Sharon, I dont trust what your reading. It is the wrong meter for this. All this shows is that the transister is changeing states, nothing more. It does not show if it is makeing ground, which I suspect it really is.
Do this for me. Put the red wire on the relay where it is supposed to go to. The terminal that you would attach the tan wire? Do not put on the tan wire, but put the red test lead to the relay terminal instead. Put the other test lead to ground. Turn the key run. Do you show 12 volts? ( first verify that you have 12 volts at the red wire. ) You should have 12 volts at both.
Yes, the pump does not run. But, keep in mind that I got that reading WITHOUT the tan wire hooked up. And without the yellow and orange wires hooked up. I have wondered all along if there is something that is causing that tan wire not to ground properly. It travels from that relay to the self tester through the firewall near the steering column, as far as I can tell. It does not get grounded anywhere in between onto the body of the car.
That tan lt/grn wire goes to the engine control module, according to the wiring diagram I have. And that is in the dash, behind that firewall, near the steering column. Right where the engine control module is mounted. I am not sure if it does anything there other than ground. Can you tell me?
I ask this question because I was wondering if I can possibly test this out by NOT connecting the tan wire to that relay and just connecting the other three wires. Then check the volts on the nipple for the tan wire. Is that a possibility? Or will not having that ground, with the other wires hooked onto the relay, cause damage?
Sorry, I didn't see this post until after I responded to your other post. Okay, let me just clarify this. Hook all three wires to the relay (orange, yellow, red). Then hook a wire up to the last nipple of the relay and attach it to a good grounding spot, instead of installing the tan wire? Do you want me to put the tester to any of these wires? Or just try it with the grounding?
I forgot to answer this question earlier. No, the car does not run if I jumper the yellow and orange wires. The fuel pump runs, but the car does not start. I am sorry for not answering it earlier, Thomas. Take Care, Sharon
Practice time : If I'm reading Thomas' instructions correctly, you are to put the meter from that grounding wire to a ground. In other words, you are repeating the same test as before (with the tan wire disconnected) but the only difference is you have grounded that terminal on the relay. I believe you should read no voltage this time, and the fuel pump should be running.
Theory time : Voltage is technically termed "potential difference". It is the difference in potential between two points. If the difference is greater than zero, then you have power, potential energy, that is capable of doing "work". If your potential difference, or voltage, is zero then you have no power, no potential energy.
Applying the theory : With the relay's primary circuit disconnected (tan wire disconnected) you have 12 volts of potential difference between that and "ground". Ground is, by definition, zero potential. It is your reference point. Having 12 volts there means that if you connect that circuit to ground (thereby completing the circuit) you can achieve some work being done by the electricity. In this case the work is closing the relay's contacts to that the secondary circuit is completed (closed). When you connect that terminal to ground, it then has the same potential as ground (naturally, it's connected). That is why I expect you to read zero volts while doing this test, and why I expect the fuel pump to be running.
Combining these two tests allows you to determine whether or not the relay is functioning as it ought to be. In any set of tests, you must have isolated precisely one variable in order to draw any conclusions from them. The isolated variable here is whether or not the primary circuit on the relay is closed.
You are not looking for anything but continuity. It does not need to be hooked to anything but the tester.
Being that is not part of the circuit, it does not matter.
That is correct.
I've already told you , it only goes to the ECM and EEC self test connector. Look at the schamatic, it is correct.
I have already lead you through that test. You claimed there is 12 volts there.
"Sorry Thomas, I had another situation to attend to. I checked the volts on the red wire in the start position. On my scale, it reads a little over 12+ volts coming through when I put it on the 10 setting. That would be reasonable. Then I connect the red wire to the relay, put the positive lead on the tan wire and put ignition on start. I show a little over 12+ volts all the time I am cranking. I hope that helps you to see what it is doing.
Thanks sooooooo much for trying. Take Care, Sharon"
Now here is what we have.
12 volts to the relay on the red wire. good condition
12 volts through the relay coil with no ground attached. good condition You claim that you can jump the yellow and orange wire the pump runs, and you are even able to smell fuel, proving the pump circuit is good. With all wires installed to the relay, and when the original relay socket was in place you have 0 volts on the tan wire indicating a complete circuit, meaning pump should run. Even though you are not using the correct meter, you have what appears to be a good ground, although it appears to be making ground all the time. So If all is "hooked up" correctly, that relay should turn on the pump as soon as you turn the key to run. Yet you say that the pump does not run.
So what does that mean? If the relay is installed correctly, every time your turn the key to run, the pump should come on. What can be wrong? Relay not installed correctly. Wire gong to wrong terminals. Bad relay. Misunderstanding of what you are seeing and doing resulting, because of that giving incorrect information back to us.
In simple terms, you are describing "voltage drop". A voltage drop is the amount the voltage lowers when crossing a component from the negative side to the positive side in a series circuit. Voltage applied to a series circuit is equal to the sum of the individual voltage drops. In this case the resistance of the fuel pump relay coil ( industry average ) is
80 ohms. 12 is the working volts. So the current will be .15. 12/80=.15 amps ( current ).
The voltage drop is calculated as current x resistance = voltage drop. .15x80=12. So if the voltage is dropping 12 volts and you start with 12 volts, you see 0 on the ground of a completed circuit. Current will be .15 on the whole circuit. It does not change.
Unfortuneately, you appear to have a second problem, this is assuming that after jumpering the yellow to orange, you are physically operating the ignition switch/key, attempting to start the engine as would normally be done.
Here is the odd thing I have been trying to figure out since trying this. I put the wires on all the connectors, except the tan one. I put an alligator clip to that connector of the relay and the other end was clipped to the alternator housing to insure a good ground. When I turn the key to 'on' only, I do not hear the relay click, but I do get a clicking noise in another area of the car. I also do not hear the pump run. When I put the key to 'start' and try to crank the engine, I get nothing.
About the clicking noise I am getting while in the 'on' position when doing this test. It is located on the passenger side. I can hear it with the passenger door open very well, but when I go to the engine, either above or under the car, I can't hear it as well. And I can hear it through the glove box okay, but again not as well as through the door crack. I have taken a digital pic and put a section of garden hose in where I heard the sound best:
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That is the passenger side door and that hose is inserted just about 4 inches into the fender area. That seems to be where it is the loudest. I hope that helps. Thanks Thomas. I am pretty much staying focused on what you are telling me and trying to follow this through with you. Thank you for hanging in there with me, regardless of all the hurdles.
Here is the odd thing I have been trying to figure out since trying this. I put the wires on all the connectors, except the tan one. I put an alligator clip to that connector of the relay and the other end was clipped to the alternator housing to insure a good ground. When I turn the key to 'on' only, I do not hear the relay click, but I do get a clicking noise in another area of the car. I also do not hear the pump run. When I put the key to 'start' and try to crank the engine, I get nothing.
About the clicking noise I am getting while in the 'on' position when doing this test. It is located on the passenger side. I can hear it with the passenger door open very well, but when I go to the engine, either above or under the car, I can't hear it as well. And I can hear it through the glove box okay, but again not as well as through the door crack. I have taken a digital pic and put a section of garden hose in where I heard the sound best:
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That is the passenger side door and that hose is inserted just about 4 inches into the fender area. That seems to be where it is the loudest. Okay, an addendum. I tore the passenger side coverings off of that area and kept narrowing in until I found it. It is in the driver side kick panel. There is another relay in there. If I have all wires hooked up on the fuel pump relay EXCEPT the tan wire. I ground the connector for the tan wire to the alternator housing, I get the clicking in this relay under the kick panel in the passenger side; when I turn the key to 'on'. I can feel the click also. Is this an expected situation Thomas? That the fuel pump relay would not click, but this relay would? Do you have any idea what this relay is? I tried to find it on the parts locater at AutoZone. No dice.
This was my concern from the 'get-go' because there was such a conflict on the wiring diagrams. If you recall, I kept asking if someone could send me a wiring diagram specific to my 1988, because the ones that I had (86 and
92) did not match 100%. They were very close, but not perfect. The ones that I have posted to the group were the closest:
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According to the old part number stamped on that relay, it crossmatched on AutoZone's website as the fuel pump relay.
The other relays, however, do not match that wiring diagram. I am going to send give you a pic of the relay housing and explain to you what is inside there. Then I will do a pic of the passenger side, kick panel and it's wires. Give me a few minutes. I still have to ask myself why grounding the wire to one relay would cause another relay to click.
Okay, here is the complete story on the relays. The original relays that I started working with are here (driver side, front of engine, near windshield washer/overflow tank), under the two rectangular black housing units:
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As you can see, I still have the fuel pump relay out and working on it. Within the right side housing are two relays. One had a part number that crossmatched on the AutoZone site as the EEC relay. It was originally brown. The wire config for that one is black, red/lt green, large orange/black, large black/orange. The other relay in that housing is I believe the WOT relay. The wire configuration is black/yellow, large tan/lt grn, red, orange/blue. In the left housing was the fuel pump relay. I crossmatched that on the autozone website by part number also. It was originally green in a green socket. It is the one with the large orange, large yellow, red, tan/lt grn wires. On the front side of that whole housing unit is mounted another ?relay. Not sure about this one at all. The wiring configuration is yellow, yellow, black, and a yellow wire jumped across two connectors.
Lastly, here is a pic of the relay inside the passenger side kick panel:
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Sorry the pic is a little blurry. It is green and black in color. And the wire configuration is white/purple, blue/black, large yellow/green, black. Notice the yellow wires also coming into that area. They are all in the same wire housing. Makes me think there may be some connection eventually to the fuel pump relay above. Obviously there is, since grounding that relay is causing this relay to click when I turn the key to 'on'!
As you can see Thomas, the only wiring diagrams that I had that even came close to matching my car's configuration are the ones that I already posted:
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And it did not match the EEC relay wires 100% (note solid black wire is shown as black/lt green on diagram) and none of the other relays were on these diagrams. I can tell you that the diagrams that I have for 1992 match some, but not all wires, and does not show all the relays. And the ones I have for 1986 are the same. And the ones that AutoZone has are nothing like it and the ones that Anthony sent aren't either. I kept saying that I couldn't follow the diagrams totally because they did not match. Maybe now you will see what I have been up against.
If anyone can find me a wiring diagram for my 1988 Mercury Grand Marquis,
302, fuel injected that match the wire configuration that I show up above, I sure would be excited to get them.
I still wonder why grounding one relay would cause another relay on the opposite side of the car to click. There is some connection here, obviously.
One last thing. I can not find a cross matched number for the relay in the passenger side kick panel. The second number is rubbed off a little, but I tried different variations of it. Still couldn't find it. It looks like E3AB-14512 or E7AB-14512.
Let me backup a minute and restate everything again. You told me to test the fuel pump relay (that is in the engine compartment, near that washer tank) by connecting all wires except the tan/lt grn wire. You told me to take the connector for that wire and ground it to a good solid ground and see if that relay clicks. You expected it to click if it was functioning correctly.
I did this and that particular relay DID NOT click. But the relay in the kick panel of the passenger side, did. Is that normal?
Well, the wiring diagram that I have displayed on that web pages does not even show this relay in the passenger side kick panel. And it obviously is a part of the circuit that goes from/to the fuel pump relay or it would not click when I ground the wire on the fuel pump relay. I would think that would be of some import.
Why not, why would something that does not show on the wiring diagram but is affected by the grounding of the first relay not be of concern to me? I would think that in order to troubleshoot a circuit, I need to know all the items on the circuit and what they do and what triggers them.
NO, I did not say that. I did not hear an audible click on the fuel pump relay, I heard it on the relay in the passenger side kick panel. I connected a ground to the fuel pump relay and heard absolutely no click on that relay. The click was heard on the kick panel relay.
No, I didn't say that the relay worked when I made a jumper for it. I jumped the yellow and orange wires and got the pump to turn on only. I did not get the engine to turn over. I did not get the magnet to activate properly. I just forced the fuel pump to turn on. That does not mean that all circuits involved were completed. It just means that the circuit that goes from the hot wire on the fuel pump relay to the fuel pump was completed. It doesn't prove that the ground side of that relay is being completed properly. Just because the voltage is coming out of the ground connector, it does not mean that when I attach the wire it is actually being properly grounded. The current is not grounding on a wire alone, obviously. It needs to find a solid ground. What if the ground connection is bad? What would happen then?
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