3sge pinging

[NeoNasty]

In my celi from the time I got it, in a higher gear under slight load its pinging its head off.

I usually run it on either 95 or 98ron fuel. Last night I set the timing to the correct (10degrees) and not its even worse. I put it back to around 7degrees and now its better, but still there. My missus car with a 3sfe does the exact same thing. Perhaps its just a rattling sound?

Anyone want to come over and have a listen? Any ideas on what Ican do to fix it? When the timing was at about 5 degrees, it idles like shit. and starts missing sometimes. The thing is that when I really boot it, it sounds OK just around the 2Krpm range.

I replaced the sparkies, rotor button and distributor cap.

Im in chadstone if anyone else is near.

*grumble* friggin car.

[sillycar chick]

I had the same problem with my 3T when I got it, and have been playing with my timing for 2 years... finally last weekend we managed to get rid of most of the pinging, but its coming out soon so I dont really car anymore....

Since you have done plugs, rotor and cap, whats left? It could still be the timing somewhere, but what else is involved in this? Spark plug leads (check resistance with meters), timing chain/gears/guides could be too flogged out - if this is DOHC engine, you may be able to get an idea of the condition these parts are in by taking off your timing cover. You can also double check the components in your dizzy to see if they are throwing your timing - is it old school dizzy or electronic? It its old school, check points condition and gap or just replace as theyre pretty cheap, replace the condenser unit, check for play in the dizzy shaft (side to side) there must be no play at all in this.

Then we can also go into the internals of the engine - do you know the history of your engine? Has someone built it to non-standard specs, as having too high compression with low octane fuel = detonation which i guess imitates rough timing? ( I have never heard an engine actually detonating, only know what it is and what happens when it does it). Maybe try some octane boost in your next tank and see if it settles down a bit?

Knowing more about your engine in relation to the above questions can help us understand where the problem lies so we can help you fix it!! Good Luck

[RWDboy]

If your engine is knocking/pinging then that means the timing is too advanced ... if you are having problems with detonation (pre-ignition) - then that means something is going wrong with either the fuel mixture, the temperature of the intake, or alternatively there is some kind of hot spot in your combustion chamber.

You've tried playing with the idle ignition advance (note that idle ignition advance is very vague, you are better off adjusting your ignition advance at 3000rpm rather than at idle where 100 or 50 rpm difference can change the overall advance significantly) and replaced the plugs etc - to no avail.

Assuming that your car isn't over-heating, and that the general temperature of things is normal ....

Next thing would be to check your ECU for error codes to make sure it's not trying to compensate for something that isn't busted, or it's possible your Throttle Position Sensor isn't functioning properly and the ECU isn't richening up the fuel mixture enough at Wide Open Throttle ... if the ECU, and TPS come up fine, chuck it on a dyno and check the a:f ratio at W.O.T.

Then you could try playing with different spark plugs (spark plugs may be getting too hot and pre-igniting the fuel), try de-coking the engine, and then if that doesn't work, you could always take the head off, pull the pistons out and get them acid-bathed.

[NeoNasty]

Its a 3sge. From unknown source. Its been changed. I was told that it was a 2nd gen short motor from an MR2 with the 1st gen gear bolted onto it. However I dont think it was, as I was told when I came to register the car that the engine was once registered in a Celica. Thus, cannot be a 2nd gen?

I checked the spark plugs, and them dont look white, they are a nice brownish/grey colour. I changed the timing belt around 2K kms ago. Its EFI so points arnt a prob.

I have run the car on regular unleaded and the sound is worse, so it looks like pinging.

It has the old flat top cam cover, so finding leads is provign to be hard. The part that goes into the engine and too the spark plug is too long. urg!

On another point, I raced my missus in her Auto 3sfe SV21 camry. LOL I thought she might be close, but by the time I was half way through 2nd gear I was 3 cars ahead.
*shrugs* 3SGE POWAH!

[NeoNasty]

Good idea. I will check for error codes. I was actually reading the haynes manual about checkign the sensors. Really? 3000RPM eh? OK, I'll do that.

The engine never gets above half way on the guage.

I put the spark plugs from a 3sfe into it. They are a lower temp, but its still doing it. I will put the stockies back in.

[sillycar chick]

I have only worked on T series engines, so I dont know all that much about the S series. But principles of engines are all the same. Is it possible they have a different head on the engine or had it shaved? May be an idea to do a compression test if you have access to a tester, and see if its too high? Keeping in mind that if the cam timing has been changed, your readings wont mean squat.

But seriously, if she runs worse on unleaded, I would really suggest a belly of octane boost. If there is significant difference in the pinging, it may suggest the engine has a higher compression ratio than standard. This would mean you would have to run octane boost all the time, which can be expensive or get your cams retimed to reduce the cylinder pressure when approaching TDC or put a head shim in to reduce the compression ratio. If you have been told it has 1st gen gear on it, then obviously someone has played with it and there is every chance your compression ratio is higher ie head could be shaved. And if you beat the 3sfe it may be quicker than standard, but it depends on the weight difference between the two vehicles...

Try the octane boost and post up your findings.

[NeoNasty]

Will do. Tonight I'll check for error codes. reset them. See if they re-occur, therefore stopping 10 year old codes freaking me out. Put the old sparkplugs back in. Get some octane booster into it. See what we get

[wiso]

could you have put the timing belt back on wrong? code it be a tooth advanced or retarded throwing your timing out

[NeoNasty]

Nah I think Its all good. when I tried to do it myself, I put it 1 tooth out. But my mechanic fixed it for me.

[RWDboy]

Octane boost *might* help as it is more knock-resistant. But there is no way you should have to put octane boost into a standard 3S-GE!

[sillycar chick]

Octane boost *might* help as it is more knock-resistant. But there is no way you should have to put octane boost into a standard 3S-GE!

Fair enough, but we dont know if it is standard or not. The owner has suggested the possibly that other engine parts have been fitted, which is why I have suggested it. But if it is standard, then yes, it shouldnt need it.

[RWDboy]

*nods* (10 char)

[myne]

Stupid question, but did you short the T and E1 pins on the test connector before adjusting the timing?
Doing that puts the ECU into diagnostic mode and fixes the timing at what the computer things is 10*. Then you simply make what the computer thinks and reality match.

[wiso]

hmm that really shouldn't affect it, cause if he did just adjust normal timing with out shorting the pins, it would be running about 2/3 degrees when it is bridged, and it wouldn't be running, it would be stalling, bridged you can never get it below 5 degrees without it stalling

[NeoNasty]

Yes I did the timing correctly. Its set at about 7 degrees.

I got an error code of 12. No RMP signal. So Ive reset the ecu, went for a small drive, while booting it and no new codes. Will check again tonight.

Tonight Im going to pick up some injector clean..