Page 1 of 2
Seeing erratic timing at idle even though its set at 27 all
Posted: Tue Apr 13, 2021 2:30 pm
by Mr DOHC
Hi gurus.
My idle timing is very erratic even thgouht i have 27 degrees put in at 400,800,1200 at all load points. As you can see its hovering around 18-22 degrees.
What could be causing this? i cant see anything that might be skewing the base timing
- Snip
- Capture.PNG (28.88 KiB) Viewed 2377 times
- 1i.xdl
- Log
- (342.13 KiB) Downloaded 132 times
Re: Seeing erratic timing at idle even though its set at 27
Posted: Tue Apr 13, 2021 5:08 pm
by 'quipt4it
Have you set the Base Timing in Diagnostic Mode (10 degrees).
There are always fluctuations in distributor mechanisms. Play between the cam and distributor gear, end float etc.
Re: Seeing erratic timing at idle even though its set at 27
Posted: Tue Apr 13, 2021 6:05 pm
by vlad01
This completely normal, what you are seeing is the idle spark control from closed loop idle in action. It uses spark timing to speed up/slow down idle in real time, this is why the spark is all jumpy.
Also there is a separate idle spark table, default values are around 20º, that is probably why they aren't changing as the main spark table is used for off idle conditions.
Re: Seeing erratic timing at idle even though its set at 27
Posted: Tue Apr 13, 2021 6:35 pm
by Mr DOHC
vlad01 wrote:This completely normal, what you are seeing is the idle spark control from closed loop idle in action. It uses spark timing to speed up/slow down idle in real time, this is why the spark is all jumpy.
Also there is a separate idle spark table, default values are around 20º, that is probably why they aren't changing as the main spark table is used for off idle conditions.
I haven’t had a chance to set my IAC right so that might be an issue. But the idle spark is set to 27 as well from 20-60 kph and it idles at 45 so I don’t know how that could be it.
Re: Seeing erratic timing at idle even though its set at 27
Posted: Tue Apr 13, 2021 6:36 pm
by 'quipt4it
Your Idle Spark Advance (as a function of MAP) is 22.15 degrees, it looks to be idling in the 60 KPA region.
Bump the 60 KPA Idle map to 27 degrees if that's what your aiming for.
Re: Seeing erratic timing at idle even though its set at 27
Posted: Tue Apr 13, 2021 7:51 pm
by Mr DOHC
'quipt4it wrote:Your Idle Spark Advance (as a function of MAP) is 22.15 degrees, it looks to be idling in the 60 KPA region.
Bump the 60 KPA Idle map to 27 degrees if that's what your aiming for.
I swear I changed that!
Re: Seeing erratic timing at idle even though its set at 27
Posted: Tue Apr 13, 2021 8:24 pm
by 'quipt4it
Swearing is not the same as doing lol
Re: Seeing erratic timing at idle even though its set at 27
Posted: Tue Apr 13, 2021 8:26 pm
by Mr DOHC
ok, i cant change that, everytime i do, and then go bakc in its set back to 22. Is it changeable?
Re: Seeing erratic timing at idle even though its set at 27
Posted: Tue Apr 13, 2021 8:28 pm
by 'quipt4it
You have to hit enter, it will show up in red, then it will go in.
Although 100 will show as 89.65 haha
Re: Seeing erratic timing at idle even though its set at 27
Posted: Tue Apr 13, 2021 8:58 pm
by Mr DOHC
did that, uploaded to emulator in realtime, nothing, saved to bin on PC, nothing.