Misfire / Catalytic converter

[jakeyf08]

On my way home my I noticed a very serious misfire and the SES light began flashing. When I got home I crawled underneath and the CAT was glowing orange. Prior to this issue I had a p0420 (bank 1 lean). Is the glowing orange a sign of a plugged cat? muffler? and if it is plugged...this is more than likely causing the misfire? Or could the misfire cause the cat to do this? I don't want to go out and buy a new cat if it is not the problem and I would like to do a tune up if needed.

Thank You in advance.

[old_master]

The misfire is causing the converter to overheat. P0300 series DTC's are almost always caused by secondary ignition faults. Spark plugs, plug wires, distributor cap, rotor, ignition coil. Repair the misfire ASAP or the converter will be permanantly damaged, (if it's not already).

[jakeyf08]

I just replaced the plugs, wires, cap, rotor and started the truck. SES light started flashing again and there is still a misfire. Scanned it and a p0302 code came up cylinder 2 misfire. This is the same misfire I had prior to the tune up. Only thing i did not replace was the coil. Could the CAT be bad now? blocking the exhaust and still causing a misfire? or Should i start to look at the coil first?

[old_master]

A faulty ignition coil will not cause only one cylinder to miss. Double check the plug wires. Notice wire placement on the cap:




If that's ok, #2 injector might be stuck open or closed, or a problem with the wiring to the injector.

[danielsatur]

If Catalytic converter was plugged, there would be random misfires on random cylinders.
The Engine will stall, because of no exhaust flow.

If the catalytic converter is blown (P0420), it will give poor emissions, and you might hear a
little rattling down stream of the exhaust.

[jakeyf08]

Yes everything was ok with the wiring and I double checked the cylinder two wire and it one on the plug and cap. I started the truck and still had the same problem. How could I test the injector? should I test fuel presuure?

[danielsatur]

Roll the injector just like a COP, Spark plug, or wire to another cylinder.

Note: If an injector is getting a signal, or clicking sound doesn't mean
it's getting the flow rate thats needed for a good fire.

[old_master]

Big job to roll injectors on CSFI, need to remove the entire injector assembly and disassemble it. Also, you can't access them with the engine running to check for clicking sound. Not even sure if you could safely swap wiring without damaging the connector. Checking fuel pressure isn't a bad idea but, a leakdown test will tell if an injector is stuck open, and an injector balance test will tell if it's stuck closed. You can also check the wires to the injector for power and pulse, but you'll need a noid light to test for pulse. You can use a test light to check for battery voltage at the injector, it's a pink wire. Don't use the test light on the ground circuits at the injector pack, it can damage the driver in the PCM, you need to use the noid light to test for ground pulse.

[jakeyf08]

I went ahead and replaced the fuel injectors. I did notice carbon wash out but nothing serious. I got everything back together and drove it for about 7 miles and SES light came on again (NO MISFIRING THIS TIME).
Still have the P0420 code but also have P0507 (Idle control system rpm higher than expected). I did notice very high idling at first but after driving it for 10-15 miles it no longer idles high when at a stop light or upon starting. Finally I have a P0700 (Transmission Control System Malfunction). I have never thrown either of the last two codes....any help is greatly appreciated. I have no idea what the problem could be.

[old_master]

The P0507 is usually related to the Idle Air Controller, (IAC). The pintle may have been disturbed when you removed the plenum. A bidirectional scan tool can reset it immediately, but it sounds like it reset itself already. The P0700 might be setting due to the P0507. The P0420 is indicating the catalytic converter might have a problem although it could be any one of several things causing it to set. Clear the DTC's and perform a drive cycle http://www.obdii.com/drivecycle.html and see what DTC's return, then post them here in the order they are retrieved.

[jakeyf08]

Finally had some time to complete the driving cycle. I cleared the codes, completed the cycle, and the SES light came on. I scanned the vehicle and the P0420 was the only that came up. I have a fairly new catalytic converter ( less than 2 years ) and replaced the o2 sensor on the cat when I put the new one on.

[old_master]

Provided there are no other DTC's present, there are only two things that can set P0420: exhaust leaks, or a problem with the catalytic converter itself, (wrong converter, poisoned, or damaged, see post #2).