Failed E-test massively

[pathfounder]

I took my 97 Pathfinder in for the annual government moneygrab, and it failed big time. All three readings at 40 km/h were double the maximum.

 

A year ago, I had it in, and it passed easily. All numbers were less than 50% of the max.

 

Back then, the truck had a dead KS, and the MAF was malfunctioning, which caused the truck to run poorly at any time other than idle and full throttle. One of the rear O2 sensors was also in bad shape and would often trigger the CEL. Mileage was 9mpg, city or highway. Now, the truck has a new KS that works, runs like a champ, and gets about 15-18mpg.

 

I got through the test with a "conditional pass". It was given a fuel system cleaning (which was a waste, I'm sure of it) and I was told that I likely needed new cat(s).

 

There's only 12 months and 10000 km (6200 miles) between now and then. Is this believable, or did I just get hosed?

[rgallant]

It is possible you have a failing cat, I know here in Vancouver they can cause air care fails. How do they test over there via ECU or with equipment in the tail pipe ?

[pathfounder]

Sniffer.

[Alkorahil]

Engine timing advanced/retarded too much.

Bad engine temperature sensor.

Bad catalytic converter.

[sewebster]

don't cats generally fail because of engine problems?

[Kingman]

don't cats generally fail because of engine problems?

 

Sometimes. An excessive rich run can blow out a cat within seconds, same with overheating.

[sewebster]

Sometimes. An excessive rich run can blow out a cat within seconds, same with overheating.

 

So other than engine problems, how else do they die? Old age where all the catalyst gets used up? It seems to me that that would happen very slowly and a change from passing with flying colours to failing with twice over the limit would not happen in one year.

[Kingman]

Does your exhaust smell funny like rotten eggs? If so then that's a failed cat, and the rotten egg smell comes from running leaded fuel through the engine. It's not supposed to happen with all the regulations and technology nowadays, but it does happen on occasion from some gas stations.