Cel Po 430

[MS2KSE]

I was coming home from the beach yesterday and the CEL came on, pulled into a Autozone and had it read, PO 430, Cat efficiency below threshold,[bank 2]This is a Fed. Miata with only one cat. Any suggestions on whats going on

[Tom @ Fast Forward]

That is really weird. You don't have a "bank 2". That is for V6 or V8 engines. P-0430 is not a valid code for a Miata as far as I can find? Are you sure they read it right?

[MS2KSE]

That's what I thought :confused:he said, I'm having it looked at later this week, I'll info you'll what they find.

[MS2KSE]

Latest update, with CEL on, went for lunch, NO PROBLEMS, get in and as I was leaving the parking lot, the car started acting like it has done twice before, both after short drives, acts like about 1/2 power, needs to be keep in lower gears, sounds coming from underneath the car like a major exhaust leak, about 6 miles of this and ALL at ones the full power is back. took it to shop, two codes PO 420 and PO 300, they ran a bunch of scans but they couldn't say for positive what was going on. ????

[Tom @ Fast Forward]

420 is a bad rear O2. Would not cause a problem. 0300 is random missfire in random cylinders. 0301, 0302, 0303 and 0304 is random missfire in cylinders 1, 2, 3 and 4 respectively. As you didn't get any of those, I suspect it is something to do with the coils. The codes are here http://www.fastforwardsuperchargers.com/Install/Codes.pdfhttp://www.fastforwardsuperchargers.com/Install/Codes.pdf (http://www.fastforwardsuperchargers.com/Install/Codes.pdfhttp://www.fastforwardsuperchargers.com/Install/Codes.pdf)


Make sure you have no wires close to the EGR valve at the rear of the engine that could have burned through and/or shorted out.

When you go to start the car, are you turning the key on and letting the cards calibrate before starting the engine? If the engine doesn't start for some reason, be sure to turn the key off and start over from scratch. I turn the key on and watch for the passenger air bag light to go out as a signal that I have waited long enough.

[MS2KSE]

[QUOTE=Tom @ Fast Forward;13472]420 is a bad rear O2. Would not cause a problem. 0300 is random missfire in random cylinders. 0301, 0302, 0303 and 0304 is random missfire in cylinders 1, 2, 3 and 4 respectively. As you didn't get any of those, I suspect it is something to do with the coils. The codes are here http://www.fastforwardsuperchargers.com/Install/Codes.pdfhttp://www.fastforwardsuperchargers.com/Install/Codes.pdf (http://www.fastforwardsuperchargers.com/Install/Codes.pdfhttp://www.fastforwardsuperchargers.com/Install/Codes.pdf)


Make sure you have no wires close to the EGR valve you mean the tube that runs from the back of the intake manifold over to the ehxaust manifold ? at the rear of the engine that could have burned through and/or shorted out.

When you go to start the car, are you turning the key on and letting the cards calibrate before starting the engine? If the engine doesn't start for some reason, be sure to turn the key off and start over from scratch. I turn the key on and watch for the passenger air bag light to go out as a signal that I have waited long enough.

[Tom @ Fast Forward]

That tube runs across the back of the engine and then bolts to that black plate that I supply. Then a small stainless tube runs from the black plate to the throttle body adaptor. Also, mounted to the black plate is the EGR valve. Any of that will run hot enough to melt wire.

[MS2KSE]

thanks for the time Tom,, mine is stock so not sure where to look ?

[Tom @ Fast Forward]

Ah. Sorry. If it is stock, how many miles on the car and are the coils original?

[MS2KSE]

75K +-, everything is original as far as I know, looks like it's time to start looking for mew coils ?

[Tom @ Fast Forward]

Hard to diagnose over the net but it could be. They do have a history of failing. My first coils went at about 70,000. I replaced them with the SplitFire COPs and those lived about 60,000 miles. My new ones now are stock Miata coils and run great with about 5,000 miles so far.