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11,220 Posts
This isn't even funny any more at this stage. Most of you will be familiar with the problem from vage but for those of you who aren't....
Basically the problem is this:
When the car is cold and you start it up it starts straight away and most of the time it idles fine, but touch the accelerator and it just starts to miss and cuts out. The odd time it won't even idle when you start it and just cuts out again. Try to start it straight away in either case and it won't start. Leave it for half an hour or so and it will start ok. Let it warm up for a few minutes before touching the accelerator and it will run fine.
When the engine cuts out and you are trying to start it it sounds like there's no compression so I did a compression check to see what the story was. Result, absoutely zero compression on 2 of the 4 cylinders, full compression on the other 2.
But now it gets really interesting, I knew if I left the car for a while it would probably start, so I left it for half an hour and did another compression test, and had full compression on all cylinders!
Sometimes the car starts and runs ok from cold. There was even a time back a few weeks ago when it was perfect for 4 days in a row.
Now when this first happened I suspected a mechanical issue with the tappets or something like that due to the fact that the compression was coming and going.
Then someone suggested that the reason for the loss of compression could be washdown due to overfuelling and/or a weak spark.
So at this stage I have been through everything I could think of that could be affecting the spark or fuelling.
I have swapped the following parts with ones that are known to be working:
Tappets
ECU
Tci-h unit (little unit that controls the spark at different revs, sits on top of the ecu)
Distributor
Knock Sensor
Coolant Temp Sensor
ISV
Fuel pressure regulator
Coil
And tested the following:
Airflow meter
Throttle position switches
Connections to all of the items mentioned in the above lists
The obvious things like plugs, leads, cap and rotor arm are all brand new.
The alternator is charging ok and the battery is good (I read somewhere that low voltage to the injector rail can cause overfuelling)
At this stage I'm thinking it's either a problem with the loom or else as fasteddie suggested on vage the pressure control valve in the oil pump could be stuck causing the pressure to be too high when the engine is cold, thus pumping the tappets up enough to open the valves and cause the loss of compression.
I'm going to do an oil pressure test then swap the pump over and do another oil pressure test to see what difference that makes.
If that doesn't work then the next job will be to swap the loom for another one.
Anyone got any other ideas? I'll consider anything at this stage to get the thing going.
Basically the problem is this:
When the car is cold and you start it up it starts straight away and most of the time it idles fine, but touch the accelerator and it just starts to miss and cuts out. The odd time it won't even idle when you start it and just cuts out again. Try to start it straight away in either case and it won't start. Leave it for half an hour or so and it will start ok. Let it warm up for a few minutes before touching the accelerator and it will run fine.
When the engine cuts out and you are trying to start it it sounds like there's no compression so I did a compression check to see what the story was. Result, absoutely zero compression on 2 of the 4 cylinders, full compression on the other 2.
But now it gets really interesting, I knew if I left the car for a while it would probably start, so I left it for half an hour and did another compression test, and had full compression on all cylinders!
Sometimes the car starts and runs ok from cold. There was even a time back a few weeks ago when it was perfect for 4 days in a row.
Now when this first happened I suspected a mechanical issue with the tappets or something like that due to the fact that the compression was coming and going.
Then someone suggested that the reason for the loss of compression could be washdown due to overfuelling and/or a weak spark.
So at this stage I have been through everything I could think of that could be affecting the spark or fuelling.
I have swapped the following parts with ones that are known to be working:
Tappets
ECU
Tci-h unit (little unit that controls the spark at different revs, sits on top of the ecu)
Distributor
Knock Sensor
Coolant Temp Sensor
ISV
Fuel pressure regulator
Coil
And tested the following:
Airflow meter
Throttle position switches
Connections to all of the items mentioned in the above lists
The obvious things like plugs, leads, cap and rotor arm are all brand new.
The alternator is charging ok and the battery is good (I read somewhere that low voltage to the injector rail can cause overfuelling)
At this stage I'm thinking it's either a problem with the loom or else as fasteddie suggested on vage the pressure control valve in the oil pump could be stuck causing the pressure to be too high when the engine is cold, thus pumping the tappets up enough to open the valves and cause the loss of compression.
I'm going to do an oil pressure test then swap the pump over and do another oil pressure test to see what difference that makes.
If that doesn't work then the next job will be to swap the loom for another one.
Anyone got any other ideas? I'll consider anything at this stage to get the thing going.
