Timing mark revolves around crankshaft pulley

[nsa]

I put a timing light on my Toyota 3RZ engine, tippex on the timing mark, sensor on spark plug wire for cylinder one, nearest the front of the engine.

The timing mark stayed steady for a while, slightly out of spec, then it proceeded to slowly revolve anti-clockwise around the crank. I think this is the same way as the crank. If the rubber inside my harmonic balancer had sheared wouldn't the mark revolve clockwise?, because it's turning more slowly than the crank? If I apply the throttle the mark speeds up.

It's a chain driven engine, the belt on this pulley drives the alternator and power steering pump. The car starts fine, battery runs OK, power steering works. It does get bogged down at low revs, which is why I was checking the timing. However, the cylinders have 200psi each so I don't think that's the problem.

[steveo3002]

are you saying it moves when viewed with a timing light? if so its the ignition advancing

[nsa]

steveo3002 said:

are you saying it moves when viewed with a timing light? if so its the ignition advancing

Yes, exactly. I confess I haven't run the engine completely up to speed before doing the timing test. If it does the same thing when the engine is warm am I likely looking at an air/fuel ratio problem somewhere?

[steveo3002]

is there not a procedure to setting the timing , all my cars have been disconnect this or that , then the timing stays static and check it

could be normal what youre seeing

[CrutyRammers]

Almost certainly won't be the balancer and I can't see why it would be anything to do with the fueling. It's the ignition timing, plain and simple, and may well be normal as above. Is it a distributor or electronic ignition?

[nsa]

Yes. Connect two terminals in the OBD1 diagnostic port, neutral gear. That's when I'm seeing the issue. It could be that the idle is higher than specified in the FSM because the engine wasn't fully warmed up. I was just very surprised to see that mark move around the crank.

[nsa]

Distributor

[steveo3002]

nsa said:

Yes. Connect two terminals in the OBD1 diagnostic port, neutral gear. That's when I'm seeing the issue. It could be that the idle is higher than specified in the FSM because the engine wasn't fully warmed up. I was just very surprised to see that mark move around the crank.

manual should state the temp and rpm to check it at

[nsa]

Is it possible or likely that a clogged catalytic converter can throw out the ignition timing? My O2 sensor is new and OEM, it's directly in front of the catalytic converter, which is possibly blocked.

[paintman]

nsa said:

Yes, exactly. I confess I haven't run the engine completely up to speed before doing the timing test. If it does the same thing when the engine is warm am I likely looking at an air/fuel ratio problem somewhere?

Before you start worrying about this,that or the other get the engine fully up to temperature. With the idle speed stable then do the ignition check. The marks should stay more or less in line with occasional slight movement if your idle isn't totally stable.
If you increase the revs then the timing mark will move if the auto advance mech is working properly.

[GreenV8S]

Does the timing mark stay within a narrow range - say 40 degrees or so? If so, that's likely to be normal spark timing changes. If the mark shifts around the whole 360 degrees that would suggest the pulley has come apart.

[tapkaJohnD]

nsa,
if the outer 'inertia ring' of your crank damper has lost adhesion with the rubber of the damper, and the hub, then not only will you lose your TDC indication, but any ability to drive the alternator, water pump(?) etc, and most seriously, any crank damping capability.

You would be best advised to replace the crank damper.
John

[phumy]

Check the key-way on the crank, i had exactly the same as this on a Golf GTi, the key had broken and allowed the pulled to spin at a different speed to the crankshaft

[stevieturbo]

nsa said:

Distributor

What ?


And WTF ?

[nsa]

Electronic fuel injection via a distributor. "Electronic ignition or distributor?" isn't really a valid question so I thought I'd just post a picture of the engine.

[littleredrooster]

nsa said:

Electronic fuel injection via a distributor. "Electronic ignition or distributor?" isn't really a valid question so I thought I'd just post a picture of the engine.

The question was valid, and relates to the ignition, not the fuel injection. FI has f-all to do with your original question...

The question was "Does it have electronic ignition (i.e one coil pack per cylinder) or 1 coil and a distributor?"

In answer to your OP, if the timing mark moves about one-third of a revolution when the revs increase and then comes back at idle, that's perfectly normal. That's showing the ignition advance is working.

If it is revolving all the way around, it sounds like the crank pulley has delaminated, or the woodruff key has sheared. (Other posters have already pointed this out in separate posts.)

Is this perhaps the first time you have used a timing light?

[stevieturbo]

Have you even looked at the crank pulley to see if it looks ok ? and verified the TDC mark on it is TDC and has not moved ?

And no sense trying to an idle check, if the engine is not at idle, and you also do not know if there is any adaptive timing for idle control, although if you have enabled a test mode and all parameters for this test are met, then timing should be static.

[LimSlip]

littleredrooster said:

In answer to your OP, if the timing mark moves about one-third of a revolution when the revs increase and then comes back at idle, that's perfectly normal. That's showing the ignition advance is working.

If it is revolving all the way around, it sounds like

120 degrees advance is very far from normal! 30 degrees would be reasonable, about a 12th of a revolution.

[nsa]

Saturday morning is the first chance I've had to have a look at the crank pulley. With some effort I can turn the outer ring independent of the inner ring. New OEM one ordered, I'll report back after it has been fitted.

Thanks everyone, this forum is invaluable to enthusiastic amateurs like me.

[tapkaJohnD]

nsa said:

Saturday morning is the first chance I've had to have a look at the crank pulley. With some effort I can turn the outer ring independent of the inner ring. New OEM one ordered, I'll report back after it has been fitted.

Thanks everyone, this forum is invaluable to enthusiastic amateurs like me.

Absolutely the best decision! Inertia ring crank dampers have been used for fifty plus years. This is one from a Triumph Vitesse, straight six engine, whose ring fell off in use. Luckily, the engne was idling, else the spinning ring could have caused as much damage as an armour piercing shell!