That's right, I am losing it. Nobody can figure out what is going on and I am told repeatedly that this is "normal". F*ck this, if this is normal I am never buying a GM car again and getting rid of this one as fast as I can ! Ok, let me calm down, maybe there is still hope.

I have a partial throttle pinging problem which gets worse in the hot weather and has been growing
progressively worse in the last 2 months (i.e. lately, it happens even on cool days). My coolant temps are normal. I only use 92+ gas .
I don't have any codes. I had fuel/intake system cleaned by the dealer, sparks and fuel filter replaced (~$600 spent and I am no closer to a solution).
I am 100% stock with ~50k miles on the car. I used to live in much hotter
climate and the car never pinged. I pulled my maf and checked for intake leaks, everything looks
perfect.

It is heard as aluminum clanking/rattling-type noise which last anywhere from a few clanks to a ~10-second rattle and happens when the throttle is opened, i would guess, about 25-30%. It is not very loud.

I re-set my PCM few days ago, and immediatly after that the ping got MUCH worse, it returned to "usual" frequency after about an
hour of running the car. It never happens (at least I can't hear it) in neutral or when the throttle is opened more then 1/2.

Now I am thinking it might be the o2s. They are not throwing any codes, but I looked at the scanner when dealer hooked it up and the left one fluctuates between 80 and 800 at idle (once I am running closed loop) while the right one sits around 800 pretty consistently. When I pointed this out to the dealership mechanic, he said "it's pretty normal" "the scan tool doesn't take readings with he same frequency as the car's computer" "since there are no codes, o2s are fine". When I asked him about the ping, he kept telling me
it is completely normal for my mileage, there is nothing to worry about, the reason is that "there's no EGR on your car" and that "We have spoken to GM engeneers about this problem in the past, and they maintain that this does
not hurt the engine".

Do other people with similar model/year/mileage experience this problem? I do not have a scan tool so I am pretty limited in what I can look at myself...

Any help is greatly appreciated.

 

ttt for ya

 

Well I blamed it on CA fuel (91oct ) But now I think maybe..... they all do it with anything less than 93oct, because it seems the guys on the East coast don't really mention that much.
Both of mine (2000 SS A4 and 2001 TA 6spd) do it terrible!
Unless its really cool out.

 

could the car have plugs in it that are way too hot? I'm not really sure if this would be the cause of your problem- just thought I'd throw it out as food for thought.

 

It doesnt sound like a jingle does it? Just tossing that out there cause my car had it and it was H-Pipe resonance, went to X and it STFU.

 

If one O2 is not moving, like in not moving at
idle then it's not normal. Even if the Tech2 is
slow, it will catch a swing sooner or later.

If you have one injector that's drooling, over-
delivering or stuck open (like a driver short
fault) the other three will be rolled back to
make average O2 voltage right, meaning one
fat boy and three starving dogs. The dealership
should have the means to do on-car injector
balance tests and other things of the sort. But
some people "don't have the tools" no matter
what's on the bench. A $5 "noid light" would
suffice to test the driver fault theory and any
EFI mechanic ought to have one, if not something
better. A bad O2 usually fails low, not high/fat
and this smells like a fuel problem compounded by
a fool problem at the dealership.

 

So what kind of import are you going to get that's going to make you forget about the problem?

 

Thanks for responses, here are my comments in no particular order:

The engine is kind of hot, pretty much anywhere from the block to the airbox silencer - even rubber hoses are hot to the touch after ~30minutes of driving. Coolant temp gauge usually sits just below 210 mark.

When we pulled old plugs they looked really white.

my car has been through 3 shops now, how hard is it to catch a faulty injector???

Is there any kind of "home test" I can do on the injectors?


with my kind of finances, I am looking at this fine machine:

 

It seems like I've heard of the 01-02's sometimes running lean, but that could be wrong. Either way I don't think its normal.

Couple random thoughts. You might try some NGK TR6 plugs gapped at around 0.045. This helped a lot in my case when I went to ported MAF ends with HPP3 back when. Just a thought. Also, if you're not getting satisfaction from your dealer give Roy Robinson up here in Marysville a call - I've been very happy with them.

 

Well, if you're going with that kind of import, then i'd at least consider this...

 

some more thoughts...

I have been told many times it's the fuel. I have been filling up in this area for almost a year now and started pinging only about 2 months ago. I have tried switching stations but the problem is getting worse and worse. In fact, today it would do it ALMOST EVERY TIME I would push the gas pedal, even after the car sat with open hood for an hour.
For comparison, a month ago it would only do it like once or twice a week.

I am taking a vacation next week and we were planning to go to california. After listening to the ping today, I am really worried about this trip. How much damage is this really doing to my car? Is it safe to take a trip like that (over 1k miles each way in a week) with this problem?

I am going to do TB bypass and fan switch(in the mail) to try to keep temps down, at least until I figure out what the hell is going on or get another car (something that I would REALLY hate to do).

 

Gawd busas are hands down the sexiest thing on the road.

 

Have to tried using a engine cleaner such as Gm Topend, or Seafoam? Might be carbon buildup. Install a catch can too. A 160 thermostat with a manual switch might help. I have part throttle pinging and kr but only when I Tap the gas not when I'm accelerating or at wot.

 

dealer used "engine vac" or something like that - it helped for about a day then the ping came back.

I am thinking of doing this, could it be my problem?

 

I'm far from a tuning expert, but it sure does sound like a fuel or MAF issue to me. Its definitely NOT normal - especially since you're 100% stock. Have you had a chance to AutoTap and watch your LTFT's at all?

I'd consider reposting this in the Fueling & Injection forum as well.

 

ok dude my car had the exact same thing i pulled the heads and one of teh seats was sticking out do the same and look at your seats!!!!!!! if it aint that then who knows beats me.

 

o yea deff pull the heads and check the SEATS i can almost guarantee you it is that. check your oil are you burning alittle more than normal. is your oil level lower than you expected?? Pull your heads and check the SEATS all of them.

 

You know, from what I've heard of true 'pinging' due to using crappy gas in a high compression engine, this doesn't sound like the description of it at all. It's called 'pinging' because the sound is a higher pitched 'ping'. From what you have described, my limited knowledge would lead me to pull the valve covers and check your valves and heads out. I wonder if you don't have a top end problem.
Dan

 

eeek.... valve covers? seats? I' m a total newb in there. Is this a driveway project (what do I do/what do I look for?) or do I need to take it to the shop to check those out?

Thanks again for all the help!

 

Try doing a search on amw catch can, there also a sponser>>>>>>>>>>
it somewhat helps w/ pinging.

Mark