4.6L Pinging at low RPM

[A1cntrler]

Over the past 2 weeks I've been hearing some pinging at low RPM in higher gears under light acceleration. I'm not really sure how long it's been happening, as I can only hear it with the windows down and along a certain stretch of road where there are walls or a higher curb along the roadway.



Here are the ingredients that seem to cause it to happen:



-Engine is completely warmed up (Temperature runs normal)

-Light acceleration in top gear (35-45mph, slight incline or light gas pedal pressure to maintain speed)





If I turn the O/D off or force a gear change it goes away. It will continue to ping until the gear changes bringing the RPM up.



-108,000 miles on the '07

-Plugs were changed about 3500 miles ago. All were clean and no carbon build up causing any breakage. I used OEM Motorcraft plugs.

-I only use Top Tier gas (Regular)

-I am using a tune from Torrie. Stock tune to improve the shifting/throttle response. This tune is new (less than a year old)



I've been using Lucas Upper cylinder lubricant/Fuel Injector cleaner about evey 10k miles since new.



Should I try replacing the O2 sensors? Cleaning the MAF? Fuel filter is fairly new (10/12k maybe)





I've watched videos to make sure it is pinging and not timing chain/Cam Phasers/etc. The only sound it exactly matches is the Pinging videos.



I'm confident the inside of the motor is clean. Regular oil/filter changes since new, quality synthetic oil. Only Motorcraft oil filters used. I doubt this is an issue with carbon build up on the piston causing detonation.



There are no codes existing or pending when checked using my OBD scanner and checking with my SCT tuner as well.



Any ideas?

 

[Vic Sorlie]

I wouldn't replace O2 sensors unless they're throwing a code that turns on the CEL. Try scanning for pending OBDII codes. Cleaning MAF sensor and throttle plate couldn't hurt.

 

[EddieS'04]

You might try reloading the tune you are using. I found that after long period of time. My '04 gen1 gets a little slugish. After I reload the tune it peps up.

You also could do some data loging with the xcal. send the results to torrie along with the tune used.

 

[A1cntrler]

Thanks for the suggestions. I'll pick up a can of MAF cleaner spray tomorrow arms clean that. Also I'll look into logging with the XCal. Didn't know it was an option.

 

[Todd Z]

Mine has done this from day 1........ 80K on my 2010 now..



Todd Z

 

[A1cntrler]

When I heard it at first I started looking for issues on the Internet. Read a lot of tsb's for many years and a surprising number of them stated that the engines were just noisy by design, and investigation /repairs would not be reimbursed. Not sure why it took me 108k miles to first notice it.

 

[Richard L]

Carbon may be building up in the engine that requires a SeaFoam application of the MAF may need cleaning.



It can also be caused by the EGR valve sticking. Usually this will throw up a CEL, but that may only happen if it senses a problem with the EGR position sensor valve (Differential Pressure Sensor Controlled EGR valve)?



When the EGR system is working correctly, it is recycling a metered amount of exhaust gas back into the intake. This is an inert gas (already burned and contains no oxygen) so it helps reduce combustion temperatures to reduce air pollution. If the EGR is not operating for what ever reason, combustion temperatures can increase causing pre-ignition that we hear as pinging.



...Rich

 

[A1cntrler]

I've cleaned the MAF and the Throttle Body. I also reloaded the tune onto the computer. So far so good. I've given it two days listening like a hawk for any sign of the sound. I thought I heard it once, but it was a Blazer in front of me rattling like mad that I heard when I passed him in the turn lane.



Hopefully all is well now.

 

[Tim Holt]

You might need the tune tweaked to reduce the advance at certain points. You could also run higher grade gas.