Astra MK4 Z18XE Erratic Idling
Discussion
I posted on general gassing but I didnt get any hits and have been suggested to post here so, Ill copy + paste into here
Hi all,
I have an issue with my Astra in which it has erratic idling issues (more of a chugging or a misfire not excessive jumping just twitching but you can feel it through the car, it dips rather than builds); I have previously bought a new mass airflow sensor of fleabay for cheap £20 ish sterling, I have recently replaced the thermostat and I have a small hole on the gasket between the cat and the mid section of the exhaust (soon to be fixed).
I have replaced the oil, oil filter, fuel filter, replaced the coolant coolant, checked that all pipes are securely fitted (no vacuum leaks), cleaned the throttle body, new sparks, checked the fuel injectors (that was a pain!!!) basically a good old service
What I have noticed whilst doing this, the old sparks where chard and slightly oily (a black and sticky substance so I assume oil ...durrr), a slight hole in the exhaust as previously mentioned (which I don't think is a major issue), however one weird thing the car seems to miss fire when warm.
The car runs fine when cold however when it starts to heat up / when the automatic choke goes off ?, this seems to be the problem. The Haynes manual suggests timing belt however Kwikfit (please don't torch me for this) replaced the belt / kit / water pump 15/20k ago so again I don't believe this is the cause. Another thing to note when I hold the rev's at 1k the chugging disappears ?
Another suggestion I read was the EGR valve however I believe the Z18XE doesn't have one from what my googling has suggested ?
I have read that the coil pack also is an issue, Im sure I read somewhere to try this (please correct me if I'm wrong) to take the coil pack out, turn upside down and leave the sparks in it and turn the engine over. However I didn't see any sparks but that said I don't know if the sparks were fully connected as they were just wresting in the coil pack. (certainly wasn't going to hold them in).
Edit: I forgot to mention that my earth strap is currently just "hanging" on and needs crimping and screwing in, I will be doing this today and will update accordingly
A few more updates that might help diagnose the issue....
For a while there has been a tick near the belts of the car Im not sure if it is a kwickfit fail or what to be honest, it appeared sometime after the belt change so I don't think I could blame them. Also I thought it may be the aux tensioner and belt due to the Haynes manual recommended there looked after yearly (cant remember what it exactly said) .... I have bought a new belt and tension-er, but I put the belt under pressure and the ticking still kept on going (this may of caused the engine light) so it may be a screw in the timing belt box ?
I did get the car and spanner symbol from time to time and the good old owners manual informs me that this is an electric fault, so I assume the previous earth strap was knackered I don't think this will appear now since its been fixed.
Also the exhaust has been sealed now.
Only thing I can think is the coil pack, maf sensor or timing belt (going from haynes and other forum threads) but I cant see why it would be these due to the fact the chugging only comes into effect when it goes it warms up ?
there is an engine warning light after I did all the fixes but I didn't have my reader with me at the time, I will find that out tonight.
P0170 - Powertrain: Fuel Trim Bank 1
Now according this this thread (below) P0170 can be running rich or lean??
P0170 Rich Exhaust C-30
P0170 Lean Exhaust C-30
http://www.astraownersclub.com/vb/sh...d.php?t=229...
This error has appeared before however I put it down to the issue being with the thermostat running to cold and thus the engine running a little rich ?
Other readings I was given on Idle this was outside and standing still for approx 2 mins at -3C outside temp,
Fuel Trim short Term: 12.5% (bank1 12.5%)
Fuel Trim Long Term 11.7 bank 1 11.7
Idle 824 RPM
Fuel System 1 status: closed loop using oxygen sensor as feedback for fuel control
Air Flow Sensor 2.73g/s
Readings on a steady rev
Fuel Trim short Term: -4.6875% (bank1 -4.6875%)
Fuel Trim Long Term 11.7 bank 1 11.7
Idle 2347 RPM
Fuel System 1 status: closed loop using oxygen sensor as feedback for fuel control
Air Flow Sensor 7.9g/s
No both myself and my mate have no clue about these readings however, we thought it might give someone a better idea.
any ideas chaps ?
Hi all,
I have an issue with my Astra in which it has erratic idling issues (more of a chugging or a misfire not excessive jumping just twitching but you can feel it through the car, it dips rather than builds); I have previously bought a new mass airflow sensor of fleabay for cheap £20 ish sterling, I have recently replaced the thermostat and I have a small hole on the gasket between the cat and the mid section of the exhaust (soon to be fixed).
I have replaced the oil, oil filter, fuel filter, replaced the coolant coolant, checked that all pipes are securely fitted (no vacuum leaks), cleaned the throttle body, new sparks, checked the fuel injectors (that was a pain!!!) basically a good old service
What I have noticed whilst doing this, the old sparks where chard and slightly oily (a black and sticky substance so I assume oil ...durrr), a slight hole in the exhaust as previously mentioned (which I don't think is a major issue), however one weird thing the car seems to miss fire when warm.
The car runs fine when cold however when it starts to heat up / when the automatic choke goes off ?, this seems to be the problem. The Haynes manual suggests timing belt however Kwikfit (please don't torch me for this) replaced the belt / kit / water pump 15/20k ago so again I don't believe this is the cause. Another thing to note when I hold the rev's at 1k the chugging disappears ?
Another suggestion I read was the EGR valve however I believe the Z18XE doesn't have one from what my googling has suggested ?
I have read that the coil pack also is an issue, Im sure I read somewhere to try this (please correct me if I'm wrong) to take the coil pack out, turn upside down and leave the sparks in it and turn the engine over. However I didn't see any sparks but that said I don't know if the sparks were fully connected as they were just wresting in the coil pack. (certainly wasn't going to hold them in).
Edit: I forgot to mention that my earth strap is currently just "hanging" on and needs crimping and screwing in, I will be doing this today and will update accordingly
- ######################################################
A few more updates that might help diagnose the issue....
For a while there has been a tick near the belts of the car Im not sure if it is a kwickfit fail or what to be honest, it appeared sometime after the belt change so I don't think I could blame them. Also I thought it may be the aux tensioner and belt due to the Haynes manual recommended there looked after yearly (cant remember what it exactly said) .... I have bought a new belt and tension-er, but I put the belt under pressure and the ticking still kept on going (this may of caused the engine light) so it may be a screw in the timing belt box ?
I did get the car and spanner symbol from time to time and the good old owners manual informs me that this is an electric fault, so I assume the previous earth strap was knackered I don't think this will appear now since its been fixed.
Also the exhaust has been sealed now.
Only thing I can think is the coil pack, maf sensor or timing belt (going from haynes and other forum threads) but I cant see why it would be these due to the fact the chugging only comes into effect when it goes it warms up ?
there is an engine warning light after I did all the fixes but I didn't have my reader with me at the time, I will find that out tonight.
- ######################################################
P0170 - Powertrain: Fuel Trim Bank 1
Now according this this thread (below) P0170 can be running rich or lean??
P0170 Rich Exhaust C-30
P0170 Lean Exhaust C-30
http://www.astraownersclub.com/vb/sh...d.php?t=229...
This error has appeared before however I put it down to the issue being with the thermostat running to cold and thus the engine running a little rich ?
Other readings I was given on Idle this was outside and standing still for approx 2 mins at -3C outside temp,
Fuel Trim short Term: 12.5% (bank1 12.5%)
Fuel Trim Long Term 11.7 bank 1 11.7
Idle 824 RPM
Fuel System 1 status: closed loop using oxygen sensor as feedback for fuel control
Air Flow Sensor 2.73g/s
Readings on a steady rev
Fuel Trim short Term: -4.6875% (bank1 -4.6875%)
Fuel Trim Long Term 11.7 bank 1 11.7
Idle 2347 RPM
Fuel System 1 status: closed loop using oxygen sensor as feedback for fuel control
Air Flow Sensor 7.9g/s
No both myself and my mate have no clue about these readings however, we thought it might give someone a better idea.
any ideas chaps ?
after replacing the thermostat the temp gauge reads what it used to do when I first got the car doesn't go higher than 80, it was about a year ago it started hitting 90 and was hideously cool last winter and this it was just none existent moving of the needle, but as I say the needle moves to the same temps as it used to when I got the car.
From what I've read astra mk4's are prone to over cooling... ?
From what I've read astra mk4's are prone to over cooling... ?
adyady1066 said:
Fuel trim lean on bank 1 is the pre cat lambda sensor and doesn't always trigger the EML. Disconnect it while it's running and see if it makes a difference. The X/Z 14/16/18 XE engines are pretty much bullet proof. Shame the sensors don't works as well. (ex Vauxhall mechanic)
cheers for the reply but a few questions what should removing the sensor achieve an error light or can I clean of the sensor, also just to confirm this is this the pre-cat sensor (not my engine but its where I believe the sensor is)
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cheers again!!
Without reading through the entire feed again, have you looked at cleaning the throttle body (potentiometer)? DO NOT USE CARB CLEANER OR ABRASIVE CLEANING AGENTS. Just use a little pot of petrol and a toothbrush. They have a habit of collecting dirt around the butterfly and get jammed up causing the idle control valve which is built in to fluctuate. Just soak it in petrol, clean as best as possible and clean the O2 sensor. It'll stop the revs staying high between gear changes and help to rid you of your management problem. If you do nothing eventually the cat will melt due to overfuelling and excess fuel burning off in the exhaust. You'll also fail an MOT with the new laws that came in on 1st January this year.
Hi I went to my local motor salvage and bought another coil pack this was acutally worse than my current one and I checked on astras owners club to see if my pre + post cat sensors were working by the looks of it they were....
http://www.astraownersclub.com/vb/showthread.php?t...
I also took it into another specialist and they reccomended I put my stock air intake back on for them to perform all their tests on I quote "their big machine". So I have and the engine warms a little quicker and doesn't cool as quickly when driving. But idleing is still jumpy on cold and Im taking it in on Wednesday to said dealer to find why as well as the tickey noise from the aux/timming belt (which has been there for over a year now)
http://www.astraownersclub.com/vb/showthread.php?t...
I also took it into another specialist and they reccomended I put my stock air intake back on for them to perform all their tests on I quote "their big machine". So I have and the engine warms a little quicker and doesn't cool as quickly when driving. But idleing is still jumpy on cold and Im taking it in on Wednesday to said dealer to find why as well as the tickey noise from the aux/timming belt (which has been there for over a year now)
Edited by anonymous-user on Monday 30th April 21:19
Hi cheers for the reply but yeah I had cleaned the throttle body, with carb cleaner in the initial post. cheers though 
Update:
I bought a new coil pack and it seems to of fixedd it 99% I have an exhaust leak somewhere which is why i think its a tad juggy but VERY SLIGHTLY although i could be being paranoid. another thing to mention I was suggested sticky valves / maf / pre + post cat sensors EVERYTHING I WAS TOLD ON A FORUM TO BE TOLD FOR £60 BY A VAUXHALL MECHANIC DAM IT! but alas Im 99% there
Update:
I bought a new coil pack and it seems to of fixedd it 99% I have an exhaust leak somewhere which is why i think its a tad juggy but VERY SLIGHTLY although i could be being paranoid. another thing to mention I was suggested sticky valves / maf / pre + post cat sensors EVERYTHING I WAS TOLD ON A FORUM TO BE TOLD FOR £60 BY A VAUXHALL MECHANIC DAM IT! but alas Im 99% there
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