Cold Starting Problems

[Siban]

Been having problems with cold starting the Noble recently which MV are having problems getting to the bottom of.

When I start the car cold it basically wanders around from 1000rpm down to as low as 250rpm before then conking out. MV found one of the turbo pipes was loose and then replaced one of the Lambda sensor's last week but it's still playing up.

For my reference, what do other people's car's do from an rpm perspective when you hit the start? The ECU should adjust the revs to about 750-1000 and then stay there constantly? Mine is wandering about all over the place which suggests there is still some electrical gremlin in there somewhere.

Cheers,

Simon.

>>> Edited by Siban on Thursday 30th December 18:51

[AMG Merc]

Siban said:

Having been having problems with cold starting the Noble recently which MV are having problems getting to the bottom of. When I start the car cold it basically wanders around from 1000rpm down to as low as 250rpm before then conking out. MV found one of the turbo pipes was loose and then replaced one of the Lambda sensor's last week but it's still playing up. For my reference, what do other people's car's do from an rpm perspective when you hit the start? The ECU should adjust the revs to about 750-1000 and then stay there constantly? Mine is wandering about all the place which suggests there is still some electrical gremlin in there somewhere. Cheers, Simon.

Simon, this must be frustrating for you - my 3R idles at around 650rpm and is just about rock steady and, even from a cold start, needs no blipping of the throttle to "settle" the idle.

Sounds like MV will be taking a process of elimination route to solving your problem - they will get there!

[joust]

Sounds like a dodgy lamda sensor to me (but you say that's been replaced), or another air leak in the system.

Either or both will do what you describe.

Added after YS post: Mine did something very similar not so long ago, but "hunted" all the time. Moley fixed it with a new Lamda sensor and exhaust manifold gasket, so it could be something like that?

J

>> Edited by joust on Friday 31st December 00:47

[yellowshed]

Simon,

If MV get really stuck, then you could always pop round the M25 to Roush in Essex. I'm sure we can get this sorted. It's definitely not right - the cars should run fine at a similar idle to when hot. Does yours hunt when hot, too?

Feel free to call me on Tuesday at the office if you want more of a chat.

YellowShed
01277 261400

[m12_nathan]

Every time a post like that appears it makes me proud to own a Noble, supurb support from the factory, the dealers & even the actual person that created the engine map. Awesome

[Siban]

Thanks for the responses guys.....much appreciated.

Trevor,

Only seams to be hunting when it's cold.....once it's warmed up it runs fine which I think is a little odd. I'll let MV have one more go at getting the problem fixed and if still no luck then I'll give you a call.

This is a great forum......have had Frazzer's and Lotus's before but I find this forum the best I've probably come across.

Thanks again.

[mc101]

m12_nathan said:

Every time a post like that appears it makes me proud to own a Noble, supurb support from the factory, the dealers & even the actual person that created the engine map. Awesome

err... eh? need a directory of whose who :-)

[m12_nathan]

Yellowshed (Trevor) does the engine mapping for Noble and works for rousch (a service centre).

Noble encourage all staff and dealers to get drunk and post at 23:30

[mc101]

ooo... and they are close(ish) to me .... Cheers Nathan.

[joust]

Siban said:

Only seams to be hunting when it's cold.....once it's warmed up it runs fine which I think is a little odd. I'll let MV have one more go at getting the problem fixed and if still no luck then I'll give you a call.

Without wanting to set you on a wild goose chase, I have that with the Quattro (similar thing - highly stressed turbo engine...)

It turned out to be the exhaust manifold and inlet manifold bolts had come undone slightly, and so when everything warmed up the manifolds expanded and closed the gap. The bolts were removed, "redlock" (I think) applied, and it was fine for the next few years until the whole manifold had to be replaced due to further cracking (a well known problem on Ur-Quattros).

Worth getting MV to tighten everything up around there and/or replace the gaskets?

J

[LaurenceFrost]

Just another thought - could the engine coolant temperature sensor be playing up slightly? If it's not reporting that the engine is cold then the fuel mixture will not richen, meaning the engine has a hard time running when cold.