I saw a post from Fuel Moto claiming that in their dyno experience the ECM/ ion sensing system detects ping and corrects timing so quiclky that it is very difficult to identify by ear. Jamie also said it could be heard but it would be very faint. I also see a lot of posts about pinging; if a person can easily hear pinging would it be safe to say that the condition is severe since the ECM can not fully compensate. How do you describe the sound of pinging? Anyway, I want to try a little advance in my PC III map, just wondering if there is any way to acurately identify ping while riding under load. I can see it on the PC III program in the garage, but that doesn't help out on the road.

 

I thought pinging was too MUCH advance, and you need to retard the timing..or raise octane???? I had some pinging- sounds like marbles rolling around in a tin can- usually just when bike was hot and under a little load. Bought PC-V with fuel moto map- haven't heard it since..
Way to go Jamie!!

Postman

 

It sounds like ball bearings rattling around, metal noise in upper end of engine. Retard timing, not advance, only needs to be done at the rpm's where pining occurs. Gas, lugging, higher temps, heavier loads, timing off.... lots of causes.

 

"I can see it on the PC III program in the garage, but that doesn't help out on the road."
Sorry, poor comunication on my part. I am not experiencing pinging at this time, but I have the ability to see it while connected to the PC III if it occurs.

 

To me pinging sounds like little pebbles getting thrown up under the rear of the front fender.

 

If you have no pinging, then you can advance the ignition timing until you do... in order to improve performance.

 

A set of ear plugs can help more easily detect the pinging by drowning out all the wind noise and exhaust noise...

 

I'd suggest that if this is a new area to you, that you leave it unexplored.

the price of an error can be high.

pinging sounds as described above.

what is it?

it is the mixture igniting too early, causing the flame front ( as the mixture really burns, not explodes) which can cause the rising piston to meet resistance before it gets to the top of the compression stroke, expanding gasses can also try to push past the valves ( such as "sneezing" or backfiring through the intake---evo carbed harleys would often do this at about 1800 rpm unless modded).

causes include:
ignition timing too advanced--- timing is calculated so that the peak expansion of the gasses occurs when the piston is ready to travel down the cylinder on the "power" stroke.
assuming that it takes about 3 milliseconds for the flame generated at the plug to move through the mixture, the mixture needs to be fired earlier at higher rpms to achieve the peak expansion at the proper time- this is "advancing the timing" ( retarded timing may mean that the gasses are expanding after the piston is on it's way down already...less power produced.

low octane: octane describes the resistance to compression ignition- like a diesel...the high octane mixture can be squeezed and the plug ignites it when we want, rather than random ignition from compression ( OR from a hot spot in the cylinder which is so hot it acts like a plug to ignite the mixture- rough casting flash or damage to the piston can cause this)

too lean mixture can cause pinging

and heat: higher cylinder temps are equivalent to advancing the timing.



modern motor controls try to compensate by setting changes by the ecm, based on sensor data.

H-D has used methods are far back as the early 80's the VOES switch attached to the manifold would retard timing when the intake vacuum dropped ( such as whacking open the throttle) so as the resist pinging.


persisent pinging can cause motor damage, usually holes burn in the pistons.

my 09 in completely stock condition pinged at 2800~3200 rpm at highway speeds on 6% uphill grades. XIEDS solved that. the slightly richer mixture can resist pinging until ignited by the ecm


on my '53 FL, the left hand grip turns the points housing, rolling it back advances the timing, rolling it forward retards timing.---- in this situation it is AMAZING the difference of just 3 or 4 degrees of timing can make.

Retarded timing at lower RPMs can increase torque ( like to pull away from a stop) advancing timing increases fuel economy and high end power

mike

 

All good input, thanks to all. Although timing advance is a new area of exploration for me, I fear no machinery or it's subordinate systems. I've been doing the tuning with a Twin Scan + WEGO for a good while now and I'm confident I can tweak the timing without causing catostrophic failure. It's a great tool so I'm kinda surprised that it doesn't datalog the timing/spark knock. Any suggestions on how to approach this would be welcomed; '06 SG, Stage I, 2:1 FM head pipe, PC III, timing currently "0" in all cells front and rear tables. Haven't heard any pinging that I can distinguish so far. Currently tuned lean and wanna keep it that way. An example of a timing advance table would be great, I know the values won't necessarily work for my map, but I will be able to see how the advance transitions across the table.

 

IIRC, the maximum the Delphi ECM can yank timing is 8 degrees. The trick to setting timing is datalogging a run, then looking at where and when the ECM is pulling timing. Start reducing it there and in the cells surrounding it until it goes away. Similarly, you can advance it elsewhere until it starts yanking timing.