Missfire on all 4 again, fueling ?. Help...!
12-27-2010, 03:53 AM
#1
Registered User
Thread Starter
Join Date: Apr 2009
Location: East Sussex
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
Missfire on all 4 again, fueling ?. Help...!
I have put some new copper in a while back and changed the plug seals whilst at it, and was fine for a good while whilst I left it to idle and warm up. But soon after it start to missfire on idle badly.
I attributed this to perhaps a dodgy set of plugs or it didn't like the coppers so just replaced with with the NGK OEM plugs, and its still doing it.....
The car idles fine if you hold the revs above say 2K, but as soon as you let it idl normally its missfiring badly. I checked with hand diagnostics tool and just getting missfire on all 4..
Now I've read many threads and posts, and rightly or wrongly have eliminated the MAP sensor, lambda, and cam sensors as I can't seem them givining this sort of problem.
So having read a few threads my attention is drawn to fueling, and just wondering best place to start. I can't see it being clogged injectors as the missfire is not common to one cylinder ?, so therefore perhaps a dodgy fuel pump or clogged fuel filter causing low fuel pressure.
Has anyone suffered anything similar and could a fuel filter really cause such symptons ? Any thoughts greatly received as I can see myself chasing my tail with this. I do have AA so tempted to call them out and see what they come up with as they could check voltage reading to thr various sensors and might even be able to check the fuel pressure..
My 'S' is a late MY01, and covered 120K miles. Plugs and coil packs have been changed, and tappets have just been gapped.
UPDATE - SORTED SEE MY LAST POST
!
I attributed this to perhaps a dodgy set of plugs or it didn't like the coppers so just replaced with with the NGK OEM plugs, and its still doing it.....
The car idles fine if you hold the revs above say 2K, but as soon as you let it idl normally its missfiring badly. I checked with hand diagnostics tool and just getting missfire on all 4..
Now I've read many threads and posts, and rightly or wrongly have eliminated the MAP sensor, lambda, and cam sensors as I can't seem them givining this sort of problem.
So having read a few threads my attention is drawn to fueling, and just wondering best place to start. I can't see it being clogged injectors as the missfire is not common to one cylinder ?, so therefore perhaps a dodgy fuel pump or clogged fuel filter causing low fuel pressure.
Has anyone suffered anything similar and could a fuel filter really cause such symptons ? Any thoughts greatly received as I can see myself chasing my tail with this. I do have AA so tempted to call them out and see what they come up with as they could check voltage reading to thr various sensors and might even be able to check the fuel pressure..
My 'S' is a late MY01, and covered 120K miles. Plugs and coil packs have been changed, and tappets have just been gapped.
UPDATE - SORTED SEE MY LAST POST
!
12-27-2010, 04:44 AM
#4
Member
Hi Rob, as Joeh says are you sure it's all 4? If it genuinely is it will sound absolutely bad. When one cylinder misfires it's pretty bad!
I wouldn't believe the code too much as it's difficult for the ecu to differentiate between one cylinder and another.
I would opt for the injectors too.
Cupracing - good point but I think the way the cables go you can't get them wrong from memory.
I wouldn't believe the code too much as it's difficult for the ecu to differentiate between one cylinder and another.
I would opt for the injectors too.
Cupracing - good point but I think the way the cables go you can't get them wrong from memory.
12-27-2010, 05:34 AM
#5
Coilpacks can be swapped around doesn't matter which way.
If its misfiring its fuelling related, it may sound obvious.
If the fuel filter hasn't been changed then it will be a little shit up, but wouldn't cause any problems IMO. The fuel filter and fuel pump are at the extreme end and IMO wont be it. You can check the fuel filter/sock, it isn't as hard as everyone makes it out to be
.
How does it drive normally when your foot is not foot to the floor i.e not booting it?
How have you ruled out the o2 sensor?
Things to check, based on what your have said.
Is the car getting up to temp correctly, have you monitored the ECT?
Monitor o2 sensor voltage, also driving car normally not in WOT.
Check ICV (idle control valve).
How is the air-filter condition.
Have any vacs lines came loose.
Worth cleaning connections on the ECU and sensors, water and cold weather seem to bring out electrical gremlins.
Its a process of elimination I'm afraid, I've had this twice in the past. IIRC once it was a coilpack with oil causing arching, the other time an injector never had a problem since.
If its misfiring its fuelling related, it may sound obvious
.If the fuel filter hasn't been changed then it will be a little shit up, but wouldn't cause any problems IMO. The fuel filter and fuel pump are at the extreme end and IMO wont be it. You can check the fuel filter/sock, it isn't as hard as everyone makes it out to be
.How does it drive normally when your foot is not foot to the floor i.e not booting it?
How have you ruled out the o2 sensor?
Things to check, based on what your have said.
Is the car getting up to temp correctly, have you monitored the ECT?
Monitor o2 sensor voltage, also driving car normally not in WOT.
Check ICV (idle control valve).
How is the air-filter condition.
Have any vacs lines came loose.
Worth cleaning connections on the ECU and sensors, water and cold weather seem to bring out electrical gremlins.
Its a process of elimination I'm afraid, I've had this twice in the past. IIRC once it was a coilpack with oil causing arching, the other time an injector never had a problem since.
12-27-2010, 06:41 AM
#6
Registered User
Thread Starter
Join Date: Apr 2009
Location: East Sussex
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
H Guy. I'm fairly sure its not all 4 at once despite what the diagnostics is showing up as like you say it wouldn't even run. I think its probably just one cylinder misfiring or might be a couple jumping around all of them.
It really does sound and feel electrical but i've run out of of things to try. I have changed the plugs with 2 different sets and have a spare set of coils I have used.
I guess I could be very unluckly and have one dodgy coil pack from each of the sets I have, so its not going to cost me anything other than time to try and mix and match 8 coil packs to see if one is messing about. This is where someone like AA with there fancy on board machines and volt meters etc could probably pin point if one particular cylinder or sensor is mucking about very quickly.
From my experience of O2 sensors on other cars I have had when they do fail all that ends up happening is the car runs open cricuit and runs a bit rich and doesn't make any difference on WOT as the O2 sensor only comes into play at idle conditions. And the plugs dont look like that have been overfuelled and again its appears to only be on one or possibly 2 cylinders.
I recently cleaned out the ISCV and all it does it control the idle of the car and again my problem is very much a missfire not and idle, and not the symptons you would expect from a faulty ISCV.
Thinking about it more I think your probably right about the fuel filter not being the issue even though its probably not a bad idea to change it at some points. I think I will try experimenting with my coils packs first, then put some injector cleaner in the fuel tank, then try AA to see what there diagnostics show up, then scratch my head some more...
I hate problems like this, fortunately is not daily driver so can afford to keep chipping away at it. I don't like to admit defeat and like to solve problems myself first if i can... But currently has me a little stumped.. Oh well for now i'll look on the brightside and its a good way of figuring out how my 'S' works and what sensor does what and where it is...
It really does sound and feel electrical but i've run out of of things to try. I have changed the plugs with 2 different sets and have a spare set of coils I have used.
I guess I could be very unluckly and have one dodgy coil pack from each of the sets I have, so its not going to cost me anything other than time to try and mix and match 8 coil packs to see if one is messing about. This is where someone like AA with there fancy on board machines and volt meters etc could probably pin point if one particular cylinder or sensor is mucking about very quickly.
From my experience of O2 sensors on other cars I have had when they do fail all that ends up happening is the car runs open cricuit and runs a bit rich and doesn't make any difference on WOT as the O2 sensor only comes into play at idle conditions. And the plugs dont look like that have been overfuelled and again its appears to only be on one or possibly 2 cylinders.
I recently cleaned out the ISCV and all it does it control the idle of the car and again my problem is very much a missfire not and idle, and not the symptons you would expect from a faulty ISCV.
Thinking about it more I think your probably right about the fuel filter not being the issue even though its probably not a bad idea to change it at some points. I think I will try experimenting with my coils packs first, then put some injector cleaner in the fuel tank, then try AA to see what there diagnostics show up, then scratch my head some more...
I hate problems like this, fortunately is not daily driver so can afford to keep chipping away at it. I don't like to admit defeat and like to solve problems myself first if i can... But currently has me a little stumped.. Oh well for now i'll look on the brightside and its a good way of figuring out how my 'S' works and what sensor does what and where it is...
12-27-2010, 06:58 AM
#7
Temperature sender
Does it start okay from cold but not idle well when hot and not hot start (long cranks?)
If non of the above, could be low fuel pressure.
I had a cap off a Redex bottle in one car that got stick on the pickup in the tank
Does it start okay from cold but not idle well when hot and not hot start (long cranks?)
If non of the above, could be low fuel pressure.
I had a cap off a Redex bottle in one car that got stick on the pickup in the tank
Trending Topics
12-27-2010, 07:00 AM
#8
I can tell you from experience you definitely can't rely on the fault code getting the right cylinder.
I guess injectors would be the obvious thing to try. Quite a few of us have had injector faults. It doesn't cost much to get them cleaned and tested (injector cleaner did bugger all in my case).
I guess injectors would be the obvious thing to try. Quite a few of us have had injector faults. It doesn't cost much to get them cleaned and tested (injector cleaner did bugger all in my case).
12-27-2010, 08:54 AM
#10
Banned
Join Date: Dec 2009
Location: Brummmmmmm
Posts: 1,431
Likes: 0
Received 0 Likes
on
0 Posts
Along with what Irvatro says, it couls also be an air leak in the intake. Check and double check your vaccuum lines and check and double check the intake trackt to make sure there are no air leaks. You can check for air leaks by getting soapy water and wetting joints to see if anything is sucking in or blowing out.