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Matt, Engineer
Category: Car
Satisfied Customers: 21860
Experience:  Honors degree in Mechanical Engineering, worked 8 years as a Formula 1 engine engineer.
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How can I get my 1990 testarossa to pass an emission test?

Customer Question

how can I get my 1990 testarossa to pass an emission test?
Submitted: 5 years ago.
Category: Car
Expert:  Matt replied 5 years ago.

is the car fitted with a cataylst and what level of HC and CO is it required to pass?
Customer: replied 5 years ago.

the car does have a catalytic converter.

Hclimit 52 reads 85 CO%limit 0.29 reads 1.74

Expert:  Matt replied 5 years ago.

OK I'd 1st recommend a couple of bottles of this stuff:

I was skeptical until I used it, it really does what it says

also check that the ignition advance is set correctly as if a bit retarded this will create higher than normal emissions

Check for exhaust leaks before the O2 sensor as if this has been experiencing an exhaust leak then it will have been running very rich as the sensor will see the extra air pulled in as fresh / lean fuelling and be adding fuel to compensate.

this can lead to catalyst failure as the extra fuel can re-light inside and melt the catalyst

The best way to find an exhaust leak is to run the engine from cold and feel around the exhaust joints with your bare hands - you'll have about 30 seconds before it all gets too hot and you should feel any escaping gas blowing over your fingers

Customer: replied 5 years ago.
how can I tell if the catalytic converter or oxy sensor is bad?
Expert:  Matt replied 5 years ago.

well if you remove the catalyst so you can see the honeycomb you can see if its melted or collapsed as you should be able to see through it

however an easier one is to unplug the oxygen sensors and see how the car drives without them, if its suddenly a lot worse then the sensors were doing something and can be assumed to be OK, if unplugging them doesn't nothing then chances are they weren't working in the 1st place