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compression low

Low compression
#1
Hello,
15 days ago my astra j 1.7 CDTI went into safe mode. I drove the car back to home in limp mode for about 10km. Day after I was booked in local garage. But the car has no power. Suddenly, after 200m the car stopped. It starts for 2sec and again stop... To cut the story garage was diagnose totally corked DPF filter. Cause: two injectors were corked by bad fuel. Anyway, DPF is now out completely (strait pipe) and remap done and injectors repaired. But now, service struggle to adjust injectors electronicaly 'cause they said cylinder 1 and 2 has low compression, about as I remember 14bars, other two are over 20 bars. The car was given back to me now. I am driving the car with no issues. Now has more power, starting normally, consumption is normal. Everything looks ok. Now, I am wonder if they want to build the job for them self or is some serious issue.

Any suggestion will be well noted.

Zoran

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#2
(18:th-Apr-2018, 08:45:57)Brnjas Wrote: Hello,
15 days ago my astra j 1.7 CDTI went into safe mode. I drove the car back to home in limp mode for about 10km. Day after I was booked in local garage. But the car has no power. Suddenly, after 200m the car stopped. It starts for 2sec and again stop... To cut the story garage was diagnose totally corked DPF filter. Cause: two injectors were corked by bad fuel. Anyway, DPF is now out completely (strait pipe) and remap done and injectors repaired. But now, service struggle to adjust injectors electronicaly 'cause they said cylinder 1 and 2 has low compression, about as I remember 14bars, other two are over 20 bars. The car was given back to me now. I am driving the car with no issues. Now has more power, starting normally, consumption is normal. Everything looks ok. Now, I am wonder if they want to build the job for them self or is some serious issue.

Any suggestion will be well noted.

Zoran

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Today I was toking to my friend mechanic. He said bad compression can be various things (head gasket, valves, O rings, pistons,...). So now I don't know what to do? Should I measure compression in other garage? Is that big job and what are normal values of pressure for cylinders?
Again, I drove the car yesterday and no issues with ignition, turbo, consumption. Even so I check oil level and is normal. So, I believe this remap i good. Only thing I notice is in high acceleration I have bigger BLACK smoke and in place during ignition but this is normal with no DPF I believe...
My car is Astra 1.7 CDTI, 176000 passed on clock.

Please, anybody can advice me what to do next?

Thanks in advance,

Zoran

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#3
There are lots of things as you know it could be, I would let a garage check compression.

In terms of the black smoke yes with no DPF.
Astra-J 2.0 CDTI S/S
Retrofitted AFL, TPMS, Navi950, BT, DAB, Rear Camera, Infinity sound system, Towbar, Flexfloor & more.
I can do programming and retrofits using genuine GM MDI and Dealer software.
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#4
Thanks Rusty,
Yes, I need to check with garage compression. Yesterday some strange noise came from engine bay. Sounds like I can hear valves or something metal making noise, of course SERVICE CAR SOON, ENGINE POWER REDUCED came on dash. Switched the car off immediately and started again, no issues at all. I am really confused what is going on. But anyway I need to visit garage. As they said this job will cost around 1000-2000euros. Is that possible?

Thanks
Zoran

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#5
It depends what it is causing the issue as to cost to fix. if it's major engine work you might find getting another engine is cheaper.
Astra-J 2.0 CDTI S/S
Retrofitted AFL, TPMS, Navi950, BT, DAB, Rear Camera, Infinity sound system, Towbar, Flexfloor & more.
I can do programming and retrofits using genuine GM MDI and Dealer software.
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#6
(28:th-Apr-2018, 07:07:20)Rusty2009 Wrote: It depends what it is causing the issue as to cost to fix. if it's major engine work you might find getting another engine is cheaper.
Thanks, Rusty

Will figure out something. I'll post results...

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#7
Update of low compression.
Another service measured compression and the results are as follows:
No. 1 cylinder= 25bar
No. 2 cylinder=25bar
No. 3 cylinder=15bar (two tines measured same)
No. 4 cylinder=13bar (two times measured same)

Now car is smoking bad, but I mean bad black smoke with black particles exiting from exhaust pipe. Special when first starting in the morning. Huge black circle on the floor. During driving and when I step on gas HUGE black cloud behind me, like I am driving bloody tractor.

I checked with my mechanic and he said not good mixture( too much fuel and too little air) causing particles.

Can be:
Exhaust or inlet Valves stacking with carbon as I was repairing bad Injectors or even valves deformed,
Piston rings worn out, regarding this I notice now engine is consuming some oil (for 900km=200ml of oil) and when engine is running I opened the oil cap and there is some pressure coming from and fumes (small), is that normal? (somebody said when piston rings are worn out can be pressure when I remove oil cap).
Had gasket is not because is not mixing oil and water. No leaking anyware.
Car is pulling good over 1500RPM. Below is slugish and shaking slowly.

Any other ideas pls be welcome...

I have been rapped last time in official Opel service. And now I need to know what is going on. I know I need to remove head to look at valves and anything but some help will be appreciated.

Sorry for loooonnng text. Now I am feeling desperate...

Zoran


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#8
@vocky maybe best to advise here he's more into the mechanical side of cars than I am.
Astra-J 2.0 CDTI S/S
Retrofitted AFL, TPMS, Navi950, BT, DAB, Rear Camera, Infinity sound system, Towbar, Flexfloor & more.
I can do programming and retrofits using genuine GM MDI and Dealer software.
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#9
the original fault (two blocked injectors) has possibly caused the valves to get coked up, your options are limited and removng the cylinder head for inspection of the valves is probably a good idea.

However a replacement engine might be cheaper if you plan on keeping the car for many years
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#10
Thank you Rusty, vocky

Yes. I understand it is cheaper to just swap engine, but unfortunately I could not find in around countries or in mine this engine or higher/ lower to swap.
Problem in Montenegro is I can not pass MOT test with all this black smoke even when idling. Personally, I like this car and I don't want to sell it for a while.
So, know only option is to remove head and see what us going on with valves, pistons, rings, etc.
I will reply what was the problem.
Thanks guys...

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#11
Because you still have 13 Bar of compression it's more likely to be the cylinder head than the rings
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#12
Cylinder head. Right. How this can happen? I don't understand. I am driving this car normally. With no too much pressure. Never overheated. Do you think maybe this happen because of cloaked injectors in past time?

Did I understand you well? You are pointing at cylinder had gasket right?

Zoran

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#13
possibly the head gasket, but more likely to be the valves are not sealing correctly due to carbon deposits
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#14
Thank you vocky,

Head gasket? Hmm. But I do not have symptoms of blown had gasket like milky deposits under oil cap or fumes from coolant bottle, nothing like that. Oil consumption is normal last time I checked. Beside black smoke only what I notice when engine is running and when I open oil cap is coming a little pressure, not sure is that normal or not. And around 1500 RPM car is shaking again little bit no matter what gear is Maybe because of low compression?

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#15
a build up of carbon on the valves

valves are not sealing

you need to rebuild the cylinder head
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#16
Thanks vocky,

Will check the valves and report back.

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#17
Ok sitrep everyone,

Car was in service measured compression again, and Vocky you had right the problem was blown head gasket on those two cylinders with low compression.  Repaired and now the car has power like before, starting immediately and I will enjoy couple more years in it. 
Thank you everyone

cheers Zoran
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