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Jeff Shackell
United Kingdom
42 Posts |
 Posted - 09/10/2011 : 22:28:08
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I wonder if anyone can advise on a problem I have with an intermittent misfire. I have read up (twice) on past posts on misfires, my misfire is strange in that the engine runs fine for the most part and today I had a good run round but later in the afternoon the engine started misfiring.
This happened a couple of weeks ago but I thought the problem had gone away. So now, as before, the engine runs OK on all 4, then the next minute it's on 3 or whatever is happening, then with a bit of jump its back on 4. The day ended crawling home again on 3, fortunately not far.
It has been suggested to change the condenser, if I order one from Swiftune (as mentioned on here) which is competition condenser, would that be the correct one? It mentions it is for an A series. Where might I get a replacement coil from?
I have changed the plugs and everything looks OK but then I don't really know what I'm looking at. I love driving the J2 about and would like to understand this issue before moving onto other matters with the engine. If it runs perfectly well one minute but not the next I presume this is ignition or fuel rather than something internal.
Thank you for your thoughts in advance.
Jeff |
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kimber
United Kingdom
1529 Posts |
Posted - 09/10/2011 : 22:49:11
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Could be a number of explanations for this.
I take it you have changed the plugs? If not, I would do so. Even new ones can be defective.
I would then establish which cylinder is going intermittent and then establish that you have adequate hot valve clearances on that cylinder.
If its peculiar to one cylinder, its unlikely to be a coil/condensor problem.
If you have supressor type plug caps, they can give rise to misfiring
Have a good look inside the distributor cap for evidence of tracking.
I did once have a sticking valve which gave that sort of symptom intermittently when hot.
The only other thing I can think of is possibly one of the carburretor pistons sticking in the slide when hot
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Alan Bertram
United Kingdom
199 Posts |
Posted - 09/10/2011 : 22:53:20
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Jeff, there is a simple condenser test kit you can make shown on page 16 of the October Safety Fast magazine, using this should solve it if your condenser is at fault.
Regards,Alan
PA 0397 |
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Jeff Shackell
United Kingdom
42 Posts |
Posted - 10/10/2011 : 07:41:29
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Thanks so far for your replies. Yes I changed the plugs for new NGK, it was however running fine before on the old plugs. My only thought behind all this is that I topped up the radiator before the misfiring started and it blew water out, quite a bit of which seemed to run down past the distributor etc. Then it misfired. That was over two weeks ago though, one would have thought that any water that got in somewhere would have dried out by now. The plug caps are the ones that are held on with little nuts, not like on the PB that push on. I think as you say I need to find out which cylinder is playing up. Thanks again.
Jeff |
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kimber
United Kingdom
1529 Posts |
Posted - 10/10/2011 : 08:52:46
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quote:
Originally posted by Jeff Shackell
Thanks so far for your replies. Yes I changed the plugs for new NGK, it was however running fine before on the old plugs.
Put the old plugs back in and see if it runs OK again. You may have a faulty new plug. More common than you might expect. |
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David Allison
United Kingdom
665 Posts |
Posted - 10/10/2011 : 12:41:16
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Jeff
It is also worth checking the coil is facing the right way up.
A lot of people make the mistake of fitting a coil with the king lead facing downwards (aesthetics) and this is a mistake because the cooling oil inside the unit no longer covers the coil and the bottom end of the coil overheats.
Faulty plugs are not unknown and it is worth checking.
Faulty condensor is though also quite likely.
However the water inside the distributor can cause issues for a while after it all dries out.
The water can indeed hang around for weeks and even self perpetuate (condensation) because of heat build up.
Plus you can also get corrosion inside which can cause issues.
Additional to this a loose condensor fixing with water underneath it will corrode and cause an intermittent bad earth.
I HATE ELECTRICS! and probs so will you by the time you have sorted this.
Regards David |
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george
United Kingdom
862 Posts |
Posted - 10/10/2011 : 13:24:42
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| the symptoms you describe happened to me and it turned out to be a sticking dashpot piston ,cured by recentering the jet [fiddling it about a bit] Geoff |
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DickMorbey
United Kingdom
3677 Posts |
Posted - 10/10/2011 : 14:31:43
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Afternoon all,
I have just seen an article written in 1971 by Ian Cornish and published in the TR Register's TR Action newsletter. It contains a step by step guide to the tracing of ignition system faults and includes a brief comment on misfires. Although it contains some references to TRs, the general thrust is absolutely pertinent to Triple-M cars. The step by step guide is especially helpful./
I will send it to Nick Feakes for possible inclusion in the Technical downloads area.
Best wishes
Dick |
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kimber
United Kingdom
1529 Posts |
Posted - 10/10/2011 : 18:45:43
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| Just to repeat, you (one) can save an awful lot of frigging about by first establishing whether it is peculiar to one particular cylinder. If it is, it narrows down the cause considerably and rules out things such as coil, condensor, etc. |
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David Allison
United Kingdom
665 Posts |
Posted - 11/10/2011 : 07:29:09
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I totally agree with Kimber here - you do have to isolate the problem.
If it is one cylinder or one situation - this is much more important than chasing rainbows.
First principles first!
Regards David |
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Rodney Collins
United Kingdom
424 Posts |
Posted - 11/10/2011 : 09:49:47
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Its funny electrics seem to be most owners nemesis ( wife is out and she has tided my desk can't find me dictionary so might have spelt that wrong) anyway when I rebuilt the P type all went well untill I had to wire it all up! Peter Green kndly sent me a very easy to follow wireing diagram. Still made no sense to me however my brother was an electrical engineer in the Royal Navy and did the electrics on choppers ( sea kings) he did it in ten minutes!
Rodney
PS we really need spell check! |
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Colin McLachlan
United Kingdom
991 Posts |
Posted - 11/10/2011 : 10:27:25
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Rodney - spell check - just type in the word and then Google it. I use Google Chrome as my browser, so all I need to do is highlight the word and right click, and one option that comes up is "search Google for..." I also get a spell check option doing this, which I presume comes with Google Chrome. Did you know that Nemesis is, inter alia, a hypothetical dwarf star circling our sun beyond the Oort Cloud. Google is your friend!
Colin
PA 0613 - MG3242 |
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Rodney Collins
United Kingdom
424 Posts |
Posted - 11/10/2011 : 11:48:28
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Colin
That puts it about as understandable as T MMM electronics! Good choice of words I think!
Rodney
PS found my dictonary. |
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Nick Feakes
USA
3376 Posts |
Posted - 11/10/2011 : 13:40:41
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I use Firefox (a really good browser), it has a spell checker built in which highlights incorrectly spelled words as you type (in all programs you access). The database is American but it is simple to add (the correct) spelling of a word by right clicking on the underlined word and selecting "Add to Dictionary".
I do have a spell checker for the forum that I can add if you want me to but it doesn't check spelling as you type, only if you click the "Check spelling" icon. I will install it on my test forum and see how it works before adding it here.
Nick
Webmaster |
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Jeff Shackell
United Kingdom
42 Posts |
Posted - 11/10/2011 : 18:24:58
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Thank you all very much for your thoughts on the misfire. Clearly I have some investigating to do. I am not the ideal candidate for MMM ownership but will not be put off!
Jeff |
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PeterL
United Kingdom
1723 Posts |
Posted - 11/10/2011 : 23:09:32
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Jeff
Do you have a local nogging and natter? If you do, pop in and discuss the problem over a pint, I am sure you will find a whole lot of willing helpers who all think they have the answer... should be fun, particularly if the car is in the car park!
Cheers
P |
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