erratic idle and pulsewidth

[just.adam]

As always, thanks so much for the help I always find on this forum. I am hoping that someone can help me with my issue.
I have my idle sorted pretty well but as it idles, it drops RPM unexpectedly and at the same time i see a big spike in pulse width.
This issue is not just at idle but also at cruise. It should be noted that it seems less frequent when the ecu is not connected to megatune. Engine runs well and makes good power otherwise. Here are my hardware details:
MSII V 3.57
2.3 L 4cyl Mercedes / Cosworth 16V
Ford EDIS 4
33lb / hr high impedance injectors
Jeep 4.0L Throttle Body / TPS (IAC disabled)

This datalog shows idle and a period of me holding the throttle at 2500 or so rpm. You can see the spikes in PW and RPM.
Any ideas?

datalog201105312120.msl

Here is my msq

4th try.msq

Thanks again,
Adam

[kjones6039]

Adam,

Several things jump out at me:

rpm is very erratic as is tps
clt spikes ~10 degrees constantly
the spikes in tps is causing huge spikes in mapdot which I think is causing the spikes in pw (accel avtivation)

Let's see what the experts say, but it looks like some sort of noise effecting a lot of those signals.

Ken

EDIT: battery voltage seems to fluctuate a lot also

[Matt Cramer]

Yep, pulse width spikes are definitely your acceleration enrichment, adding too much fuel.

[just.adam]

Thanks for the ideas guys. it gives me a place to start.

Ken, I had the same thought. I do not see these spikes in TPS in megatune but when I saw the log, that is what made me think noise.

Matt,
I am going to try reducing my accel enrichment first but I only turned it up to remedy poor throttle response. Should I be looking elsewhere to improve it?

[just.adam]

Adjusting down the acceleration enrichment did the trick. Nice smooth idle now. I am still confused on how to get the throttle response back. I tried small positive adjustments to the acceleration enrichment and I get the idle issues before I get great throttle response. I do have the X-tau turned off. Perhaps I will try that. The engine physically squirts a single injector in the center of 2 seperate ports as it is a 16 valve. There is a knife edge arrangement in the intake that splits it to each port.

Thanks again guys for your help

[Matt Cramer]

You'll want to adjust your TPSdot or MAPdot threshold, whichever one is making it trigger when it shouldn't be.