Rich/lean lambda values during acceleration

[MaBaMM]

Hi Members,

today we went to the test track for the first time with our car and we got some serious problems with our engine or application.

We used a applied map from the dyno to the car. We set for all loads lambda to 1. In very high load we set it to 0,9 or 0,85.

As we crank up the engine the lambda value was around 0,9. Also when the engine have optimal temperature.

What can be the reason for that?
All sensors are the same. The mapping and other settings are the same. No changes. No Trims or Compensations for Fuel wich would it change.

On the track we have instructed our driver to give high throttle shocks and hold them for a second. Then he should let out the throttle compelety and do it again for the whole track.
We heard many ignition fails. And the driver wasnt amused.

After this short stint we look at the loggings and notice lambda values from 0,9 to 3.
Look at the logging below.
I think it is normal when the throttle is pushed very fast to the maximum the lambda value will be leaner. But not from 0,9 to 3.
Also the lambda value wasnt hold the aim value of lambda 1 or 0,9. It is changing rapidly also when the throttle is even 100%.

We have looked on all other channels to search the reason for such a bad behaviour, but we didint found it.

Where should we search?

It seems the fuel enrichment by acceleration isnt active or to less.
Fuel enrichment by acceleration/deceleration on the M800 is an easy function, but how can we set up this by the M150?

Thanks for your help.

[David Ferguson]

Did you tune the engine on an engine dyno or a chassis dyno? Was the exhaust system fitted to the car the one that was used on the dyno? Anything else different such as airbox / air filter, fuel pressure?

Normally, the M150 uses Fuel Film Modeling to determine extra fuel needed when pressure and load requirements change. You enable this with "Fuel Film Mode". The simple first step to to change "Fuel Film Primary Scale" to see if you can find a value that allows your engine to stay responsive -- in many cases that's all that needed. If you have secondary injectors, there is a corresponding "Fuel Film Secondary Scale" as well.

I looked at your data, I see Ignition Cylinder x Output Diagnostic change to 5 (Ignition Cut is active) -- you don't log the Engine Speed Limit, so I can't tell if this is a revlimiter around 7200 RPM because the engine coolant is only 64 degC.

[MaBaMM]

Hi David,

We tuned on an engine dyno.
Fuel pressure is the same. Oil pressure is different because on the car we have a dry sump on the dyno no dry sump.
Exhaust system is fitted. The only difference is that we just have one lambda on the car and four on the dyno.

Ok i have expeceted that this will be the right function. We also have enabled it yesterday but there was no great change.
We will set up this function an look how it works.

So we have looked on all rpm limiters but all are set to 11000rpm.
There is an ignition cut during up shift but this is not the reason.

We will logg more chabnels and also the rpm limiter to fibd the reason.

Thank you

[David Ferguson]

Suggest you log Engine Speed Limit as well as Engine Speed Limit State (this will tell you the reason for a speed limit). Another good one is to setup the Warning Light Resource and log Warning Light and Warning Source (the reason for the Warning Light).

[MaBaMM]

Hi David,

Our major problem was that we dont have applied the fuel film. So in the moment when the throttle change from 20% to 100% the engine load increase rapid but the fuel doenst reacts on it so fast.

We fixed it. Thanks a lot