...third MOT coming up on Saturday and in subsequent MOT's they've always told me it's running rich - and take it to a Nissan dealer and get it sorted. They always give me a new MOT, so I've never bothered taking it to Nissan (don't like the idea of spending money).

 

It regularly returns in excess of 30mpg (its an NA) so it can't be all that rich.

 

Anyway, is there a simple method of reducing the fuel in the mix? Or should I just take out the air filters (ie increase the air) for the duration of the test - would that do it?

 

...and before I had the 2nd test I removed all of the AIV (never to be replaced) stuff and it still gave the same readings.

 

Ideas would be appreciated.

 

many thanks

 

Jack

Hello Jack,

 

Is this what you're looking for? - http://300zx-twinturbo.com/tech/co/co.html

 

Vijay

Vijay

 

...thanks for the info, but that's not it. If you remove all of the aiv equipment (which I have) you finish up blocking off the pipe mentioned. And I've tried the emmissions test with it blocked and with it open. Open it gives a different reading on one side, not much, but enough for the tester to comment that each bank of cylinders read different.

 

Mine still passes the test, with it open or with it blocked - they just say it runs rich. So the question is, how do I get it leaner...

 

 

Again, any ideas would be appreciated.

 

many thnaks

 

Jack

Every Z runs a little rich at idle.

 

a few basic things that might help lean the mixture:

 

-clean throttlebodies + reset ecu.

-clean/replace airfilter(s)

-check timing, for a NA you can set it to 17BTDC without too much worries

-check TPS voltage (idle : ~0.4 volt) and clean the connector

-check Temp sensor connector

Lymon

 

...that's great info - I'll do all of those things.

 

many thanks for your help.

 

Jack