HarleyTechTalk

Dyno & Tuning Zone => AFR & Tuning Zone => Topic started by: 1stop on June 18, 2020, 01:24:48 PM

Title: accel enrichment at idle on logs
Post by: 1stop on June 18, 2020, 01:24:48 PM
i got an 09 cvo (stock)in shop that has erratic idle. logging with Powervision & using Megalog viewer to read logs. im getting accel enrichment at idle. Looks like only at hot idle. tps toggling between 5 & 6 %. anyone seen this? possible cause? not working the throttle at all 
Title: Re: accel enrichment at idle on logs
Post by: aharp on June 19, 2020, 02:27:41 PM
I have not. Does the kpa vary enough to cause the timing to change or is it all set the same in that general area? It's interesting because I wonder if the small rapid change in throttle plate is enough to trip the accel enrichment table
Title: Re: accel enrichment at idle on logs
Post by: kd on June 20, 2020, 05:13:46 AM
Is the engine open or closed loop and up to temp for this reading?
Title: Re: accel enrichment at idle on logs
Post by: Sunny Jim on June 20, 2020, 05:35:40 AM
Does it have a performance cam? Hi Compression?
Title: Re: accel enrichment at idle on logs
Post by: Hossamania on June 20, 2020, 07:58:46 AM
Quote from: Sunny Jim on June 20, 2020, 05:35:40 AM
Does it have a performance cam? Hi Compression?

OP says stock.
Title: Re: accel enrichment at idle on logs
Post by: Jamie Long on June 20, 2020, 04:34:36 PM
Quote from: 1stop on June 18, 2020, 01:24:48 PM
i got an 09 cvo (stock)in shop that has erratic idle. logging with Powervision & using Megalog viewer to read logs. im getting accel enrichment at idle. Looks like only at hot idle. tps toggling between 5 & 6 %. anyone seen this? possible cause? not working the throttle at all

In your tune what value is in the Fuel> Acceleration Enrichment Multiplier table?
Title: Re: accel enrichment at idle on logs
Post by: Pirsch Fire Wagon on June 21, 2020, 02:42:58 PM
Check Intake AND Throttle Body Seals before moving forward. I have seen this while tuning but not with the PV. Can you post a screenshot capturing it?
Title: Re: accel enrichment at idle on logs
Post by: rbabos on June 22, 2020, 08:40:33 AM
Acel fuel will trigger on a crappy idle due to rpm fluctuations and rapid MAP changes that is a side effect. Usually bad afr at idle for whatever reason. If there's timing changes within this rpm lope area,  that feeds into it too, exaggerating the condition for bad idle. Not so much the settings in the Acel fuel table but the conditions that trigger it in the first place. Smooth the idle and it won't trigger it .
Ron
Title: Re: accel enrichment at idle on logs
Post by: Jamie Long on June 22, 2020, 10:29:35 AM
Quote from: rbabos on June 22, 2020, 08:40:33 AM
Acel fuel will trigger on a crappy idle due to rpm fluctuations and rapid MAP changes that is a side effect. Usually bad afr at idle for whatever reason. If there's timing changes within this rpm lope area,  that feeds into it too, exaggerating the condition for bad idle. Not so much the settings in the Acel fuel table but the conditions that trigger it in the first place. Smooth the idle and it won't trigger it .
Ron

If the Acc Enrichement "Multiplier" value (not the Acc Enrichment table) is changed from 1.0 it can very much cause this exact issue as it essentially breaks the tune. It could also be a host of other things including an intake leak, improperly tuned VE & spark tables, etc...
Title: Re: accel enrichment at idle on logs
Post by: 1stop on June 23, 2020, 03:52:28 AM
it as a stg 1 harley cal. exhaust is stock. was running poorly. ended up being plug wires. just never seen that before. will be paying attention to it next time i log another bike.