1G-GTE Stalling out on removal of Oil cap.

[Quint]

When the oil cap is removed, the engine has a very hard time running and eventually stalls out.

Any one know the cause? Never seen an engine do this before.

[jondee86]

When the oil cap is removed, the engine has a very hard time running and eventually stalls out.

Any one know the cause? Never seen an engine do this before.

Taking the oil cap off while the engine is running lowers the dynamic
compression. That gas you feel coming out is leaking from the cylinders,
and the cap keeps it in. Once you take the cap off the compression drops,
and the engine goes off tune.

TRD do a high compression oil cap, you might want to look at getting one
of those.

Cheers... jondee86

[Bling]

Can I ask why you would take the oil cap off while its running?

[MrOizo]

Its because you have a AFM.

its letting air in through the PCV in after the AFM.

[Adoom]

Its because you have a AFM.

its letting air in through the PCV in after the AFM.

What he said.
Sorry jondee86. but you is crazy.

[Lloyd]

As MrOizo said. Few cars do it, some of the Fords die instantly when you twist the cap off

[Quint]

Can I ask why you would take the oil cap off while its running?

Engine developed a really bad knocking, took it off to help me figure out whether the noise was coming from the head or the block.

Turned out to be the head, on further inspection


one of my oil feeds has blocked up causing the lobe to heat up and break

So now i need to find replacement cams and shims. Anyone know of rough pricing etc.?

[Quint]

Its because you have a AFM.

its letting air in through the PCV in after the AFM.

mmmm cool, cheers.

[MAGN1T]

The air is probably getting past the piston. Your motor's probably rooted. unless of course the PCV valve isn't hooked up properly.
On any GOOD motor it won't do this.

General PCV setup there should be a hose from the intake manifold to PCV valve. This is normally nearly closed with intake vacuum, it opens more with less intake vacuum. There's another hose from valvecover to intake piping as a vent. That allows air into the crankcase and from crankcase to intake manifold. The crankcase should always be at atmospheric pressure. With a turbo car under boost the PCV valve should fully close and the vent relieves any pressure buildup.

Steve

[mjrstar]

my 1ggte runs fine with the rocker covers removed.. a few little splashes of oil. which cam are you after? i have a spare I'm just not sure if it is intake or exhaust.

[Quint]

After intake, the exhaust side has the gear on it while the IN side doesn't.

you run it without rocker covers? you one crazy bastard !

[mjrstar]

After intake, the exhaust side has the gear on it while the IN side doesn't.

you run it without rocker covers? you one crazy b**tard !

i'm familiar wit which cam is which.. I just can't remember which one of the pair i have is ok.. the pic showing the cam and injectors is a bit of a give away also..

one has damage to the bearing surfaces and one is fine. I'm in aussie so won't be able to confirm if i can help you out for a little while...

I just had it running to diagnose a noise the car had.. i don't see any major problem with that... i wasn't about to take it for a drive or anything..

[sergei]

The air is probably getting past the piston. Your motor's probably rooted. unless of course the PCV valve isn't hooked up properly.
On any GOOD motor it won't do this.

General PCV setup there should be a hose from the intake manifold to PCV valve. This is normally nearly closed with intake vacuum, it opens more with less intake vacuum. There's another hose from valvecover to intake piping as a vent. That allows air into the crankcase and from crankcase to intake manifold. The crankcase should always be at atmospheric pressure. With a turbo car under boost the PCV valve should fully close and the vent relieves any pressure buildup.

Steve

Bollocks. Every single AE101 I have seen stalls immediately when oil cap is removed. Everything with a fuel pump relay switch in the AFM will stall, because on idle there is very little of flow and the follower almost touches the switch, a little bypass will cause it to stall. As for the PCV not functioning, it has nothing to do with this: there are 2 lines going to the rocker covers, one via PCV, another straight to the middle of inlet hose just between AFM and plenum - this one is the bypass that will cause it stall.

[strx7]

The air is probably getting past the piston. Your motor's probably rooted. unless of course the PCV valve isn't hooked up properly.
On any GOOD motor it won't do this.

General PCV setup there should be a hose from the intake manifold to PCV valve. This is normally nearly closed with intake vacuum, it opens more with less intake vacuum. There's another hose from valvecover to intake piping as a vent. That allows air into the crankcase and from crankcase to intake manifold. The crankcase should always be at atmospheric pressure. With a turbo car under boost the PCV valve should fully close and the vent relieves any pressure buildup.

Steve

Amen. 1.6 Suzuki escudo's have a problem with the front pipes blocking up and removing the oil filler cap is a sure fire way of telling how blocked the pipes are. Its because the engine has become reliant on its on exhuast pressure into the crankcase to run. Remove the filler cap and blah they die. Fit extractors and hello, its like a new engine.

[strx7]

Bollocks. Every single AE101 I have seen stalls immediately when oil cap is removed.

thats a pretty BROAD statement considering AE101's covers all the following engines 4AGE 20V, 4AF, 4AFE

[sergei]

Bollocks. Every single AE101 I have seen stalls immediately when oil cap is removed.

thats a pretty BROAD statement considering AE101's covers all the following engines 4AGE 20V, 4AF, 4AFE

I meant 20V silver top.
And they stall because path via oil cap, rocker cover, breather hose is easier/similar to path via AFM flap and air filter.

[MAGN1T]

It just goes to show how many faulty Toyotas there are then. Crankcase has to be at atmospheric pressure otherwise the oil pressure gauge will never read correctly(if you have one).

Steve

[jondee86]

TRD high compression oil cap FTW More compression and more
oil pressure !!!

Cheers... jondee86

[sergei]

It just goes to show how many faulty Toyotas there are then. Crankcase has to be at atmospheric pressure otherwise the oil pressure gauge will never read correctly(if you have one).

Steve

It has nothing to do with pressure, the crank case is below atmospheric pressure on idle. What happens is the engine starts sucking small amount of air via oil cap and breather line (rephrasing my previous statement for those who did not understand) instead of having all air metered on through AFM. Any substantial leak between AFM and head will cause the engine stall on idle (for those AFM with fuel pump switches). If you have a vehicle with a flap AFM and know that it has fuel pump switch in it remove a hose from either A/C idle up or breather that connects to main intake pipe after AFM, it will certainly stall (or at least drop RPM, as the ECU will meter smaller quantities of air)....

[MAGN1T]

You don't understand how the PCV system works.... re read my other post.

The PCV valve meters the air going into the intake manifold from the crankcase.
The vent hose from before the throttle body (to the crankcase) flows air into the crankcase to keep it at atmospheric pressure under all conditions...... unlesss it gets blocked.

Steve