Ae92 Gti16 Issues

[Viterbo]

My brother has a Corolla GTi16 (AE92 hatchback) with the 2nd gen 4AGE and he's running some issues that I would apreciate help with.

 

1 - Cold start idle is 1300/1400 rpms when I think it should be around 2000rpms and drop to around 900. He is idling at 900 when fully warmed up but at idle I think it's too low and perhaps this is related to what's next.

 

2 - If he turns off the engine when fully warmed up and, let's say, 10 minutes later, he starts the engine again it suffers from idle hunting for a few seconds before stabilize.

 

3 - When he goes to a closed parking lot like an underground parking from a shopping the idle also gets crazy and sometime the engine stalls.

 

4 - Although valve seals have been changed twice(!!) the engine floods with oil when going in gear with no throttle applied like when going down a hill. As soon as he presses the clutch the revs come down and the engine stalls. When started again it blows a cloud of oil smoke through the exhaust. This really seems to be oil sucked through the valve seals when in great vacuum conditions, but changing them twice, although it helped a bit, the problem stays.

 

Can anyone give some help?

Thank you

[altezzaclub]

I have a RWD 4AGE with the waxstat controlled cold idle, I'm not sure if yours is the same. Cold idle is about 1400, straight from starting up at -2deg, and warm is 1000 when it behaves.

 

Under the throttle body is an air bleed into the inlet that is closed and opened by a wax cylinder in the water system, same as a thermostat. I think the waxstat responds quickly to random temperature fluctuations in the water, as I have a good cold idle and warming up idle, but it will randomly die when the motor is at full running temp. When you slow down and cruise through a carpark the motor struggles to dump heat it was getting rid of by the 50kph airflow a minute or two before. At slower speeds the water flow is also different, and the 4mm hoses might not flow water cleanly enough to give the waxstat the right temp.

 

I figure a straight air leak in the inlet would give a constant problem, and the only variable thing seems to be the waxstat.

 

Your oil smoke problem does sound like valve guide seals, I don't know why they would leak after being replaced, You only need them on the inlet valves as the exhausts are not under suction. More help may come from putting an o-ring on the stem above the seal, which is all seals used to be. When the valve opens the o-ring goes down and touches the top of the guide (or the seal in your case) & this puts the drop of oil on the outside of the guide instead of running down the stem.

 

What is the blowby & the oil usage like?? Blowby carrying too much oil up into the cam cover??

[LittleRedSpirit]

You might have an incorrect pcv system that pressurises the engine and forces oil into the cylinder, either that or its blocked maybe so the head pressurises with spare combustion gasses and forces oil out.

[Viterbo]

I'm not sure how to check that blowby to the cam cover...

I thought the same about a vacuum leak, it would be constant.

And yes this engine has that waxstat thing.

That oil issue only happens when letting the car rolling in gear. If my brother runs without letting that happen the engine has no oil consumption.

 

 

LittleRed and is it possible to check and eliminate that pressure without disassembling the engine?

[Viterbo]

Few more data:

 

Timing was below 0 degrees, distributor fully turned and I can only get around 2 degrees of advance. I think I'll need to advance a tooth to set it to 16º.

ECU had error code 3 which relates to igniter information missing 4 times in a row.

[altezzaclub]

I'm not sure how to check that blowby to the cam cover..

 

You could pull the hose off the intake manifold and extend it into a plastic bottle, then block the hole into the intake with tape and try driving it. That isolates the drilled passages inside the intake manifold from the equation. I'm not sure what is in the tappet cover under the hose outlet, there is usually some thin metal splash guard with mesh to stop oil getting thrown into the pipe. If you have the tappet cover off you could give that a blast with petrol or brake cleaner to get rid of tar. Watching the plastic bottle will also give you an ide of how much oil is getting pushed out by compression.

 

My 4AGE model doesn't have a PCV valve, I'm not sure if that is for all 4AGEs. If the breather system is blocked the extra pressure should blow the dipstick out a little, as the system relies on the dipstick sealing to stop air leaking into the intake. I've never tried it, but while it is idling just pull the dipstick out and see if the idle changes.

 

Does it smoke when you drive away after idling at the lights??

 

Getting the timing right might improve the performance even if it doen't stop the oil problem!

[Viterbo]

Only time the car smokes is after it stalls for having come in gear with no throttle applied.

If I stop at a red light without it stalling and then drive away it doesn't smoke at all.

[Hiro Protagonist]

My 4AGE model doesn't have a PCV valve, I'm not sure if that is for all 4AGEs.

 

I don't think any of the 16V 4AGEs have a PCV valve, just the breather line (which despite going to the intake manifold is actually cross-drilled through to before the throttle plate, so it never sees vacuum)

[altezzaclub]

I don't think any of the 16V 4AGEs have a PCV valve, just the breather line (which despite going to the intake manifold is actually cross-drilled through to before the throttle plate, so it never sees vacuum)

 

OK, thanks, so the bit I read somewhere about the importance of the dipstick seal is to stop blowby getting out, not air getting sucked in.

 

If I stop at a red light without it stalling and then drive away it doesn't smoke at all.

That is the time you have the inlet manifold at high vacuum and sucking hard to pull oil down the inlet valve guides.

 

It is a very strange problem, and it doesn't seem to be a problem of the valve stem seals. Maybe it is more unburnt fuel from when it stalls, something related to timing or idle speed or a broken sensor. Have you had time to move the distributor and set the timing correctly?

 

Can we distinguish between a cloud of oil smoke and a cloud of fuel smoke??

[Viterbo]

I think oil smoke is blue and the smell is really unique also, fuel smoke is darker I think..

[altezzaclub]

Yes, that is what I believe too, so it is definately oil smoke. So it must be either getting up past the oil rings or down past the valve stem seals. Maybe the oil rings are just worn enough to do this under vacuum, but not worn enough to let oil up generally.

 

Don't push the clutch in when going downhill, then all will be fine!.

[Viterbo]

Yes, that is what I believe too, so it is definately oil smoke. So it must be either getting up past the oil rings or down past the valve stem seals. Maybe the oil rings are just worn enough to do this under vacuum, but not worn enough to let oil up generally.

 

Don't push the clutch in when going downhill, then all will be fine!.

 

When going downhill the solution is to put in neutral and let it roll.

The problem is my brother is tired of the problems and wants to sell the car, but he doesn't want to take the risk of going to show the car to a potencial buyer and the car reveal this problem.