Poping or Misfiring Under Hard Accelearation

[svt2205]

Anyone have any ideas of what I should be looking for? I'm new to the tuner world and have had my Grphyon installed for only a few weeks. First, I'm not entirely sure it's related to the tuner or if it's just my truck.

But under hard accelleration, I'm now getting a poping sound. Sounds just like something has shifted in the bed and banged into the tailgate. That's really what I thought it was, until I noticed it with nothing in the bed.

My truck is an 07 5.4 with 63K on the clock. This occurred yesterday, the second day in a row where we saw wonderfully warm day time temps. Warm being relative, it was in the low 50's. I was running the Gryphon on level 2. I run 87 octane fuel. I looked for codes and it found none. I have since returned to stock and it doesn't do it. I did notice, it had a hard start once since returning to stock.

Let see, what else might be helpful? I just changed my oil (motorcraft 5/20SB and 820S filter (maybe it's S820, not sure which the letter sequence is). My air and fuel filter have less then 2000 miles on them.

I'm out of my league here, so any suggestions would be helpful.

Thanks

[Jackpine]

Henry, what you're describing doesn't sound like "ping". That sounds like marbles rattling in a can. I think you are saying you hear, and possibly feel a "clunk" under fairly aggressive acceleration or perhaps between deceleration and quick acceleration?

If so, I get that too at times, and I don't worry about it. I think it's related to shift strategies in the tunes that cause the clutch to lock up faster (less slippage, firmer shifts).

If this sounds like what you have, then Bill can tell both of us if there's anything to be worried about.

- Jack

[Power Hungry]

Henry,

What level did this happen in? Also, did it only happen one time? If more than once, is it easily repeatable? Does it occur during a shift, or just during acceleration?

Let me know. :)

[svt2205]

Thanks for taking a look.

Jack, I'm familiar with pinging, I had 2 4.6 modulars that were heavy pingers. That said, it could still be something like that, but it sounds different. I stand with my it sounds like something that's shifted in the bed and bumps into the tailgate, a sort of pop or light thud. Best I can offer for description.

Bill, it happened any time I stepped down hard on Friday afternoon and again Saturday morning. I had originally thought it might be due to the nice warm air we had (50's) but it was only 37 the following morning and it still did it.

I was running the canned level 2. It occured while accelerating, in gear. I did not notice anything during a shift. This only occured while under hard acceleration, say more then 50% pedal. I had been running on Level 2, since 3/15 and put over 1000 miles on without a hitch.

Returning to the stock tune seems to have things back to normal.

FWIW, I have AutoTap software. You know the package that allows you to read/clear codes and monitor, on a laptop, all sorts of different sensor output. If I knew what sensors to look at, I could set things up (probably not until next weekend) and see if I can see anything.

Thanks guys for taking the time to look into this. You're time/help is appreciated!!
Henry

[Jackpine]

Henry, I'm sorry if what I said sounded like the "idiot treatment". It was just that I was not sure if you were getting repeated "thumps" (like: thump, thump, thump, ...) or only one.

In your last post, what you described really DOES sound just like what I've experienced now and then. I felt it maybe twice on our recent trip to and from California, in moderate traffic, when I would accelerate to move quickly into a passing lane. I can hear it and I can feel it, and it sounds like it's something going on behind me.

I wonder if there's any way it could be coming from the differential? (I assume you have traction lock, like I do)?

- Jack

[svt2205]

No worries Jack, I know you're trying to help. Sometimes it's hard enought to describe things when you're talking directly to someone. It's even worse when we communicate via email or posting on sites. I always try to take it all in stride, knowing that most folks are only trying to be helpful.

I'm still thinking it's engine related, as the noise has gone away, since returning to stock. Then again, it's also only in the 30's again, so we'll see when/if it ever warms up again.

Thanks again for your thoughts and help. It's greatly appreciated
Henry

[svt2205]

FWIW, I wemt from stock back to Level 2. Whatever this is, is still there. I'm going to see if I can narrow down exactly what the heck my truck is doing.

[soutthpaw]

I see Bill asked this but don't see an answer. Can you easily repeat the occurance. For example every time you give it more than 50% throttle from a stop you get the thumping??? if so what are the exact conditions that it occurs at. This is very useful info in diagnosing the problem...

[jimmyv13]

Maybe a COP???

[svt2205]

I hadn't answered because I wasn't sure. Unfortunately, it occurs each and every time. However, it does not do this when returned back to stock.

I wish I knew where to look but the truck is still getting me to and from work so. It's only an annoyance right now.

[svt2205]

Thought I'd follow up on my last post. This problem seems to have fixed itself. I now think I filled up with a load or two of crappy gas. I do now notice some very minor pinging but I would think our local fuel suppliers are still pumping the lower BTU winter grade fuels.

Thanks for those who tried to help.

[Jackpine]

Minor pinging shouldn't hurt, but I still don't like it. You COULD retard the spark by 0.25 degrees, which would probably get rid of it (and shouldn't cost you much in power). I wonder if you're running slightly lean? That can cause pinging too.

- Jack

[88Racing]

I don't like that it fixed itself?
Now there is pinging?
Could have been bad gas but maybe check the fuel filter?
Could have gotten water from the station.
Try the timing as Jack posted earlier. Keep us posted.

Lars

[jfuller5]

Does this happen on take off from a stop or will it do it when accelerating while already under motion? If it does it on take off what you explain sounds like the slip yoke on your driveshaft binding on the spline and then freeing up, that gives you the kick in the but that feels like something hitting the tailgate. Pull the driveshaft and feel inside the slip yoke, is it rusty? If is feels real sharp on edges of spline it may be worn and binding causing wiindup in drive line tahe it lets loose and bangs. T see if this is the issue pack the spline with a good grease and reinstall shaft in truck and try it out. If it has a 2 piece driveshaft lube both splines. Good luck JF

[Desert Racer]

I had a miss I guess you could say. i added +10 for WOT fuel and it has went away and my truck seems to run so much better. I do have a aftermarket intake though.