My 97 Honda Accord is giving Code P0301 and Code 1399. In addition to this at idle the CEL blinks. This goes away on a flat road, no load, however when loaded, up hill for example, the light blinks. I have checked the plugs, the wires, the distributor, and the rotor, all look to be OK. Any thoughts on a direction to go?
A flashing CEL while driving is a misfire indication. DTCode P0301 is an OBD2 Cyl #1 Misfire code.
A misfire can be caused by ether an ignition or fuel issue. If you have checked all of the ignition parts and tested them to be in operating ranges. You could begin testing the fuel supply system. It could be a week fuel pump or inoperative fuel pressure regulator or a faulty fuel injector. I would start with testing injector No.1.
With the engine running you could place a long metal/wooden rod (screw driver) and touch one end on the body of the injector and your ear to the other. You should hear sharp clicks, make sure they all sound the same if one doesn't sound like the others that would be an issue. That's one of the easy ways to check for operation. The other is, with the engine off, check the resistance between the two pins of each injector. It should read 2.5-3.5Ω, anything other than that and they should be replaced.
As for testing flow of the injector. That is something that has to be done with the injectors out of the car on a test rig.
Thanks all. Changed Plugs, Wires, Rotor, and Cap and the problem went away. Not sure which fixed the problem, however and the car has over 200,000 miles on it these things needed to be done. Any way thanks as the problem is fixed.
I'm having the same problem with my 2000 Accord EX SULEV. It was running fine at 7 p.m., then at 8 p.m. when I left work to go home it started up and ran very rough then the cel came on and I got the codes p301 and p1399. A mechanic told me a couple of weeks ago that I need to clean the throttle body. Is there any online resource for the procedure? I don't have a Haynes manual for the Accord.
No, but I thought they had been changed when I had the 105,000 mile maintenance a couple years ago. It cost $1200.00 so I'll have to check the receipt. Anyway, I'll look at the cap and rotor first. It's at 145,000 miles now. I had a wire go bad suddenly on an Escort GT used to own, so that can happen. One second it was fine, the next second...poof!
I replaced the coil today based on a local mechanic's diagnosis (low resistance on the primary circuit) and still no improvement. He also tested it by removing one spark plug wire at a time and noticed that the misfiring didn't really change much with any of the spark plug wires removed, so it's sort of a general misfiring. What other components could cause this? As I said before I've replaced the cap, rotor, wires, and plugs. I'm thinking it could be the ICM or mass airflow sensor.
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