Thread: Pulsation at Idle

I am running the NEMU system on my DE with S3 cams. JK set this up for me and tuned it last fall. Then I got distracted by other things and I'm just now starting to learn the software and it's capabilities.

I'd appreciate suggestions on how I might resolve one small issue. My engine is slow to return to idle after the throttle closes and sometimes it will even go through one or two cycles of pulsing engine speed before it drops down to a normal idle. For example, I might be cruising at 40 mph and come upon a stop sign. I throw in the clutch, pop it into neutral and let the clutch out while braking. The idle drops to 1400 RPM then increases to 2000 RPM before slowly dropping down to normal idle (the last drop might take 5-7 seconds).

Any thoughts would be appreciated. I already checked base idle speed and it's on spec.

Thanks.

Bill

I wonder if there could be a vacuum leak in the brake booster system somewhere?

Dave

pm'd you...

Thanks for your responses. I will check out the possibility of a vacuum leak, but I think that this is probably associated with the tune. I oculd be wrong, but my recollection is that it started when I got the NEMU set up.

Check your timing.

Tps issue?

Sounds kinda like some unmetered air may be getting in the system.

How's the PCV routing?

Thanks for the suggestions...

I'm waiting for a warm day to follow up in this.

Bill