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YOUR RESEARCHSC Missfire - Page 1 - Porsche General - PistonHeads UK
Reported or suspected cause
fuel related, i had a miss at idle
Reported cause
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Discussions that report identifying a cause
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Reported cause
My problem was fuel related, I had a miss at idle which gradually got worse.
SC Missfire - Page 1 - Porsche General - PistonHeads UK
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Leading evidence: 'fuel related, i had a miss at idle' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'fuel related, i had a miss at idle' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check next' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that report identifying a cause
1
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0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Reported cause · Original poster
Right after my visit to Spanners on Thursday, he feels problem is more fuel injection (uh oh)
SC Missfire - Page 1 - Porsche General - PistonHeads UK
Run v smoothly
Performed · outcome unconfirmed
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0
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Unsuccessful attempts
1
Discussions
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
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Performed · outcome unconfirmed · Original poster
It has recently returned from a lenghty pit stop of about 6 weeks, prior to which it ran V smoothly
SC Missfire - Page 1 - Porsche General - PistonHeads UK
failed ht lead am looking into price
Suggestion or failed attempt
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Identified cause
1
Suspected cause
0
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
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0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause · Original poster
both good suggestions, here is up-date, problem originally appeared to be on cyl3 but now i think its cyl 5 popped plug out had the engine cranked over, but no apparent spark against engine block, plugs are less than 10K old so suspect failed HT lead am looking into price for complete set with German Swedish.
SC Missfire - Page 1 - Porsche General - PistonHeads UK
Check next
Suggestion or failed attempt
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Unsuccessful attempts
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Discussions
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
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0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
Let me know if you still can't track it down, and I will tell you what I checked next.
SC Missfire - Page 1 - Porsche General - PistonHeads UK
Replace leads about
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Discussions that contain suggestions
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Suggestion · Original poster
than leads/plugs etc, seemed reluctant to simply change leads about, so i've been on to Douglass valley who have a set of leads to fit at a fraction of cost of new, so will try that next week, I was always taught to start with the most basic faults first, and not reach for the chequebook to solve everything, some people seem to judge you by your wheels, and charge accordingly WHICH IS WRONG
SC Missfire - Page 1 - Porsche General - PistonHeads UK
Set with german swedish
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Discussions that contain suggestions
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
both good suggestions, here is up-date, problem originally appeared to be on cyl3 but now i think its cyl 5 popped plug out had the engine cranked over, but no apparent spark against engine block, plugs are less than 10K old so suspect failed HT lead am looking into price for complete set with German Swedish.
SC Missfire - Page 1 - Porsche General - PistonHeads UK
Set £70 btw =right picked up a spare lead
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
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Discussions
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Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
Leszek, tried spotting sparks after dark, but couldent' see anything this time, as you quite rightly say, not any lead will do, as the plug tips, are so far in the head,(about 4 1/2" deep) needs something a bit specialised, i'm getting the one lead off it today after running it round the block with lead actually off plug, (it sounds/goes just the same, connected,) and take it to match a replacement, if i find one and it does the trick, i'll be on to porschapart on monday for a whole set £70 BTW =Right picked up a spare lead from v helpfull shop (Sheltune) and popped that on, it still miss-fires, this sounds a bit more involved unfortunately
SC Missfire - Page 1 - Porsche General - PistonHeads UK
Test missfire
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
rich, why dont you swap side to side( use other bank) I have an sc and although ive never taken any bits off, i think one lead must fit for you to test the missfire.
SC Missfire - Page 1 - Porsche General - PistonHeads UK
failed ht lead am looking into price
No successful repair reported for this finding.
0
Identified cause
1
Suspected cause
0
Reported fixes
Read evidence and context
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause · Original poster
both good suggestions, here is up-date, problem originally appeared to be on cyl3 but now i think its cyl 5 popped plug out had the engine cranked over, but no apparent spark against engine block, plugs are less than 10K old so suspect failed HT lead am looking into price for complete set with German Swedish.
SC Missfire - Page 1 - Porsche General - PistonHeads UK
Coverage and how to read this overview
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
16 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
PistonHeads: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
1 acknowledgements have no verified action link; they do not establish a repair result.
Outcome without a verified action link
have looked at rotor arm bit grubby so cleaned it up, no difference, this is what happens with lengthy pit-stops no way am i parking this up over winter
Rich - just caught up with my mails and PH.
My problem was fuel related, I had a miss at idle which gradually got worse. I identified which cylinder by pulling each plug lead whilst the engine was running.
I then swapped bits, plug leads, plugs etc with another cylinder to see if the problem moved. I was getting a healthy spark if I put a spare plug on the suspect lead whilst the engine was running (don't try this without all the plugs fitted - spark and unburnt fuel - say no more!).
If you don't find anything you can try swapping fuel injectors and see if the problem moves.
Let me know if you still can't track it down, and I will tell you what I checked next.
Danny
both good suggestions, here is up-date, problem originally appeared to be on cyl3 but now i think its cyl 5 popped plug out had the engine cranked over, but no apparent spark against engine block, plugs are less than 10K old so suspect failed HT lead am looking into price for complete set with German Swedish. have looked at rotor arm bit grubby so cleaned it up, no difference, this is what happens with lengthy pit-stops no way am i parking this up over winter
Ps posted to Rennlist might be worth a try eh
>> Edited by rich 36 on Sunday 13th July 19:34
Danny, that was to be my next trick,
however, Mr Spanners is going to 'scope' it for me on Thursday evening, and hopefully make me up an appropriate lead from new, which will hopefully do the trick, had a ring around, this morning, full set of braided leads £100+ VAT Ouch!
Right after my visit to Spanners on Thursday, he feels problem is more fuel injection (uh oh)
than leads/plugs etc, seemed reluctant to simply change leads about, so i've been on to Douglass valley who have a set of leads to fit at a fraction of cost of new, so will try that next week, I was always taught to start with the most basic faults first, and not reach for the chequebook to solve everything, some people seem to judge you by your wheels, and charge accordingly WHICH IS WRONG
I don't understand why you don't just swap the lead from the missing cylinder to one that is working. You could eliminate an HT prob in a couple of minutes - with spending any cash?
rich, why dont you swap side to side( use other bank) I have an sc and although ive never taken any bits off, i think one lead must fit for you to test the missfire. If not then take one off another car, doesn't have to be a porsche, just something with normal ht leads as the sc doesn't use anything flash. Good luck
EW, lead on Cyl1 (lhd 1st) is the shortest lead on the car and won't reach any other plug, and no, like you i thought any other lead would do, so scrap yard sol me a long connector'ed vauxhall lead (nothing else will reach that far into cylinder head) but got it home to discover, terminals are not the same at all Bahhh
Just buy one (long) lead, and then try it on all cylinders in turn (with others connected). You will then be able to see if each lead is OK or not for minimal outlay.
Mike.
Sorry guys......but just trying to fit any ignition lead, even from a 16V motor will not do! I've been there and have tried that!
The leads are different in length,and have deep spark plug shrouds!!! they are also individually earthed.
On my car, I found that the plug shroud had perished significantly on No3 cylinder, and was shorting out against the engine bay connections / fuel lines.
this is only visible when dark, but you can hear a characteristic "click" when the misfire occurs on idle.
Decent leads / connections are the only answer here!
I hope this helps.
Leszek.
Leszek, tried spotting sparks after dark, but couldent' see anything this time, as you quite rightly say, not any lead will do, as the plug tips, are so far in the head,(about 4 1/2" deep) needs something a bit specialised, i'm getting the one lead off it today after running it round the block with lead actually off plug, (it sounds/goes just the same, connected,) and take it to match a replacement, if i find one and it does the trick, i'll be on to porschapart on monday for a whole set £70 BTW =Right picked up a spare lead from v helpfull shop (Sheltune) and popped that on, it still miss-fires, this sounds a bit more involved unfortunately
>> Edited by rich 36 on Saturday 26th July 18:13
After 2 years trouble free motoring, the racing car has mysteriously developed a missfire, there is no popping or backfire, it just suddenly stopped firing on i think Cyl#3 front N/s i took out the plug
(with some difficulty) and had the engine turn over without any great spark showing, so is it a new set of HT leads,
It has recently returned from a lenghty pit stop of about 6 weeks, prior to which it ran V smoothly
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