Hi Folks,

Posted on here before about my Westfield with standard 1.8 Zetec blacktop engine, GSXR600 TBs and Megasquirt ECU. Although the engine starts and runs OK, it is slightly uneven with AFRs fluctuating between 13- 14.5. It's been like that really since I got the ECU installed and running but I decided to park it and get on with the rest of the build. I'm now at the stage where I can see the IVA looming and need to address the uneven running because I can't see it passing the emissions test with the fluctuating AFRs and uneven running. I've ruled out anything that relates to a particular cylinder (plugs, leads, injectors etc) and I'm now beginning to think there's something fundamentally wrong with my MS setup. I've balanced the TBs with a manometer and it helped but I'm still getting the misfire and the AFRs meandering up and down (plugs are black & sooty). I'm using Alpha N algorithm but I've heard that TPS is the way to go with TBs? Also haven't touched dwell - currently set at 3.1 with spark duration of 0.9. I've experimented with the fuel and ignition map but none of it made much of a difference. I'm in Glasgow and I'm having difficulty finding anyone local who does MS, especially since the car is not on the road yet and would have to be trailered to a rolling road. I'd appreciate any input from you chaps.

Cheers,

Paul.

http://www.extraefi.co.uk/MAP_Alpha_N.htm


have a read of that if you haven't seen it before, with my TBs I use TPS, bogg bros actually filled in the vacuum ports on the bike iTBs for me, that is how certain they were that MAP wouldn't work.

however, if you are using Alpha-N that is TPS.. but maybe you don't have it set in all places and if you have the MAP sensor plumbed in it is getting a bit confused?

Thanks for the tip Chris,

The settings were indeed different for fuel and ignition as described in the article, it will be interesting to see if it helps any.

So TPS is Alpha-N! I'm assuing then that my vaccum take-off is redundant and I can remove it then?

Cheers,

Paul..

mine is, just has no hose going to it in the MS. block it off engine side, else it will just suck air in and uneven things up that side(possibly)

OK, so I changed the setting for primary ignition load to Alpha-N and fired it up again with much the same results. However, when I disconnected the vacuum pipe from the MS and plugged the manifold end things changed dramatically. The AFR dropped to 11.1 or so and remained very stable, connecting the vacuum back up increased the AFR to 13 - 15 varying as usual. My next question would be, is there another area within TS that the MAP is affecting? I would have thought that disconnecting the vacuum pipe would make to difference if I had removed all references to it in TS.

cheers,

Paul.

I can't explain the blocking off vs not, except to think some air must be getting in. however, if it is better when blocked off, I would leave it like that. Then you just get on with adjusting the fuel map. A low AFR means too much fuel.

How about the project settings, is that set to Alpha-N ?

At the bottom of the link, there is a link to tuning your MS.

Did you build your MS ? did it come pre configured for something?

Here's a guy with the same issue:

http://www.msextra.com/forums/viewtopic.php?f=101&t=44378

One of the replies states that the "Multiply Map" checkbox causes this behaviour but MS states that 99% of installs require this.

Built the MS myself and just used the base settings, adjusting the required fuel from what I'm seeing on the AFR gauge.

It does seem to be much happier when running rich but that's obviously no use for emissions/IVA

cheers,

Paul.

you've lost me there, I'm gonna guess you are on MS2 or 3.. I am using M1 extra.

Yeah, I'm using an MS2 V3

P