bshell

iTrader: (24)

I do get ping under part throttle, but the majority of it is at WOT and high engine loads (high rpm - wot in 1st, 2nd, 3rd, 4th...low rpm - wot 5th, and 6th). It shows up in my scanner shortly after the engine is warm, and after I've been in traffic for a while. Unfortunately, the weather over here doesn't change much, so I don't know if it goes away in cooler conditions. In my case, at WOT my LTFTs lock in positive and my O2s hover around 830-880mV. Would a malfunctioning egr cause this w/o throwing a code? I don't mean to hijack, but a previous poster said they changed everything except the egr.

Maybe the egr is not the culprit if Josh removed his and showed no effect on kr.

Josh McGrath

iTrader: (4)

Well, I can assure you, and if these other guys are having the same problem, they'll agree too.

It is deffinatly NOT false knock. I can hear mine ping even with the ac fan on high. And sometimes, if you keep the throttle in the same place when its pinging, it doesnt stop, it would ping constantly.

What kind of mechanical issues will make it ping?


How do I post logs too?

EDIT: There is -ZERO- ping at WOT except when the petal is about 20-35% down... before that, after that, zero ping.

I also have a Walboro 255 inline pump too.

TAQuickness

iTrader: (28)

mechanical issue - sky's the limit. If you have a lifter on it's way out or dead, broken valve spring, bent push rod, any type of anomaly in the valve train, exremely heavy carbon deposits, failing PCV (blowing excessive amounts of oil back into the manifold), lean conditions, etc...

One thing that would be easier than pulling the heads would be to install a fresh set of plugs, drive for about 10 miles, then pull the plugs (and post the pics of the plugs).

Do you mean that any time you apply ~25-30% TPS that you get pinging?

Josh McGrath

iTrader: (4)

Yea, but only at low RPM. And doesn't ping at all when revved at idle.

bshell

iTrader: (24)

If it were something mechanical (broken), wouldn't it make noise regardless of rpm, throttle position, etc?

longdaddy

that's what I was thinking too... And I don't imagine it would be so temperature-dependent if the problem was purely mechanical.

bshell

iTrader: (24)

I'm beginning to consider the harsh reality that my combustion chambers may look like TAQuickness'. Maybe running the car for ~90K miles with the stock PCV system caused enough carbon buildup to make seafoam treatments not work.

Josh - you said you only get pinging at part throttle in the heat and not at wot? Are you running at high engine loads during the pinging (uphill, high gear, etc)? Are you also saying that you get 0 kr at wot and high rpm?

Tim98Z28 - Have you had any success unplugging the MAF yet?

TAQuickness

iTrader: (28)

A mechanical ailment wouldn't necessarily cause KR all the time. Imagine you had a marginal lifter, and under certain RPM's, the harmonics from the engine caused the failing lifter to become more pronounced.

bshell

iTrader: (24)

True, but would ambient temp also play a role? Some of these people are saying that the problem goes away (or is at least reduced) when the weather is cooler.

I can see how a marginal component (lifter, etc) would only show itself after the engine is warmed up and the oil is thinner. But do today's oils change viscosity that much while warming up?

Josh - on your logs, does it show both banks leaning out the same or are they mismatched? Do you get any misfire codes? It would seem to me that a failing valvetrain component would show consistent problems on one bank, not both.

TAQuickness

iTrader: (28)

the fact that ambient temp appears to play a role in it makes me think it has more to do with carbon build up.

One of you guys take your plugs out and post some pics.

Bshell - FWIW my internals are no where near that funky anymore!

Tim98Z28

I have not unplugged the MAF yet. This will need to wait for the weekend to play with it. What I’m going to try is get out and drive the car until the pinging problem starts. Then I’m going to pull over and unplug the MAF and see if the problem still exists. Here is an example of how to make the car ping (can do it on demand this time of year). I’m driving down a city street doing about 45 MPH. With my M6 and 4.10 gears I’m in 5th gear turning approximately 1800 RPM. Pushing slightly on the throttle just to keep pace with traffic the car will ping like crazy. Trying to casually accelerate up to about 55 MPH the car will ping violently all the way. Once beyond 55 MPH (over 2200 RPM) the problem stops. The same thing happens when doing 70 MPH on the freeway while in 6th gear and will keep pinging under light throttle up to around 80 MPH. If I drop to a lower gear and keep the RPM’s over 2200 or so then I don’t have the problem. In general, gear selection is irrelevant as long as the RPM’s are between say approximately 1500 to 2200 or so. The car will do it in any gear with the outside air temp over 85 to 90 degrees. The hotter it is outside, the worse and louder the problem is. When it hits 120 outside (yes this is Phoenix) the car is too scary to drive. It sounds like it will explode. In these severer conditions the problem will show itself at an even wider RPM range and wider throttle position range. Imagine 8 small metal coffee cans with say a dozen marbles in them. Shake the crap out of all 8 cans and that’s the sound my engine makes when it’s at its worse. It will keep doing this until I do one of two things…get out of the throttle or push the throttle much further down. Oh…btw. My wife’s car is a 2000 SS A4. Her car does show signs of this problem but at a much much smaller amount. For the last 3 years I’ve blamed this on our cheap 91 octane gas, but seeing people here running 93 with the same problem makes me wonder if it’s the gas or not. And remember, during the winter months (the high temp for the day at 50 or below) neither car does it at all. My plugs are fine and I've tried TR55's and TR6's with no difference.

TAQuickness

iTrader: (28)

Tim - what do your plugs look like? I imagine they have little purple dots all overthem from the detonation.

When you give it more TPS, you are getting more fuel, which in turn is cooling your intake charge and richening up a bit.

Tim98Z28

It's been months since I've pulled any of the plugs out, but never have I seen little purple dots on them. They always looked pretty good to me. A bit oily, but nothing excessive. I guess I can pull a few out this weekend and take some pictures.

bshell

iTrader: (24)

I had already planned on pulling my plugs this weekend. I'll take pictures of what they look like. I do think its weird that Josh and Tim98Z28 could be picking up kr and pinging at light throttle / light load and have it go away at higher % throttle.

TAQuickness - did you add / remove anything that keeps the carbon away, or has it just not come back yet? Those pics of your engine build up are awesome!

TAQuickness

iTrader: (28)

Has not come back - mostly because of the catch can. It's a home-made-looks-like-***-but-works-freaking-great catch can. It has a 1950's VW bug fuel filter in-line with the manifold line. It catches about 1 teaspoon of oil per 100 miles (before replacing the pcv valve. Also do a seafoam treatment every other oil change.

technical

Another, yet more rare, condition that can cause a lean mixture and possibly pinging is clogged injectors. They would have to be clogged to a certain point that the lack of fuel + heat would cause this situation. I'm am however less inclined to believe that everyone who has posted about their car pinging has bad injectors. It is possible for those who are experiencing ping at cruise *AND* WOT could be looking at bad injectors.

Josh McGrath

iTrader: (4)

I get only the p0300 random code when I idle for a while, but thats because of the cam. And have since fix that with a tune.

As for the 'leaning out' question, if by that you mean LTFT's, then no, it doesn't lean out. In fact I have seen it ping audibly at -7.

I think it has something do with one of the sensors, because under open loop, (warm up, but its one one of the loops), it doesn't ping at all.

Can someone tell me how to post logs?

TAQuickness

iTrader: (28)

Josh - have you done a CASE/CKP relearn since you put the new cam in?

I think you can post logs by making them a zip file.

During your warm up, the car is in open loop. the stock OL table is very rich and would explain why you are not getting pinging then. After you get to correct operating temp, the car corrects it's self to 14.63:1 AFR. You shouldn't be pinging at stoich

Josh McGrath

iTrader: (4)

I bought the car with the cam in it, so I assume that it was done. The missfire test works and am throwing no codes, so I assume that it was done. It has never thrown and crank sensor code.

I was thinking about making the car run very rich Like, -12 and see if it still pings. Im gonna get to the bottom of this for usit kills me! And it might working on my car in the Texas heat.

EDIT: I have run seafoam twice and it pings the exact same way not minutes later.

I still cant figure out where the button is to post the zipped logs.

TAQuickness

iTrader: (28)

if it kills you, I'll let everyone know how you died!

Even if the CASE/CKT relearn has been done, it won't hurt to do it again. There have been cars that don't throw the crank code, but do throw the random misfire code. Mine has done it before...