GM 3.1L Pinging...WTF?!

[pjturkey]

If anybody has any ideas, I desperately need them. Car is 1995 Olds Cutlass Ciera 3.1L. It seems to ping when I slow down, turn a corner, and speed up (especially going up hill)......I tried manually downshifting but it doesnt really seem to help much. If I nail it to get around someone it seems to do it as well until the car gets moving. Also doesnt happen when car is cold (although it does not run hot).

In one form or another I've done the following:

-Using premium gas (seemed alittle better but doesnt do enough to justify it). I've ran about 5 tanks through it.

-New Spark plugs 2 heat ranges lower and new wires. (when I replaced them, a few were brown and very very crusty)

-Cleaned the whole EGR system and Throttle Body (new gaskets etc)

-New fuel filter

-replaced upper and lower intake gaskets (used the good fel-pros). This was to fix a coolant leak.

-Replaced Heater Core (was also leaking)

-Replaced Transmission (reverse reaction drum exploded)

-New PCV

The car gets 21-23 MPG and doesn't really seem like it has any vacuum leaks. Car has 121k on it. Only things I noticed were a small stumble on takeoff sometimes and every now and then a slight miss at idle that I can fix by tapping on a couple of the injectors with a socket extension (already tried injector cleaner). Short of replacing all 6 injectors ($$$$$), any ideas? I'm kinda committed with all the other crap I've done to the car so I need it to last!

I'm swear.... I'm never buying something that doesn't have a carb and distributor again!

[BAD LS1]

oil or oil vapor in decent qauntity getting into the combustion will make it knock alot. regardless of the new PCV valve, check the entry point of where the pcv valve goes into the intake tract for oil, not just a little dampness but alot.

[pjturkey]

Ok, I just realized that there was a stupid little plastic tee that the PCV tract runs to that fits into the intake plenum. The old one was broken and nobody seemed to have the part i needed so I used a metal tee and RTV'd it in with a piece of hose. I can't really check it now, but when I had the throttle body and intake off, there was oil all over the intake plenum/throttle body. It wasnt like there was a huge pool of it, but a decent coat. When I had the intake off, the injectors themselves looked clean but the cast metal around them was black.

I do notice that there is some smoke when I remove the oil fill right after driving (Blowby?) I wouldn't say it's excessive and it's not like its puffing out if you take the cap off while the car's running. It goes through a quart about every 2000 miles. If it is sucking in too much vapor or oil, is there any way to fix it or am I SOL?

[BAD LS1]

A catch can in the PCV hose routing before it dumps into the intake. Even just a water seperator from an air compressor would work in a case like that. deff sounds like the oil vapor is a contributing factor. the intake should remain relatively dry to souty, not damp or wet looking with oil. oil drastically degrades the octane rating of fuel, thus allows it to knock.

[pjturkey]

Makes alot of sense. Thanks much, will give it a shot!

[pjturkey]

Ok, just got a a filter from harbor freight and put it in the line between the pcv valve and intake. I then sprayed a can of throttle body cleaner into the tee leading to the intake. It still seems to ping so im assuming it takes some time for all the oil and crap to work its way thru. I noticed there is another tube from the other valve cover without a pcv valve leading to the throttle body. The plastic fitting doesnt stay ib the valve cover that well. Can I just cap the throttle body side and put a breather on it? Not quite sure what that tube is for

[BAD LS1]

That other tube is a fresh air intake vent tube so the crank case can breathe. It's fine to put a breather on that and cap off the intake connection. Make sure that intake connection is capped or you will create another headache with maverick air after the mass airflow sensor. Basically the crankcase venting will then be independent, which is only done for emissions and removing vapor from the crankcase via the intake vacuum. However this vacuum is no where near strong enough to actually help promote better ring sealing and such, that's what pumps are for. Sorry for the round about way of getting to the point.

[pjturkey]

Ok, just was driving around for a while and it seems alot better. Real test will be tomorrow on the freeway. Like I said, I'm sure it'll take some time for all the oil to work its way through. I'm kinda new to working on newer stuff but what you said makes alot of sense. Thanks for the help!