Setting the Accel Sourse in M84

[otto69]

I must be doing something wrong.
I'm trying to change the Accel Source from MAP to TP, but even though I change the # in the 'Accel Source' setup the Accel tables still remain in MAP / RPM.
The main fuel table uses MAP, is this why the accel tables cant be changed to TP ??

Reason is, I can't tune out a hesitation on acceleration with MAP / RPM and wanted to try TP / RPM.
Any help will be greatly appreciated.

Clayton

[rsscotty]

I'm under the impression that you can set the Accel source to TP in Misc. setup, then go to your accel table you want to adjust. If you have dual axis showing, right click on the screen and click on Axis Setup. At the top left corner you will see x and y axis. Click on y and then uncheck the enable box and then click on OK, and this should get rid of the map axis on the setup page and you can adjust your needs just by rpm. This then should be based on TP since you set that in your Accel Source. The RPM axis should be sufficient to tune the accel, since I don't think you can make a dual axis with TP and RPM.

You can do the same in all individual accel and decel tables.

[Scott@FP]

The table axis channel sources are locked on M84.
It isn't map and rpm, its efficiency and rpm. If your efficiency calc method is set to TPS, effcy is TPS, if set to MAP, it is pressure. Accel source sets the channel who's delta change triggers accel fuel, the accel tables determine how much and when. As previously stated you don't HAVE to use the Y axis in the accel tables, you can turn them off, but there's really no reason to, with MAP as the Y axis you want higher amounts of accel fuel when at low RPM and low MAP, to zero accel fuel at high MAP and high RPM, with accel source as TPS.

[otto69]

Thanks Guys
Yeah I tried to change the table axis and it appeared locked, at least it wasn't me pressing the wrong button...
I'll try the single axis and see if that helps.
Scott, when you say

Accel source sets the channel who's delta change triggers accel fuel

and I'm using MAP as efficiency. If I go back to a single axis (rpm) and have the accel source set as TP, the accel fuel will be added by the TP and not efficiency (MAP in my case) ??
The problem I'm having, there is a hesitation off idle (slow and quick throttle movements) no matter how big or small I make the numbers in the accel clamp and sensitivity tables it's still there.
Would there be something else that could cause or effect this ??
Sorry, first time with EFI and there's no Motec dealers near me.
cheers

Clayton

[Scott@FP]

Log Fuel Accel at a fairly high rate so you can see the effect. Its the rapidity and magnitude of the change in the accel source that triggers accel, and the axis channels X or X and Y determine when and how much. Accel Threshold has a large part to do with it as well, set this too high and accel won't trigger, set too low and it triggers too much.

Accel source- MAP= Rate of change and delta change of MAP (above Accel Threshold setting) triggers accel fuel.
Accel source- TPS = Rate of change and delta change of TPS (above Accel Threshold setting) triggers accel fuel.

Accel tuning triggered by MAP is tricky and sensitive, I don't recommend trying it at first.

Clamp sets the maximum amount of accel fuel, by default RPM x Effcy Y.
Clamp Comp lets you increase the clamp via RPM X and coolant temp Y, need more accel fuel with cold engine to zero extra fully warm. Can probably just use coolant temp Y.
Table values are in % IJPU, so if you have large injectors with a small IJPU, numbers will be much higher than say an IJPU of 10.
Sensitivity is where you set sensitivity higher for low RPM/load and nearly zero high RPM/load

You'll want higher sensitivity and a higher clamp the lower the RPM and MAP value.

Also the main fuel table needs to be close to correct before any meaningful accel tuning can be done. Slow throttle application with a dead spot is not an accel fuel issue, its either main fuel or timing.

[otto69]

Thanks Scott
I'll have to read up on logging and how to setup and read it. What would be a high rate for logging fuel accel ?
I set the 'Accel Threshold to 50 as per the on screen recommendation, could I try a smaller number say 40, 30 or is this just a band aid ?
Thanks for the breakdown of the values required for the tables, it's making more sense as time goes on.

The fuel map was setup on the dyno and the low load sections was done on the road.
IJPU is around the 43 at idle and lambda looks good.

I'll have a play with the ignition and see if that changes anything.
cheers

Clayton