Rpm Stutter

[remski2]

Hi.

I've been trying to hunt down my rpm "stutter" for few weeks now with no luck.

I happens while in 1-2nd gear at around 1500 rpm. 

 

Attaching map and a log.

Thanks.

Remi

 

[cj]

Couple of things to look at

1) your ignition timing change a lot from 1500-2000rpm so any change in engine rpm in this range results in a large change in output power so the change is magnified. you may be able to smooth this ignition table just over 1000rpm or so

2) you are running very low injector pulse widths. Looking at the logs, it looks like the first thing to move when the rpm starts to fluctuate is fuel pulse width. it very quickly builds into a bigger problem where i'm guessing the car bucking causes your foot to press the gas pedal a little in time with the rpm jumps and its all down hill from there, but the rpm jumps start before the AP moves. The first couple fluctuations are tied only to what look like very small fuelling changes, but at those low pw's a small number matters, especially if its in the non-linear response range. What injectors do you have, and is the dead time+ SPW data for them correct at your used fuel pressure?

[remski2]

Hi.

I have ID 1000's. I hope I scaled them correctly as there are two different charts.

One is Subaru specific and the other is a general one for ID 1000. (I've believe I've used the general one)

 

Fuel pressure was set to about 52psi with the vacuum reference hose off. 

FYI... I smoothed out the ignition and will try to test it today. 

 

Thanks

Remi

[remski2]

So.. 

Changing the ignition didnt help. I've made all the cells the same and still the same thing.

I've made all fuel cells pretty close to each other and nothing as well.

 

Remi

[remski2]

Well.. I think I figured it out.

I've played around with injection timing and made 0-2000 rpm the same and the stutter is gone.

Hope this helps somebody.

Remski