3S-GE (Gen1) ping...

[oldcorollas]

does it do it at higher revs, or only when you drive like a grandma

many newer cars always ping when loaded up low in the rev range... they just suck

are you using 95/98 fuel? 91 is probably a bit crap...

have a look thru spark plugs, see if pistons are carboned up.

does it only happen at light loads?? check the O2 sensor output. if it only happens when in cruise or light throttle, could be that and worth checking (at the times it does it)

umm.. try and isolate what engine speeds and load make the problem... ie, work out a repeatable procedure to make it happen..

if, as you say, it is pinging when you are letting out clutch.. perhaps it is not actually pinging.... valve train rattles? you could try with a thicker oil perhaps?

[Jorrs]

does it do it at higher revs, or only when you drive like a grandma

many newer cars always ping when loaded up low in the rev range... they just suck

thats true, my mothers camry 1999, 5sfe does that.

[oldcorollas]

thats true, my mothers camry 1999, 5sfe does that.

cos she drives like a grandma

if ppl stopped trying to take 20km/hr corners in 4th gear.... it wouldn't happen

[Andrew162]

Thanks for the suggestions guys. I thought there wasn't a PCV on my engine, at least I never saw it. Ok to clear up doubts, base timing (10*) was set at the stock 750rpm and she pinged her tits off when driving normally (read: "grandma-driving"). Currently it's ~8* but I'll do as our grand-master Stew suggests and try to see when it does it at repeatable times. Only problem is I'm in a bit of a hilly area, straights and slight inclines are a bit hard to come by. Might take it to the industrial estate for a bit of a test.

I don't really thrash it all that much, I'm quite proud of my 600km per tank on a 21 year old engine. When I give it a bootful though, it doesn't seem to happen as much. Light throttle and cruising is when I can get it to happen, but how do I check the output of the O2 sensor?

It happened a few times in 1st and 2nd gears but I don't know (I hope is isn't) valvetrain rattles. See I don't even know when this car had it's last major service, let alone an engine overhaul.

[jonra23]

Sounds more like pre-igntion than detonation as it is happening at light load conditions , caused by as a few people have said carbon deposits getting heated enough to start the combustion process before the plug sparks, or too hot a plug.

Have you pulled the plugs recently to see what they are like?
Pull the plugs, clean or replace and decarbonising would be the first step i recon.

regards
jon

[mongrel]

go the subaru decarboner dude, it works a treat!

[Merudo]

that upper engine cleaner stuff works brilliantly!

[Andrew162]

#2 spark plug is the dirtiest, it's looking a bit carbony/oily. What is the best stuff to clean the plug with?

Also does anyone have a name of a good de-carbonising treatment like this Subaru stuff that's been mentioned?

Thanks again.

[kingmick]

If there just normal plugs just put another new one in! not worth muching around with.

[Andrew162]

ok got the Upper Engine Cleaner from Subaru this afternoon, gonna do a compression test on the cylinders before and after this cleaner is put through the engine. Should be doing this tomorrow.

[Andrew162]

Time to see if I could get rid of this ping. I've been told the pinging in an engine can be caused by the compression in one or more chambers being too high, thereby increasing the chances of pinging by igniting the fuel before the spark can ignite it.


I removed the plugs to check their condition, which was fair to average on most of them, but #3 (not #2 as thought before) was looking darker than the rest.


I wanted to do a compression test on the cylinders to see how they were fairing, and a procedure had to be followed to do this...

- remove CDI connector (above coil lead, held in with a clip, black and orange wires)
- remove coil lead at one end
- disconnect air hose from throttle body, but keep AFM connected
- remove connector to cold-start injector, located on the throttle body


So, starting from #1 cylinder (as pictured, closest to the alternator belt), make sure that the rubber plug is seated into the spark plug housing and is secure. The compression tester gauge stem is long enough so you don't have to remove the rocker cover. You'll need to have someone turn the key on the ignition for about 3 or 4 cranks. You may hear the engine pop a bit. When the gauge doesn't move anymore, stop cranking the engine. Write down the reading that your individual cylinders produce in PSI (pounds per square-inch, or lb/in2, or in KiloPascals (kPa). Most people use PSI.


So after the readings are all taken, plug the spark plugs back in, distributor leads, CDI and coil lead all reconnected. Re-seat the air tube back onto the TB, lock the airbox back into place. Plug in cold-start injector and the restart the engine.


Earlier I went and got some Upper Engine Cleaner from Subaru, having been told that this stuff works wonders on engines of all sorts. Now since you can't actually spray this stuff directly into the throttle body butterfly due to the air hose to the TB being connected to the AFM, if you try to remove the air hose from the TB while the engine is running the car will stall. So I needed to find another way to get the can's contents into the throttle body somehow.


By removing the vacuum hose of one of the VSV's, I could get the tiny nozzle supplied with the can of Upper Engine Cleaner into the vacuum nozzle. Directions are:

1. warm engine to normal operating temperature (done)
2. with ignition turned off, remove convenient vacuum hose (doesn't say which one) from the intake manifold and spray approx. half the can into the manifold using the nozzle supplied with this can.
3. allow the engine to stand for 5 minutes.
4. start the engine and run fast enough to prevent stalling while spraying the remainder of the can into the manifold. (this was a bit tricky, trying to keep the engine's revs up while spraying the can into the manifold)
5. stop the engine as the can empties and allow to stand for 5-10 minutes.
6. restart engine and rev engine to purge any remaining foam.
7. reinstall the vacuum hose.
8. road-test vehicle to ensure good performance.
9. extremely dirtry systems may require re-application.

So having followed steps 1 through to 7, here's what the plugs looked like after the process...

Got any blacker?? The #3 cylinder was a bit of a concern as well after I removed that plug, because the plug hole started releasing oily smoke immediately after removing the plug. I shone a torch down into each of the cylinders, and the best way to describe it was like looking at charcoal. I'm just wondering what benefit this can was supposed to provide. To add insult to injury, the compression didn't change (even marginally) after the treatment was put through it.


I couldn't in good conscience put those plugs back into their respective cavities without at least trying to clean them up a bit first. I got out the Metho and an old nail file (a bit of emery paper will do), and proceeded to lightly cleanup the plug surface. The electrodes were the worst, but I gave the core/tip a light going-over as well. So above is the end result of that.

Results: Each cylinder's compression was rated at 1034.2kPa (150 Psi), which is slightly down on factory specs (between 1080kPa (156.64 Psi) and 1275kPa (185 Psi)), which is within the 100kPa tolerances on this engine's specs, but still doesn't explain the pinging.
So, going by these results, I'm no closer to finding out what's causing the pinging in my engine under light loads, except for that anomaly with cylinder #3. Just seems a bit bizarre...

[Andrew162]

I hear the ping when it's warm, not all the time. Ok so the plugs might need replacing, but what about the black shit all over the pistons? Surely they need cleaning as well right? Replacing spark plugs in this case is like sticking a band-aid over a broken leg.

I did the purge on the system and got all the white/grey smoke out as much as I could, and it stunk the place out. After that I removed the plugs and they were black. The piston-tops are still black if I shine a torch down into the chambers.

From what I've seen, this car has never run excessively rich (which would be a conundrum anyway, you don't attribute rich mixture to pinging), the exhaust pipe has always been a light to mid grey inside.

All I want is to get rid of the stupid ping, not have the pistons coated to the hilt with carbon because of a product that's supposed to work.


So I don't think it would be the timing belt, otherwise it would be running like a bitch from the start... and I checked the distributor for 'play' this afternoon as well, nothing even looking like it's gonna move freely. Checked air hose already for leaks/cracks, AFM is in good shape from what I can tell. Air filter (K&N panel filter) is fine, fuel filter only just got changed over (was pinging before as well), and injectors have just had a service and are ticking away happily at idle.

Asides from putting in Premium next tank to see if that temporarily fixes it, I'm all outta ideas.

[Vios-GT_07]

have you checked your fuel pump??

try swapping it with another second hand good condition if you don't have a fuel pressure gauge.. or better yet, check your fuel pressure against other 1st Gen 3S-GE owners..

[Andrew162]

Already covered this in the 162 thread, if it were fuel pump it would cough & splutter all the time.

[RobST162]

I would definitely put 98 RON petrol in and that will make a difference (it can't help but!) till the solution is found.

pinging as badly as you suggest I wonder if the timing belt might be 1 tooth off.. :?

ahd yes, fuel filter perhaps.. but I think you did that yeah Andrew?

and you'd be getting 600ks out of a tank if it was running uber lean... that's only highway stuff usually... unless you use almost all 60 litres every fill??