SEH Compression test

[Nova_Tek]

Just did one on my dads Cav as it started running like my 1.2 (which died of a gunshot the the headgasket lol )

it's come up with the following reading:

Cy 1: 181 Psi/12.5 Bar
Cy 2: 188 Psi/13 Bar
Cy 3: 188 Psi/13 Bar
Cy 4: 188 Psi/13 Bar

I'd say that's good! Looks like it's an ignition problem.

:thumb:

[Nova_Tek]

So after the compression test I fitted new leads, rotor and dizzy but she still runs rough. Sometimes she will start up ok and then a few mins later run rough again.

No fault codes appearing.

Ideas as to what it could be?

[Damo]

You tryed air flow meter mate.

[Nova_Tek]

From past experiences when the airflow meter had gone breast up it would fire up the EML. I may have a spare one in the garage to try out so thanks for bringing that up.

Any other ideas?

[AlexW]

Try CTS.

[Nova_Tek]

Where is that located on the SEH?

[AlexW]

Erm No idea. Bigblocks are gay.

Will have a blue 2 pin plug though.

[Nova_Tek]

Is that the little sensor that shows the engine temp on the clocks? (as its blue lol)

[AlexW]

No, 1 wire does that.

[Nova_Tek]

Hmm, really do not know where that is and the Haynes isn't next to me. It's not the one in the Rad as that the fan switch.

[Will F]

Is that the little sensor that shows the engine temp on the clocks? (as its blue lol)

Its a blue oblong plug with another single wire going to the sender for the dash....

It will be on or near the thermostat

[Lewis.]

its on the back of the engine, between the head and the alternator near the timing belt cover.
and it will be a pain to get to cos the alternator is it the way.
got an SEH an my astra

[Lewis.]

mine runs like crap all the time, its had almost every sensor on it replaced, but it still runs poorly.

the idle control valves stick on these too, makes them idle a bit lumpy

[Nova_Tek]

Its a blue oblong plug with another single wire going to the sender for the dash....

It will be on or near the thermostat

That's the only other coolant related thing I could see. But I know that it's for the temp guage.


its on the back of the engine, between the head and the alternator near the timing belt cover.
and it will be a pain to get to cos the alternator is it the way.
got an SEH an my astra

Will have a look at that, don't matter about the alternator I'll just take it off.


mine runs like crap all the time, its had almost every sensor on it replaced, but it still runs poorly.

the idle control valves stick on these too, makes them idle a bit lumpy

All the sensors are original except for the AFM which was changed. It's never had a sensor fault before, so far it's been brilliant. The idle control vavle has also been very good, I normally clean it every service so I doubt it's that.

The car runs as if its lost power so I doubt it's the ICV anyway.

[Lewis.]

That's the only other coolant related thing I could see. But I know that it's for the temp guage.


Will have a look at that, don't matter about the alternator I'll just take it off.


All the sensors are original except for the AFM which was changed. It's never had a sensor fault before, so far it's been brilliant. The idle control vavle has also been very good, I normally clean it every service so I doubt it's that.

The car runs as if its lost power so I doubt it's the ICV anyway.


the idle control valve is meant to shut when the throttle is opened, so if it is failing to shut (due to being knackerd, not dirty) then it will be getting extra un-metered air so will lean off and run crap. they are the same as all vauxhall 2.0 engines so see if you can borrow aknown good one off someone and try it.
also TPS tends to go so it doesnt ever quite fuel correctly, and cannot respond to fast throttle movements

if all the sensors are original then that is only more of a reason for one to have failed.

[Nova_Tek]

I have a spare ICV in the garage which was totally working when it got removed off an NE, so I'll give that a go when I find it. As for sensor faults, surely one going wrong and not working/out of range would show up when doing a fault code test.

[Lewis.]

I have a spare ICV in the garage which was totally working when it got removed off an NE, so I'll give that a go when I find it. As for sensor faults, surely one going wrong and not working/out of range would show up when doing a fault code test.

certainly worth a try if you have one :thumb:

yeah they should but it depends whats up with them. AFM for example almost never show up on any code reads for some odd reason

[Nova_Tek]

When we had the AFM fault many moons ago it always made the light come on and gave the AFM code when flashed. We changed that and the EM Light stopped coming on, so it should show up, going on from past experiences.