 fuel pump issue
Post by: Pigpen52 on August 19, 2008, 05:56:31 PM
3.8  hopefully will be able to pull the codes tonight...just curious..does it matter that the battery has not been holding a charge?...I mean will that effect the codes? Where would you get an EEC and about how much are they?
Title: 84 fuel pump issue
Post by: Pigpen52 on August 19, 2008, 08:18:53 PM
Ok...when I tried to read the codes... I would get 12 volts with the key off...when I turned the key on it would got to 3 volts and not change...am I doing something wrong?
Title: 84 fuel pump issue
Post by: softtouch on August 19, 2008, 09:52:42 PM
Quote from: Pigpen52;232748
Ok...when I tried to read the codes... I would get 12 volts with the key off...when I turned the key on it would got to 3 volts and not change...am I doing something wrong?


If you have the jumper on and the meter hooked up as shown that's all there is to it.
The voltage should drop to zero when you turn the key on. Then it should pulse up to 12 volts with the code pattern. Sounds like another indication that the EEC is bad.

If you had 12v when you tried to pull codes it should have worked.
You should try to get an EEC from an 86 or 87  3.8 CFI. They have some improvements over the 84 and 85.

I don't know if they are available anywhere other than a junkyard.
No idea what it will cost.
Maybe someone else can help here.
Title: 84 fuel pump issue
Post by: jcassity on August 20, 2008, 12:12:29 AM
If he grounds out the eec at the fuel pump relay in the trunk and the car does not run,,,,,,,,,, IT tells us there is a broken wire from the eec to the fuel pump relay,,, but no break from the eec splice point out to the eec self test connector.
Still one more probable fault to check i would think since the eec self test conn tan/light green wire is just a branch circuit of the load.

If the car does run then.......
there are no options for him except opening up the eec and making the repair.

EEC is bad.

Leaving it grounded at the trunk is a work around with no real ill effects until he locates an eec. That was a suggestion i offered because I had to do it myself on the old motor.

Sorry, at that time, i did not see anywhere in his posts where he said he tried to start the car.

Ill assume that post 12 is when the eec got fried.  Not doing this properly will fry the eec.  I read post 12 front to back about a dozen times trying to figure out what was being said.  I can only assume the worse case senerio based on what was said. 


PigPin52-
did you prob or troubleshoot the fuel pump relay prior to coming here for help?  If so,, just keep in mind, bypassing or inerting power into the incorrect point on the relay may have spiked the eec right up the ground side of the computer with 12v.
Title: 84 fuel pump issue
Post by: Pigpen52 on August 20, 2008, 08:00:40 AM
ok...I am pretty sure I hooked it up exactly like the diagram said...so I assume the eec is bad...on when I jumpered the connection at the fuel pump relay, I just made a jumper and went from the constant hot wire for the pump, to the pump...did not mess with the control side of the relay...  Now since I can jumper the test wire at the front of the car and have the fuel pumps run I assume there is not a bad wire or connection...right?  SO..now to find an ecc...this is starting to get expensive...wish I could just put a carburator on it...will a 4412 bolt on?...lol
Title: 84 fuel pump issue
Post by: jcassity on August 20, 2008, 04:25:03 PM
Quote from: Pigpen52;232814
Now since I can jumper the test wire at the front of the car and have the fuel pumps run I assume there is not a bad wire or connection...right? 



no sir
scroll back up and read the begining of my last post, there is still hope that this is a simple problem.
What color wires did you jumper on purpose and by accident at the fuel pump relay?
Title: 84 fuel pump issue
Post by: softtouch on August 20, 2008, 05:56:21 PM
Quote from: Pigpen52;232814
ok...I am pretty sure I hooked it up exactly like the diagram said...so I assume the eec is bad...on when I jumpered the connection at the fuel pump relay, I just made a jumper and went from the constant hot wire for the pump, to the pump...did not mess with the control side of the relay...  Now since I can jumper the test wire at the front of the car and have the fuel pumps run I assume there is not a bad wire or connection...right?  SO..now to find an ecc...this is starting to get expensive...wish I could just put a carburator on it...will a 4412 bolt on?...lol


It can be changed to carb. It would require a different distributor and ignition system. You would have to bypass the high pressure fuel pump.
Try shopping around here and see what you can find.
http://car-part.com/
Title: 84 fuel pump issue
Post by: Pigpen52 on August 22, 2008, 07:16:25 AM
Sorry it took so long to reply...I belive it was the yellow and pink wires that I jumpered...did not mess with the control wire side of the relay... 

Softtouch...I was more curious if the holley two bbl. would bolt straight up..(cause if nothing else I am going to put a carb. on this thing and put it in a pure stock class at the dirttrack).I doubt the pump in the tank could keep up..so I would guess I would have to use a regulator(or change to a low pressure secondary pump....but why would I have to change ignitions?  It will run if I put gas straight down the throttle body....
Title: 84 fuel pump issue
Post by: softtouch on August 22, 2008, 03:44:46 PM
I have no personal experience converting to a carb, but other people on here have done it.
Your current distributor has no vacuum or centrifugal advance. That is all controlled by the EEC based on sensor inputs.
You would want to change to a Duraspark ignition that does'nt require a computer.

Have tried to find an EEC for it?
Here are some I found:
http://car-part.com/  Select "engine computer" from the select part drop down.
Title: 84 fuel pump issue
Post by: softtouch on August 22, 2008, 04:03:50 PM
From the 84 shop manual: the the 3.8L and 5.0L engine was equipped with a Motorcraft 2150-2v carb for the Canadian market.
Don't know how that compares to the Holley.
Title: 84 fuel pump issue
Post by: Pigpen52 on August 22, 2008, 09:48:30 PM
I have not given up on the eec yet...plan on going to a pick a  part soon....but just thinking out loud...I have a 4412 I just pulled off my daughters mustang 2 (circle track dirt jr mini) have a friend the runs thunderbirds...think an eec of a ford..or a 5.0 would work?


Ok...looked at that link...a little confused...what is the difference between the eec and the ecu....I only saw parts for the ecu......
Title: 84 fuel pump issue
Post by: softtouch on August 22, 2008, 10:07:28 PM
Quote from: Pigpen52;233226
Ok...looked at that link...a little confused...what is the difference between the eec and the ecu....I only saw parts for the ecu......

EEC ECU MCU different names for the same thing. You do want one from a 3.8 though.
Title: 84 fuel pump issue
Post by: Pigpen52 on August 25, 2008, 07:24:37 AM
Thanks for the link..going to try and order today...found a couple for 15 bucks...hope they work...lol