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Surging Idle - DynoJet

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I have been running around in circles trying to get this surging idle to flatten out. Anyone tuned a Can-Am X3 with DynoJet software? I am running out of ideas on things to try...

The motor idles well while under the cold start enrichment but when it comes out...the surging begins. The factory ECU is very limited in tables and options but the DynoJet re-flashing platform is very affordable for customers so I am trying to stick with it instead of throwing on an Emtron.

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Be sure you don't have any vacuum leaks.

Sounds like you just need to add a bit of richness overall to the idle area. Can you change the requested AFR (Lambda)?

I absolutely can. It seems to be happy idling around 0.83. Just seems extreme to me to idle that rich. Not sure if E85 will foul plugs that rich?

I should probably give some build details...

900cc 3 cyl

garrett 2860 turbo

E85 with 1300 cc injectors etc

Cams - I have details if it helps

How about if you change the target from 1.0 lambda to 0.95 (or as low as 0.90 if it needs it). Your problem could be the minimum pulse width with 1300cc injectors, pretty big for a 300cc cylinder volume.

0.90 helps settle the rpms for sure but still has some surging from about 1400-1600 rpm (target is 1350-1400).

Blue - Target Lambda 1.0

Red - Target Lambda 0.90

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Next, I would try to change the ignition timing -- it's about 6 degrees when the RPM surges, how about reducing it to 4-5 degrees at idle and see what happens. Or perhaps the timing is retarded enough to be adding turbo energy -- so you should also try advancing it a bit to see what that does (it might allow you to close the throttle stop more).

Lastly, since you have changed cams, is there any Engine Speed that will smooth the warmed up idle (1600? 1800?).

For injectors I went with Injector Dynamics 1300 XDS at the setting below with 1 exception. On the injector scaling I am set at 0.051500. The VE table won't taken over ~300 value so to run 3 bar map sensors I'm trying to trick the ECU into a closer to stock VE value (2.5 bar) for the fueling I need.

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I thought the same on the timing... I drop it 2 degrees will little effect but I may not understand how the table is effecting timing. Here are the timing tables and options I have.

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Since I assume you're in idle control, you might look under your "idle" folder for appropriate settings. Also note, I edited my earlier post while you were typing your latest...

Inside the idle option are only idle speed options. I will test some timing changes and post back.

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After a few re-flash's in attempts to find the best table to retard the timing...I believe we found success! 3 repeat tests with a nice calm idle. We'll see how it cold starts but I think I'm ready to work on some stuff outside the IDLE!

Next question, what's the preference, push closer to lambda 1.0 and keep the timing retarded 5 degs or keep it at 0.9 lambda and try to get some timing back?

Update photo of data log on current idle.

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