Here's a dyno showing my A/F. I have metallic HFCs and am getting a CEL.


What does Dr. Tony make of this?

 

The cel could be due to a number of reasons.
Catalytic inefficency seen by the sensor, an air leak upstream of the sensor, or something completely different.

Do you know there are no air leaks? Leaks actually let air in during the scavenge phase of the exhaust pulse. And this can cause the cel too.

Can you find out which kind of CEL it is? A code number?
Can you hear even the faintest leak noise under the car?

 

Could you swing by Julians to check the code?
If the cel is due to sensors seeing a reduction in catalytic efficency, I would like to send you a prototype part for testing.

No charge. Just put it on and let me know your results.

Email me your shipping adress.

 

When I first installed the exhaust/HFCs I did have a leak that was very noticeable at the driverside CAT. I went to MRC and as my car was being dynoed Julian confirmed the leak. I subsequently fixed the leak and all seems fine now.

I have an autoscanner which I use to reset the codes from time to time. The codes read as follows:

P0420: Catalyst System Efficiency Below Threshold (Bank 1)
P0430: Catalyst System Efficiency Below Threshold (Bank 2)

I suspect if there was still a leak it would only be on the driverside bank, not both, since the passenger side was good from the start.

I would love to be your test mule Tony, as I have nothing to lose and it would be my pleasure to help the Z community.

Check PM for addy.

 

Very good. You have the right codes.

Lets fix it.

 

Thanks Tony, I'll have my fingers crossed. I'll get in touch with Julian at MRC, and hopefully we can all benefit from your mechanical know-how.

 

Only P0420 for me... looks like on HFC (berk metallic) is working enough but the other doesn't...
GRRRRRRRRR

 

I would like to see some test pipes with the elbow bung for the O2 sensor like some have, filled with the same metal substrate that is in the stock cats, that way, the exhaust flow is not restricted, but the O2 sensors are still behind the substrate, giving the readings of stock cats.

Don't know how costly this would be though.

 

Updates?

 

They are being installed this weekend.

 

Anything new?

 

Need more test time.

 

Any idea of a time frame? I'm patiently waiting as I've been wanting test pipes for a while and haven't bought them due to the CEL. If there is a fix, I will be the first in line.

 

i threw up the SES light pretty much as soon as i pulled away from the shop. i drove around for about 100 miles before i did the nonfouler fix. after installing the nonfoulers and reseting the ecu, my light is still coming on. my mpg has even seemed to drop a fair amount.

 

You have an exhaust leak at the manifold/test pipe interface.

 

PM'ed

 

I wonder if the increased vacuum running through the PCV system could be causing some of the issue (excess oil in the combustion chamber). Anyone notice smoking with the test pipes? I have read that excess oil can preclude proper O2 sensor operation, but I'm not 100% sure on the mechanism for that or if the sensor is permanently or only temporarily impaired (if at all).

 

ok i have been reading this and maybe i missed it.... but what sensor is P2A03 refering to? I brought mine to a shop last week for it and he said the O2 sensor in my driver side header was bad so i changed it and i still throw the code every ~20ish miles, with headers HFC but i dont think that matters b/c i put my stock cats back on a while ago and was still throwing the code

 

You probably have an exhaust leak causing the code.

 

ok i checked my service maunel CD for P2A03 (Bank 2) and P2A00 (Bank1)

The condition for detecting is the A/F is running to lean or too rich for a specific time.

Under possible causes it lists
-Air Fuel Ratio sensor 1
-Air Fuel Ratio sensor 1 heater
-Fuel Pressure
-Fuel injector
-Air intake Leaks
Just thought id post this up b/c i was getting confused with everyones theory for why the CEL were being thrown for these codes. If anyone wants me to look up a code for them and post something similar to what i just did lemme know...