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Topic: Maybe electrical, but fuel pump doesn't run (Read 1853 times) previous topic - next topic

Maybe electrical, but fuel pump doesn't run

Hello... I have a 88 Cougar LS V6 that is driving me crazy. Drove fine until a week ago, then refused to start. When I turned the key on I didn't hear the fuel pump turn on and pressurize. So, I thought new pump. Replaced the pump, still did not turn the pump on when key was turned. Already checked and verified the interia switch. After tearing my trunk apart tracing the wires from the pump, ran across the relay, replaced. Still does not work. I shorted across the relay and the pump runs fine, 40 PSI on the fuel rail, but now the engine will turn over but not start. Verified fire at distributor, plugs, but will still not activate the pump when the key is turned, so I am wondering if the problem that is keeping the pump from running is also stopping the injectors from working.
any ideas as to what to check next would be appreciated.

Re: Maybe electrical, but fuel pump doesn't run

Reply #1 –
im not sure what you mean by "jumper the pump" but i assume you mean you grounded out the tan wire. 

did you jump the yellow to pink / black?

this sounds like another one with an eec acting up.
pin 22 on the eec give your ground to the relay and this wire(tan/light green) is located at pin 22 and up at the self test connector.

Re: Maybe electrical, but fuel pump doesn't run

Reply #2 –
ignition switch could be actin up
It's Gumby's fault.

Re: Maybe electrical, but fuel pump doesn't run

Reply #3 –
The fuel pump relay that you jumpered to make the pump run has two voltage sources to it. As jcassity says it is not clear which one you used when you jumpered it.

The yellow wire (color codes may not match your car) is hot all the time and goes to a contactor point that will power the pump when the relay picks.

The red wire is hot through the inertia switch when the EEC power relay is picked by the ignition switch and goes to the relay coil.
The relay will pick when the EEC grounds the other side of the coil.

Jcassity pointed out that the grounding wire from EEC pin 22 also goes to the self test connector. Turn the key on and ground the tan with green dots wire at the test connector. If the pump runs you know the problem is the EEC pin 22 not providing ground.

Looking at the self test connector with the two plug holes at the top and the row of four on the bottom it should be the right end one of the row of four.

If it does not run, the relay is not picking or the yellow wire is not hot. I hope you have a volt meter at this point.

Let us know what you find.

Re: Maybe electrical, but fuel pump doesn't run

Reply #4 –
Thanks for the info.  I am now down to two possible points of failure, ignition switch or the EEC.  I was jumpering across the yellow to pink wire, not grounding out the wire from the EEC.  Providing I can find the EEC, is there any way to help determine where the problem lies, ignition switch or EEC?
 

Re: Maybe electrical, but fuel pump doesn't run

Reply #5 –
the EEC self test connector should be in the area of the drivers side strut tower
It's Gumby's fault.

Re: Maybe electrical, but fuel pump doesn't run

Reply #6 –
Does the pump run when you ground the wire at the self test connector with the key on?

Re: Maybe electrical, but fuel pump doesn't run

Reply #7 –
I grounded the tan wire at the relay and the pump functions.  I have gotten under the dash and have found what I think would be called the EEC (auto parts houses classify it as an ECM), a beige box with 1 board in it, two wiring harnesses.  Not much to it, if this is the right item.  Just to the left of the steering column on the inside of the firewall. 
I also removed the bottom cover from the steering column and found the ignition switch.  It appears to be separating slightly, with about 1/16 of an inch play at one end, so it wiggles/opens-closes when you grasp the wires and work back and forth.

Re: Maybe electrical, but fuel pump doesn't run

Reply #8 –
The beige box you found is the cruise control computer, separate from the main computer. The EEC-IV module is behind the passenger side kick panel.

It sure sounds as if the ignition switch is the problem. Changing that should solve your starting issues and allow you to operate the car as normal, without grounding the tan wire.

Re: Maybe electrical, but fuel pump doesn't run

Reply #9 –
after reading your initial post, im a little confussed as to what the actual problem is. 
Is it the fact that before your engine would not turn over but now it does?

confussed,, sorry.



Quote from: kstroud_ok
  I was jumpering across the yellow to pink wire, not grounding out the wire from the EEC.



bad move ,, not good.

Quote from: kstroud_ok
Providing I can find the EEC, is there any way to help determine where the problem lies, ignition switch or EEC?


remove the cover off the pass side kick panel below to the right of the glove box.

im pretty sure if you throw in another eec, it will correct the problem.  Running you car like it is now wont hurt anything other than the pump running all the time with the key on.  I would test this theory out by making the inertia switch disengage.



to anyone else reading this,, stay away from this relay if your not confident in how circuits work. You can fry your eec quickly with a direct voltage spike by guessing which wires are doing what. 
If you feel you need to verify the pump runs,, only ground the tan wire.

If the pump does not run by grounding it at the trunk relay or up at the self test conn, then its a broken wire,, if it runs,, you probably looking at getting a new eec.

Im sure the part on the circuit board that fries is nothing more than a diode burnt open and whatnot but i dont have the schematic for the eec so i just stay out of it.  I took mine apart to check various diodes and such but found nothing unusual.

Re: Maybe electrical, but fuel pump doesn't run

Reply #10 –
I know this is getting to be a long post on something that seems simple, but I hope I am almost there. 
I found the EEC in the kick panel on the passenger side.  Are there any posts that can guide me through getting this thing out?  There isn't much room to manuver. 
I appreciate all the help and extreme patience of everyone who have left me posts on this thread.

Re: Maybe electrical, but fuel pump doesn't run

Reply #11 –
your on your own there bro,, its tucked deep into a bracket.  all i can suggest first off is to disconnec the GREEN lug which is a ground wire. the head of the bolt gets in the way when you try to pull it out.  just finagle with it and it will come out.  cut some factory zip ties and undo or cut plastic clips and loosen up the harness.

the eec connector is held on with a 10mm bolt,, no this bolt does not come out so dont make it do so.  just loosen it up and then pull up on the main chassis  harness.  there are a couple loose ends in there not connected to anything so keep track of that part as well.

Maybe electrical, but fuel pump doesn't run

Reply #12 –
I had the same problem with my T-Bird two weeks agao. It turned out to be the ECC relay. My dad whose a mechanic and I did every single test possible and then we saw this relay by the passenger kick panel where the computer is. We crossed the wires with the ignition switch on and the fuel pump activated and the distributor had a spark. So I bought a new relay replaced the old one and the problem was solved. The relay is the same as the fuel pump relay.