BDR conks out .. now what? place your bets what it turns out to be.

[anthonym]

Driving along after ten minutes, engine simply stops as if i had turned off the ignition. This happened recently and I replaced the coil which seemed to solve that issue.

 

Everything is new. It has points. I an electronic ignition Ignitor ready to fit (replaced it with points last time this happened, to rule it out.)

 

Maybe a blown fuse? I will be checking and running through the usual process chasing the voltages and spark, but this has to be something blown or come loose or fallen off: it just stopped - and wouldn't start again.

 

If it starts again when cold that will be something. And i will be wondering what fries coils.

 

coil (again?) - points fitment rattled loose? a low tension wire fell off?

 

is there a book that lists the diagnostic process? i always forget something.

 

also a robot for removing the carbs (I SO dislike that job to get access to the dizzy etc.)

 

definitely demoralised after 80 days working on her.

 

not again.. javascript:insertAtCursor(document.postpage.message,%20' ☹️')

 

one clue (or not) temp was rising faster than I expected.

 

oil and coolant were ok. air pockets possible i guess.

 

anyway, first thing I will check is for spark at the plugs.

 

fuel is full. will check at carbs.

 

Anthony

 

 

Edited by - anthonym on 20 Sep 2012 20:37:56

[markc]

Hi Anthony

 

Try running the car with the fuel cap loose, my friend had an issue once before when the breather for the tank was blocked.

 

Regards

 

MarkC

 

[anthonym]

will try. not had that problem for 30 years, but if right will save me an awful lot of messing. didn't feel like that does though, which is a more strangled feel rather than an like someone just threw the off switch.

[Jason Plato]

have you been filling up on E90 ?

 

may have blocked the fuel system with all the crap from 30 years of normal fuel ?

 

use the 97 pump as its only 5% ethanol

[anthonym]

30 years ago was a diffrent car..

 

cleaned out the system from tank to carbs.

 

using some stuff supposed to deal with the ethanol, mind, not managed too many miles yet, only a couple of fillups.

 

have ordered abunch of books from amazon.

 

right ticked off.

 

reckon some wire has fallen off... typical shakedown problems.

 

anyway, she is back in the toybox in disgrace

[anthonym]

good job i as up an alp rather than down... just rolled home.

[Myles]

Sounds electrical if it was a sudden cut, doesn't it. Fuel-type things would at least give you a bit of warning before dying (coughs, surges etc.)

[Golf Juliet Tango]

Anthony

I confess, I loose track of where you are and in which car!

So many miles, even I am envious.

Good luck with tracing the fault.

[pugwash]

small wager on the Rotor Arm. Internal crack. goes to earth through dizzy spindle when under load.

 

test by removing dizzy cap and apply hold (using gloves) end lead coil to dizzy to the metal part of the rotor arm. fiddle with points to cause field collapse (or turn the enging over). If the lead sparks to the arm its broken.

 

probably other ways to test but this is I think the most exciting! 😬

[charlie_pank]

It needs:

spark

air

fuel

 

air and fuel in the right proportions, spark at the right time.

 

Which is it not getting?

 

From your writings above I'm sure you know how to check the spark, if you want to check the fuel/air remove the air filter and spray in some easistart while turning it over - does it fire into life? If yes you've either got too much air (perhaps a leak - you did just remove the carbs IIRC) or not enough fuel - are the float bowls filling ok?

 

C

 

[charlie_pank]

When you say 'wouldn't start again', would it turn over?

[anthonym]

Yes turns over no prob.

 

[anthonym]

Guess what? She fails the fuel test! Nothing coming out of fuel thehose to carbs. Check dasbiard fuel switch. It is off. The question is, will she now start or have I merely knicked the switch off since?

[charlie_pank]

'Dashboard fuel switch', that sounds pretty easy to test...

[anthonym]

yes. guess what? no spark from the coil (actually two coils, both new, one fitted couple weeks ago, one out of the box yesterday). ..

 

using both a new and the existing (recently new) HT lead connected to a spark plug (an old one) and the coil HT out: no spark. Unpleasant surprise.

 

so, some meter readings all Volts:

 

Battery from battery + to chassis 12.2v

 

Ign Switch wires to coil, disconnected from coil, across each other + and - = 7.17v

I gather (from some notes) that 6 to 9 volts is expected.

 

Ign Sw wires connected to coil (SW to positive and other to -ve )

 

 

Ignition ON

Reading across + and - of coil

With Points OPEN (took ages to be sure of this)

Low Tension (LT) lead from distributor Connected = 10.7v

Low Tension (LT) lead from distributor DISConnected = 0.0v

With Points CLOSED (so this is coil voltage to Earth.. I think)

Low Tension (LT) lead from distributor Connected = 10.7v

Low Tension (LT) lead from distributor DISConnected = 0.0v

 

I gather with points open battery voltage is to be expected, so I guess 10.7 isn't so bad given the 25 year old wiring from the Ign Switch.

 

The points were gapped at .3mm so changed that to about .45 - not that I think dwell angle is the problem.

 

Seems unintuitive that the points open and closed readings are the same.

Also I am struggling to understand why adding the LT lead creates the 10.7 voltage - I am reading diagrams and Haynes Electrical Manual explanations, which is where I got these tests from. ISBN 0 38345 03049 Section 17 page 109 Ch 6 Ignition ...

Maybe now my head is not inside the engine bay it will be easier to understand.

 

Points are new, not pitted.

 

Both coils gave these readings. I did them so many times to be sure I had it right, likewise making sure the points really were open (dizzy cap off).

 

I did not do this test yet: "With the coil HT lead held close to earth, flick the contacts open and note if sparking is present and healthy. If not check the capacitor.

 

Presumaby "flicking the points" open requires a screwdriver or similar or turn the engine over with ign key... or remove the dizzy completely, but I don't fancy that becaus eit means removing the carbs and putting it back correctly to where one marks it. I watched the mechanics make a meal of that part, but they could fix it and then check the timing - which was what led to finding the coil was goosed (cracked) because of the jolt he received while setting the timing with his hand on the dizzy.

 

The LT lead appears intact, being new. No apparent earthing inside the dizzy.

 

That leaves really, the capacitor .. and I don't have a spare .. and the shops are miles from here... and it's hissing down with rain.

 

hmm..

 

or: refit the electronic ignition.

 

but I really would like to identify the problem.

 

[Pooh_R]

If I understand what you have done correctly, you are measuring the voltage across the LV terminals of the coil and get 10.7V with the wiring connected and 0V with the wiring disconnected. This doesn't change whether the points are open or closed.

 

Normally the battery 12V supply (possibly though a resistor which is shorted out when starting to increase the starting voltage) energizes the coil, the other side of which goes to the points and on to earth.

With the points open, the voltage should be the same along the circuit down to the points, i.e. supply voltage

 

If that is correct, there is current flowing to create the volt drop across the coil which means a path to earth between the coil and the dizzy. This could well be the Capacitor is conducting. You could repeat the measurements with the capacitor disconnected.

[anthonym]

You could repeat the measurements with the capacitor disconnected.

aha! thank you.

 

 

[anthonym]

update: new condenser and points arrived from Redline.

 

Fitted and car started - running very rough, probably gap/dwell. Will refit electronic ignition now I know where the problem was - whether it was points or condenser I have surrendered.

 

Anthony