Technical Crankshaft sensor fault ?

[Mar4ix]

Punto mk1 , 1.2 , 8v, '99 engine.

what would be crankshaft sensor fault ?
Ive noticed couple times, i have difficulties start it from cold, not always, but sometimes.
Also she is running rough, feels like misfiring, but not proper misfire ... and emissions are 0.6 % on idle, and 3 k revs, 0.5 % ... causing me fail MOT. New lambda, new temp sensor (well a year approximately), maff sensor put from another punto, no change at all. vacuum pipes are new, those fancy one , white color.
wonder if old one was hard type pipes, those what i have now are soft silicon one, was buying for nissan skyline turbo charger , but didnt use them.
Timing properly set. Compression perfect. , headgasket changed. Good oil.
Planing try put another ecu also.


thanks

 

[fingers99]

99 Car should be SPI, I think, so very unlikely to be ECU. You should have no MAF sensor, but a MAP sensor.

If the thing is misfiring, it will fail emissions -- no ifs, buts or maybes, it'll fail.

Plugs, leads? Do the old start it up in the dark, look for blue flashes, trick.

Can't see it being the TDC/Crank/RPM sensor -- generally they'll cut out and refuse to restart or give a very hard misfire -- almost like a rev limiter. If you like, get someone to woggle the lead while you crank the engine (or vice versa).

Providing the hose really is vacuum hose, it should be fine. You could test that it is by seeing if it flows air at a 1.5 bar vacuum. (Mityvac, etc.) If it does, it'll be fine. Using pressure hose is a no-no however pretty it is.

 

[Mar4ix]

I have changed ECU, no difference at all. even it from 1.1 engine, mine is 1.2.
How to check MAP sensor. I have changed one while ago, but didnt noticed any difference.
I had bad leads before, when got from motorfactors, new leads was acting same, sparks in dark time, but then i bought expensive ones... 60 GBP is from ebay.... sporty ones, those doesnt show any sign of spark in dark .

vascuum houses i got from them - http://www.ebay.co.uk/itm/Nissan-Sk...arts_Vehicles_CarParts_SM&hash=item336cf4e18d

hope they selling right hoses

 

[s and b]

0.6 could be a failed cat