Greetings! I searched the forum for information regarding a particular problem I recently encountered on an 04 Altima. There is a intermittent engine misfire. It usually happens when idling and doesn't light up the MIL. I browsed the web for information regarding this problem, but I found little help.
As luck would have it I had a similar problem on my 2000 Maxima. There was a full write-up on the code P1320. Basically, I had to probe the ECM with the car idling and while revving the engine to pinpoint the faulty coil. After a little digging, I found the appropriate values for a similar procedure on an Altima (see attachment).
I tried removing the glove box to access the ECM. Four screws at the top, and one on each side. After a bit of fiddling, the ECM harness cover popped right off. In my vehicle, the harness was too tight and I was unable to probe the ECM. I tried to gently move the wires to the side but it was no use. Instead, I probed the coils right at the connector.
There are three wires going in the connector. The rightmost wire is the one you want to probe. I inserted a thin wire into the female connector, routed it out of the connector, and plugged in the coil. I tested each coil with the car warmed-up and idling, and while revving at 2,000 rpm. I have included the oscilloscope screen shots. Two coils were bad.
The ECM Pin-Out PDF has the information on the wave form of the coil voltage. If you have access to an oscilloscope, awesome. If not, make sure the voltage does not spike above 4 volts when revving.
I bought a few replacement coils at AutoZone. I installed and checked them all. One was bad off the bat, the next two were within spec.
This was all done today, so expect an update within a 2 weeks. The engine misfire happened about twice a week for a few minutes. As a side note, the spark plugs were recently changed and we ran some fuel additive. The problem persisted so we tested the coils.
My screen shots are in the zipped file. There are 15 total, properly labeled and in BMP format. If you check out my screen shots, pay no attention to the max voltage observed by the oscilloscope. It was an error on my part.
As luck would have it I had a similar problem on my 2000 Maxima. There was a full write-up on the code P1320. Basically, I had to probe the ECM with the car idling and while revving the engine to pinpoint the faulty coil. After a little digging, I found the appropriate values for a similar procedure on an Altima (see attachment).
I tried removing the glove box to access the ECM. Four screws at the top, and one on each side. After a bit of fiddling, the ECM harness cover popped right off. In my vehicle, the harness was too tight and I was unable to probe the ECM. I tried to gently move the wires to the side but it was no use. Instead, I probed the coils right at the connector.
There are three wires going in the connector. The rightmost wire is the one you want to probe. I inserted a thin wire into the female connector, routed it out of the connector, and plugged in the coil. I tested each coil with the car warmed-up and idling, and while revving at 2,000 rpm. I have included the oscilloscope screen shots. Two coils were bad.
The ECM Pin-Out PDF has the information on the wave form of the coil voltage. If you have access to an oscilloscope, awesome. If not, make sure the voltage does not spike above 4 volts when revving.
I bought a few replacement coils at AutoZone. I installed and checked them all. One was bad off the bat, the next two were within spec.
This was all done today, so expect an update within a 2 weeks. The engine misfire happened about twice a week for a few minutes. As a side note, the spark plugs were recently changed and we ran some fuel additive. The problem persisted so we tested the coils.
My screen shots are in the zipped file. There are 15 total, properly labeled and in BMP format. If you check out my screen shots, pay no attention to the max voltage observed by the oscilloscope. It was an error on my part.