Pinking

January 23, 2006

Forgive me if this has been covered but I was unable to find another thread that describes it.

I have a 1997 RAV4 GX (2.0 litre 5 door) and has covered 157,000 miles. At around 2000 revs, the car pinks quite a bit. I worked for a diagnostic company and used a tester we had that said I had an IGt fault. I've looked into this and it seems it has something to do with the ignition timing. I recently took the car to Toyota who, after disconnecting the Battery and clearing any codes (the Battery was flat and needed replacing) said their diagnostic reported no faults. Not surpising since they'd just cleared them.

The car doesn't pink if you drive at 30mph, put the car in top and floor it. It seems to do it when you are at mid(ish) throttle, ie, accelerating and the revs get to around 2000 at operating temperature. And it will do that on a flat road.

Has anyone had a similar problem? I asked Toyota if they checked the timing with a light and their reply was that it is not adjustable so there was no point. Maybe, but it would highlight a problem if it turned out to be wrong. Also, I suspect the timing would look OK at idle since it doesn't pink then; only on load.

Any ideas, please!? I need the car to be as right as possible as I need to pull a caravan.

Thank you for your help,

Percy.

January 24, 2006

Had the same isssue, sort of. Mine feels dead at around 2800 to 3000 rpm too. I changed the plugs and give my intake manifold a clean which made it better.

But yes, i know what you mean. Toyota said mines ok. But I can't help but feel it ain't quite correct.

January 25, 2006

Thanks for that.

I changed the plugs about 7k miles ago but I've never thought about cleaning the intake manifold. I changed the air filter at a similar time but maybe the intake is a bit clogged.

Any other ideas?

Percy.

January 25, 2006

Has yours got a distributor? Not sure when they stopped using them.

January 27, 2006

Yes it has got a distributor and it looks as though it is adjustable. I did try to adjust it once but there is a bolt that is impossible to get to because it is underneath. I think the ECU would take over from the distributor anyway once the engine is started. Is my mixture too lean? It passed the MOT OK last year so the emmissions are at least not high. What about higher octane petrol? I tried that once as well but I already had 95 petrol in the tank. Also the high octane stuff is expensive. Could it simply be that the engine has covered a lot of miles?

I went to my old workplace today and tried their own vehicle tester on it and it said there were no errors. Typical.

Would checking the timing with a strobe tell me anything at idle?

Sorry about all the questions. I just don't know where to start.

Percy.

January 27, 2006

The distributor is a good place to start on yours, especially the vacuum circuit that controls it. Mine is a slightly newer 98 model, and these don't have a distributor. So in my case the timing is controled direct by the engine ECU.

Actually, now i'm not so sure about the distributor on those thinking about it. I can't remember if it is a traditional type vacuum controlled distributor or not. Something tells me they aren't. If they are ECU controlled, then they are most likely not adjustable. If this is the case then i'd start looking at the vacuum circuit all around the intake manifold and check for leaks. Check the pipe to the MAP sensor too. It could also be the knock sensor that's failed, or failing causing the timing to not adjust correctly.

There are so many possibilities with a fault like this one. If it is pinking noticabley, then it will need to be looked at. Pinking, or pre-ignition can cause damage to the valve seats as the petrol and air mixture is actually igniting before it should.

Sorry I can't be of much help, but this is like many faults very awkward from the other end of a computer.

May 29, 2006

Hello again.

The car is still pinking or knocking. I took the old rotor arm off and it and the dist cap were quite bad. I replaced the arm and cleaned the cap but it still does it. I didn't really believe it was going to be the cure but I thought it might be a culmination of things.

Anyway, I'm lucky enough to have access to AutoData which is a garage trade database giving LOADS of information on all kinds of vehicles. It has information on what to do if your car knocks so I set about going through it all. The first thing is, of course, the knock sensor (KS). It shows a diagram of it's location, but I can't find it!!

Does anyone know where the knock sensor is and, better still, could someone take a photo of it so I know what it looks like as well?

Thanks for your help

Percy.

May 29, 2006

I believe it's right down the back of the engine, in probably one of the most least accessible places! Basically, it's near the injection manifold somewhere down there!

May 30, 2006

You are using Platinum tipped Plugs????

May 30, 2006

You are using Platinum tipped Plugs????

Erm.. no. Should I? I mean, surely it can't be that critical. After all, it's not a high performance engine. In fact, I put in 97 octane petrol, quite a bit and it has improved but not like I think it probably should.

I'm not disagreeing with you, but I wouldn't have thought that it would make that much difference. Of course, I might be wrong. Trouble is, I don't really want to spend what I imagine is quite a lot of money on platinum tipped plugs only to find out that it is the KS.

If the KS, or any other sensor was playing up, would it make the MIL lamp come on? Could it be a build up of carbon? The car has done 160,000.

Thanks for your help.

Percy.

May 30, 2006

I had this problem and it was down to Plugs as some plonker had just replaced the originals with the cheapest available. A decent set of Platinum Tips will only set you back £20,I'm guessing thats less than a KS and if you do change them the bonus is they last for 60,000 miles ;)