Yeah its back...i am convinced its carbon...but who knows lol....it started on third tank of 87 real bad...dont use truck much......tried a friends MAF...still the same..did notice my ranger has knock sensor on the block p/s......fill with 89 and techron additive ..it has slight ping now when a/c is on around 2,000 rpm...if the radio is on you dont hear it....yesterday fitted 180f thermostat, no change.
I did read that Ford dealers say use 89 and that vulcan engines ping a little...

 

I think Ford has a computer reflash for this.

 

3.0l Vulcan uses 9.3:1 compression ratio so doesn't take much to make it "pingy".

Yes, carbon build up is a double whammy, it raises compression ratio and retains heat, both cause pinging on 87 octane.

Just check the spark plugs, carbon will coat the whole cylinder, spark plug included, if spark plug is clean then carbon isn't the problem.

EGR system is there to lower cylinder temperatures, that lowers NOx emissions during acceleration and higher speed, above 40mph, driving.
Because it lowers cylinder temps it also helps prevent pinging.

Yes, your '03 3.0l does have a Knock Sensor, computer should be advancing spark timing to stop pinging before you even hear it.
Computer should also turn on CEL(check engine light) if knock sensor is failing.
Does CEL work?
Does it come on with the key on?

 

Yes check engine light working with key on...thought knock sensor retards timing...no egr

 

Depends on you point of reference, lol.

If computer detects Knock then it "advances" when the spark occurs to ignite air/fuel mix before it can self-ignite(ping).
Pinging/self detonation can occur from heat or compression(which is also heat), octane is the number of complete 8 molecule carbon chains by volume, remaining carbon chains are open ended, an open ended carbon chain isn't as stable an 8 chain, so it is easier to self ignite, higher octane numbers have less open ended chains by volume.
The ping noise is cause by two ignition points, or more, inside the one cylinder, the noise is caused by the two flame fronts colliding.
Diesel engines often have this issue, two or more ignition points, so sound pingy, they are build to handle a bit of that, but it is still hard on the engine.


If spark was happening at 20deg BTDC with pinging, computer moves it to 22deg BTDC.

Generally if you change spark to a higher BeforeTDC number it is considered advancing spark timing.
Lower BTDC number is retarding spark timing.

Spark ignition is not when cylinder creates the most power, it takes a few degrees of crank rotation for the flame front to spread, then you get full explosive force of the air/fuel mix.
You want that to occur After TDC, of course, lol, 10-15deg ATDC gives the piston the most leverage to add power to the crank.
If you advance the spark timing because of pinging then full explosive power may happen between 5-10deg ATDC, so you lose leverage and so lose power

The time it takes the flame to spread inside a cylinder is fixed, but it does very a bit, richer mix flame front spreads faster than leaner mix, leaner mix burns slower but self ignites easier.

Crank speed varies alot, i.e. RPM, so the time it takes crank to spin from 20deg BTDC to 10deg ATDC changes alot.

At 3,500rpm spark will be happening at 30+ deg BTDC giving flame front enough time to spread and fully explode at 10-15deg ATDC

 

Thanks Ron interesting information, did pull spark plug no carbon on the tip but a little around the ends of the threads like any other plugs I have seen...when it pings I can push on gas pedal down shifts..no ping...seems just around 2k when it pings light load...in 04 I bought a new edge 3.0 no problems, sold it at 20,000 miles

 

Checked with dealer (in my post few months back) and they said no re flash after giving my vin

 

If pinging goes away under load and no load then it can't really be a heat issue, IMO.

Light load pinging could be air/fuel is too lean.

No load is a richer mix as is high load, light load, cruising along, is when computer tries for best MPG, so leans out the mix.

Might be worth the investment to get a Bluetooth OBDII unit, they are not much.
These can display live data on your smartphone or tablet while driving.
You could see fuel trims and O2 sensor data live while pinging was happening
Also see why knock sensor is not detecting it

 

Today was thinking about the spark plugs AGSF 22FM that i fitted some months back...i did keep the ones i removed Autolite 104s...i remember only one of the 104s had carbon the rest had brown tan....the 22FMs are a hotter plug. So went back to that cylinder and pulled the spark plug...my pinging problem must be carbon build up with that cylinder, the po had the heads rebuilt 25k ago so it could be rings....the 180 stat and 89 octane does help but does not fix the problem...second pic is the 104s same cylinder carbon on plug....i think the po had this problem...engine has stock plug wires ...could weak spark cause this....engine runs perfect

 

Could be intake valve guide seal is leaking a bit of oil down the valve stem on that one cylinder, causing the carbon build up just on that one spark plug.

But I would expect newer heads would have newer seals.

Leak down test can tell you if rings are leaking too much.

 

Thanks Ron.....not worth going any further with it...I only use the ranger for garden work..

 

If you ever do find the cause post back the fix.

Seems the 3.0l is right at the edge for pinging on 87 octane, any small change seems to set it off, the pinging

 

Something i may have overlooked...the idle rpm was always 1,000...cold start up 14...12...then back to 1k....no cables binding...Engine normal temp...(went back to 192 stat)..pulling vac lines off still 1k....then pulled wire connector off idle control valve ..still 1K. So i turned the idle screw/bolt out until i could get 3mm feeler guage between the bolt and the throttle linkage...idle came down to 800....engine idles smooth no roughness...never had time to road test temp here today 98f...dont think this will have anything to do with the ping...but thats something else sorted

 

No idle screw on fuel injected engines, no Jets so won't work, that screw is the an anti-diesel screw and can also be used to fine tune TPS closed throttle voltage.

Generally with IAC Valve unplugged RPMs should be under 600 closer to 500 or engine may even stall if anti-diesel screw is set correctly.
Odd that it won't close throttle plate lower than 800 RPM

 

Adjusting the throttle plate screw/bolt brought down the rpms...will cold start again today...could the MAF be controlling the idle speed.....any 03 owners out there can do the same thing unplug the IAC...and see what happens
Thanks

 

Engine coolant needs to be warmed up when you unplug the IAC Valve.
Cold start idle with IAC Valve hooked up should be above 1,000rpm

Warm idle could be as high as 800 with automatic trans in Park, manual trans 650-700rpm

 

Big change today started cold rpm about 14...dropped to around 850rpm hot...unplugging IAC dropping to around 600...great now the test drive morning 20 miles ac on temp 60f.....where did the ping go lol............coming back 70+f...ac on i had to floor it to get it to ping, but only a little, ping is 80% gone. could temp change things?...pleased with results ...i will use 89oct
Thanks for the help..