Tipo fails MoT on emissions | Technical matters | Back Room Forum

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Thu 8 Dec 2005 16:22

Tipo fails MoT on emissions - local yokel

My 1.4 injected Tipo failed the Mot on emissions - tester had never seen them higher at about 9.1 (should be <0.something).

History is that after driving through a very wet patch of road a couple of months back it developed a chronic misfire. New plugs, points and leads failed to cure it, found to be timing, so had new cambelt fitted - ran fine, but consuming way too much fuel. Gave it a treatment of injector cleaner, still no improvement, so put in in for early test to see what else it failed on, with a view to fix if cheap.

It starts and runs fine, except it's doing 25 mpg driven sensibly, on medium runs.

Is there something I'm missing here - say ECU failure? Seems unlikely that the timing is/was incorrectly set (by a professional), given that it's otherwise running acceptably.

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Thu 8 Dec 2005 17:24

Tipo fails MoT on emissions - bell boy

map sensor
cts
lambda

any of them or all. i would suspect the map

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Thu 8 Dec 2005 17:36

Tipo fails MoT on emissions - Spanner

Did engine cut out after driving through water?
If the cambelt slipped then timing will be out, but as this model has electronic ignition and timing is controlled by ECU, it could be that timing belt was put on a tooth out.However this engine is an interference type, so there could be possibility of valves hitting piston. It could be distributor drive being out by a tooth whilst belt was replaced?

Another possible reason for high fuel consumption is air leaks/vacuum leaks in induction side of engine i.e inlet manifold gasket problems, vacuum hose leaks due to perished/broken connectors. Listen out for hi pitched hissing noise from inlet side.

The water could have damaged the catalyst and/or oxygen sensor. Sudden cold water on a very hot cat matrix can cause thermal shock to crack cat and cause partial blockage and poor running/hi exhaust back pressure.
A broken oxygen sensor will cause high emissions and increase in fuel consumption. Get garage to carry out exhaust back pressure test or at least check oxygen sensor.
Andrew

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Thu 8 Dec 2005 19:16

Tipo fails MoT on emissions - Civic8

>>The water could have damaged the catalyst and/or oxygen sensor. Sudden cold water on a very hot cat matrix can cause thermal shock to crack cat

would agree with that,Oxygen sensor failure more likely IMO?
--
Steve

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Thu 8 Dec 2005 23:11

Tipo fails MoT on emissions - rhubarb2

Have you got a multimeter? If so, disconnect the cts and check the resistance across both terminals...High resistance cold, little resistance at operating temperature....

As Oldman says map sensor, first check is the pipe that runs from the map sensor to the manifold..Remove the pipe, check its not blocked, spray some carb/brake cleaner through it.......

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