QuestionHi Roland,
The site told me to ask a new question, too many follow ups.
I tried to get the codes, but the check engine light never blinked. After the last "on", the light stayed on a few seconds and then went out and didn't come back on. Usually when I try to start a car and it fails, the dummy lights all stay on. On this, the only one that stays on is the oil pressure light, which is obvious since there wouldn't be any pressure. It's almost as if the car "thinks" its running.
I also re-tested for spark, and I am getting it. Just no funcion to the fuel pump, and the ASD relay also isn't clicking, don't know if it should or not.
Oh, and PS, my father gave me some misinformation yesterday, it is a 93, not a 96. So far everything you said matched up with my 93 though. I think they are mostly parts compatable anyway. Sorry.
AnswerQUESTION: I've been trying to get this concorde started all day. All relays and fuses are good. New fuel pump installed. Still, the fuel pump does not engage, or turn on, when the key is turned. Been checking the wiring. The blue wire connecting to the pump is hot, the dark green/black stripe wire is not. The 2 black wires appear to be grounded fine. On the back of the relay box, the red and 2 blue wires have power, none on the green. Is the green supposed to be ground or power? On the fuse panel box inide the car I have power running thru the fuel pump fuse. Anyway, don't know what else to do to get this fuel pump to turn on. I don't think this car has an inertia fuel cut off, then again if it did the pump should go on for 1 second and it doesn't. Completely stuck here.. Thanks in advance.
ANSWER: Hi Steve,
The problem is that you need to get 12V on the dark green/black wire at the fuel pump. That power comes from the fuel pump relay's points when it closes which is sourced from the red wire at the relay which you say has power. The relay points will close when there is 12v on the dark blue/white wire(which in turn comes through fuse 18 behind the dash which in turn gets its power from the ignition switch) AND the dark blue/yellow wire has to be grounded by the pcm. Now the trick is when you measure for voltage at those dark blue wires at the relay with the relay plugged in you are looking essentially at both wires at the same time because the acturation coil is what separates the two wires, so if you have 12 on one you will have 12 on the other if the relay is in the socket because the resistance of the coil is near 0 ohms. What should be the case, with the relay removed, is that when the ignition is "on" there should always be 12 on the dark blue/white. The dark blue/yellow will read 12 and then 0 for about 1 second because the pcm grounds the wire momentarily when you first turn the key to run. It then returns to 12 until you start cranking the engine at which point it is grounded again (if the pcm sees that the engine is indeed turning over via the pulses from the cam and crank sensors). It continues that way until the engine dies and then the pulses stop and the ground is lifted from the dark blue/yellow wire so the relay opens and pump stops. This is all for fire safety in the event of an accident. The exact same set up is present on the ASD relay so the spark coil will be shut down. So try checking out the dark blue wires with the relay removed.
You can try jumping from the red to the dark green/black at the fuel pump relay just as a test that the pump and its power source is ok. That should make the pump run, but it isn't a safe way to go except as a test. Then the issue is if you have 12 on the dark blue/white why isn't the pcm even grounding the dark blue/yellow for 1 second when you first turn to run (if that is the case, verify that). It could be that the dark blue/yellow wire is disconnected from pin 51 of the pcm, or that the pcm is not working right, or it isn't getting power for itself to operate. The pcm should have battery all the time on pin 4, and the same 12v on pin 9 which is supplied to the dark blue/white wires of the ASD and fuel pump relays. So check continuity to pin 51 and the voltages to the pcm.
You can get back to me via the "thank and rate" tab where there is a 'comments' section.
Roland
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QUESTION: Thanks, that was fast.
I checked all the wires in the relay box, but I realized that I have drained the battery by leaving the key on so long when I was tracing the wires. It was at about 9V. I just put it on the charger. I figured I could jump the red and green, and when I did the green tested at 9V where it connects to the pump, and I could feel the pump running.
Now, is 9v too low to engage the relay? I'm thinking that I'll need a full battery to see if that is working.
If it doesn't I'll go ahead and check the pins on the PCM. How do I know which pin is which though? I don't see any numbers on there, so from which point do I start counting?
Thanks
Steve
ANSWER: Hi Steve,
The 9v might be too weak to close the relay points, so wait for the battery to recharge it and if necessary to then do the other tests.
On the plug, holding it with the terminals facing you, the short side tab up/long tab down, start at 1 at the upper row far left and go across to 20, then cycle back to the middle row far left at 21, etc. I am assuming that 51 has 12v on it when it isn't grounded, but I guess it could also be just "floating" with neither voltage or a connection to ground. So you may have to check resistance to ground rather than for voltage to change when you test it with the relay removed. Please let me know what you find if you do test it.
Roland
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QUESTION: I have checked pins 4,9 and 51 on the pcm harness. 9 and 51 have 12V, 4 has only about 4-5V. This is with the harness unplugged from the PCM. Perhaps the PCM isn't getting enough power? I also grounded a spark plug and plugged it in to a wire, and when starting the car no spark was emitted. But I'm not 100% sure the plug was grounded correctly. So there is the chance that there is no power to the fuel pump or the coil pack.
So this is making me wonder if it is a bad PCM, but then again that plug #4 having only 4-5V worries me too.
51 had 12v on it whenever the ignition key was on "on". It never did go back to 0 for me. I don't have an ohm meter so I can't check resistance when there is no power.
Answer: Hi Steve,
Sorry, my mistake, my eye slipped down one line: it is pin 3 that has the red/white 12v power all the time. So that looks OK except for the way pin 51 is behaving.
So the problem is that you never see the pin 51 drop to 0V? Not even during that 1 second of time just after you turn the ignition to run?
Were that the case, then I would say the pcm is bad. BUT if it will drop to 0 on the black/yellow and cause the run of the fuel pump for 1 second, but then won't do it when you are cranking (also check for 12V on the dark green/black at the fuel pump relay at time when the ignition key has just turned to run) then your problem is that either the cam or the crank sensor signals aren't coming to the pcm which would if otherwise cause the pcm to ground the dark blue/yellow on 51.
By the way, we never spoke of fault codes as you just came initially with a situation where you told me you had replaced the fuel pump as if that was the only problem you had, no other history.
It may be that you really have a cam or crank sensor problem. Turn the ignition key 'on-off-on-off-on and leave on', doing that in 5 seconds or less elapsed time. Then watch the check engine light to begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat the key routine and do a recount just to be sure. Then group the numbers in pairs in the order of appearance to form the two-digit fault codes. The last pair is 55, which means 'end of readout'. If you get an 11 (crank sensor) or a 54 (cam sensor) then that is the answer as to why you aren't getting spark and fuel pump action.
Let me know if this is the real answer.
Roland
Hi Steve,
The '93 and '96 should be identical. I'm working with a '94 manual.
The ASD relay is working (even if you can't hear it) if you are getting spark because that relay is what provides power to the spark coils. The fuel pump relay should work as well in tandem with the ASD relay as both are powered at their actuation coils by the same pair: dark blue/white and dark blue/yellow wires. So you could try switching relays and see if you lose spark but gain fuel pump action. Otherwise it has to be something wrong with the wires themselves/the fuel pump. That of course assumes that you have 12V on the red/wgute wire at the ASD and at the red at the pump relay. I wouldn't worry about 'no codes' if you are getting spark, but just in case make sure that you accomplish the on-off, etc in 5 seconds or less. That should work too.
