idle timing with Holley HP efi
03-17-2021, 01:20 PM
#1
idle timing with Holley HP efi
Engine is 1400hp procharged Gen7 sitting in a nordic heat Spinning Max 5 34P, the problem I am having is putting it in gear and it stalling........
I watch the idle bubble drop to new fuel cells and it gets rich and stalls.
I am thinking i need to lean those areas out so it doesnt stall. It idles at an afr of 13.2.
I am using timing control for idle,
Anyone have this problem?
I watch the idle bubble drop to new fuel cells and it gets rich and stalls.
I am thinking i need to lean those areas out so it doesnt stall. It idles at an afr of 13.2.
I am using timing control for idle,
Anyone have this problem?
03-17-2021, 02:04 PM
#2
Registered
I'm not running EFI, but I am using timing for idle control. I have found that by ramping up the timing below your idle set point it works much better than just idle control alone. I ramp up to 36 degrees by the time it gets down to 500rpm plus idle control it works perfect.
03-17-2021, 02:42 PM
#5
Registered
I assume the IAC is still in play? and responding quickly to the controller commands, or with the Procharger has the IAC been replaced with another source for Idle air control?
Just a thought not knowing the details of your engine management setup.
Just a thought not knowing the details of your engine management setup.
03-17-2021, 02:48 PM
#6
Registered
I tuned my 502 with Holley EFI last summer. You can get away from that problem easy. Are your idle timing near 10*? If you have more idle timing, retard it near 10 so you can screw idle air little up. Then watch what route MAP value go on chart when engine stalls and make agressive timing advance to those points, I use 25*. Take ignition controlled idle off from basic ignition setup, it doesn't work on my engine. It have to done straight to ignition chart.
After that tune fuel map right, if you have O2 sensor connected it's easy to adjust AFR to somewhere 12.5-13 when idling on gear, 14 is ok on neutral.
Hope you get some help.
After that tune fuel map right, if you have O2 sensor connected it's easy to adjust AFR to somewhere 12.5-13 when idling on gear, 14 is ok on neutral.
Hope you get some help.
03-17-2021, 03:40 PM
#7
I tuned my 502 with Holley EFI last summer. You can get away from that problem easy. Are your idle timing near 10*? If you have more idle timing, retard it near 10 so you can screw idle air little up. Then watch what route MAP value go on chart when engine stalls and make agressive timing advance to those points, I use 25*. Take ignition controlled idle off from basic ignition setup, it doesn't work on my engine. It have to done straight to ignition chart.
After that tune fuel map right, if you have O2 sensor connected it's easy to adjust AFR to somewhere 12.5-13 when idling on gear, 14 is ok on neutral.
Hope you get some help.
After that tune fuel map right, if you have O2 sensor connected it's easy to adjust AFR to somewhere 12.5-13 when idling on gear, 14 is ok on neutral.
Hope you get some help.
Are you using timing for idle control? ASM told me to throw out in the entire area 15-18 degrees then timing idle control has a better chance
I do use the IAC i had it on slow but seems best idle is medium or fast
03-17-2021, 04:10 PM
#8
Data log , see which cells it stalls in , increase timing in those cells .
Air fuel ratio makes a little difference but not a whole lot . (on my blowers anyway)
Also under Idle, you want P term to be up there .. I think mine is near 60 .. that way the ECU reacts quickly to prevent the stall.
Not sure at which point I took a picture of my timing but here it is .
Air fuel ratio makes a little difference but not a whole lot . (on my blowers anyway)
Also under Idle, you want P term to be up there .. I think mine is near 60 .. that way the ECU reacts quickly to prevent the stall.
Parameters - Idle Spark - P Term
Description: The speed at which the ignition timing is varied to maintain target idle. It is scaled from a value of 1 to 100.
Parameters - Idle Spark - D Term
Description: The D term helps eliminate overshoot.
Not sure at which point I took a picture of my timing but here it is .
03-18-2021, 07:00 AM
#9
Registered
OK yeah that was what i was told. I need to bump timing UP on those cells then look at fuel. I
Are you using timing for idle control? ASM told me to throw out in the entire area 15-18 degrees then timing idle control has a better chance
I do use the IAC i had it on slow but seems best idle is medium or fast
Are you using timing for idle control? ASM told me to throw out in the entire area 15-18 degrees then timing idle control has a better chance
I do use the IAC i had it on slow but seems best idle is medium or fast
My engine is 502 mag efi, that engine iac is so slow that it not help nothing. Late idle timing make engine idle slow, so you put more basic idle air in and engine idle good. When on gear, advanced timing with little bit more air gives more power to idle on gear
03-19-2021, 11:01 AM
#10
Geronimo36
Gold Member
I've found that the surge is not always a result of timing that a lot of time is results from the cells being too rich or too lean above or below the target idle speed. Basiclly when the engine senses a change in MAP it will go lean or rich and then you get the surge. The timing can fix it but the real problem is in the big differences in the tables above and below. You can see this when you're in live mode and the green dot is moving all over the place while it's surging. Once you smooth those tables it usually gets better. Takes a lot of patience sometimes.
