QuestionQUESTION: Hi Roland,
I'm at work right now, but I believe the oil light does stay on while the key is in "on"position but engine not running. The check engine and cruise lights turn off as they normally did. Would a glitchy ignition switch make the car die while driving? Would it prevent spark at the plug?
Thanks again for all your time!
ANSWER: Yes it could but that is not the only reason, of course. It could prevent spark. But you could check the output of the crank sensor and the cam sensor (though the distributor was just replaced, to be sure of it) because you need signals from those to get spark and injector output synchronization. Check whether you get any pulsing out of those sensors by measuring between pins 43 and 33 (cam), and 43 and 32(crank) at the pcm while you turn the engine by hand via the bolt on the crank pulley, with the ignition 'on'. It should show pulsing between 5v and 0.5v several times per revolution. If not, then that sensor is bad. The wire colors at the sensors are: black/light blue (43), tan/yellow (33) and gray/black (32).
Roland
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QUESTION: Thanks Roland,
Is the cam sensor part of the distributor on the 2.5L? Can you explain exactly how to test these? Do I need an oscilloscope? I have a multi meter. I can't seem to find any specifics on where to test.
Thanks!
ANSWER: Yes, the cam sensor is in the distributor and is probably alright since you just bought a replacement. So you would want to test the crank sensor which is located on the side of the engine next to the firewall, just at the seam between the engine and the transmission, just about the the trans housing. You can either get your test leads there at the harness for the sensor but that may be tricky to reach, or you can probe its sensor signal and ground wires at the pcm plug using straight pins to pierce the insulation. I described the wire colors or the pins to seek out in my last response. You turn on the key, you put a socket and wrench on the crankshaft pulley bolt, and you turn the engine by hand. The voltage should oscillate between 5 and 0.3V if the sensor is good. If not, then replace the sensor.
Roland
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QUESTION: Thanks to your instruction, I was able to check both sensors and the ignition switch fuse. All checked out as you described. I noticed though that the fuse for the distributor had no voltage. Is that normal when the engine is not running? Is it possible that something is wrong w/ the distributor/rotor since it was so incredibly difficult to put the rotor on? Otherwise I have no idea what else to check. Thanks again for all your help.
AnswerHi Gabriel,
I assume you mean the 12V supply to the spark coil is not present when you mention the 'fuse for the distributor', correct? Otherwise tell me which fuse. It is correct that the automatic shutdown relay, which provide the 12V for the distributor, does not do so unless the engine is running or at least being turned over by the starter motor. That relay won't close unless the sensors tell the pcm that they 'see' the engine turning. It is a safety feature in the event of an accident so that spark and fuel pump are both shut down should there be an accident that stalls the engine.
Check the rotor to see if it is conducting between the rotor center spring clip and the tip. About the only other reason for no spark would be a problem with the coil 'driver' wire: black/gray wire on pin 6 of the 6-way plug at the distributor to pin 4 at the pcm.
So check that also.
Roland
PS If you didn't replace the distributor cap then check that the resistance between the rotor button and the coil tower contact is 5,000 ohms or so.
PPS: By 'check' I mean to test for continuity between the pin6 of the 6-way at the distributor and pin 4 at the pcm plug. Dynamically, if you tapped that wire with a pin, and you turned the key to run, it would show 12V momentarily and then cut off when the asd relay opened. But then when you start cranking it the asd relay would close but then the pcm would by pulsing the wire to 0V 3 time per engine rpm which might be 'seen' by you voltmeter as a slightly lower rms voltage than the voltage that your saw for the second or so when you just turned the key to run. Otherwise you would need a scope to see the rapid pulsing on the wire. With each pulse a spark pulse is generated by the igntion coil. You have said that you are getting pulses on the cam and crank sensor wires, so in theory the pcm should then pulse this 'driver' wire to cause the requires spark pulses.
Thanks for the rating/nomination
