Jump to content

Over Run Fuel Cut


Recommended Posts

Yes, can work ok.  Those settings look reasonable - KPa might need tweeaking - depends what your engine actually does and suggest that the coolant temp should be 70ºC.  You only really want it to do it when fully warmed up and you are right off the throttle or it makes for a jerky drive.

 

Nick

Link to comment
Share on other sites

The default settings are quite conservative, agree with Nick that it looks fine. I had it down to 0.7s delay, 1150rpm, 30kPa, 45c and 4% TPS, though that was after months of refining the VE table.

 

It's a must have with the megasquirt, the fuel savings you'll make versus not having it (or running carbs) are substantial!

Link to comment
Share on other sites

Thanks Nick/Richard,

 

Had a bit of time to play with this today, I set the RPM to 1250, Delay to 0.7s, Temp to 70°C, 30kPa as I seemed to be around mid 20's on the overrun and the TPS at 4% as mine is at 3% at idle. This had no adverse affect to the smoothness of the drive and I could see the AFR reading go off the scale lean on the overrun, so I'll just leave that as it is as it seems to work fine.

 

One odd thing though is that my Smiths rev counter drops to 0 as soon as the fuel cut kicks in and comes straight back as so as I touch the accelerator and the fuel cut stops, the revs on the Tunerstudio dash are still, any ideas?

 

Darren

Link to comment
Share on other sites

 

One odd thing though is that my Smiths rev counter drops to 0 as soon as the fuel cut kicks in and comes straight back as so as I touch the accelerator and the fuel cut stops, the revs on the Tunerstudio dash are still, any ideas?

 

Darren

 

 

That's odd. Mine definitely didn't do that on either the MS1 extra firmware (Vitesse, some time ago) or on MS2 extra firmware that I had on the PI.

 

Vitesse currently doesn't have it as using MS2 with original B & G firmware which doesn't have the facility.  I could upgrade I suppose but the B & G is seamless whereas the Extra version on the PI would do strange things sometimes.

 

Where are you taking the tacho signal from?

 

Nick

Link to comment
Share on other sites

The Microsquirt must be turning it off then - possibly turning the whole spark off?  My Vitesse tacho is driven by the diagnostic output on the EDIS plus a little amplifier circuit that mimics the coi,l so wouldn't have been affected as EDIS would run all the time whatever the ECU did.  Likewise, my PI tacho (current sensed) was triggered by the coil supply and also had EDIS.  Seems like a very odd thing to do though.....

 

Nick

Link to comment
Share on other sites

I did try to pick up the tacho signal from the coil originally but it didn't work, though that was before I'd had it converted so that might be an option if I can't resolve through Tunerstudio. On the plus side it's a visible reminder that I'm saving fuel  :banana: .

 

I posted the question on the MSExtra forum, but need to supply a data log, job for the morning.

 

Darren

Link to comment
Share on other sites

As the points pickup in the distributor is no longer needed

why not remove the condenser, fit a pullup resistor and take

this for the tacho?

 

By the way: I would set the TPS to 0 and 100% with

Tunerstudio because whenever something is changed

with the throttle the electronics can be quickly adapted.

Link to comment
Share on other sites

  • 2 weeks later...

As the points pickup in the distributor is no longer needed

why not remove the condenser, fit a pullup resistor and take

this for the tacho?

 

Dizzy long gone, I have the Ford Coil Pack mounted there now.

 

By the way: I would set the TPS to 0 and 100% with

Tunerstudio because whenever something is changed

with the throttle the electronics can be quickly adapted.

 

Are you saying that the TPS should be calibrated to 0% at it's partially open idle position? I calibrated the 0% without the throttle cable connected so it was fully closed, then opened up slightly to get the desired idle speed, so it's currently at 3% at idle.

 

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

I am running an older version of the MSExtra Firmware, so may just update it to the latest version in case the rev counter thing is just a bug, as it seems nobody else has this problem, the MSExtra Forum has provided no clues either.

 

Just so I don't screw up my current tune during the process, obviously I save it and reload the after the update, but are there any settings that will need manually changed after. I seem to recall reading that some sensors need re-calibrating after a firmware upgrade, but can't find where I read that.

 

Darren

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...