AFM settings

[V8ish]

This is a repost from the s series room, hoping you guys might be in a better position to help me out:

I've just bought a new AFM (E-bay bargain @ £43. Following the details from the the V8 website (RPI I think) I've just set it up.

I've also set the throttle pot to 0.35v.(had to do a bit of filing down on the screw holes to get enough adjustment)

It ticks overs sooo much better but the website only suggests between 1-1.5v for a non cat car at the AFM. I've gone in between at 1.25v. I can't really feel much difference between 1-1.5v, so the question is can I go far wrong with 1.25v's and what should I be looking out for?

(I dont have a lamba probe)

Cheers
Grant

[griffter]

Doesn't seem to make much difference to anything. I did some tests on the effect of CO trim voltage on a rolling road and the difference was negligible. I ended up with 1.1v as an optimum. If anything the RPi settings are a bit high - but like I say the difference is negligible and their experience is greater than mine. I think it really is a base idle CO setting - not much more.

[blitzracing]

On the catalyst fuel map, this adjustment is ignored, as the ecu can set its base fueling dependent on the lambda feeback. As a matter of interest I fooled the ecu into thinking the fueling was perfect by clamping the lambda voltages at .45 volts each, and then played with the setting. There was no mixture change right up to 3.5 volts. It does however have a significant effect on the fuel mixture (ie CO output) on the not catalyst fuel map. I asked Mark Adams why there was a setting value on the RPI web site for the catalyst map, and he simply said it was the factory setting the AFM were set to.

Mark

[V8ish]

Interesting, I did think it had more of an effect. I'm sure the car is idling a hell of a lot better and is more responsive. Maybe this is down to the throttle pot adjustment more than anything as it was way out.

Thanks, I'l leave it at 1.25 then.

[That Daddy]

V8ish said:

Interesting, I did think it had more of an effect. I'm sure the car is idling a hell of a lot better and is more responsive. Maybe this is down to the throttle pot adjustment more than anything as it was way out.

Thanks, I'l leave it at 1.25 then.

I would get the idle CO level checked anyway(garage,MOT centre)as already said on the non-cat cars this is your only idle CO adjustment,otherwise you may be driving round with a high CO and thats just waisting fuel,just because the car is idling nicely does not mean you have a sensible CO level,infact on the contrary the RV8 will run quite happily rich on idle with the owner knowing none the wiser,your pocket will know though

[blitzracing]

Just a thought, a very worth while upgrade to a pre cat engine is to install a couple of Lambda probes, (This will need a couple of threaded rings into the exhaust manifolds, plus a bit of wiring. You probibly already have the sockets in your loom tucked away some where) and run a TVR Chimaera chip. You also need to change the tune resistor. Then the ECU can run the engine at its most efficient. I really dont understand why Range Rover did not do this as the 14cux has all the nessasary bits built in. Hold on, it saved the cost of two lambda probes!

Mark