Anyone using aftermarket Catalytic Converters
 

Is anyone here using any aftermarket catalytic converters on their E39 540i

I read up some guys running Magnaflow high flow cats on bimmerforums.com, but im not sure if its gonna pass emissions test for us here in canada. They are actually improving performance.


Im experiencing a missfire at cylinder 4 only when car is given a pedal to the floor (High rpms and higher speed). Check engine starts to flash a few times and then remains on. Once i turn the engine off and them back on everything runs smooth. I swapped out the ignition coil at RMP however the symptom is back, rulling out the faulty coil.

Reading up a bit on these symptoms leads towards a clogged cat or even a faulty O2 sensor. The only code that does come up is the missfire cylinder 4.

Comments and suggestions are always welcome.

Fuel pump?

You could have a bad/clogged fuel injector in cylinder 4 or quite simple the plug could be bad internally. Does the tip of the #4 plug look different from the others....that should tell you what's happening.

You don't have to use a Magna flow Performance CAT, you can use any of the CATs sized for Mustang or Camero. In the past I've had good luck with Catco CATs, emissions not a problem and no performance issues.

A clogged cat will cause all the cylinders at the Bank to misfire not only one cylinder.

Since your car is a 97, the cats are built in the rest of the exhaust. 99+ got them integrated into the manifold.
Why not drop the entire exhaust system and taking it for spin, that will determined if you have a bad cat or not.

Also you can try parts from a different cylinder.

hey bud, i did use a high flow magnaflow cat with a magnaflow cat back exhaust in my e36. the exhaust system was installed by bimmersport. i went for an etest last feb and had no issues. the car passed with no problems

Thanks for the comments fellas. Yea clogged cat would trigger any cylinder so must be injector.

Right now I'm I'm going with the injector cleaner route.
So far I put one bottle of Lucas injector cleaner into the tank and we'll see how it goes.
I havent tried pushing the car hard. Maybe after the second bottle of cleaner I'll give it a rip.

Dado, the cheapest best way to clean the injector is to remove it and back flush it with carb cleaner, the second way is to take it to a shop that will disconnect the fuel supply and hook up a containter with a mixture of cleaner and gas to clean the fuel rail as well as all the injectors.

I know a place in Markham but none out west but I'm sure there are quite a few that will perform that service.

high flow cats are same sh!t as brand new OEM cats. Slightttttttly more flow. Tested this one many many cars.

Yungs Auto at 221 Bethridge Rd in etobicoke does this as well.

A Friend Of Mine Had This Problem Turned Out To Be Something To Do With The Rear Intake Cover On His.