Diagnose this misfire please, video attached. Hyundai Coupe
Discussion
Hi.
I've filmed, uploaded and typed this on my mobile so bear with me and apologies for the quality.
My sisters Hyundai Coupe 2.0 has been standing for about 9 months now and I've been trying to get it running now she's back from travelling abroad. It was working fine when she left it.
I've changed the oil and filter, fitted a new battery and filled it with new fuel and it started on the first crank and ran ok for a while. It then started revving really high and idling at about 2,000 RPM. it then coughed and spluttered then revved back up. It's doing this repeatedly now and won't idle properly. See the videos below.
Once a load is applied like air conditioning or the lights being turned on, it idles more smoothly, idling at about 1,200 RPM then rising up to 1,800 RPM and returning back to 1,200. It does this repeatedly but doesn't splutter.
I did remove each HT lead but it made very little difference to how it idled. When running with a HT lead disconnected it idled high and didn't splutter. It actually idled a bit smoother! It didn't seem to make a difference what HT lead I disconnected.
The only thing I have noticed is yellow jelly on the oil filler cap which would suggest possibly a problem with the head or gasket. I don't think it was there before we changed the oil.
Below are a couple of videos. I'd appreciate any comments on what you think is wrong.
Dan
http://www.youtube.com/watch?v=heUaSybIKIQ&fea...
http://www.youtube.com/watch?v=KA0WDEI7DFo&fea...
http://www.youtube.com/watch?v=7fH376VgSHY&fea...
I've filmed, uploaded and typed this on my mobile so bear with me and apologies for the quality.
My sisters Hyundai Coupe 2.0 has been standing for about 9 months now and I've been trying to get it running now she's back from travelling abroad. It was working fine when she left it.
I've changed the oil and filter, fitted a new battery and filled it with new fuel and it started on the first crank and ran ok for a while. It then started revving really high and idling at about 2,000 RPM. it then coughed and spluttered then revved back up. It's doing this repeatedly now and won't idle properly. See the videos below.
Once a load is applied like air conditioning or the lights being turned on, it idles more smoothly, idling at about 1,200 RPM then rising up to 1,800 RPM and returning back to 1,200. It does this repeatedly but doesn't splutter.
I did remove each HT lead but it made very little difference to how it idled. When running with a HT lead disconnected it idled high and didn't splutter. It actually idled a bit smoother! It didn't seem to make a difference what HT lead I disconnected.
The only thing I have noticed is yellow jelly on the oil filler cap which would suggest possibly a problem with the head or gasket. I don't think it was there before we changed the oil.
Below are a couple of videos. I'd appreciate any comments on what you think is wrong.
Dan
http://www.youtube.com/watch?v=heUaSybIKIQ&fea...
http://www.youtube.com/watch?v=KA0WDEI7DFo&fea...
http://www.youtube.com/watch?v=7fH376VgSHY&fea...
VxDuncan said:
Can't see the videos, but i'd investigate the idle control valve and or lambda sensor. An "italian tuneup" (a good "spirited" run may help unblock everything, though if it doesn't fix it don't keep doing it incase it's running lean and therefore hot.
Yes, unfortunately I can't take it for a blast because it's not taxed, insured or MOT'd at the moment. The plan was to get it running and then take it for an MOT. EDLT said:
Have you checked the plugs?
After that, give the idle control valve a clean with carb cleaner. In fact it wouldn't hurt to do the whole throttle body if you have to take it off.
I was beaten by the spark plugs!! They're in a really deep hole between the cams and my socket could unscrew them, but wouldn't lift them out of the holes. After that, give the idle control valve a clean with carb cleaner. In fact it wouldn't hurt to do the whole throttle body if you have to take it off.
I was at my mums garage so only had a few tools on me and couldn't find anything that would help me get them out. I do plan to get them out when I can. I think I will give the idle control valve a good clean, and the throttle body as you say. I just need a day off to do it.
jayfish said:
MAF ?
dit to add diconnect the maf and it should run in a basic map, if this is relatively smooth and idles ok you may have your answer
I did plan to disconnect the MAF to do exactly this but it got late and I was cold so I left it. I will try this when I do the plugs and idle control valve next time I'm round. dit to add diconnect the maf and it should run in a basic map, if this is relatively smooth and idles ok you may have your answer
Edited by jayfish on Wednesday 26th January 23:26
Thanks.
I should also add that the engine stinks! I thought it was just because it hadn't been run for a while, but I've left it running for 20 minutes on two occassions now with the headlights and AC turned on so with a good load on the engine and the smell seems to be getting worse if anything. Also, the exhaust it quite thick and white and seems to be very moist. The smell is like a sulphur smell.
I had similar, do a compression test first and go from there.It's possible it isn't actually misfiring, just low on compression in 1 cylinder hence why there doesn't seem to be a great difference in note when leads are removed. As said start at the basics and get a compression test done.
I can't hear popping of fuel in the exhaust, and given the HT lead test, the spark is possibly ok.
The first video, when you go round to the engine bay, it sounds like there's a vacuum leak? There's a sucking noise i think? Am i making that up? Can anyone else hear it? That would give the behaviour you're seeing too.
That would be like a vacuum hose perishing over time could cause this.
You could diagnose it with a vacuum gauge on the intake manifold, but if you don't have one a tin of carb cleaner is cheap & useful if you need to strip out intake components. If you spray carb cleaner liberally around, under, over, all about all intake & vacuum pipes, listen for a change in revs. Just trace every hose that comes off the intake manifold and any top breather or crankcase ventilation pipes. If in doubt, skoosh it :-)
Should identify the leak.
The first video, when you go round to the engine bay, it sounds like there's a vacuum leak? There's a sucking noise i think? Am i making that up? Can anyone else hear it? That would give the behaviour you're seeing too.
That would be like a vacuum hose perishing over time could cause this.
You could diagnose it with a vacuum gauge on the intake manifold, but if you don't have one a tin of carb cleaner is cheap & useful if you need to strip out intake components. If you spray carb cleaner liberally around, under, over, all about all intake & vacuum pipes, listen for a change in revs. Just trace every hose that comes off the intake manifold and any top breather or crankcase ventilation pipes. If in doubt, skoosh it :-)
Should identify the leak.
It may need connectging to the hyundai diagnostics system to have the throttle adaptation set if it's been sat with a flat battery for weeks. If the ECU loses this setting the idle speed goes all to pot and it revs up and down randomly. My Audi has to have this done every time you disconnect the battery!
OctyVrs said:
I can't hear popping of fuel in the exhaust, and given the HT lead test, the spark is possibly ok.
The first video, when you go round to the engine bay, it sounds like there's a vacuum leak? There's a sucking noise i think? Am i making that up? Can anyone else hear it? That would give the behaviour you're seeing too.
That would be like a vacuum hose perishing over time could cause this.
You could diagnose it with a vacuum gauge on the intake manifold, but if you don't have one a tin of carb cleaner is cheap & useful if you need to strip out intake components. If you spray carb cleaner liberally around, under, over, all about all intake & vacuum pipes, listen for a change in revs. Just trace every hose that comes off the intake manifold and any top breather or crankcase ventilation pipes. If in doubt, skoosh it :-)
Should identify the leak.
Might have a vacuum gauge at work. I'll have a look. Thanks.The first video, when you go round to the engine bay, it sounds like there's a vacuum leak? There's a sucking noise i think? Am i making that up? Can anyone else hear it? That would give the behaviour you're seeing too.
That would be like a vacuum hose perishing over time could cause this.
You could diagnose it with a vacuum gauge on the intake manifold, but if you don't have one a tin of carb cleaner is cheap & useful if you need to strip out intake components. If you spray carb cleaner liberally around, under, over, all about all intake & vacuum pipes, listen for a change in revs. Just trace every hose that comes off the intake manifold and any top breather or crankcase ventilation pipes. If in doubt, skoosh it :-)
Should identify the leak.
fatjon said:
It may need connectging to the hyundai diagnostics system to have the throttle adaptation set if it's been sat with a flat battery for weeks. If the ECU loses this setting the idle speed goes all to pot and it revs up and down randomly. My Audi has to have this done every time you disconnect the battery!
It seems to rev up over 2,000 RPM ok, but is lumpy on the way back down so I don't think it's as you suggest. Gassing Station | General Gassing | Top of Page | What's New | My Stuff