11 years of ownership and I can't believe I am writing a 'wont start' thread, but frankly guys, I'm stumped. I did a long trip yesterday, 160 miles mostly motorway, and this morning I jumped in and the starter churns away happily as always, but no fire. I eventually got it going with a jump from the modern. It ran and revved fine, so I set off, but it stumbled about 20 yards from the house, and promptly died. It sounds like a spark problem. I have fuel to the carb, and it's squirting down the throat ok. I suspected the electronic ignition module next, so I swapped it for brand new points and condenser, but still the same. I swapped the coil for my spare, still nothing. Could it be something further up the food chain of the ignition circuit? 1600 twin port, stock carb, 034 svda dizzy. I do have an ignition relay fitted. I haven't checked that yet, what would I look for? Sent from my ONEPLUS A6013 using Tapatalk
Fuel getting though, but is there enough fuel? I’ve had a couple of blocked fuel filters causing erratic running
Yes, no spark at the plug. I also tried for spark at the coil by holding the central HT lead against the engine, which prompted swapping the coil out for my spare. Healthy looking squirt down the throat of the carb. I can hear the solenoid clicking too. Which suggests there is power to the coil. Sent from my ONEPLUS A6013 using Tapatalk
If you put the ignition on and open and close the points with a small driver does it spark there that will tell you if it’s the coil I would think.
I haven't tried that. If it sparks at the points, doesn't that mean a bad condenser? Sent from my ONEPLUS A6013 using Tapatalk
Could be but you had the problem with the electronic ignition in but that does not mean that they could both be bad.
The running 20 yards is sort of like how far a carburettor float bowl full of fuel takes you too.. Or the carb is flooding the engine and it dies rich..Dont keep stamping on the accelerator or it wont start. If it starts with more 12 volts from another car, then I would check the battery voltage - it might be that your alternator has stopped charging the battery. The extra welly from another battery might just be clearing the fuel that you are merrily spraying into a big puddle by stamping on the pedal.. You are sure you have tried just placing foot hard on the pedal and cranking for 30 seconds ? Or the ignition switch has a burnt run contact so it cranks but wont fire.. check the coil for 12V with ignition on. Use a light bulb if you havent got a meter.
You might have something there Mike. Filmore developed a new 'feature' a few weeks ago. When you turn off the ignition at the key, he sometimes continues to run. Not like chugging or running on, but runs normally, with the ignition light lit. Does this sound related? Sent from my ONEPLUS A6013 using Tapatalk
Additional info. He's also been stumbling at low revs. I thought this was carb related, as it's a new 34 pict 3 and I thought I may have not set it up right. But what if the stumbling is spark related. Could the dynamo/regulator be on its way out? I have a spare reg I can try. Sent from my ONEPLUS A6013 using Tapatalk
The running on could just be that the shutoff solenoid is knackered and not closing, so then the engine keeps running at idle with the ignition light on because the alternator voltage is higher than the ignition switched 12 volts feed in the dash. Check the voltage on the solenoid on the side of the carb when its like that - if its 12 volts or so, the ignition is not turning off. If there is zero volts there, you should not be getting spark for the ignition and it could be running as a hot-bulb engine using glowing carbon deposits in the engine to ignite the mixture. This is why VW had to fit the shutoff solenoid, to stop fuel being fed into the engine while it runs on. Those carbon deposits may have got there because the setting up of your new carburettor is not right yet, and running it for 160 miles on the motorway would have given enough time for build-ups. My progressive has no solenoid, and early on when it was jetted ultra-rich and the engine was hot it did actually run on sounding like a tractor after a few motorway runs. The low revs stumble can also be down to strange sticky ignition advance - also the starting could be related - if the timing is too advanced it gets very hard to start, as the firing happens before the piston gets to the top and if you are cranking and it fires before the piston gets up there, it initially slows the piston, then the engine goes over TDC and it pushes the engine forwards again. Remember that an engine will stumble with not enough fuel to air , or too much fuel to air. Unlike e.g. hydrogen, petrol only burns over a certain smallish percentage air to fuel ratio range. I would start with the standard service - check the valve clearances cold, that there is nothing strange there. Look at the spark plugs, if they are black and sooty then this may be killing the spark. Check the compression (in case this is a problem - could maybe possibly be driving for 160 miles on the motorway with a random tune on the carburettor has done some bad stuff) Set the static timing if you have points to the 7 degrees BTDC . If you have a modern electronic ignition module, you have to set the timing to 7 degrees BTDC when the engine is cranking or idling. May need a helper to turn the key. Try to make sure the engine is not running over 1000 rpm when you set the timing , or it may be unstable as the distributor introduces centrifugal advance at higher RPMs. Try to get the engine started, and when it has warmed up and the choke has stopped operating, make sure the throttle screw at the back is just not touching the stepped cam. Then adjust the air volume and mixture screws until it idles around 850 rpm. Then adjust iteratively for the lean best idle setting where the idle speed drops off if you move the mixture screw either way. I found that then unscrewing the mixture screw a tiny bit seemed to help stumbling, and improve the pickup.
Thanks Mike. I appreciate the support. I've just come in from another session with him, and he is running again, in fact better than before. It was a bad ignition relay I fitted, ironically to ease the load on the 47 year old wiring. I put said 47 year old ignition wire back on the coil and off he went. Several other issues seem to have cleared too. The low revs stumbling has gone, it's not running on when you turn off the key, it's running smoother, and it's starting a lot easier. And weirdly he sounds more like a Volkswagen should. Clearly it's been an issue for some time, steadily getting worse. Live and learn. Sent from my ONEPLUS A6013 using Tapatalk
