Opel Astra H 2010 Z18XER VVT problems

[liviu2004]

This one was without hope. Owner had issues with its VVT system, previously he went to two independent garages and the last resort was with the Opel dealer.

He spent so far 200 euro on diagnostics and next to be done were camshaft positioners, value 400 euro and in case that failed, engine ecu for 800 euro. Quote: "2 weken terug zat ik met electrisch probleem.(zie mijn andere post hier) hiervoor was hij ook binnen geweest, diagnose kostte me 200€ en luidde eerst vervangen nokkenasverstellers +-400€ en indien niet opgelost vervangen ECU+-800€." Dealer gave no warranties that after these, problem would be solved and money would of not been returned. It is black on white on email.

He wanted to give it a try with another ECU and he found me. I had an spare ECU we could play with so we met. Told him in advance these ECUs don't fail so often.

We started with few basic questions and learned that car has 144290 km, oil is 10.000 km old, unknown type. Battery 2-3 years old. Also that the engine light comes on at the engine start. The exhaust camshaft actuator has been replaced with a new one, didn't fix it, then the intake and exhaust actuators have been swapped around, also did not fix it. The last mechanic said that the exhaust actuator does not receive power.

I had my doubts about this statement, how did they check it?
A resistance measurement was performed and found ok and also battery voltage to the plugs were found correct.

The ecu fault code reading gave:
P0014(66) Exhaust camshaft phasing mechanical reference position range/performance.

falt code always present.png (1.36 KiB) Viewed 5976 times

Failure records showed:

freeze frame p0014.png (1.98 KiB) Viewed 5976 times

With engine running idle and fault code present, these values I got:

idle data.png (2.03 KiB) Viewed 5976 times

The trouble is, Opel does not show you what needs to be the reference value. It keeps you in the dark. There is no actuator test possibility. At that moment I could not tell if -107 degrees was a good value or not. How do I go from here?

We talked about our options here and put on the table what can be defect, excluding what was done till then. And we concluded:
1. Camshaft sensors.
2. Chain.
3. Oil pressure.
4. Camshaft positioners.
5. Timing.
6. ECU.

Because basically he wanted to know if the ECU was bad, I gave it a try and mount mine in. Of course it didn't solve the problem, but he was relieved 800€ were saved.

Next, can it be a timing issue? I've setup my Pico scope to camshaft sensors and crankshaft sensor, all hall type and with the help of the Library Database, concluded that the exhaust camshaft values did not really match:

14.3 degrees difference, can this be our problem, timing off? I was not sure. I know for some engines VVT plays with +/- 10 degrees and for sure 14.3 would set you off. The scope of the sensors did not give any signs of concern. There was no chain rattle so I kind of excluded chain problems.

An oil pressure measurement I could not perform, I could not access under the car in a safe manner and I also missed the adapters for the pico transducer.

There was only one thing which bothered me. How is it possible for an camshaft, that during start, it goes from +24 to -107 degrees, in a matter of 2-3 seconds, and that without any sort of oil pressure. How is that mechanically possible?

I was very confused also looking to these captures, follow the red line other 3 pages from start engine:

The exhaust camshaft sensor does not drop from 5V for a very long time. This is very odd but why? After engine starts, it looks good. I can't blame the sensor.

Then we had the idea to swap the intake and exhaust cam sensors, to record again, is there a difference. And boy it was, the engine was not starting anymore. And then it started to make sense. ECU is using the value of the intake cam and crankshaft sensor to start ignition and spark. It was like ECU didn't got the right sync and would not fire. We crank it several more time and finally it fired. The exhaust side error was now gone. To be sure, we swapped them again and guess what, engine fired up each time, but putting again the exhaust cam error.

But how is this possible? And then he said, I changed these 2 sensors a month back, because I had an error for them and garage swapped them both with new ones. Because he had a good relationship with the garage, we rushed there (was saturday late) and were able to get the old parts back.

I looked at them, one was a bit damaged than the other, so I used the remaining one I thought was good and there you had it, problem gone, VVT was working again.

On a closer examination of the new parts, I found marked on it Siemes VDO. How was that possible? This company does not exist anymore from 2011 and any parts now made, are just VDO. A quick google show me one result on guess what, Aliexpress. So I assume those were fake parts. No wonder the red line did not go down when needed.

Lesson learned, be aware what you're buying. And never ever ever leave the old parts back. Especially if the problem is not solved.

Here is how an original sensor looks like:

After all this, this was the owner reaction: "Liviu hier op forum hielp me toen.bleek een van de eerder vervangen sensoren (nieuwe dus) stuk te zijn. geluk dat ik liviu hier had anders had dit grapje moe ook nog eens 1000€ gekost zonder resultaat…dat noemen ze dan een officiele dealer bezoeken…"

I can say that the last words are not very pleasant towards the oficial dealer.

Until next time.

Joe public.

[Steve Smith]

Hello and thank you for taking the time out to post this information.

Sharing such knowledge is very generous indeed and will help others in the future no doubt.

Like the role we have is not difficult enough, we are now contending with inferior replacement parts, often branded with names we can trust but not 100% sure whats in the box!

Thank you again, take care......Steve

[Mark Dalton]

I'm going to express some sympathy for the Opel dealer here, I work in a dealership myself and have come across similar scenarios numerous times and now when we hear this sort of complaint from customers alarm bells are just going off all over the shop. More than once we've been burned by cheap electronic parts fitted by independent mechanics, who were "saving" the customer money. Good diagnosis like yours in this case does not come cheap and does not always come quickly and we've even had times where we have become the bad guys because we couldn't "fix it" quickly like the "other guy" did!
That said, a Dealer should be the last word in diagnosis for their product and back their diagnosis, they have the manufacturer behind them after all.