Advice on Pinging issues with PV Target Tune
so it could well be that you timing needs to be altered-
when the throttle is opened suddenly, like to accelerate, the timing should retard.
on most motors the intake vacuum is used to control this...on an old v8 a vacuum advance on the distributor was used, on the carbed HD's a VOES switch on the intake and now with EFI a sensor- ensure that the timing is retarding when the vacuum drops. ( on my old panhead, the left twist grip controls timing- the rider advances and retards spark timing to keep the motor working as best as you can- on old cars the spark advance might be a lever on the steering wheel)
fuel mixture- too lean will ping- alot of riders and crap tuning techs will not recognise a vacuum/advance problem and just add fuel- that would be the guys with soot on the backs of their bikes- you've seen and smelled them on the road.
tuning is always a balancing act and the multiple factors have to be considered, just "more fuel" isn;t always the fix and too rich is bad for performance and bad for the motor over time
physical problem: "glow plug" carbon deposits built up in the heads or pistons and/or a sharp protrusion of metal, a sharp edge can get hot and act as a glow plug, causing the fuel/air mixture to ignite before the spark.
previous pinging can cause these sharp edges as the metal is damaged- it only gets worse
If you are working with FM, the better the info you give them regarding throttle position and rpms, the better they can work with you- I am sure that they can give you best advice.
Mike
Last edited by mkguitar; Feb 16, 2017 at 10:15 AM.
so it could well be that you timing needs to be altered-
when the throttle is opened suddenly, like to accelerate, the timing should retard.
on most motors the intake vacuum is used to control this...on an old v8 a vacuum advance on the distributor was used, on the carbed HD's a VOES switch on the intake and now with EFI a sensor- ensure that the timing is retarding when the vacuum drops. ( on my old panhead, the left twist grip controls timing- the rider advances and retards spark timing to keep the motor working as best as you can- on old cars the spark advance might be a lever on the steering wheel)
fuel mixture- too lean will ping- alot of riders and crap tuning techs will not recognise a vacuum/advance problem and just add fuel- that would be the guys with soot on the backs of their bikes- you've seen and smelled them on the road.
tuning is always a balancing act and the multiple factors have to be considered, just "more fuel" isn;t always the fix and too rich is bad for performance and bad for the motor over time
physical problem: "glow plug" carbon deposits built up in the heads or pistons and/or a sharp protrusion of metal, a sharp edge can get hot and act as a glow plug, causing the fuel/air mixture to ignite before the spark.
previous pinging can cause these sharp edges as the metal is damaged- it only gets worse
If you are working with FM, the better the info you give them regarding throttle position and rpms, the better they can work with you
Mike
I am sure you'll get this sorted- I forgot to mention octane- I do pretty ok on 89 but 91 allows the ecm to fully advance spark timing.
fully advanced timing is used for economy ( mpg) at part-throttle cruising
fuel additives such as sea-foam can cause trouble here too until it runs through
one more thing: the ecm uses ion-sense to evaluate the state of burn in the combustion chamber, and this will help control spark. many models have problems if the plugs or wires are changed from stock spec- even screamin' eagle can cause problems
mike
I am sure you'll get this sorted- I forgot to mention octane- I do pretty ok on 89 but 91 allows the ecm to fully advance spark timing.
fully advanced timing is used for economy ( mpg) at part-throttle cruising
fuel additives such as sea-foam can cause trouble here too until it runs through
one more thing: the ecm uses ion-sense to evaluate the state of burn in the combustion chamber, and this will help control spark. many models have problems if the plugs or wires are changed from stock spec- even screamin' eagle can cause problems
mike






