My immaculate EF Fairmont has 180,000 and has always pinged a little under medium acceleration (once you put the foot flat the pinging stops after about half a second). It seems similar to the piging I used to get with late model 351Clevelands wherby the vacuum advance was not backing off quick enough and subsequent dizzy work and good hi-octane petrol can fix.

I recently pulled out the injectors and got them serviced hoping for more fuel economy but alas this didn't help the economy and now the thing pings really easily once it has gotten nice and warm.

Perhaps it has a bit of carbon build up but I would like to know if anyone else has had this problem as I believe they all PING (Detonate).

They don't all ping (well shouldn't anyway) but the mid range of EFI Windsors are particularly prone to detonation due to the way the EEC is tunes. Basically it maintains a lean 14.6 AFR along with a lot of timing (30-45deg) with light/medium throttle primarily to increase fuel economy. Once the WOT/open loop fuel and timing maps are selected (which normally happens after around 4 secs of medium throttle, or pretty much instantly with full throttle), it runs a lot richer with less timing advance so pinging stops. The main thing to check is base timing, set it to the factory 30deg and you should be fine, if it still pings then I would check the MAF sensor because it is probably running a bit leaner than it should. Carbon buildup could also cause a bit of pinging, run some engine/carby cleaner spray or even water through the intake to clean it out and see if that helps.

When I first got my 5.0 ute I had the same problem. I had it at the mechanic for a week or two as he eliminated and checked suspect components and no fix. I had it at chiptorque and it was diagnosed as a faulty MAF, Still no fix. At the time I had to travel see a dealership mechanic to rectify. I was told then, that it was a problem with the distributor components and it was a problem with this model that was fixed during first couple years of routine servicing.

Problem fixed, however I was hesiatnt to play with the 5.0ltr myself at the time at try different things. So I dont really know what it was. Since then I have had the 5.0ltr on the stand a dozen times and the problem has never come back. I suggest now that EDXR8 is on the money, it would have been a problem with the tuning of the EEC and the ford dealership would have easily rectified the problem at there workshop.

Retard the dizzy a little !

Bit late on response, but clean the MAF sensor with some electrical contact cleaner.

my dads ef xr8 had the same problem and I just cleaned the MAF sensor with some metho, try not to damaged the element and it fixed it.

the sensor gets covered in s**t thats baked on, i dont know what it is, its sort of like carbon and it sends incorrect airflow info to the ecu which makes it run lean.

change the fuel filter as well if you havent done it in the last 10,000km.

Could be happening when the car is at medium throttle which would mean the O2 sensors. If it doesn't happen at WOT, it is because the car is reading from the MAF sensor and ECU maps.