Hot Starting

[alien1974]

I have noticed lately when i go to start my car when its hot it takes two attempts, but when its cold it starts first turn? its on 97k, plugs where done at 63k, does anyone else have this issue?

[Mybikes a cx500]

Possibly the ECU temp. sensor?

[Titch LS]

Matthew, I agree with Ian, it could be a failing coolant temperature sensor telling an already warm engine that it's cold, hence, the poor warm start.. It can be easily tested with an ohm-meter though, once the sensor is unplugged. One sign of it's failure is a noticeable drop in mpg.

[alien1974]

going to test it tomorrow, whats the best way while in situ? should i test it unplugged while the engine is running or not

[steve2006]

Not easy to test these things as you really need to know the temperature during the test but I would measure the resistance when the engine is cold then again at normal running temperature and see if the figures match these

At 0 degrees C resistance should be between 4000-7000 Ohms

At 80 degrees ( fully warmed engine) between 200-400 Ohms

[steve2006]

Just checked on Amayama and OEM sensors are £12.16 plus shipping so put an enquiry in for a couple.

[alien1974]

I checked it when it was hot and got 277 ohms so it must be working properly, so er pass, i have read that some people have had this issue with the mk4, to quote the honest john review "Fuel consumption amazingly good, particularly on the MK4 (R reg onwards) with 5 speed box Easy 30 mpg on the motorway and 23-24 round town"

[Mybikes a cx500]

Perhaps get a dealer to check for fault codes?

[alien1974]

Yes i will when it goes for the next service in 2000 miles, as i get 22 and 16 respectively

[aviator888]

LS400 was noticeably better on fuel than LS430.