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1990 Mercury Cougar Fuel Pump problems. CO/FFS code

Tiny
TYHACKETT
  • MEMBER
  • 1990 MERCURY COUGAR
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 100,000 MILES
I have 1990 Merc Cougar with fuel pump problems. Pump is not getting constant power to it and I am getting CO And FFS codes on digital display @ fuel gauge.I have checked all wiring and connections from fuel pump in tank to power dist box and all seems fine. When I put alternate 12v power to pump it works fine. Thanks for any help you may be able to lend. UPDATE.I changed the fuel pump relay and the problem persists The car will run for about five minutes or so and then power is lost to pump again.
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Friday, March 27th, 2009 AT 10:54 AM

8 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
FUEL PUMP RELAY Remove relay from vehicle. Connect battery voltage to terminal "C". Ground terminal "D". See Fig. 8 . Measure resistance between terminals "A" and "B". Resistance should be less than one ohm with power applied and greater than 10 k/ohms with power removed.
Page 1 of 1 SYSTEM/COMPONENT TESTS - EEC-IV -1990 Mercury Cougar LS


https://www.2carpros.com/forum/automotive_pictures/62217_FPR_2.jpg


FUEL INJECTORS (PFI) 1. Connect tachometer to engine. Run engine at idle. Disconnect and reconnect injectors individually. If each injector causes a momentary drop in engine speed of at least 100 RPM, injectors are giving proper fuel delivery. RPM drop should only be momentary as ISC will attempt to re-establish correct idle RPM. 2. Replace any injectors that do not cause sufficient drop in engine speed. When test is complete and all injectors cause equal drop in speed, shut off engine. In order to check curb idle, refer to emission control specifications on decal in engine compartment. Page 1 of 1 SYSTEM/COMPONENT TESTS - EEC-IV -1990 Mercury Cougar LS 3/27/2009
INJECTOR CIRCUIT 1. Disconnect all injector harness connectors. Using digital ohmmeter, check resistance across terminals of each injector. See appropriate injector resistance table. 2. On PFI models, disconnect injector bank harness connector, check resistance of injector bank. See PFI INJECTOR BANK RESISTANCE table. Repair wiring or replace any injector circuit not within specification.
Resistance is,3.0= 15.-18.0
3.8= 13.5-16.0 OHMS
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Friday, March 27th, 2009 AT 11:21 AM
Tiny
TYHACKETT
  • MEMBER
  • 8 POSTS
Thanks for the reply merlin2021.I changed the relay and the problem is still there. Thanks again for trying to help.
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Sunday, March 29th, 2009 AT 9:48 AM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
You may need a new ignition switch, test continuity as shown here:


https://www.2carpros.com/forum/automotive_pictures/62217_Cougb_1.jpg



https://www.2carpros.com/forum/automotive_pictures/62217_cougc_1.jpg



https://www.2carpros.com/forum/automotive_pictures/62217_coud_1.jpg


And this is your pump wiring and self test connector, you might want to read the codes...


https://www.2carpros.com/forum/automotive_pictures/62217_Couga_2.jpg

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Sunday, March 29th, 2009 AT 12:57 PM
Tiny
TYHACKETT
  • MEMBER
  • 8 POSTS
Thanks Merlin, I have noticed that sometimes when I turn the ignition switch back and forth it seems to make a difference with the amount of voltage going to pump. It is like it goes from weak voltage to normal voltage. You can hear the difference in the speed of the pump. There are times when no current reaches the pump. Could it be that the switch overheats and stops the voltage?When the car does start and run with pump working it only runs for about five minutes or so.I dont know what you mean about self test connector for pump.I dont know what the CO and FFS codes mean. Thank you for your continued help.
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Sunday, March 29th, 2009 AT 6:28 PM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
If you located the test connector, just gound it with a piece of wire, the fuel pump should run, this tells you the pump circuit is OK, It will not tell you if your ignition switch is bad, these are pretty cheap and may be worth replacing if you dont know how to test it. This is NOT the key part, but the white plasic connector.
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Monday, March 30th, 2009 AT 2:40 PM
Tiny
TYHACKETT
  • MEMBER
  • 8 POSTS
Thanks Merlin, I unplugged and replugged the ignition swith today and the car ran for longer than it has been, It ran for almost half hour before stalling and there was no voltage to the pump after that.I have not located the self test connector to test pump circuit unless it used to be at the pump connection. When I exposed the wiring at the pump on the tank there was only one wire still in the plug part of the wire side. Looks like it used to plug and click onto pump connection studs. The other wires were still there and hooked up but the rest of the plug that those wires used to be encased in was gone. Was that the self test connector too?
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Monday, March 30th, 2009 AT 4:38 PM
Tiny
TYHACKETT
  • MEMBER
  • 8 POSTS
Ok I found the test connector under the hood but I am not sure What I am supposed to ground out to see if pump runs. Please advise if I should ground the fuel pump test lead or self test output. Thanks again for all your help.I think I am at least getting closer to the problem with all your help.
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Tuesday, March 31st, 2009 AT 1:15 PM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Gound the pump test wire to test fuel pump, to read codes jump the sto to the self test output, and then turn the key on, read the MIL, by counting the flashes.
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Wednesday, April 1st, 2009 AT 2:00 AM

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