Fuel cut

[Dan_G]

This is a topic that has been discussed before (just been looking at previous posts).

Has anyone found out which of the following parameters our VR4's monitor in determining when to give the engine some lovely fuel cut?

1)Boost pressure
2)MAF signal (mass of air/oxygen)
3)Lamda sensor signal (lean fuel mixture)
4)other?

Today I accelerated (on my private test track) from moderate trottle in 4th to WOT to over take, and got fuel cut :embarasse , I backed off the throttle and noted speed, rpm and max boost(peak hold) as 80mph(ish), 4000rpm, and 0.92 kg/cm^2 (0.9bar).

Now as the boost spike was relativley low, this would suggest fuel cut is determined by something other than boost. I say this because I recently fitted AVC-R boost controller and durning set-up I had boost spikes of over 1bar on quite a few occasions but it DID NOT fuel cut.

If its MAF signal then that sucks(excuse the pun) coz theres nowt I can do apart from play with the MAF signal...which I dont fancy.... melted pistons... eek!

If its Lamda signal I can just try and supply more fuel with a fuel pressure regulator......

hmmm, any comments welcome :thumbsup:

Dan

[Kenneth]

Do a search on fuel cut, there is quite a lot of discussion about it.

From my understanding, its the MAF unit reading that determines fuel cut. The ecu will cut fuel when the air flow reaches a pre-determined level.

Due to the nature of air, cold air is more dense than warm air. Because of this, you can actually flow more air volume on a cold day with less boost than on a hot day. This may be why you are getting cut at different boost pressures.