I fail to see how a distributor can ever cause a cylinder specific misfire unless there’s an issue with the cap.
The complaint has gotten a bit convoluted. Again, at almost 300k miles a compression test needs to be (and should have been) done to verify whether or not the vehicle is even worth the trouble.
Absolutely no disrespect to the OP, but it appears that he is not a native English speaker. Perhaps it would help, familyguy, if you were to have a friend for whom English is a first language help you clarify your descriptions.
Please do not take this suggestion in any negative way. I know I’d definitely need someone to help me if I were trying to clarify an automotive problem in any language other than English. I respect your ability to speak more than one language… I myself cannot. But car problems can be complicated to describe, and English definitely isn’t the most clear of languages even to those of us who speak it well.
There were basically two areas that left me confused.
(1) is that your description of an inability to start is in conflict with your description of the way it operates, especially around town and on the highway. If it can’t start, how can you describe how it operates?
(2) is your description of the way it starts… or doesn’t. It sounds to have conflicting statements about what it does and doesn’t do.
Again, my suggestion is only to surmount the language barrier, and for no other reason. I respect your ability to speak two languages and mean no disrespect.
@familyguy, we are try to help you here but have confused us. Maybe the language issue is that you just don’t speak carspeak. Thats OK, not many do. Let me know if I have this right.
On occasion, the truck fails to start and run. When that happens, the mechanic replaces the distributor and it runs again.
When it is running, you get a check engine light and there is a code P0302. After a few months of this, it stops running again and the cycle repeats. There are no odd noises, the engine seems to idle smoothly and you adequate power and fuel mileage.
Contrary to a post above, the computer does NOT detect the acceleration of the motor after each plugs fires. What it is measuring is the amplitude of the voltage on the primary coil when the the signal to spark is sent. If the voltage is either significantly higher or lower that the voltage from the other plugs, it sets a code. The plug might actually be firing, but just not under the same conditions as the others.
If the voltage is too high, it can stress the insulation of the windings of the coil and eventually cause them to short out. If it is too low, it can cause more current to flow which heats up the coil and can damage the windings and insulation. Either way, the cause of the P0302 code must be addressed or you are destined to repeat the cycle.
Previous posts have given you information on how to address the code so I wont repeat them. I would just advise you to reread them and take them to heart. The key to this is the code.
thank keith your post is right on. my mechanic keep saying the distributor bad but he don’t know why. these are after market distributor was wondering if a Nissan dirtributor would make a different.
The why is the P0302. Try just replacing the coil instead of the whole distributor.
Edit: my bad, I just checked the factory service manual and the coil is not replaceable, the whole distributor has to be replaced.
Possibly. Only way to know absent further testing is to give the OEM version a try. Could do the trick.
Huh? So the misfire detection capability being taught for the last 20+ years is wrong and the carmakers have had some secret system in place that they’re hiding from us? Variation in crankshaft speed is the basis for all misfire detection. Ionization monitoring is in fact used by some cars but only those with a COP ignition as the electrical path through the cap, rotor, and wires contains too many variables for such monitoring.
Guess so. plus 10 letters
Ionization monitoring began 15 years ago, an ignition system monitor. The misfire monitor is completely different.
You’d think I like the taste of humble pie by now. Yes the 97 Nissan does use the crankshaft position sensor for misfire detection. My bad.
I still think that fixing the P0302 code should be a priority, but looking at the schematics of the ignition system, I did see one more possibility. In the wiring harness that runs along passenger side of the valve cover, near the top, there is a rectangular shaped bulge near the front covered by masking tape. It is the resistor for the coil and the power transistor.
The only way for this to cause the distributors to go bad is if it is shorted internally, which is not a normal failure mode for resistors. However, if this resistor ever failed in the normal mode which is to open, someone might have jumped it with a piece of wire, or just connected the leads together. This would damage either the coil or the transistor or both over a short time.
There is a connector for this resistor but I can’t find it. If you can find it, you could measure the resistance, but I would suspect that if this were the problem, you would see damage or modification.
thanks i will check that out.
There is also a capacitor on the side of the distributor, but I think it is there to protect the rest of the electronics in the truck from the spike felt on the common lead of the coil. I don’t think it protects anything inside the distributor.
Replacing the distributor 3 or 4 times is bordering on insanity at the very least.
I agree. I need a new truck. or new mechanic.