chris whitlow Posted July 26, 2017 Share Posted July 26, 2017 My car, a 1997 1.6 K Series Supersport, failed it's MOT on emissions yesterday.I'm not unduly concerned about the MOT fail as it should be a visual smoke test only so, as there isn't any, I'll go back and educate them later.What does concern me is the emissions being so far away from the target. Is this a sign that the lambda sensor has failed, or that something else is amiss, or is it what you'd expect from a car of this age without a cat? Link to comment Share on other sites More sharing options...
SM25T Posted July 26, 2017 Share Posted July 26, 2017 Was the whole system up to full temperature .... the oil takes about 15 minutes more driving time than the water. Why do you have a lambda sensor if no cat .... don't they go together ?? Link to comment Share on other sites More sharing options...
SM25T Posted July 26, 2017 Share Posted July 26, 2017 Standard Rover ecu .... or something with a switchable map ? Air leaks in exhaust system confusing the lambda sensor ? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted July 26, 2017 Member Share Posted July 26, 2017 Running well?Have you got data from previous tests?Jonathan Link to comment Share on other sites More sharing options...
chris whitlow Posted July 26, 2017 Author Share Posted July 26, 2017 Thanks for the quick reply!I don't know for certain that the oil was up to full temperature but apparently the water was.The ECU is the Caterham Supersport one.The exhaust did have leaks in the system but I've just had all the cracks welded up, could that be causing some confusion somewhere? Link to comment Share on other sites More sharing options...
SM25T Posted July 26, 2017 Share Posted July 26, 2017 Air getting in to the exhaust system could confuse the lambda sensor .... as it tells the ecu to increase fuelling. But if all leaks now sorted (before the MOT ?) .... shouldn't affect it now. Is exhaust manifold gasket air tight ? Link to comment Share on other sites More sharing options...
chris whitlow Posted July 26, 2017 Author Share Posted July 26, 2017 Jonathan,I think it's running well, others may think differently, it's not coughing and spluttering or miss firing and there are no overheating issues.I don't think I've got data from previous tests, I'll have a look, but was told last year that it only just passed. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted July 26, 2017 Member Share Posted July 26, 2017 I'd follow Ian's lines: Is there a leak in the exhaust system, starting with the new welds and then where it was reconnected? The oxygen sensor and connections. Check connections and then try another one? Is there a cheaper diagnostic route? (I've seen suggestions of disconnecting it and seeing what happens, but I think that was for poor running rather than your problem.)Jonathan Link to comment Share on other sites More sharing options...
SM25T Posted July 26, 2017 Share Posted July 26, 2017 You really must have the oil up to normal running temperature to be able to check anything on an engine ... be it compression or emissions. Ideally you want it at 70-80C ..... so a good fast run for half an hour before .... not just pottering on busy roads. Link to comment Share on other sites More sharing options...
chris whitlow Posted July 26, 2017 Author Share Posted July 26, 2017 This could be the issue as they MOTd it immediately after welding the exhaust so will only have had it ticking over to warm it up. I'll go back on Friday morning after giving it a good blast.Thanks for your help. Link to comment Share on other sites More sharing options...
Ivaan Posted July 26, 2017 Share Posted July 26, 2017 I think cam timing has a big effect on emissions, especially with the high lift SS camshafts. The overlap on exhaust valve closing and inlet opening can mean un-burnt fuel going straight into the exhaust. Link to comment Share on other sites More sharing options...
Wrightpayne Posted July 26, 2017 Share Posted July 26, 2017 On this age K the lambda sensor is in one of the primaries / manifold so depending which bit was welded, exhaust leak may not be the issue - did the lambda get re-connected?Ian Link to comment Share on other sites More sharing options...
chris whitlow Posted July 26, 2017 Author Share Posted July 26, 2017 I have adjusted the cam timing, using the DVA Supersport figures, so that could explain the difference to last year.The collector needed welding so they shouldn't have touched the lambda but I'll check the connections anyway.Thanks for all the replies. Link to comment Share on other sites More sharing options...
John Vine Posted July 26, 2017 Share Posted July 26, 2017 It looks like your car has been tested under the Basic Emissions Test rules ("Non-cat test for Vehicles first used on or after 1 August 1975"). One of the stipulations is:Ensure that the engine is hot by checking for example - temperature gauge, cooling fan cut-in or hot coolant hoses. If the engine is not at normal temperature raise the engine speed to between 2000 and 3000rpm and maintain this speed until normal temperature has been reached. ... it should be a visual smoke test only...I think that depends on whether the car is "amateur-built" or "factory-built".What is the 6th character of your VIN?JV Link to comment Share on other sites More sharing options...
chris whitlow Posted July 26, 2017 Author Share Posted July 26, 2017 The sixth letter of the VIN on the chassis plate is 'C', which is why I thought visual smoke test only, but on the V5 and previous MOTs it's been miss typed as a 'G'.This could be why they tested under the basic emissions test rules. Link to comment Share on other sites More sharing options...
John Vine Posted July 26, 2017 Share Posted July 26, 2017 The "C" indicates "Complete Knock Down", so your 1997 car is " a visual smoke test only". (There is no "G" code.)The DVSA In service exhaust emission standards for road vehicles (18th Edition) states (page 19):CATERHAM CARS The VIN Code consists of the 6th, 8th and 9th digit of the VIN number. Where the 10th digit of the VIN is equal to or less than 'W' and the 6th digit is 'C' or 'K', the vehicle concerned should be considered as 'amateur built' and as such should receive a visual smoke test only.I guess your 10th character is "V" (for 1997)?JV Link to comment Share on other sites More sharing options...
SM25T Posted July 26, 2017 Share Posted July 26, 2017 Assume your air filter is clean ? Link to comment Share on other sites More sharing options...
chris whitlow Posted July 27, 2017 Author Share Posted July 27, 2017 I'd wondered about the air filter.All I've done is given it a blast with an airline but I don't know how old it is so it could be worth changing.Any recommendations for replacement air filters? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted July 27, 2017 Member Share Posted July 27, 2017 Any recommendations for replacement air filters?What sort have you got?I used a Pipercross cleaning pack on a foam rubber filter and was satisfied. But it turned out be not very dirty anyway.Jonathan Link to comment Share on other sites More sharing options...
chris whitlow Posted July 28, 2017 Author Share Posted July 28, 2017 It's a K&N filter and looks quite old .Would it be better to buy new or can they be cleaned too? Link to comment Share on other sites More sharing options...
Wrightpayne Posted July 28, 2017 Share Posted July 28, 2017 You can get cleaning / re-oiling kits for them. Link to comment Share on other sites More sharing options...
chris whitlow Posted July 28, 2017 Author Share Posted July 28, 2017 Just looked on the K&N website (should have looked before!) so I'm up to speed now, thanks. Link to comment Share on other sites More sharing options...
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