A couple years back I installed a 160 degree t-stat on my motor because I "thought" it would be better. Well it runs fine, but I can hear a slight pinging when driving sometimes. My timing is correct at 0 base. Everything is either good or has been replaced that is usually suspect.

The knock sensor reported high knock counts even at idle, so I bought a new one. Before I install it, I was wondering if the colder t-stat has anything to do with it. The motor does not have extensive carbon build up either. The only other thing I have done to the car was add true dual exhaust. What do you guys think?

Motor: '89 LO3 w/ 72k

 

Are you SURE the outer ring on the dampner has not slipped, that can give you a false reading on the timing mark. I have my timing set up 4 degrees, it runs a lot better there but it does ping when the engine is cold, but after it warms up I get no pinging at all. For a stock L03 you NEED at least a 180 degree stat so the engine will run properly. I have a stock 195 in mine. Also the colder an engine runs the faster it will wear out, piston rings wear a lot faster if the engine temp is less than 180 degrees.

 

No, the outer ring is solid. I don't remember exactly what the temp was stock. It was either 195 or 180, and I either put 180 or 160 lol. I advanced it a bunch to make sure what I heard was pinging and it is, but very slight, even when fully warm. However, at 4 advanced with the ESC unplugged, it did not ping at all! So im assuming its the knock sensor or heavy carbon, but I doubt it.

 

Do you mean you ran the engine at 4 deg. advance with the ESC unplugged and got no pinging? Because that would prevent any advance and you wouldn't get any pinging no matter what.

 

Right. I typed it out in a confusing manner. It just pisses me off, because the car runs like a top. I guess I will install at least a 180 t-stat and install the new knock sensor. I don't understand why I would be getting high knock counts at idle right after starting the car though. Any ideas?

 

Try running some fuel system cleaner through the engine, and then replacing the O2 sensor afterward. You may have plugged up injectors, causing the engine to lean out some, which can cause a knock when the engine is cold. And hot too i guess.

 

It had a fuel injection cleaning at the dealer and I installed a new AcDelco O2 sensor :P

 

I bought a new knock sensor and am getting ready to install it. I am also running 89 octane fuel and its still pinging. The engine had both a fuel injection cleaning, and GM Top engine service. Any other ideas?

 

I'd vote for EGR valve issues. Either the valve isn't opening properly, the intake manifold passages are clogged, or the less restrictive exhaust is causing issues with the positive-pressure type valve.

(On this non-thirdgen car... )

 

The passages don't seem blocked, but I will try to remove the intake and clean them. My next step with the egr/exhaust problem will be a f-body negative backpressure valve. It seems there are a bunch of f-bodys on here with dual exhaust and no egr problems. I will keep everyone posted.

It is a thirdgen.....Caprice

 

Your symptoms are very close to what I had with my LG4 originally. I had the EGR valve off, everything looked fine. Later, when I had the manifold off to fix a coolant leak, I discovered the cross-over passage was plugged at the head - couldn't see that from the valve. After that was opened up, bingo, no more pinging problems.

 

Sounds good, I will pull the intake off and check and clean whatever i see. I would be so glad if thats the problem. I'll keep you guys informed, thanks,
Adam

 

Does it knock when you run a higher octane? If your base timing is above 0* you may need a higher octane with a 160* t-stat.

I am running a custom chip and 6* advance and I run 91 octane. I do not believe that I have a pinging problem.

 

Yes it does. I tried running 93 octane and had the same problem.