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-   -   Wild Idle After Sequential Upgrade (https://www.miataturbo.net/megasquirt-18/wild-idle-after-sequential-upgrade-63765/)

sccaax 02-24-2012 07:58 PM

Wild Idle After Sequential Upgrade
 
I just installed the sequential upgrade a couple days ago. Only real issue I have is on startup, where the idle fluctuates between 500 and 1500rpm for about 10 secs after startup. Any thoughts on what to try to adjust in what direction?

Thanks

sccaax 02-26-2012 07:26 PM

Nobody? I'm thinking ASE might be too rich...

Matt Cramer 02-28-2012 12:34 PM

Or it may be too lean. It might help if you could post a data log and MSQ.

sccaax 02-28-2012 07:14 PM

Datalog wouldn't help much, since it all happens in the first 5 to 10 seconds and probably 100% fuel related. The LC-1 doesn't start recording for about 10 seconds after start.

Can you start a datalog before cranking? Didn't realize that if so. Good to know.

It's not bugging me too bad yet, so I haven't started messing with it, but here's my mode of thinking: When I switched to sequential injection from batch, the fuel is firing directly into the cylinder on startup instead of 50% of it ending up puddling on the back of the valve and splashing around landing on the inside of the intake manifold. When starting at 300rpm, the engine isn't producing enough vacuum to pull the fuel off the inside of the manifold and vaporize it properly. Chances are, my ASE values need to be a lot lower than with batch injection. Hearing from someone that's made the switch would be helpful.

Also, I flooded the motor after stalling the other day due to this issue. Had to hold the throttle open for flood clear.

Matt Cramer 02-29-2012 03:23 PM

Yes, you can start a log before cranking. You won't capture AFR settings but it may give a bit more info. I would suspect less ASE may help matters.

sccaax 02-29-2012 08:08 PM

It's actually Cranking PW I need to change and not ASE. I have ASE taper of 2000 cycles for all temps, so that tapers over roughly 1-2mins and would show up for longer than the first 5 seconds of start. Cranking PWs are as I describe above with the pooling prior to start. ASE could probably also stand to be reduced a bit for similar reasons.


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