Hi All
Been reading through posts on the 3.0 pinging i have a 2003 2x4 flex fuel 142,000 miles it runs perfect no problems with the engine.. i fitted motocraft recommended spark plugs, old plugs good cond, burning clean new air filter, fuel filter.. cleaned the air flow meter/throttle body...using 87 oct it pings .....89 oct not as bad but still there, using the air cond makes it worse...used seafoam, onto my second bottle of techron, so what should i do next....replace the coil pack/cam sensor, but throwing parts in sounds crazy.
Last owner had the cylinder heads rebuilt and replaced the cats, the pinging must have overheated the valves etc....i bought the truck with defective trans, now repaired..

 

Couple of things come to mind, there were some software updates available in regards to pinging on the 3.0l engine, I would get VIN and call Ford Dealer to see if there are any and how much to do the update.

The update changes the spark timing, so fuel is ignited before it can self detonate(ping)

Other thing would be to check EGR valve to make sure it is clean and it's exhaust tube is clean.
And that no one has done a work around on the EGR system because they didn't want to buy a DPFE sensor, lol.

EGR(exhaust gas re-circulation) system is there to lower cylinder temperatures when engine is under load, like going uphill, accelerating or when AC is on; exhaust gases "slows" the burn in the cylinder, so less increase in temperature.
High cylinder temps cause high NOx emissions, which is officially why EGR system is used, to lower NOx emissions.

Higher cylinder temps also causes fuel to self ignite(ping), Octane is a self ignition rating, 87 self ignites at a lower temp the 89, which self ignites at a lower temp than 91, ....ect.

Side effect of EGR system is that with lower cylinder temps spark timing can be more aggressive giving better power, but if EGR flow is not good then cylinder temps climb and you will get pinging with the more aggressive spark timing.
On some engines a Knock Sensor is used, not the 3.0l, this allows the more aggressive spark timing but if Knocking/Pinging is detected the spark timing is changed, on the fly, to prevent it.

 

Thanks Ron i will contact the dealer and post results....no EGR on this model year

 

Shoot, I knew that too, '02 Rangers didn't have EGR system either.

Then yes you are down to software.

There were some faulty coil packs on the 3.0l Rangers, and a TSB about it, can't find it though, I believe it only addressed '00/'01 models though.
Pinging was the complaint, new coil pack fixed it.

Long shot would be carbon build up in cylinders or weak fuel pump(lower pressure under load).
You said spark plugs looked good so carbon build up is not likely, Compression test would tell you if that was the case.
3.0l ran about 9.3:1 compression ratio, when you get to 9.5:1 87 octane can start pinging.
Compression = heat, the higher the compression the more the heat
Carbon build up will raise compression ratio, it also gets hot spots which can cause self ignition.

Weak fuel pump can cause Lean fuel mix until computer can compensate for it.

 

Thanks...Also the heads were rebuilt, looking at them i see new paint/gaskets i have no paperwork on that.. the PO lost it and has no idea what was done....could be re surfaced that would give more compression, autolite 104s were not bad when i took them out only one of them had carbon on the tip..will call dealer Monday

 

Called the dealer gave vin....no updates.......oh yeah...they wanted to check my trucks problem $$$$

 

No, resurfacing won't up compression, "shaving" the heads does.

Another thought since Dealer was no help.
A faulty IAT(intake air temp) sensor could cause lean mix, but I would expect O2 sensors to pick that up.

Colder air is denser(hot air rises), so to get the correct fuel mix, 14.7:1, computer needs to know the air temp of incoming air.
Colder air requires more fuel added than warmer air.

On a 2003 Ranger the IAT is in with the MAF sensor, combo unit.
The two outside wires of the 6 wires are for the IAT sensor.
Inside 4 wires are for the MAF sensor.

Remove the MAF connector, key off
Set OHM Meter to 100k or so
Touch probes to the 2 outside connections on the MAF sensor.
At 50degf you should see about 60.0k ohms
At 60degF you should see about 45.0k ohms
At 70degF you should see about 35.0k ohms

So the warmer it gets the lower the ohms
If you can, blow some warm air thru sensor, hair drier but not too hot, to see if ohms are changing.

However if it is 60degF outside and you see under 20.0k ohms then that could be the cause of the pinging, computer thinks you are in Perth, Australia, and it is 120degF outside, so it is adding less fuel because of the "false" warmer air, which causes Lean pinging.


And..............stock thermostat for Fords are 190 to 195degF, this makes for better fuel economy.
You can try running a 180degF thermostat, this will reduce head temp by 10deg which could prevent the pinging or at least hold of off longer.

 

Thanks Ron..just went out and did a quick check..temp 60f ..40.3k ohms.....would the camshaft sensor cause it...i thought it was only for injector timing not ignition dont think its been changed, i did check the shaft ..no play..added a few drops of oil to the bushing...not changing thermostat...so what do i have to change maf....coil pack....cam sensor....or leave it and use higher octane

 

Run several tanks of E-85 through it. Cleans the fuel system and combustion chambers better than any off the shelf product will do. Do it several times a year as preventative maintenance. As an added bonus, you'll pick up 10hp and 15ft-lbs of torque while running it. Helps to wake up these anemic engines.

 

No E-85 in Cali ........

 

Cam shaft sensor could cause it, but never heard of that.

CKP(crank position) sensor sets spark and fuel injector timing, and engines just used these for years before CPS was added.
Yes, CPS is mainly for Sequential fuel injector timing, but also plays a roll in spark timing.

CKP sensor can tell computer when #1 piston is at TDC, but can't tell computer if it is Compression stroke or Exhaust stroke, with Ford's Waste spark system that didn't matter since all cylinders get spark at their respective TDCs, compression and exhaust stroke.
Although there were some Sequential fuel injection systems with just CKP sensor most were Batch fire injection, half the injectors open, and alternate, on each full revolution of the Crank, intake is kept full of fuel so when intake valve opens fuel mix is pulled in, so small step up over a carb, lol.

With CPS added computer knew when #1 intake valve would open, and 2, 3 ,4 ,5 and 6.
So Sequential fuel injection could be more precise, better MPG and lower Emissions.

CKP sensor is still the master though, engine can't start without CKP pulse, but can start with no CPS pulse.
And the computer compares both pulses, if they don't match computer disregards CPS pulse and will set a code saying they don't match, but engine would keep running.

You could try marking the base of the cam synchro housing, then rotating it slightly one way, then drive it, then rotate it the other way and drive it to see if it makes a difference or if you get a CEL and code.

 

Thanks Ron..good info..the pinging only starts at full temp not warm up....i have read on the forum that the sensor should be replaced at 100k as it drives the oil pump and most gears fail....my sensor has about 12 thou play in the gear.
I will try the rotating next week....if i get a cell that means its ok right

 

The 180 t-stat may help then.
Does your OBD2 scanner do live data?
Would be curious to know coolant operating temp, 192-195degF is spec with no load(stock t-stat temp), 215degF on a longer uphill grade.
Ford dash temp gauge usually has 210-215degF as mid-point

The bushings in the cam synchronizer wear out, which is odd since 3.0l distributor bushings didn't, and it is basically the same setup.
Yes, if they fail oil pump is off line and major engine damage can occur.
I did read somewhere that a 3.0l with failed CPS(no pulse) would die and not restart, which is also odd, but that software(shutdown) may have been added after the bushing issue was a known problem, so instead of major engine damage from no oil pressure(assumed from no CPS pulse) just a tow would be needed and new Cam synchro.
Never encountered this though, just recall reading it somewhere, not sure if it is true.

Not sure how far off the CPS needs to be to get a CEL and code?

 

Update...i think i have another problem i pulled one spark plug out AGSF22FM (front bank drivers side) it was white...others were a little sooty, this was after a 30 mile freeway run. Checked for vac leaks ...none....checked with stetherscope on the injectors left bank, at idle and the lean cylinder did not click as loud as the others, could not get to the rest of them....So i think the 02 sensors are seeing a lean condition and are giving more fuel to the other cylinders, ...but would that cause pinging...i have injector problem...still running techron ...performance is perfect no misfire ..

 

That spark plug is too white :)

No, Lean causes pinging, Rich would be less pinging, gasoline cools down things, but that one cylinder could be pinging

After engine is warmed up, try disconnecting MAF sensor, then start engine and drive it, see if there is less pinging.
Just wondering if MAF is off a bit, with no MAF data, CEL will come on, but computer will use Factory air flow tables based on RPM and Throttle position, which will be biased Rich because that is safer than Lean.

Next would be de-carbonizing the cylinders with some Seafoam poured into Vacuum hose of running engine, gotta be careful but it does work, if that's the problem

 

Thanks Ron.......but why one cylinder lean, Yes i agree that one cylinder could be the problem...already done the Seafoam 2/3rds in the Vac hose rest in gas..running second bottle Techron now... unplugging the MAF will try that....but what about the injector not spaying enough fuel....in that lean cylinder.....did notice yesterday during warm up onramp to the freeway A/C on it was pinging a little....load on engine....I still have the old autolite 104s they were all brown color....the ford plugs burn hotter....might try putting one of them in that lean cylinder..

 

May have fixed problem...pulling off/on/off/on connector to injector/lean cylinder could have cleaned injector....no pinging on road test, morning weather here 10AM was overcast and foggy have to see when its warmer weather....checked MAF ...65F 27.50 OHMS

 

Still have a little pinging so it looks like a temp problem...thinking MAF but the only way is to start replacing parts...would 80f thermostat lower gas milage ...or forget about it

 

Yes, 180degF t-stat would lower MPG, but if it stops the pinging then it would raise MPG.
Pinging reduces power, it can also blow head gasket, it eats away at the softer metal ring used on the head gasket to seal head to block.

 

Next run out i will unplug the MAF and see if it pings...if no ping i can get a new one off ebay

 

Today i got to normal temp and pulled MAF connector...pulling away i noticed a harsh upshift in the trans...MAF must have something to do with trans...anyway road testing the pinging got worse, but i must say the pinging is not the ear piecing crackle that i have heard on other vehicles..no check engine light, checked ecu codes po113...then cleared...dont have OBD2 streaming data.... that leaves the 02 sensors and the cps....they have never been replaced...

 

Unplugging the MAF, or other main sensors, puts transmission(computer) into "limp" mode, won't hurt anything but shifting will be harsher.
Limp home mode

 

I have a new camshaft sensor complete on the way, went with Motocraft....wow over 500 views on this....replacing this because it has never been changed, and i am sure there will be some wear/plus the thought of it going out and killing the engine.... lets see if it stops the pinging. I will re post next week...

 

Sensor came yesterday..lubed it well and added a few drops in the top bushing......road test no pinging, hoping this is my problem ...i am using 89 oct when it gets low i will go back to 87....that will be the test

 

Thanks for the update :)