It was a different number can't remember if it was hotter or colder plug they looked the same just had a different number.

 

Good to know, I will pull a plug and see what we have.

 

Good advice and basically what I would recommend if I was answering this question. Haven't actually had time to play with intentional leaks and fuel trim readings yet, The only time it does it is when we are working the truck hard and working hard ourselves and the diagnostics are on the back burner...

Got to take a rainy day sometime and try this with a load.

 

I have the same problem with my 04 F250 CC LB 2WD V10, I solved it by running premium fuel when I tow. I can use 87 octane when driving back and forth to work with no issues as soon as I load the truck down the pinging comes back.


Truck tows fine with premium fuel.

 

Disconnecting vacuum from FPR: at WOT there's near 0 vacuum anyway so disconnecting it will do near nothing.

Creating leaks to fool the O2 sensors: I assume the system goes into open loop at heavy throttle as most do so the O2s would be ignored and leaks would do nothing for it. And listening for pinging with exhaust leaks at full throttle, well you might think it stopped pinging because of the noise from the leaks.

Mine pinged quite a bit but did it at different throttle positions and it varied by conditions. I don't think it ever pinged at WOT. After replacing the knock sensor it only pings on rare occasions and it's a brief ping.

If your fuel pressure is good my only thoughts would be wrong plugs, carbon build-up, or the knock sensor. I assume that if you ran with a scanner hooked up and the knock sensor were working you should be able to see the timing change as the knock started. I never thought to try that with mine, wasn't thinking.

 

The V10 doesn't go into open loop except when at WOT for a long time. I think the 5-star tune makes this happen much earlier, but stock it doesn't happen right away.

Also, disconnecting the FPR vacuum will cause the pressure to jump from 28-30 to 38-40 lbs (or at least, it SHOULD - and this should be checked). This could theoretically overcome the short/long fuel trims and it'll start to run rich - which could overheat your catalytic convertor.

 

Somewhere I'd heard of something called a 'performance delay' with the V-10 (I think from Banks) but couldn't find any specifics about it, now it makes sense; thanks. It was stated to be a 30 second delay. Guess I should plug my scanner in when I take the truck out again.

If one could force it into open loop he might get some or most of the power that comes from a tune. Maybe a manual switch to open or short the O2 or some other sensor's output? The computer should go open, but I don't know how quickly or how much fuel it would add or what the timing would do.

 

Don't know where the WOT discussion came from or actually if the truck even pings at WOT, it isn't mine so I don't have a lot of seat time in it but it is raining so maybe tomorrow I can play with it some.... I can assure you without it the catalytic converter is a NON issue.... and will check the fuel pressure.

 

You said 'under a heavy load' and I mistook that for WOT, sorry, my mistake.

So it sounds like it may be similar to what I had going on before I did the knock sensor replacement.

 

So the knock sensor can actually affect the timing and make it ping? Previous posts seem to have different opinions on that?.... heavy throttle with the torque converter locked up and it pings like a bunch of marbles in a a tin can...

 

My '00 was pinging a bit when I pulled our gooseneck cross-country when I would hit grades or strong headwinds. Usually with the TC locked, just before it would drop out of overdrive. I put 91 in it the next fill-up after I first heard it, I usually run 89 loaded, and it reduced the occurrence substantially. But not completely. 93 made no difference over 91. Never pings unless I've got a lot of weight, even on 87. I learned when pulling to back off just a bit if I detected detonation and it would stop. I wasn't going to be traveling very fast up those grades anyway, what's another 5mph slower?

 

The knock sensor is supposed to feel the ping and retard the timing. So the best answer is that it can't cause ping, it can only help stop ping. It's also been said that the computer will only retard 4 degrees upon the sensor detecting ping so it may not be able to stop ping if the conditions need more than 4 degrees to stop it.

On some older engines I've tested knock sensors by tapping near them with a hammer and watching the timing move with a timing light. With newer stuff you should be able to see it that way or with a scanner. 2 problems: I don't know if the computer will retard at idle or if there has to be a load on, and the sensor on this motor is buried in the valley and I don't know if there's a way to get a tool close enough to it to make it feel the test 'ping'. If you had a scanner hooked up and watching the timing I assume you should see the timing drop back when the engine starts pinging if the sensor is working.

The sensor is a pain to get to, gotta remove the intake manifold (on my '99). I was planning to install one somewhere else and leave the old one, but I couldn't get the connector apart. It's behind the passenger rear corner of the intake (on my 99) and I was able to sneak a hand in to it, but couldn't get it to disconnect. I don't recall the year on yours, but when I was searching around I found that some years supposedly have dual sensors mounted to the heads and possibly accessible without intake removal. If you don't know on yours you should be able to go to the Ford parts counter with your VIN and they pull up a schematic type thing showing the part number and where it's mounted, tho some aren't very clear. You'll at least know if it's a single or dual sensor.

 

Here is my opinion:

The pinging is fuel related.(kind of)

Most fuel these days is E-10. During closed loop operation (light load) the O2 sensors maintain a lamba of 1 (14.7 for pure gas, 14.1 for E-10). E10 is what most gas stations sell, and what most people put in their tanks. In other words our engines run richer on E-10 than pure gas at light loads.

During open loop (heavy load) the pcm reverts to a set fueling table that is based on pure gas with a target AFR of around 12.5. The O2 sensors are not used and become irrelevant in open loop operation.
Problem is E-10 is not pure gas and it's ideal afr for high load is about 12.0. Since 12.0 is 1/2 a point richer than 12.5 our pcm is causing the high load ping because it was not programmend to fuel to 12.0 during open loop.

It does NOT take WOT for pcm to go into open loop. Heavy towing and about 1/2 to 3/4 throttle will put pcm into open loop. Basically when vacuum hits zero in hg it can happen.

Heince our motors run lean in open loop (high load). The real fix is pcm reprogram to hit 11.5 to 12.0 in open loop. Or trying to put nonethanol fuel in tank.

Now I don't want to say it's a cure all solution, because there are many other factors. Most fuel injectors for instance loose some of their flow due to being dirty after a 100,000 miles or so. Some loose their ability to have a good spray pattern.

This can cause lean conditions too. So my advice is make sure fuel system is up to specs, make sure charging system is up to spec so pump gets right voltage. That alows correct fuel pressure to injectors. If all that fails and you still have ping, look to pcm and or fuel type.

 

The trouble with the E-10 theory is that these trucks were DESIGNED for it.

Way back in the early days here, Fredvon4 and I got into a discussion how our trucks didn't care about E-10, versus some people who thought it did. Turned out Fredvon4 and I had the exact same PCM calibration.

If the truck pings with E-10, something is going on. These V10's are meant to deal with just about anything.

And if the knock sensor is bad, the PCM will never tell you because it doesn't care, if it's OBD-I. If it's OBD-II there is supposed to be a test performed at some point where the PCM advances the timing up to where it thinks it should ping, and then listen for a detonation. If it doesn't happen, it might (or might not) throw a code.

The knock sensor stuff can only pull 4 degrees total. Which is not a lot.

(I'm saying the above, thinking we're talking about 2000-2004 2-valve V10s, I have no personal knowledge of the 1999 non-PI head F-series V10)

It's time to go back to basics. Clean the MAF, check for vacuum leaks, change the fuel filter, check the fuel pressure after that. At idle, it should be 28-30 lbs. Disconnect the vacuum to the fuel pressure regulator, it should jump to 38-40. Put the vacuum back, and take it for a test drive, and at WOT check the fuel pressure. It should still be 38-40 lbs.

You could in fact have a bad PCM where it's knock sensor input is bad, and it can't hear the pinging. At this point, datalog it with a tuner/scanner and check the knock sensor functions, and make sure that the PCM is even seeing the knock, AND bothering to pull the max 4 degrees timing (there are PIDs for these).

--

Side note: Keep in mind the flappy bellhousing cover. At times, when mine was making noise, it could be interpreted as pinging.

 

Well, I would have to disagree based on my Wide Band O2 readings.

Before my SC, open loop readings with E-10 were around 12.5, not 12.0. So to say they were designed for it, may be true, but mine was not. For E-10, open loop needS to be around 11.8 to 12 afr. Which means pure gas would be around 12 at open loop.....which mine was not.

Mine went to 12.5, or my Wide Band O2 sensor is lying.