Use a bulb-type test lamp (not a voltmeter or LED) to check for power between the Red/White and Black wire terminals at the coil. If it doesn't light or lights dimly, check from Red/White to battery negative. If that lights brightly then the ground wire is bad, if it doesn't then the power wire is bad. In either case check the wires at the coil, it's not uncommon for them to fatigue and break inside the insulation after repeated removals. Also take a look at the female terminals, make sure they aren't corroded or broken. If you don't find any power problem, with the engine running, put a voltmeter on the remaining wire (it will be a different color for each coil) and compare the reading with a coil that is firing at the same RPM. The readings should be about equal, if they aren't then the signal wire is bad or the driver in the ECM has a problem. If they are equal then the coil should be firing, so you probably have a problem with the connector pins.
P0300 code! No fire on cylinder 1!
Ok I have a 2008 Nissan Altima that I recently inherited from my brother in law. Car has 178k miles and it's fair share of flaws which I plan on fixing! The car runs fairly rough at idle with a slight loss in noticeable power! When doing my analysis I unplugged each coil 1 by 1 and all seemed to be firing except for cylinder#1! So I swapped everything sround(spark plugs &coils) only to come up with the same results! I checked the wiring connection itself and all seems to be in working order. I pulled the soark plug and had someone crank it over while I held it collide to the engine block and it seems like I'm getting no spark! Tried this with 2 different coils and plugs and same results! In further investigation I'm thinking I have a stopped up catalytic converter which I have a new upstream and downstream on order(should be here by this weekend). Im at a loss for words on what can be my cause for lack of fire! Can it maybe be the crankshaft or camshaft senor? Is it something maybe im missing? Please all input is welcome! Thanks
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Most definitely what I had in mind if all else checks out! The ECM! But I'm goin to purchase a test light and see what comes out of the coil female connection! Note: the coil ends were changed but I tested for continuity as far back as I can cut into the harness(actually have to reinsulate it) and all checked out well! I'm about to try and see if there's a difference in my voltage readings from my ecuUse a bulb-type test lamp (not a voltmeter or LED) to check for power between the Red/White and Black wire terminals at the coil. If it doesn't light or lights dimly, check from Red/White to battery negative. If that lights brightly then the ground wire is bad, if it doesn't then the power wire is bad. In either case check the wires at the coil, it's not uncommon for them to fatigue and break inside the insulation after repeated removals. Also take a look at the female terminals, make sure they aren't corroded or broken. If you don't find any power problem, with the engine running, put a voltmeter on the remaining wire (it will be a different color for each coil) and compare the reading with a coil that is firing at the same RPM. The readings should be about equal, if they aren't then the signal wire is bad or the driver in the ECM has a problem. If they are equal then the coil should be firing, so you probably have a problem with the connector pins.
There's no output spec, what your meter is reading is an average between the trigger pulses and the dead time between pulses. It varies from model to model, that's why you if you don't have a scope, you compare to a known-good cylinder. Based on those readings it sounds like both 1 and 3 may have problems, otherwise you should be getting a P0301 (cyl 1 misfire) and not P0300 (multi-cyl misfire).
Ok think maybe I should look into the ECM? Or take it to a local mechanic and let them have at it?There's no output spec, what your meter is reading is an average between the trigger pulses and the dead time between pulses. It varies from model to model, that's why you if you don't have a scope, you compare to a known-good cylinder. Based on those readings it sounds like both 1 and 3 may have problems, otherwise you should be getting a P0301 (cyl 1 misfire) and not P0300 (multi-cyl misfire).
I think check on the coil power first. No-spark situations on individual cylinders aren't rocket science, you need solid 12V power, solid ground, and signal. Making sure the power and ground are solid is why you use a lamp and not a multimeter, the bulb needs power and a bright bulb instantly tells you the supply is healthy. In any case, one of those three things is missing, you just need to find out which and why.
Will do! I'll keep you updated as I figure it out!
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