Spark knock? O2 sensor? Power loss?

[zach44102]

Been having some kind of ping sound under load from 2-3k only happens in gear not in neutral. Seems like its down On power but im not sure really. I noticed my MPG has suffured a bit from bad o2's that i used when i had a custom exhaust made. I have my previous ones that im going to swap in.

What does spark knock sound like, feels like the car is pulling timing under WOT

 

[zblackbeast]

You'll know the difference from say rod knock to pinging.. try pulling codes and see if anything is stored.. then I would look into maybe the ECT sensor and the knock sensor itself. If its pinging, I doubt its pulling timing, it could be that its flooding out.

 

[jnrock]

What are you refering to by pulling toming?

 

[zach44102]

Thanks clay, I should recalibrate my wideband and see where the AFR is at.

 

[93rev2sev]

If you hear what sounds like pebbles hitting a tin roof, that's spark knock.

 

[zach44102]

To me it sounds like a rattle of some sort maybe like if you could imagine a pebble in your cylinder boucing around. But it happens only in gear and moving under loud from 2-3k. Does not happen sitting still in neutral.

 

[zach44102]

Just re calibrated the wideband. I know im not seeing the usual afr's. I need to see what the wideband reads at WOT. I know crusing around town when letting off the gas or getting back on it i saw it dip down to 10:1. Cruising was in the 13-14:1's.


O and it also only does it on a warm engine. Cold engine=no sound

 

[jayro]

Just re calibrated the wideband. I know im not seeing the usual afr's. I need to see what the wideband reads at WOT. I know crusing around town when letting off the gas or getting back on it i saw it dip down to 10:1. Cruising was in the 13-14:1's.


O and it also only does it on a warm engine. Cold engine=no sound

An a/f in the 10's would definitly hurt your power numbers. As far as your cruising a/f it maybe a little on the rich side. I would pull codes to double check things. If your O2's are going bad they will report a false lean condition causing the computer to add more fuel.

As far as the hot/cold thing. The computer handle fuel differently prior to the car getting up to operating temp causing it to be rich. Then it it switches once you reach operating temp.

That kinda points to o2's or a temp sensor.

 

[rubydist]

You'll know the difference from say rod knock to pinging.. try pulling codes and see if anything is stored.. then I would look into maybe the ECT sensor and the knock sensor itself. If its pinging, I doubt its pulling timing, it could be that its flooding out.

if the engine is pinging (spark knock), and if the knock sensor is working, then it most definitely WILL pull timing when it pings. that is the entire point of the knock sensor, and Ford pcm will pull timing very aggressively - like 2* per incident up to 10* total, for a typical Ford pcm.

just cruising around, not wot, with engine warm, the a/f should be very close to 14.7 because the engine is running closed loop and adjusting to very nearly 14.7:1. your sick o2 sensor showing lean all the time will cause the pcm to command more fuel, making it more rich, which is likely resulting in the 13-14:1 you are seeing just driving around. changing the o2 sensor should fix that.

when the engine is cold, the pcm is in open loop control and more rich, so it would be expected not to have spark knock in that condition.

most likely, imho, is that a piece of carbon is flaking off a piston or the head, and that thin edge of carbon will get hot and detonate the a/f mixture too soon when the engine is hot. recommendation - follow the shotimes "how to de-carbon" procedure and see if that takes care of it.

 

[zach44102]

[YOUTUBE]MsBh8RH0ak[/YOUTUBE]
Here is a video. By 6800rpm im 10:1

I can describe the sound more like a diesel. I stopp and checked to see if a spack plug boot popped off on the rear cause that sounds similer to that.

 

[zblackbeast]

if the engine is pinging (spark knock), and if the knock sensor is working, then it most definitely WILL pull timing when it pings. that is the entire point of the knock sensor, and Ford pcm will pull timing very aggressively - like 2* per incident up to 10* total, for a typical Ford pcm.
QUOTE]

I understand this, I should worded my original post differently.

While it still pulls timing, even 10*'s, there is a chance it is still running SO rich it pings.. I was in a rush once and forgot to plug in my ECT sensor and the sucker had NO power and was pinging like there was no tomorrow.. Even with the pulled timing, it still was flooding out.

In my origionl post I didn't think the pulling timing was the issue, I felt there was a flooding issue, and the pulled timing was just a biproduct.. Like, the timing isn't the main issue, if that makes sense.

 

[zach44102]

That makes perfect sence. Im getting new o2 bungs welded in so i can put in new o2 sensors