Can anyone advise? - Unsure what's causing misfire codes
Discussion
I'll try and keep this brief:
My missus has a 660cc Turbo Daihatsu Copen. 55k miles. Serviced by myself, to the handbook (oil change every 3k!), I have also changed air filter and put decent iridium plugs in about 7-8k miles ago.
One day it felt a bit sluggish, like it wasn't boosting properly. I traced this down to it running lean as there was a split in the plastic intercooler to dump valve pipe. I have a cheapy ebay code reader, and it showed a misfire across all cylinders, usually codes p0300, 301, 302, 303, 304. I replaced the intercooler to throttle body pipe and the power returned, so much so it showed up how poor the clutch was as it promptly started to slip in 5th, which we have now had changed.
These misfire codes keep on coming back though and its getting on our nerves. The car seems to drive fine, I.e no noticeable misfire at all. To me, once the clutch was changed it goes as well as you expect a 660cc car to go. She is of the opinion that 'something isnt right' although its hard to get useful information out of a disinterested woman who just expects cars to run forever.
I have noticed with her car its quite a messy engine, there is an oily residue/grime/film over a fair bit of the wastegate plumbing and intercooler and a couple of the coils (it uses a coil over plug set up) - although we did run it for 10 minutes without the oil cap in and I am not sure whether this is the cause of the oil or whether it is some type of leak. I can't see any splits in hoses but visually it would be hard to tell.
The spark plugs are fine and clean, no fouling, no evidence of poor engine health. The car has never cut out, however I started it the other day on a cold morning and it felt like it was running on 3 cylinders for a few seconds before it ran normal.
If it was a coil issue, I would expect one, maybe two to be duff and throw a code, not all four.
Other than simply removing the negative terminal on the battery for 10 minutes to reset things I am stumped.
Any advice welcome, thanks
My missus has a 660cc Turbo Daihatsu Copen. 55k miles. Serviced by myself, to the handbook (oil change every 3k!), I have also changed air filter and put decent iridium plugs in about 7-8k miles ago.
One day it felt a bit sluggish, like it wasn't boosting properly. I traced this down to it running lean as there was a split in the plastic intercooler to dump valve pipe. I have a cheapy ebay code reader, and it showed a misfire across all cylinders, usually codes p0300, 301, 302, 303, 304. I replaced the intercooler to throttle body pipe and the power returned, so much so it showed up how poor the clutch was as it promptly started to slip in 5th, which we have now had changed.
These misfire codes keep on coming back though and its getting on our nerves. The car seems to drive fine, I.e no noticeable misfire at all. To me, once the clutch was changed it goes as well as you expect a 660cc car to go. She is of the opinion that 'something isnt right' although its hard to get useful information out of a disinterested woman who just expects cars to run forever.
I have noticed with her car its quite a messy engine, there is an oily residue/grime/film over a fair bit of the wastegate plumbing and intercooler and a couple of the coils (it uses a coil over plug set up) - although we did run it for 10 minutes without the oil cap in and I am not sure whether this is the cause of the oil or whether it is some type of leak. I can't see any splits in hoses but visually it would be hard to tell.
The spark plugs are fine and clean, no fouling, no evidence of poor engine health. The car has never cut out, however I started it the other day on a cold morning and it felt like it was running on 3 cylinders for a few seconds before it ran normal.
If it was a coil issue, I would expect one, maybe two to be duff and throw a code, not all four.
Other than simply removing the negative terminal on the battery for 10 minutes to reset things I am stumped.
Any advice welcome, thanks
duncancallum said:
Have you done the plugs and leads?
Hi mate, plugs are iridiums, done 7k ago, these were all in great nick when I checked them.The car doesnt have leads, it has 4 individual coil packs that go into the bores. If the issue is with these I cant fathom why all 4 would be throwing codes at once. I hope it isnt these as they are pretty hard to find and expensive.
but are they the correct plugs ? Just because you bought iridiums or plugs you think are good, some engine setups can be very very fussy and must use the plugs the manufacturer recommends.
Also, take a look through youtube
http://www.youtube.com/results?search_query=misfir...
There are actually some great videos about diagnosing problems. Although you will of course need more than a cheap generic code reader ( which quite often gives you wrong codes )
Also, take a look through youtube
http://www.youtube.com/results?search_query=misfir...
There are actually some great videos about diagnosing problems. Although you will of course need more than a cheap generic code reader ( which quite often gives you wrong codes )
Pretty sure the plugs are correct. I will check those in due course however. Not too sure if the fault lies with the ignition system but i've been thinking its perhaps an issue with the air/fuel ratio if I have a slight leak somewhere or loose vacuum hose? Its a bit of a rats nest of tiny vacuum hoses, and not being used to turbo motors at all, I don't understand what half of the hoses do.
In fact I have just found this courtesy of an obd wesbite: There seems to be a randomness to whatever cylinders show on the code reader but P0300 is usually there:
Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.
Seems I have another line of enquiry. Anyone know how to test for vacuum leaks?
One way of checking for vac leaks is to carefully replace the vac pipes with some nice bright silicone hose from fleabay. Sounds a bit extreme, but I have found on many occasions vac leaks are tricky to find, and the pipes often let air in under certain circumstances. One or 2 especially those that operate the turbo (wastegate? I presume) might be collapsing, and over under boosting the turbo.
The other thing that might be causeing problems is the O2 sensor reacting slowly - you shoud be able to check this on OBD code reader, especially if it has a graphing function. It should be cycling about 1 per second on tick over, and faster with more oomph.
You might still have ignition problems - lean conditions at low engine revs will tend to make ignition issues worse, so high gear up a small hill with low engine revs will tend to promote misfire if it's ignition related.
After that, without being either willing to spend on a diagnostic session, or some more complicated kit, it might be hard to tell.
All the best
The other thing that might be causeing problems is the O2 sensor reacting slowly - you shoud be able to check this on OBD code reader, especially if it has a graphing function. It should be cycling about 1 per second on tick over, and faster with more oomph.
You might still have ignition problems - lean conditions at low engine revs will tend to make ignition issues worse, so high gear up a small hill with low engine revs will tend to promote misfire if it's ignition related.
After that, without being either willing to spend on a diagnostic session, or some more complicated kit, it might be hard to tell.
All the best
The "misfire" determination is done by the engine ecu, by monitoring the rate of change of the crank sensor signal. It expects the crank to accelerate twice per revolution each time a cylinder fires. If the crank does not accelerate the system flags a "misfire". Check the condition of the crank sensor, wiring and the security/cleanness of the target wheel. If these degrade, the system can erroneously flag misfires when they aren't happening.
Of course, if you actually have a real misfire, then that^^ ain't the cause.......
Of course, if you actually have a real misfire, then that^^ ain't the cause.......
Thought I would update this for anyone interested (probably nobody, but hey)
I took the top of the engine apart and thoroughly cleaned up all of the oil and gunk - amazing how many bugs and foiliage gets on top of a cam cover! I also scoured the bay for any vac leaks but all was good.
I was beginning to get rather frustrated and had the idea of going through the basics one more time, so I pulled the plugs, which looked like they had seen better days ( a bit sooty and deposited) despite being Iridiums changed only 8k previously. When I saw the soot I immediately thought it looks like its rich, I checked the air filter, my lord I was shocked how dirty it was after just 8k, a quick internet google mentioned that the Turbo Copens are quite sensitive to having a clean air filter. So there we go, it seems it was running a little bit rich and throwing its dummy out. New plugs and air filter and the missus says its running like a dream again.
Kinda embarrassed that it was something so simple, but at least I'll keep a closer eye on it. I have however noticed a rattle from the top of the engine when it's cold that disappears when its warm, so that's another thing to worry about now (thinking cam chain issues or hydraulic lifter??)
Thanks for the advice and encouragement guys
I took the top of the engine apart and thoroughly cleaned up all of the oil and gunk - amazing how many bugs and foiliage gets on top of a cam cover! I also scoured the bay for any vac leaks but all was good.
I was beginning to get rather frustrated and had the idea of going through the basics one more time, so I pulled the plugs, which looked like they had seen better days ( a bit sooty and deposited) despite being Iridiums changed only 8k previously. When I saw the soot I immediately thought it looks like its rich, I checked the air filter, my lord I was shocked how dirty it was after just 8k, a quick internet google mentioned that the Turbo Copens are quite sensitive to having a clean air filter. So there we go, it seems it was running a little bit rich and throwing its dummy out. New plugs and air filter and the missus says its running like a dream again.
Kinda embarrassed that it was something so simple, but at least I'll keep a closer eye on it. I have however noticed a rattle from the top of the engine when it's cold that disappears when its warm, so that's another thing to worry about now (thinking cam chain issues or hydraulic lifter??)
Thanks for the advice and encouragement guys
seany87 said:
....Kinda embarrassed that it was something so simple......
You won't be the first or last to suffer this.I bet a few of the experts on here don't tell of the time they spent an hour or more trying to get an engine going only to find the rotor arm laying in the wing gutter. Ask me how I know.
Steve
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