Pre-Cats Failing (Glowing RED HOT)

[Jwelsh03]

Hi,

My 1993 4.0 Chimaera was running a bit lumpy on my last drive and producing some black smoke from the rear. When I opened the bonnet the exhausts towards the front of the engine were glowing red hot. After some research I have concluded that the issue is likely the pre-cats having failed/crumbled. My options are now to replace or remove them.

Has anyone got any experience of this and knows whether if I remove my pre-cats from inside the exhaust tubes, if the car will pass its MOT (emissions testing)? Or must I replace these?

Many thanks

[Belle427]

The pre cats are not really needed for Mot purposes and it should easily pass running well with main cat in place.

[gamefreaks]

Could it be the glowing cats are a symptom rather than a cause?

The cats will overheat if they are fed excess fuel from a misfire.

[2gins]

I quite liked it when my Chimaera started emitting more pops and bangs than the norm. Eventually I figured out the plug extenders were slowly failing, replaced them, and it was much better afterwards. I didn't have glowing cats though,

I did look at taking the precats out at one point and it seems they were just put in for some cold start emissions stuff but aren't necessary for the MOT assuming it's otherwise running well.

[pits]

gamefreaks said:

Could it be the glowing cats are a symptom rather than a cause?

The cats will overheat if they are fed excess fuel from a misfire.

This, I would probably check the fuelling, pull the plugs and give them a look over, check they are all good, eventually though you will melt the cat