Turbo not idling - A fix

[MartinF]

So a little bit of a different thread, something which i hope may help others who end up with the same issue as i've just experienced.

After my trackday towards the end of last year i had two issues to fix:

• 1. The missing edges of blades from my turbo.
  2. Car not idling at all and cutting out.
  

I managed to source a replacement turbo over Christmas but didn't want to start stripping things down to replace until i had resolved the idling issue. I see too many threads on forums where people go wading in changing this that and the other and compounding their problems.

Knowing my issue was most likely a boost leak (i did double check static and ignition timing just in case things had slipped) today i decided to pressurise the intake tract and i found a leak at the back of the intake manifold.

On the back of the intake manifold is a second vacuum port that normally has a barb and a blanking cap on it, but in my case this had blown right out.

You can see in the pic below that i have temporarily blocked this with a bolt to check.


Once blocked idling returned to normal

So posting this thread in the hope that it may help somebody else in the future.

Tomorrow i will start stripping down to replace the turbo......

[[email protected]]

To be honest it's kind of freaky you posted this. As I was wondering why that hose was capped off on mine too!! Mine is still capped... may I ask what the hell that hose vacuum port does??? And why is capped?
My issue is that when I take the oil filler cap off my engine stalls!!!
May I ask if when you take your cap off does yours stall??

[thomp1983]

If your car is a rev2 turbo then it will stall as your introducing a load of unmetered air after the air flow metrr

[MartinF]

May I ask if when you take your cap off does yours stall??

I suspect it will because it's supposed to be a closed system, will check tomorrow.

[[email protected]]

May I ask if when you take your cap off does yours stall??

I suspect it will because it's supposed to be a closed system, will check tomorrow.

Thanks. If yours do stall at idle then that would be good to know as I'm worrying for no reason.

Mine is a mr2 1990 rev1 turbo

[[email protected]]

If your car is a rev2 turbo then it will stall as your introducing a load of unmetered air after the air flow metrr

Rev2 only?

[[email protected]]

I assume that capped off vacuum port was somethjng to do with the EGR as they were not in on the imports. Am I rite?

[MartinF]

Thanks. If yours do stall at idle then that would be good to know as I'm worrying for no reason.

Mine is a mr2 1990 rev1 turbo

Sorry to inform you that mine doesn't stall at idle when i remove the oil cap. It just carrys on idling as normal.

This engine is also from the same vintage Rev1 Turbo.

[thomp1983]

A rev 1 would do it aswell, basically if your car has an airflow meter as it relies on there being a constant amount that it has measured

[[email protected]]

Well this is very confusing. On one hand we have someone saying it will stall and is to do with unmetred air being done by the sensors which makes complete sense.

But on the other hand we have someone who has tried the test and it doesn't stall.

So my question is do you have the air sensors still or have you done any ecu upgrades removing any sensors?

It leads me to believe I have a vacuum leak somewhere as when I take the oil cap off it will cause it to stall??

Also how high are you idling? Because I'm at about 800 if I adjust the throttle cable to bring it above 1000 it doesn't stall

[MartinF]

Mine is on all stock sensors and ECU and idling around 800RPM.

Do you have an aftermarket BOV ?

[[email protected]]

Yes I do... I wonder if there is a way I can test it as I don't have the stock part

[MartinF]

Pic of my broken turbo out of interest.

[pbmr2]

Just a little bit of play in the bearings then

[Draven]

Looks fine, just a flesh wound

[MartinF]

Actually the shaft is fine. I suspect something which shouldn't have done got in there

[[email protected]]

There was a vacuum leak on my fuel injector rail. Replaced the 4 insulators. Started engine. Removed the oil filler cap and now it doesn't stall.
Also runs loads better now More boost.

So if you remove the oil filler and your engine stalls you most likely have a leak somewhere

[MartinF]

That's good news

[Gullzter]

I had the same issue on my old rev3 with the vacuum on inlet and it stalled the car/idled badly. The boost line had popped off, got it back on and it worked perfect again