Running lean?

[Richybaby]

Had the MOT done over the weekend (as mentioned in previous post), passed emissions ok, but they mentioned that she's running a bit lean at ldle/low revs, ok when revs picked up, is this ok/normal for these engines (450SE) or not, shall I just get her tuned or could there be something else to check first, she runs and goes great I can't say there's any problems there. What d'you recon guys?

[TVRleigh_BBWR]

Most run rich.
Is she a flapper or hotwire. as if its a flapper and its just at idle you can adjust the idle mixture on the AFM.

[dickymint]

TVRleigh_BBWR said:

Most run rich.
Is she a flapper or hotwire. as if its a flapper and its just at idle you can adjust the idle mixture on the AFM.

Personally I would leave this one alone and use the Idle screw on the plenum.

[TVRleigh_BBWR]

I thought he wanted to adjust the mixture not the idle speed though.

[tempus]

Runs great, goes great ,it can`t get better so leave it alone.Tempus

[350zwelgje]

At idle not really a worry. Important is: only when you want power and it is running lean at the same time: that can/could wreck the engine (picking etc). And as said before most (non rolling road tuned, non adjustable/rising rate fuel pressure regulator: like in properly tuned) run lean at top end, and that should worry you. If the rest of rev-range and top end is not lean, you should be ok.
Remark: If running too rich (mpg below 10? for example), the oil is flushed from the bores and gets contaminated and you can expect engine wear to go up (or you should replace the engine oil more often).

Rob

[Richybaby]

Hi guys, just for info, it is a flapper and has a rising rate fuel pressure regulator fitted, base pressure (engine not running) adjusted to 39psi/2.7bar as per the bible. Cheers.