How can I get my registration from the DMV if I have tried everything to get my 1998 BMW 740i to pass the emission test and I still fail the test after replacing the catalytic converters 3 times with Magna -flow state certified and approved for the 740i, and have nothing wrong with the 02 sensors, fuel is burning with in the specs, engine is running at 15.2 no exhaust leaks etc…certified testing from Gold Shield emission repair location.
If I understand your question, you own a BMW 7401 1998 and you are having difficulty passing the clean air test and you are using an outfit called “Gold Shield emission repair” who have not been able to get it cleaned up.
I would suggest using a local INDEPENDENT mechanic of maybe a BMW dealer. Someone in the chain is not competent. My guess is Gold Shield.
Try fixing your car first, as you haven’t tried everything yet.
Again, like I posted in your other thread, hot soak of seafoam, or a double dose of techron fuel system cleaner in the gas tank, and a long drive to clean out any intake and combustion chamber deposits that are causing the high NOx emissions.
What state are we talking about?
California…and I spoke with the Magna-Flow technician as well as Consumer Affairs in Sacramento regarding the after market product used and they both confirmed that they should be good for 4 years… but something is burning them up.
It is probably not damaged as of yet.
If the entire catalyst was damaged, there wouldn’t be any way possible that you would still have good CO emissions.
Here’s a link where someone in Texas had the EXACT same issue as you do, and read what was recommended that the owner do:
So try it.
The advice is free.
The cost of a bottle of seafoam, or a couple of bottles of techron is about $10.