Pinging on 03 Chevy 5.3 Engine in Suburban
 

I have had some pinging noise in my Suburban for some time. I have tried everything to get rid of this. Does anyone have any other ideas? The engine is in a 03 Suburban LT 4x4 thats all stock, but K+N Drop in Air Filter and Denso Iridium Spark Plugs. The truck has about 102k on the Odometer.

Here is what It does. It will not ping when its cool/cold outside. It will only do it when it is very humid or above 80 and humid. If its hot, say mid 90s and very humid as it is this time of year, its pretty bad. I can hear the pinging when I touch the pedal at around 2k rpms. Right on that initial press of the pedal it will make a slight ping. Then if I wind the Engine out, to around 5k, it will reall start to get a pinging. If I am towing my boat, and its under a heavy load, sometimes it will it around 3-4k rpms.

Here is what I have done so far.

1) Cleaned the Throttle Body
2) Ran no telling how many cans of Sea Foam, Decarbonizer through the Tank, even tried Spraying in GMS Top End clenar through the Throttle Body and also Deep Creep.
3) Changed out the Before Cat O2 Sensors
4) Make sure that the Mass air Flow sensor was clean and airfilter

Also noticed that I see this quite a bit when Pulling out of my office into traffic, you have to get on it to get out of the building on the main road. When the Temp Guage is not yet up to 200-210 right below center of the 210, then it will not ping. Just thought I would add this to see if this has anything to do with it.

Does anyone have any ideas? The truck runs awesome, just has this pinging sound. The gas Mileage is down around 3 mpg around city, just so you know from when I got it 2 yrs ago.

Bryan

Hook it up to a scanner and see what altitude it thinks it is at. The K&N may have wiped out your MAF. Do your self a favor and but the original stock brand plugs in and throw the K&N away and just put in a quality filter. If it is the MAF you may be able to clean it.

I do know about the oil from the K+N on the MAF sensor, this is why I make sure not to use to much oil on the K+N. I also make sure that the MAF is clean with the CRC cleaner for MAF sensors.

The stock plugs made it do the same thing. Only thing I have not done is change the Fuel filter. It seems stuck, as I took it to a shop also to have them do it and they could not get the quick connects to come undone on it either, so I guess it will have to actually go to the dealer.


I have one of the scanners, that will read the Data in real time also, I will try to get that and then I can post the data from that on here, when the timing is changing what RPMS/MPH all that information for every sensor in the car.

Bryan

No one has any other ideas on this?

Thanks,
Bryan

faulty knock sensor???

I just saw this thread.

Since you have been able to change the fuel filter, get it changed as quick as possible. It may not have ever been changed.

Now answer this question. How long is your 'cranking' time to start?

Did you ever get it scanned to see what altitude it thought it was at.
It would also be interesting to see what the STFT and LTFT numbers are. If you can drive it with the scanner connected it would also be interesting to se if the ECM is attempting to retard the timing at all.
As someone else mentioned it could be as simple as a knock sensor not working.

Hey Chet
With the decrease in fuel mileage, I am thinking of a ruptured fuel pressure regulator diaphram, a long crank time will verify this.

Yup, I agree. We had a rash of cars with altitude sensing issues a little while back and the main symptom was pinging.

I also saw a rash of aftermarket MAP sensors on GM throttle body equipped vehicles. The factory vacuum port is a ported source, and the aftermarket replacements required a manifold vacuum source.

The biggest complaint was for pinging.

I just haven't seen many throttle body equipped vehicles the last 4 years, and I have only one customer that still has one.

Ok Guys. Sorry about this.

I am not sure if this information will tell you the altitude or not. I am located in Raleigh, NC and we are located at 434 Feet above Sea Level, by Google. As to what the car is set to, I do not know. I have the Acront Elite Autoscanner CP9185.

As to how long it takes to start the car, its only a turn of the key, starts right up. no problems there ever. I would say max 1.5 seconds.

Here is the Information, for the 29 Frames it Recorded on the way into to work today, it only does it for about 30 secs, and this was normal driving. I tried to make it ping, as it normally will do it around 2000k, when in the throttle, but I was not able to make it happen. So not sure if this will work good or not. Also ambient air temp was 84 and low humidity. This afternoon it will be around 90 and very humid. So it should do it then for sure.

I know this data is very long, but if you wish I can put it into a .txt file, so the post is not near as long. Tell me if there are any other specific items you want me to look at on the scanner, as I do not think its recording all of them on here, when its connected to the computer.

Thanks,
Bryan

What is your MAP (hg) reading, with the key on engine off? It should read 29.9 HG (sea level).

Ill check it and post back in a little bit. About to run to lunch, so I will find out then.

its reading 29.2-29.5 for map w engine off and key on

I am at 565 feet above sea level. Most of the MAP HG's I've checked have been around 28.6 at idle. Within 30 miles I can be at 3200 feet. I use this drive to test the MAP sensor at a steady throttle. It should be down around 25.5 HG at this height.

I noticed that your MAP HG was down between 9 and 12.5 with your throttle open percentage around 10-12 %, and the engine RPM between 600 and 900.

It only increased to over 28 HG. When you were on the throttle.

ABSLT TPS(%) 65.9
ENGINE SPD(RPM)2043
CALC LOAD(%) 31.4
MAF(LB/M) 10.70
MAP("HG) 29.2

This makes me think it is hooked to a ported vacuum source, wired wrong, or out of range. 9 to 12 HG readings should be somewhere between 6000 to 8500 feet above sea level.