"Hot starting" problem - Page 3

uk_dave&gill · 4th May 2008, 22:43

OK, another question

What exactly does the cam sensor do?

efreeti · 5th May 2008, 08:08

It tells the ECU the position of the camshaft, the crankshaft sensor does the same for the crankshaft.

The ECU uses this information for all sorts of timing, idling, fueling type things.

uk_dave&gill · 5th May 2008, 10:53

So why does a faulty one stop the car starting?!

cjmillsnun · 5th May 2008, 12:35

Because the ECU relies on this information for when to inject fuel into each cylinder (sequential injection).

Barrie · 5th May 2008, 12:51

The cam sensor tells the ECU that the cambelt is not broken and that the camshaft is where it should be in relation to the crankshaft before starting. Nothing else. The crank sensor does all the rest.

Cheers.

Barrie

cjmillsnun · 5th May 2008, 12:57

Quote:

Originally Posted by Barrie

The cam sensor tells the ECU that the cambelt is not broken and that the camshaft is where it should be in relation to the crankshaft before starting. Nothing else. The crank sensor does all the rest.

Cheers.

Barrie

Cambelt? on a CDTi?

Also it DOES control sequential fueling. The crank sensor can't tell you if that particular cylinder is on compression or exhaust stroke can it.....

The crank sensor and cam sensor in combination can! It wasn't needed on earlier cars that fired all their injectors at the same time, but Euro III demanded less waste fuel (hydrocarbons).

Barrie · 5th May 2008, 14:27

Quote:

Originally Posted by cjmillsnun

Cambelt? on a CDTi?

er.... chain, of course.

Quote:

Originally Posted by cjmillsnun

Also it DOES control sequential fueling. The crank sensor can't tell you if that particular cylinder is on compression or exhaust stroke can it.....

The crank sensor and cam sensor in combination can! It wasn't needed on earlier cars that fired all their injectors at the same time, but Euro III demanded less waste fuel (hydrocarbons).

Yes, I guess I'm gonna have to concede that one

Barrie

5th May 2008, 08:08	#22
efreeti Gets stuck in ZT-T CDT 130+ (04) & 75 Tourer CDT Auto (52) & a 1998 MGF (with HGF!) Join Date: Mar 2007 Location: Halifax Posts: 903 Thanks: 0 Thanked 1 Time in 1 Post	It tells the ECU the position of the camshaft, the crankshaft sensor does the same for the crankshaft. The ECU uses this information for all sorts of timing, idling, fueling type things. __________________ Jim Replace in tank fuel pump with Peugeot alternative Dismantle and re-fit interior and seats Retrofit electric memory seats without the loom All followed at your own risk! Available to borrow: I have a home made (tried and tested) Cam Locking tool for M47 should anyone need it.

4th May 2008, 22:43	#21
uk_dave&gill This is my second home .. Join Date: Feb 2007 Location: Town Posts: 4,166 Thanks: 1 Thanked 189 Times in 105 Posts	OK, another question What exactly does the cam sensor do?

5th May 2008, 10:53	#23
uk_dave&gill This is my second home .. Join Date: Feb 2007 Location: Town Posts: 4,166 Thanks: 1 Thanked 189 Times in 105 Posts	So why does a faulty one stop the car starting?!

5th May 2008, 12:35	#24
cjmillsnun Gets stuck in Rover 75 Connoisseur CDTi & MGZT+ CDTi 135 Join Date: Oct 2007 Location: Petersfield Posts: 787 Thanks: 0 Thanked 2 Times in 2 Posts	Because the ECU relies on this information for when to inject fuel into each cylinder (sequential injection).

5th May 2008, 12:51	#25
Barrie Newbie Rover 75 CDT Connoisseur Join Date: Apr 2008 Location: Canary Islands Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts	The cam sensor tells the ECU that the cambelt is not broken and that the camshaft is where it should be in relation to the crankshaft before starting. Nothing else. The crank sensor does all the rest. Cheers. Barrie