99 neon misfiring
99 neon misfiring
working on my friends neon dohc and its misfiring again...it first started doing it while it was humid out so we suspected it was a coil or wires so we switched the coil out today and put new wires on and it was running fine for a good 10 minutes before the light came back on. the coil had 2 small cracks and a bigger one on the cylinder 1-2 side.
im getting a p0300, p0301, p0302, and p0300 pending. i moved the wires around and switched the spark plugs to other cylinders and the codes remained the same after clearing them. i noticed that the spark plug in cyl 1 was wet and it didnt seem like oil cuz it was only on the tip and not the threads or in the spark plug tube. could it be fuel coming from a leaking fuel injector? it does idle rough mostly when the car is first turned on then it goes away and itll misfire intermittently once it warms up. any and all help and advice is appreciated.
im getting a p0300, p0301, p0302, and p0300 pending. i moved the wires around and switched the spark plugs to other cylinders and the codes remained the same after clearing them. i noticed that the spark plug in cyl 1 was wet and it didnt seem like oil cuz it was only on the tip and not the threads or in the spark plug tube. could it be fuel coming from a leaking fuel injector? it does idle rough mostly when the car is first turned on then it goes away and itll misfire intermittently once it warms up. any and all help and advice is appreciated.
Rookie
Joined: Jan 2014
Posts: 60
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Grab a spray bottle and fill it with water. Wait until it's dusk/dark or turn your shop lights off. Start the car and spray water on the coil and wires and look for arcing.
If you see no arcing it may be a vacume leak. Again with car running spray the intake manifold, throttle body and other gaskets with water and listen for the idle to change.
You can also check the resistance of the spark plug wires. Visual inspection for cracking.
Check spark plug gap. What type of plugs are installed? Pull the plugs and look for at their condition to see which cylinder is misfiring. Are they covered in gas, oil and such.
Where the ceramic meets the metal is there any discoloration indicating arcing?
If you see no arcing it may be a vacume leak. Again with car running spray the intake manifold, throttle body and other gaskets with water and listen for the idle to change.
You can also check the resistance of the spark plug wires. Visual inspection for cracking.
Check spark plug gap. What type of plugs are installed? Pull the plugs and look for at their condition to see which cylinder is misfiring. Are they covered in gas, oil and such.
Where the ceramic meets the metal is there any discoloration indicating arcing?
Im back to working on it tomorrow since he just came back from vacation...the wires were switched out since they were under warranty and a new coil was installed last time. the plugs i used were champion coppers if i remember correctly. i did spray water everywhere and saw nuthin i also sprayed throttle body cleaner everywhere and there was no change in idle. I will be doiuble checking all of this once i get it in the garage...is there possibilities that there may something goin on with the timing belt? injector? what are the resistance values for the injectors?
Record Breaker
Joined: Dec 2006
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From: Baltimore, Maryland