intermittent not starting?

[maynard]

my 172 is intermittently not starting. happens not very often - but happens both when started from cold or after restartiing once being driven.

any ideas?

first thought is crank sensor as its quite common on renault engines, but not sure if it on these?

 

[SBV116]

Take it it cranks? just doesnt fire!! Yes crank sensor is a definate possibility!

 

[Timmay]

dodgy battery? happened with one of my 172's

 

[Poopensharten]

Take it it cranks? just doesnt fire!! Yes crank sensor is a definate possibility!

Is the CPS the same as TDC???

 

[mini-valver]

Yep

 

[Poopensharten]

Danke

 

[maynard]

happened again today. it cranks yeah, but then i turn it off quickly for fear of flooding the engine! i had this same problem with my old saxo vtr, changed battery and it was fine. leaves me wondering if its battery or crank sensor.

 

[davebem]

I would put a bet on it being the tdc sensor, take it off and gently clean it with a rag and wd40 and see if there is any improvement.

 

[maynard]

any ideas on how i can get to it? i presume it sits on top of the gearbox?

 

[heathbrowning]

Mine had the same fault and it was the battery. See if you can lend a one that starts a car up and if it does then bingo, get a new battery. If not then tdc sensor