Porsche Enthusiasts Club Forum

Got the old MOT tomorrow , its the first time Iv taken this car so I got all fingers crossed, on the up side she has only done 900 miles since the last MOT and half of that was getting it in and out of the garage for cleaning
Had two new Falkens 452 on the rear today so thats one thing out of the way, must say they do look good.

good luck with it mate. let us know how you get on. the 1st one is always the worse when you are getting to know a motor.

Cheers Albi,

£54 lighter for the MOT but it passed with no advisory notes

Does anyone know what the CO and HC levels should be.
The paperwork shows my CO Level is 0.18% and the HC Level is 58ppm It passed but is this a good score, does it give some idea of the condition of the engine.

nice one, i bet you were over the moon. now a bit of info on levels...

CO emissions (mixture) At the time of writing, for vehicles first used between 1st August 1975 and 31st July 1986 (P to C registration), the CO level must not exceed 4.5% by volume. For vehicles first used between 1st August 1986 and 31st July 1992 (D to J registration), the CO level must not exceed 3.5% by volume. Vehicles first used after 1st August 1992 (K registration) must conform to the manufacturer's specification. The MOT tester has access to a DOT database or emissions handbook, which lists the CO and HC limits for each make and model of vehicle. The CO level is measured with the engine at idle speed, and at "fast idle". The following limits are given as a general guide: At idle speed - CO level no more than 0.5% At "fast idle" (2500 to 3000 rpm) - CO level no more than 0.3% (minimum oil temperature 60ºC) If the CO level cannot be reduced far enough to pass the test (and the fuel and ignition systems are otherwise in good condition) then the carburettor is badly worn, or there is some problem in the fuel injection system or catalytic converter (as applicable).

HC emissions With the CO within limits, HC emissions for vehicles first used between 1st August 1975 and 31st July 1992 (P to J registration) must not exceed 1200 ppm. Vehicles first used after 1st August 1992 (K registration) must conform to the manufacturer's specification. The MOT tester has access to a DOT database or emissions handbook, which lists the CO and HC limits for each make and model of vehicle. The HC level is measured with the engine at "fast idle". The following is given as a general guide: At "fast idle" (2500 to 3000 rpm) - HC level no more than 200 ppm (minimum oil temperature 60ºC)
Excessive HC emissions are caused by incomplete combustion, the causes of which can include oil being burnt, mechanical wear and ignition/fuel system malfunction.

Thanks for the text,

Does anyone know what a health engine in an S2 should be ?

It looks pretty good actually, you may get a little more power by upping the CO a little. I assume your S2 hasn't got a Cat. It shouldn't but judt might.

Yep no cat, how do you up the CO

This is the one that had oil on the plugs a few weeks ago which seems to have cleared but the HC on the MOT picks up on oil smoke, is 58ppm low?

They are both low, good ammo against the "Old cars pollute whingers "
On the back of the AFM (Air Flow Meter) is a allen screw & turning this varies the CO mix. It'll need doing with a meter but I'd suggest upping it to around 0.5% -0.75% shouldn't impact fuel consumption but may make it a little crisper & quicker.

Mine passed today, No problems. Just need a new camshaft oil seal & o ring now as it's just started leaking & driping onto the exhaust! Still thats the first defect since last September when the Power steering pump died. Could be worse.

congrats on the MOT