Pinging????

[The Shape]

This may seem like a strange question, but exactly what does detonation sound like? I have heard that is sounds like a tin can full of ball bearings, but how loud ? Reason I ask is ever since the weather has warmed up I have this faint ticking sound that gets a worse as the car warms up. It only happens at part throttle and is the most noticeable when the RPM's drop as the tranny shifts gears (AOD). It isn't extremly loud. I am just trying to figure out if it is detonation or an exhaust leak. Like I said it is only at part throttle or when the RPM's drop that you hear it. You don't hear it at all at WOT or if you just step into it a bit hard from a light. My timing is at 10* and I have been running 87 octane. I did try a tank of 89 with no difference.

 

[OrLackThereof]

Doesnt sound like spark knock to me. At only 10 degrees of advance especially, which is stock advance. Do you hear it at idle if you rev it or anything out of gear? Spark knocks is most noticeable under load...I hear the best test is if you have a manual, put it in 5th gear and floor the pedal and listen for it. But you have an automatic, so well, I just go in as far as I can on the pedal in overdrive without hitting the kickdown.

 

[ECU5.0]

might be a slight exhaust leak. or a valve ticking...but you would hear that at idle.

 

[The Shape]

Well I don't seem to hear the same noise at idle. It is the most noticeable with the windows rolled up for whatever that is worth. But it doesn't do it under heavy acceleration which is when I would think detonation would be the most prevalent. But this seems to be the most noticable when the AOD goes from 2nd to 3d gear at part throttle and it only last a couple of second till the RPM's build back up. The loudest it has ever done it was the other day I got on the highway and had forgotten to put the car into OD so I manually shifted into overdrive anout 2500 RPM's and when it shifted I heard it pretty plainly for a few seconds then it went right away as the RPM's climbed back up a bit.

 

[ECU5.0]

hmm....weird....not really sure what that would be. someone has to know how to help this guy....come on fellas

 

[HISSIN50]

hello, The Shape. well you know im not much of an AOD guy, but i will share what i have observed. i just did some work on a chevy S-10 (4.3L, auto). it was pinging, so i made the timing like me: retarded a little. then it was good to go.

best check i have found: go find a decent hill. give it throttle as you go up. if it wont shift due to the hill, floor it and then let off the gas a lot - it will shift. then give it moderate gas (not enough to shift). it should be lugging since you are on a grade. should ping like crazy.

other things i think i know: pinging is like no real mechanical malady (header tick, valve tick, etc). it is random sharp rocks-in-a-glass like noises. other stuff is more methodical and muted. as OLT and ECU stated correctly, header leaks and valve train tick are very and often most easily noticable at idle. not so for you.

another thing: as i recall, most cars run lean at part throttle. so it makes sense that this is when you see the problem. now we have to accomodate that (much easier on EFI than carbs).

i might try backing timing off a couple of degrees and see if it goes away. you can have an increased compression ratio from things like carbon build up in the chambers or bad plug heat range (i know the latter is not true for you, just stating it). higher compression is more likely to cause detonation.

but if you back timing off and problem is gone, then you know.

i know you get hot down there - is it hot yet? i keep timing at 14* till we hit about 95* ambient temps. then i back off to 12*. all cars like different timing but the idea is the same. i know you know that, but it segues into another observation. i had detonation last summer. 92 octane did nothing, as you have experienced. and with gas prices as they are, we cant afford it (over 2 bucks a gallon here). but back timing off two degrees and good to go.

did you go to thicker oil on the last change? i know you were kickin the idea around. if you did, i would not be worried about valve train noises. if not, how is your pressure?

well, i think i have filled my space allowance. hope some of this made sense.

 

[jrichker]

Pinging is caused by a number of things:
1.) Hot spots in the combustion chamber such as carbon deposits from high mileage or excessive oil consumption.
2.) Wrong heat range on the plugs.
3.) Too much initial spark advance.
4.) Lean fuel mixture.
Lean fuel mixture breaks out into several sub categories:
A. Vacuum leaks
B. Air entering the intake without passing through the MAF
C. Failure of the MAF, BAP/MAP (Baro or Manifold Air Pressure, same sensor, different name), ACT (air charge temp), or ECT (engine coolant temp). These should set a code in the computer.
D. Leaking exhaust gases from EGR valve at WOT.
E. Clogged fuel injectors.
F. Fuel injector wiring problems causing injector not to deliver rated flow.
5.) Computer problems: (computer problems are not common like sensor problems)
A. ROM has bad data in fuel or timing table. This should also set a code in the computer.
B. Failure of one or more of the computer's driver transistors for the fuel injectors. No code set on this one.

Have you dumped out the codes?
Here's the link to dump the computer codes with only a jumper wire and the check engine light. I’ve used it for years, and it works great.
See http://www.batauto.com/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/article...c-iv_codes.html

 

[The Shape]

Thanks jrichker I don't know where you find all of your info or where you find the time to post it all. That is a great checklist to go through. And HISSIN50 I haven't changed the oil yet, but the pressure is good at part throttle I have 25 at idle and as soon as I give it gas it raises so I don't suspect valve train noise (I could be wrong however). First thing I am gonna do is double check my timing and listen really good under the hood at idle as soon as it stops raing which from the weather report it doesn't seem like it is going to do this week. Thng is like you said I have always thought pinging would be a very random noise this definently as a solid rhythym to it.

 

[The Shape]

Ok the rain let up a bit so I went out and listened to it idle a bit. If I stick my head down by the passenger side wheel well I can definently hear a ticking. So I am guessing an exhaust leak. Ok but what still gets me is it gets louder as the weater and the car get hotter. Isn't that backwards for an exhaust leak? I thought they would normally get quieter as the exhaust heated up since the metal gets hot and expands a bit

 

[grippper]

my exhaust sounds like it has bbs rolling around in there at idle.