Missfires when starting, then clears after blipping throttle

astra22bertoneauto

Re: Missfires when starting, then clears after blipping thro

You could also try another throttle body. Shame you cant borrow bits off a friends car hehe

The_Simps

Re: Missfires when starting, then clears after blipping thro

I have exactly the same problem after the car has been stood up for 2-3mths. No fault codes on mine either. Have replaced 1st lambda, plugs, and air flow sensor thingy. CTS was new in only february. Got to be either the CTS has gone again or the coil pack I'm thinking.

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Let me know how you get on Simps!

Changed the coil pack over tonight, turned then engine over and bingo ! started instantly and idled and reved without misfire, sorted I thought!

Ran it for a couple of minutes and then I turned it off to put the plastic engine cover back on, started the car again and what do you know... misfire is back 🙁

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Update incase anyone was interested.

Removed and cleaned throttle body, looked fairly coaked up but butterfly seemed to move freely, cleaned it up anyway and put back together.

Started it up and was misfiring, took above 3,000 rpm and it cleared. But everytime time ive started it since (20 ish times) it starts instantly without misfire, done 60ish miles in it now and seems all good, fingers crossed.

So guessing it needed a good clean or wiring harness wasn't connected properly :crazy:

Thanks for the help chaps! Pleased as punch cheers..

astra22bertoneauto

Re: Missfires when starting, then clears after blipping thro

Excellent! Glad you got it sorted :thumbup:

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Sorry to bring this thread back from the dead, but after 4 weeks of trouble free motoring I've got problem again with the astra.

Car is misfiring (though not nearly as badly as before) throughout the rev range when cold, after driving for 10 minutes or so it clears and then drives and idles fine.

Can't be throttle body again surely, seems to have coincided with the colder mornings. My first thoughts were to replace coolant temperature sensor ?

Any other ideas ?

vocky

Re: Missfires when starting, then clears after blipping thro

coolant temp sensor is cheap (£20 ish) and easy to change, so buy a new one :thumbup:

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Yeah, bought one the last time I had problems, but never got round to fitting it as couldn't find a slim enough spanner + it started running ok after cleaning throttle body anyway.

Do you have any advice for removing it ? There is very little space either side of it to get anything round it..

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Replaced the CTS and swapped coil packs over, still miss firing badly.

Any further ideas ?

jbaggaley

Does the outside temp show okay on dash ?

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Seems to be, was showing 6.5 degress at earlier this evening, which felt about right....

I'm thinking throttle body is playing up again maybe, as symptons are exactly the same as they were 4 weeks ago pretty much, just would have expected it to through an error code.

guy_27

Re: Missfires when starting, then clears after blipping thro

How are the earth connections? Mine had an intermittent miss which was fixed by adding a new earth from battery to body and another from slam panel to block.

MikeS

Re: Missfires when starting, then clears after blipping thro

it is not the front lambda as that does not work for a few minutes from cold

the car is revving though misfiring so i doubt it is fuel delivery related

tb position at cold is around 12% - Kpa [inlet manifold pressure should be around 36 kpa] as car warms up tb position drops to around 7% with 1-2 % variance based on how well tb is operating - kpa pressure should be 26-28

front lambda should pulse between .08 - .8 after 3 minutes - give car a good rev then watch

the symptoms your experiencing sound like a blocked cat / pre cat or ecu / wiring loom / throttle position sensor on pedal / throttle body

car misfires and runs like shit when in limp mode and will go into limp mode when those codes are activated so it might be the car in limp mode rather than the actual fault

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Thanks for your input mike,

Interesting you mention the wiring loom, we live opposite a large farmers field that was recently harvested making a load of mice and other rodents homeless, next doors brand new Golf played up around the same time refusing to start, they called RAC who couldn't diagnose it, so took it to a local garge who upon inspection found that rats/mice had chewed through the wiring loom estimating the damage at around £3 - 4k.

Just pray the astra hasn't met a similar fate, though when the car started playing up again I was 200 miles away from home and it had been fine up until then..

I think I will try a new throttle body and then persue the routes your mention i.e blocked CAT etc, how would you diagnose a blocked cat ? Literally take it off and inspect it visually ?

Just to clarify, I can return to the car around 2 hours after a long run and it will start and run fine. It is only a problem I'm experiencing from stone cold.

MikeS

Re: Missfires when starting, then clears after blipping thro

yes visual inspection for cat

from stone cold there is hardly any sensors in operation even the cts would not stop the car starting from cold

egr valve is not active nor front lambda

jbaggaley

Head Gasket ?

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Thats crossed my mind as well, no coolant loss though or signs of mayo in the oil or coolant

vocky

Re: Missfires when starting, then clears after blipping thro

extremely rare for the z22se head gasket to fail, the only time I heard it did fail is when the engine had a rad failure

m_p_rogers

Re: Missfires when starting, then clears after blipping thro

Finally had some time to take a look at the car again, bought and replacement throttle body which I cleaned and fitted this morning, checked air intake pipe which was clear.

Started engine and it really feels like that starter motor is pushing hard to turn the engine over as if there is lots of compression to push against or the battery is low (battery is fully charged, been on CTEK). Engine fired fairly immediately though but still missfiring, take it above and hold it at 1500ish revs and it clears though.

Take your foot off the acclerator and the revs immediately fall below 600 rpm it missfires a bit and then quickly stalls.

How is the idle set, is there an idle control valve ? Almost as if the engine thinks the engine is hot not applying any choke or something.

MikeS

Re: Missfires when starting, then clears after blipping thro

try putting another earth from chassis to engine block and like wise from battery to chassis / engine block

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