1993 240 high NOX

This is from the IPD catalogue

, something every 240owner should have on their coffee table. High NOX, you could have:

Lean Mixture Timing too far advanced on 1988 and older cars EGR system malfunction like: Bad Valve Broken Vacuum Line Plugged Pipe Bad Vacuum Controller Engine/cat not fully warmed up Bad Catalytic Converter

Good Luck,

--

-don

'81 242t '89 744ti

The cat converter is the most expensive item on the list, but it has gone more miles than its expected life.

-- besides carb adj., try checking/replacing the carb-to-manifold gasket and the manifold-to-head gasket as well as any other vac lines in the manifiuld after the carb. Even a leaking vac canister. An air leak there will cause lean mix.

--easily checked, and even retarding it JUST A BIT before the test can help.

--The smog test shop should check this- easy enoiugh to do by just disconnecting the vac line and connecting a hand vac pump.

--not a problem here in this case

A muffler shop can check this, but if you have a pyrometer or an infrered non-contact thermometer, try checking the temps at the header pipe into the cat, the cat temp, and the exhaust pipe temp at the exit of the cat. It should be substantially hotter going out than going in. One way to check the cat's function.

from Randy & Valerie __ __ \ \ / / \ \/ / \__/olvo 1993 960

From what you state it would seem that the converter has seen better days look in to replacing it

Yesteday I cleaned the throttle body assy, and the idle solenoid, installed new gasket on the TB to manifold, and it idles better, I have another year before I take it to emmissions again, will see about having a pre-cat and post cat reading, thanks to all who posted.

Arnold

You can buy "limited lifetime warranty " direct fit fit converter at places like Autozone in for around $100.00 .

Also, the cat can cool off enough just waiting a few minutes for the test to actually start. In Ontario, our test aborts as soon as the test program determines that the car will pass. Often, this is as the cat is warming up, so one of the pollutants is very close to the limit, but heading down. This scares people into thinking the car will not pass next time.