QuestionQUESTION: Hi Roland,
I have tested the ASD relay, and indeed there is 12v present on terminal 87, (the front pin), when the engine is cranked. I then tested what you said was the fuel pump relay, and there is something screwy here. Assuming that I am testing the correct relay, (3rd back from the front on the inboard side, and using terminal 87, (the front pin)), what I get is a constant 1.2 volts present, even if the key is not in the ignition. When I turn the key to the start position, I see the voltage go up for the second that the fuel pump run. I cannot say for sure if it is a full 12v because it stops before my digital multimeter can get a clear reading, but I have seen it go up to at least 7 volts, so I am pretty sure that it is probably going to 12 volts. When I crank the starter, the voltage drops out to zero??? I do hear the fuel pump "run on" after the starter stops running, but at this point the car is not starting anymore, as it once did. I tried swapping the fuel pump relay with the low fan relay, but I get exactly the same results, so I assume that the problem is not the relay. What now?
ANSWER: Hi Steve,
Let's check the function of the relay socket pins, with the relay removed. The inboard pin should show 12V when you start cranking and stay that way as long as you crank it. The outboard pin should show 0V when you are cranking it and for 1 second when you first turn the ignition switch to 'on'; also you use the ohmmeter, it should show 0 ohms resistance to ground during those same times. The rear pin should show 12V as it sits with the ignition off, and stay that way while you crank. The front pin is the output and it probably shows 0 ohms resistance to ground because of the fuel pump, but certainly because of the oxygen sensor heater which is also on the pin, and it would not change while you are cranking. So verify all that. After that, try unplugging the oxygen sensor, put in the fuel pump relay, and try to start it. It may be that the oxygen sensor is shorting the output to the fuel pump, but that is just a possibility, but we should test it.
Roland
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QUESTION: Hi Roland,
We may be getting a bit off track here, as the problem is not fuel related, (fuel pressure at the rail is good), but there remains no voltage into the coil pack. Given that the ASD relay looks OK, (I measured the 12v output at terminal 87 on the ASD relay when the engine is cranked), what we are left with is that the voltage is getting lost somewhere between the ASD and the coil pack. The question is, where would that be.
Steve
AnswerThe wire from the front pin of the ASD is dark green/orange and it goes to a 12 pin disconnect (black, rear of battery) and from there to a the "cross-piece" of the T-plug of the coil, passing through a splice along the way. I would check the continuity from the output pin of the relay socket to the plug at the coil.
Roland
