Z22SE Strange warm start and poor idle

[7up]

Hey there,

already asked a few questions here, but seems i'm not able to get the problems fixed myself by research.

I drive an Astra G convertible built 2005 with a z22se engine. The egr is blinded by the manufacturer already and i changed the cooling temperature sensor and read out the air intake sensor and map sensor by obd. Values seem to be ok. No luck with the temperature exchange.

My problems and actual situation: Cold start is very good. Starts and runs fine goes down to 750 rpm. Then the rpm drops and varies about 25 rpm and sometimes more and sounds like the engine will turn off but keeps running then. The more electrically things i turn on the lower the rpm gets. The engine doesnt get the rpm higher automatically. Dont know if this is normal but seems wrong to me. With lights on and only heating (no air condition) it drops to about 650 rpm and the instrumental lights begin to flicker hard.

Then i turn the engine off and try to restart it with the engine warmed up, the engine starts instantly but starts at 100rpm and goes stuttering up to idle rpm. Hope you can understand what i mean. I have bo idea what the problem could be with this two things.

Timing chain and water pump is new since 6000km and makes absolutely no noise.
If you need something to help me identify the problem just ask!

Hope my englisch isn't too bad -

Greetings from germany!

 

[Sjdickso]

I had similar issue with mine less than few weeks ago. Swapped Crank sensor / plugs / Coolant temp sensor, then the issues proceeded in the end i got a good fuel rail with a FPR in it and a recon Starter motor, once these have been swapped I have not had a warm starting issue. Might be worth looking at the Crank sesnor and starter motor ? If you swap the starter motor might as well do the sensor as its in the same area.

I hope this helps.

 

[Sjdickso]

https://z22se.co.uk/threads/starting-issues.29697/ This is my thread.

 

[7up]

Thanks for your reply. Ordered a crank sensor today to get that possibility out of the way. The starter motor works well i think, cause there is no misfire as it cranks well and directly. Already thought about the fuel rail / a leaking injector or fuel pressure regulator. I'm not very firm with engines and only do this to learn something and safe money, so this was the last thing i wanted to do when there is no other possibility left
I will keep you informed what happens after crank sensor exchange and maybe also upload a video of the behavior of the engine.

Cheers!

 

[7up]

Hey there again,

changed the crank sensor, but the problem persists. As you have done it and your problem disappeared and i read about another post where someone said the problem was one injector was leaking approx. every 10 seconds a bit of fuel, i decided to order a used fuel rail with injectors and fpr in it for a change. I first wanted to change the injector sealings but now i find it very hard to get some for a good price. Here in germany they want over 30€ for a set of sealing rings Did you use the old ones or did you took new? Anything bad in using used ones when they look good?

Thanks!

 

[IDI AMIN]

7up

https://www.ebay.co.uk/itm/VAUXHALL...400504&hash=item25893e7619:g:EjkAAOxygPtS78dc

 

[7up]

Hey,

some news here. What i've done so far now is the following:

- new CTS
- new crank sensor
- cleaned MAP sensor
- new (used) fuel rail with new seal rings
- cleaned throttle body (without disassembly)

and... the problem still persists. I have no idea why. The poor idle only appears when the engine revs dropped to the "warm normal state". When it goes slowly down on a cold start everything is fine and the needle is absolutely on point without any vary. Also when using cruise control no vary. Only when the engine gets warm it starts to drop and get up again mostly just a bit. Sometimes harder where it seems that the engine would starve, but it never does. Here is a video of the symptome how it mostly appears (havent got a hard one on video so far):

https://streamable.com/tits9

Maybe someone got a tip for me, cause i have no idea what to do