Missfires when starting, then clears after blipping throttle

astra22bertoneauto

Re: Missfires when starting, then clears after blipping thro

MikeS said:
regular oil changes with 10/40 should sort it m8

12 quid for 5 litres trade at vauxhall

I saw oil in my dealers for £55 for 5 litres last Saturday. :shock: They like to make their profit dont they!

MikeS

Re: Missfires when starting, then clears after blipping thro

i paid 38 quid for 20 litres

i am sure they got that offer on buy 3 get one free or sommit

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Ok, Op-Com has turned up, drivers installed correctly and app running ok.

What's the process for actually connecting it to the car ? (astra G) the connector is near the handbrake isn't it ? Do i need to start the car or can it just read the fault at one of the igntion stages ?

astra22bertoneauto

Re: Missfires when starting, then clears after blipping thro

remove cover underneath the handbrake & connect the op-com. Turn on ignition so dash lights are on is enough to read the code. Run op-com application. click on diagnostics button the select Automatic vehicle identification. takes a few seconds to communicate so be patient - its not instant.

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Superb, thankyou mate.

Off to try!

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

In tthe car now, how on earth do you get the cover off...

astra22bertoneauto

Re: Missfires when starting, then clears after blipping thro

m.p.rogers said:
In tthe car now, how on earth do you get the cover off...

flat screwdriver or pen knife inbetween cover & gearbox surround.

astra22bertoneauto

Re: Missfires when starting, then clears after blipping thro

astra22bertoneauto said:

m.p.rogers said:
In tthe car now, how on earth do you get the cover off...

flat screwdriver or pen knife inbetween cover & gearbox surround.

opps i mean gearlever surround.... :oops:

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

No fault codes recorded : (

Just started car and now just misfires throughout the rev range.... perhaps valve damage after all 🙁

Compression test next and proper GM's plugs :---(

astra22bertoneauto

Re: Missfires when starting, then clears after blipping thro

m.p.rogers said:
Compression test next and proper GM's plugs :---(

What plugs have you got fitted? I always use Gm plugs. They were £2 each off ebay.

Halfords sell a compression tester if you dont have 1. I bought 1 myself - handy piece of kit.

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Currently got a set of Champion plugs in, all they had left in Halfrauds.

Have a set of GM plugs coming, should be here tomorrow. Think I have a compression tester kicking around somewhere, so will try and do both at the same time tomorrow.

astra22bertoneauto

Re: Missfires when starting, then clears after blipping thro

Hopefully its just the plugs then. When I bought my blue SE1 coupe recently i found someone had put a set of NGK single electrode plugs in - engine did not like them!

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Fingers crossed mate! Car is making me sad : (

Thanks for your help though!

astra22bertoneauto

Re: Missfires when starting, then clears after blipping thro

m.p.rogers said:
Fingers crossed mate! Car is making me sad : (

Thanks for your help though!

No worries :thumbup:

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Plugs turned up this morning, going to try a compression test and plug change. Am i doing the test in the right way, I know you should do it on a warm engine, but I don't fancy running it for 5 minutes when its missing so bad.

Remove Coil Pack and plugs
Remove fuel pump relay
Test each cylinder cranking engine 4-6 times
Add 5ml of oil per cylinder for wet test and repeat

MikeS

Re: Missfires when starting, then clears after blipping thro

yes

ideally you want to see how the compression increases on each turn but 4 to 6 is fine for a rough guide

are you getting any rattles or tapping ?

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Hi,

No tapping or rattles Mike.

Just got in from working on the car, attempted a compression test but think the compression tester has had it (story of my life) as it wouldn't hold the compression in the dial. All cylinders were reading around 12-13PSI when cranking though for what its worth.

Changed to the GM plugs anyway and turned it over, still missing and threw the following error codes briefly.

P1516 - Throttle Actuator Control Position Performance
(00) - Not present

P1512 - Throttle Position Adaption Error
(00) - Not present

P1682 - Electronic Throttle Control Malfunction
(00) - Not present

New compression tester next then I think... Is there a way of testing the coil pack with the Op-com ?

MikeS

Re: Missfires when starting, then clears after blipping thro

yes i think so

go into ecu fault codes then click on checks or sommit on right hand side and you can do actuator tests on each sensor

got a feeling this could be a loom / ecu problem

little grey connector on your wiring loom above or near throttle body - this causes those faults if not properly connected

all those faults suggest is that your throttle body / wiring loom / throttle position sensor is not working properly

might be worth getting a 2nd hand throttle body

can you tell me your throttle position sensor output at idle when the car is cold & warm

should be a percentage like 8% at idle

astra22bertoneauto

Re: Missfires when starting, then clears after blipping thro

I havent found where op-com can check the coil pack (if the china clone supports that function).

Just out of interest did you clean your throttle body? Both sides of the butterfly? They can get pretty gunked up!

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Throttle body hasn't been cleaned, will clean it one evening this weekend. Will also check over the connectors to throttle body and get idle position reading from Op-Com. EML light and errors codes dissapeared when starting the car for the second time after compression test by the way.

I think i'm buy a second hand coil pack tonight, I've just got the feeling its the cause due to the intermitment (now permanant) nature of the missfire.

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