david c Posted February 17, 2018 Report Share Posted February 17, 2018 Sure sign spring is on it's way........... Braved the puddles today and took the TR4a out for a gentle drive. An absolute Moose to start up but once running seemed okay, 'till I had to put my foot down a bit to nip round a roundabout, then nothing very much happened I thought it was going to die on me but picked up in the end and we toddled of back to the garage. Thinking this is not right set about trying to diagnose the problem, out came the Gunson plug and mirror thingy. The result a sort of blue flame with a yellow / white outer on both one and two and three and four. The spark plugs had just the right colour on the tip a sort of light brown dusting as defined in the book as a "good" colour, so wound the jets down a couple of flats. the Thinking being that it was a pig to start perhaps it's running too lean. Other ideas include the distributor advance not working as it should, or last years petrol? Any thoughts please? Also knocked the brake light switch whilst fiddling and it flew apart. I can't remember but I think it was probably just a cheepie when I fitted it. Is there anything a bit more robust on the market, it's the sort that works of the back of the master cylinder leaver. Thanks all David Quote Link to post Share on other sites
PYU940F Posted February 17, 2018 Report Share Posted February 17, 2018 Would suspect the fuel, this modern stuff degrades within a few months. Go to Tesco and get some of their premium unleaded. It is supposedly 99 octane. Then go out and enjoy giving her an Italian service. (the car I mean not the other half). Bet that will sort it. I did a track day last August for the first time. Not only immensely enjoyable but since the car has never run better. Even than very intermittent miss at about 3,500 rpm when pulling hard has disappeared. The Italians are brilliant engineers! Cheers Simon Quote Link to post Share on other sites
Hamish Posted February 17, 2018 Report Share Posted February 17, 2018 +1 degraded fuel. My 3a likes shell v power And yeah give it a bit of a thrash when all the temps and pressures are good H Quote Link to post Share on other sites
kob666e Posted February 17, 2018 Report Share Posted February 17, 2018 For brake light switch BMW 3 Series: https://www.ebay.co.uk/itm/Fits-BMW-3-Series-E30-316-White-Housing-Genuine-Intermotor-Brake-Light-Switch/301891808165?fits=Car+Make%3ABMW%7CModel%3A3+Series&hash=item464a276ba5:g:wuIAAOSwdzVXrShV Quote Link to post Share on other sites
Fireman049 Posted February 17, 2018 Report Share Posted February 17, 2018 Hi David ~ I fitted a BMW brake light switch to my 3A. I didn't pay anything like £9 for it! Shop around. Tom. Quote Link to post Share on other sites
david c Posted February 17, 2018 Author Report Share Posted February 17, 2018 Nice simple answer, I'ts got to have petrol anyway, and if that isn't the problem nothing lost, like it. And that BMW switch looks the business. Thanks folks. Quote Link to post Share on other sites
PYU940F Posted February 17, 2018 Report Share Posted February 17, 2018 Weather great for a thrash tomorrow, go for a pint in Burnham, shame my suspension is in bits. Let us know if it is sorted afterwards simon Quote Link to post Share on other sites
RogerH Posted February 18, 2018 Report Share Posted February 18, 2018 Hi David, if the new petrol doesn't bring it back to life then you can check the mixture in a better way than with the colour tune. I find these a little confusing/ambiguous. Run the engine at 2500 for a minute. Kill the ignition with out closing the carb. And then check the colour or the plugs Adjust as required. You could also remove the air filters and check that the SU pistons are going up and down together. I had a problem where the interconnect shaft came loose. Only one carb working. Low rev operation can be improved with the intake air balanced. Roger Quote Link to post Share on other sites
TR NIALL Posted February 18, 2018 Report Share Posted February 18, 2018 Next time it happens Pull the Choke Out and see duz it improve,if so it’s not getting enough Juice. Quote Link to post Share on other sites
david c Posted February 18, 2018 Author Report Share Posted February 18, 2018 Two more good simple suggestions, three if I count a little run ou to Burnham. Will be ordering the BMW switch this evening and I think I will invest in a synchrometer gauge too. I have set the carbs up by ear the last few times and I'm not convinced that I am very good at it. Thanks all very much David Quote Link to post Share on other sites
rcreweread Posted February 18, 2018 Report Share Posted February 18, 2018 David Stick some Shell Optimax or BP ultimate in it and thrash it up to the Alma on thursday night - remind me to bring a bit of hose and we'll soon have the carbs whistling together - mind you it might be a bit dark so bring a torch as well! Cheers Rich Quote Link to post Share on other sites
Alec Pringle Posted February 18, 2018 Report Share Posted February 18, 2018 Hi David, my son Tom lives in Maldon, and I'm pretty sure he has our box of diagnostic tools for checking ignition and fuel . . . . . If it helps, drop me a PM and I'll put you in touch. Petrol would be my first thought, anything over a month old and it's going downhill . . . . Cheers Alec Quote Link to post Share on other sites
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