jonnyboy Posted April 14, 2019 Report Share Posted April 14, 2019 So took our 71 '6 out for a spin yesterday all fine until around 25 miles when a misfire started. This morning have checked and gapped the plugs (slightly wide), No.3 was really wet and very sooty, and led me to suspect that the injector for No3 might be on its way out. Extracted injector, replaced and bled with a good pulse and spray pattern. However misfire still very apparent so rather than freeze my buns off in the garage thought I would turn to the collective to gather your thoughts. Happy to replace leads, rotor arm, plugs if needs be in terms of elimination but it does fire up and run just not very well! It has been rather tappetity - would the symptoms point potentially at a duff cam follower/cam? Puzzled Thanks for the advice Jon Quote Link to post Share on other sites
Mk2 Chopper Posted April 14, 2019 Report Share Posted April 14, 2019 1 hour ago, jonnyboy said: So took our 71 '6 out for a spin yesterday all fine until around 25 miles when a misfire started. This morning have checked and gapped the plugs (slightly wide), No.3 was really wet and very sooty, and led me to suspect that the injector for No3 might be on its way out. Extracted injector, replaced and bled with a good pulse and spray pattern. However misfire still very apparent so rather than freeze my buns off in the garage thought I would turn to the collective to gather your thoughts. Happy to replace leads, rotor arm, plugs if needs be in terms of elimination but it does fire up and run just not very well! It has been rather tappetity - would the symptoms point potentially at a duff cam follower/cam? Puzzled Thanks for the advice Jon Have you checked no. 3 plug is sparking, you could check that but also see if pulling a lead off at a time makes any difference to how it runs, it might just be not firing on one cylinder due to no spark. Gareth Quote Link to post Share on other sites
RogerH Posted April 14, 2019 Report Share Posted April 14, 2019 Hi Jon, what make of plugs do you use.? Roger Quote Link to post Share on other sites
jonnyboy Posted April 14, 2019 Author Report Share Posted April 14, 2019 Hi Roger Currently got NGK's in there not sure how "hot" they are though. Gareth - appeared to be a spark with No 3 out and earthed to the block. Jon Quote Link to post Share on other sites
RogerH Posted April 14, 2019 Report Share Posted April 14, 2019 Recent threads suggest that NGK are not what they were and they do not like getting wet (drying doesn;t help) I had problems on my 4A. changed to Champion and all good for over a year. Roger Quote Link to post Share on other sites
jonnyboy Posted April 14, 2019 Author Report Share Posted April 14, 2019 Thanks Roger for the tip - talking to SWMbO I have authority to purchase some new components - will advise as to outcome. Jon Quote Link to post Share on other sites
Mike C Posted April 14, 2019 Report Share Posted April 14, 2019 NGK model no BUR6ET plugs fixed my misfire, but if you buy a set you will need to talk to the Finance Department. Quote Link to post Share on other sites
jonnyboy Posted May 3, 2019 Author Report Share Posted May 3, 2019 So update as follows. Replaced the No.3 spark plug with used but clean plug, misfire has reduced. Ah ha methinks So ordered New Rotor Arm and Dizzy cap (Distributor Dr.) and New Magnecor Leads and full set of new NGK plugs. Fitted Rotor Arm and Distributor cap and misfire has gone but is sounding abit "lumpy". So this weekend will fit new leads and plugs and report back. So am wondering if lack of use over past 18 months (diagnosed with epilepsy) has led to deterioration in the components to the extent that it caused a failure in one or more components? Jon Quote Link to post Share on other sites
Waldi Posted May 3, 2019 Report Share Posted May 3, 2019 Jon, sorry to hear of your epilepsy. Old cars, like old people, don’t like long periods on non-action. If you can, take the car for a longer run, give it fresh fuel, as fuel degrades pretty quickly, and can make engines running lumpy. To answer your question: there could be corrosion on items like fuses, connectors, etc, but we all know the stories of cars stowed away for decades that start with just a new battery and fresh fuel. Waldi Quote Link to post Share on other sites
jonnyboy Posted May 3, 2019 Author Report Share Posted May 3, 2019 Thanks Waldi That's what my thought was around the general degradation of components - bit like me LoL Looking forward to getting into the garage in a bit for a tinker. Jon Quote Link to post Share on other sites
Steves_TR6 Posted May 3, 2019 Report Share Posted May 3, 2019 Good luck getting the car running well Jon! i’m just up the m3 is you want help tinkering :-) steve Quote Link to post Share on other sites
jonnyboy Posted May 5, 2019 Author Report Share Posted May 5, 2019 Steve Really grateful for the offer (suspect it may involve beers?) however got home from weekend trip and have fitted new NGK plugs and Magnecor leads and it seems to have cured the misfire and according to the chief test pilot it now pulls and feels a lot stronger as a result. So looks like a bit of general degredation was the prime culprit. New leads do look good though. Pic attached! Jon Quote Link to post Share on other sites
Waldi Posted May 5, 2019 Report Share Posted May 5, 2019 Hi Jon, good you solved it! The Magnecor plug leads do look very neat, with the correct length for each plug. Where did you buy them from? Thanks, Waldi Quote Link to post Share on other sites
jonnyboy Posted May 5, 2019 Author Report Share Posted May 5, 2019 Evening Waldi Sourced them from Aldon Automotive and brilliant service - did not have them in stock but contacted Magnecor directly and hey presto a few days later they appeared on the doorstep! Price was also very competitive at less than £70 +VAT for the set (and they do look very smart) Jon Quote Link to post Share on other sites
Waldi Posted May 5, 2019 Report Share Posted May 5, 2019 Thanks Jon. Waldi Quote Link to post Share on other sites
jonnyboy Posted May 7, 2019 Author Report Share Posted May 7, 2019 Took the "6" out yesterday for a decent run and happy to report that misfire and overall performance has much improved with the new leads and plugs fitted. A very happy result! Jon Quote Link to post Share on other sites
astontr6 Posted May 7, 2019 Report Share Posted May 7, 2019 On 5/3/2019 at 12:33 PM, Waldi said: Jon, sorry to hear of your epilepsy. Old cars, like old people, don’t like long periods on non-action. If you can, take the car for a longer run, give it fresh fuel, as fuel degrades pretty quickly, and can make engines running lumpy. To answer your question: there could be corrosion on items like fuses, connectors, etc, but we all know the stories of cars stowed away for decades that start with just a new battery and fresh fuel. Waldi Also Waldi spark plugs leads degrade with age. A resistance check s/b done on them every so often. Spark plugs can also give very high resistance figures, especially the resistive types when they show 10K ohms and not 5K which they s/b. Distributor centre carbon brush also needs checking as I have had this brush spring disintegrate on me, more than once, with the repro Lucas caps. These are all areas that people s/b aware of. Bruce. Quote Link to post Share on other sites
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