Help, please.

[city998]

On the way to work, yesterday, my engine cut out as I let the revs drop approaching a red light. It took a bit to get it restarted but then it ran fine for the next fifteen miles or so until the revs dropped again with the same result. Popped the clutch while it was still rolling and it ran ok until I reached work, another eight miles. When I got out in the evening to go home, the starter cranked fine but no ignition. A passer-by cranked the starter while I pulled the coil-to-distributor cable. There were sparks but maybe not strong enough. Any ideas? I didn't even think about going out to fix it today with the bad weather but I'll need to do something on it this weekend. BTW, it's a 998 with conventional (points & condenser) ignition and this hasn't happened before. It seemed to run fine when the revs were up but died when I let them drop too low. All suggestions gratefully accepted.

[keith]

nearly swear its the points gap.... not hard to adjust: the secret is taking the grille off first: might seem like quite a lot of work, but really, quicker on the long run.
u need a large flat bladed screwdriver, a feeler gauge and an ideo of what the gap shold be.

here's some useful reading.. http://www.ime.org.uk/ime/s/starting_difficulty.html

[The Marcos Graveyard]

Good call Keith

[city998]

Thanks, guys. I can do better than a feeler gauge. I have a dwell meter. I reached a similar conclusion - points, condenser, or coil - and I'll bring all three when I go back out to try and get it running. I hate having to work on it 40 km from home but needs must! Hope it's dry Sunday and/or Monday!!! Thanks again for the help.

Bill
90 Mini City
67 Lotus Elan S3 SE FHC

[woody]

I'd cheak the vacumn pipe between carb and dizzy.Nice to see another member with good taste, Mini and Lotus for ever.

[city998]

No joy today. I replaced the condenser and tried again but no luck. The dwell was close to spec and the vacuum line was connected. There is no "coughing" or other sign of ignition. I measured the resistance of the coiul: Primary 1.1 - 1.2 ohms, Seconmdary 5570 ohms. I'll try a new coil next.

[city998]

Oops! Apologies for the typos on that last post. I was rushing and didn't proof read it before I submitted it.

[keith]

so it cranks but wont fire....
ok.. back to first principles: why do we think its the electrics? are you getting a spark at all? whats the inside of the distributor cap like? the HT terminals and rotor arm?
If you are getting a coil make sure its the correct voltage: some later minis use a 6v coil and a resistor wire for normal running, a non-resistor wire to feed the coil for starting. ... not that it should stop you starting mind if its wrong.
take a a look also for loose or split servo hose..

intrigued now... ¬¬

[city998]

Why electrics? Well, as long as I kept the revs up it ran normally. If it was a fuel problem, I'd expect it to cut out when the demand was highest, rather than at idle. If the pump was gone, it wouldn't have run normally over 30 km distance. If there was fuel in the carb bowl, it should have started even if it died afterward. I tried with full choke, no choke, throttle wide open, throttle closed. Nothing made any difference. There was no hint of ignition - no cough or sputter. Just cranked as though the ignition had been disconnected.

There is spark at the coil but I'm not sure it's strong enough. I also put a screwdriver in the No. 1 HT plug lead and held it close to the plug and saw spark there too - but again not sure it's strong enough. I just had the car serviced a few weeks ago as it's due for its NCT this week. Points are new and, now, so is the condenser. The dist cap is new too and it looked perfect on the inside yesterday when I took it off. If replacing the coildoesn't work, I want to tow it home (40 km) where I can work on it a bit more easily (albeit still outside in the Irish weather!!!

[keith]

if a new coil doesn't fix it... plugs? but they would be new after the service? pull one out and have a look at it. is it the right type for the car?
tbh even a pretty wimpy spark will fire it. hows the ignition timing? could that have slipped way off? Haynes says 10 BTDC @ 1500rpm vacum off.. if you haven't a strobe with you at the side of the road 4 degree BTDC static should get you home.

[woody]

The dashot on the carb could be sticking.

[keith]

any update on this....??? i hate to think of a stranded mini out in this snow...

[Billy]

What snow? The sun is shining in Ballyhooly!

Bill, did you get sorted yet?

Billy

[city998]

Still no joy, lads. I towed it home (40 km) on Monday after another abortive attempt to get it running. Even tried "tow starting" it with ignition on but it wouldn't fire. I charged the battery overnight and reinstalled it. There's 6 V at the coil (correct voltage through the ballast resistor) (+) terminal but only 0.4 V at the (-) terminal. I measured resistance across the LT terminals of the coil and get 1.6 ohms - normal. When I measured resistance between either coil terminal and the case, however, I get 2.7 mega ohms! I think it may be short circuiting inside. The new distributor cap had some oxidation on the terminals and I cleaned that up but still no fire.
Damn! I just remembered I have an old coil which is/should be good. I checked resistance (1.8 ohm primary and 6k ohm secondary - infinity to the case) then put it into the circuit but still no firing!! If I still had hair I'd be tearing it out now.

[keith]

iv'e seen the part of the points that makes connection with the wire going to coil (-) slip off its plastic guide and make contact with the body of the dizzy, permanently earthing it, killing any spark.
mind you that should have shown up with the dwell meter.
it possible that you "fixed" the first problem but a second one has cropped up.
now that you have it home, setting the timing to specifications, or at least fully checking it should clear up uncertainty about the spark!
a squirt of "damp-start" into the carb would be handy too.

i twice stripped down a mini's ignition system to cure *very* poor running, only to discover afterwards part of a rag stuffed down the venturi of one of the SU's

[city998]

Keith, you called it!

I remember when I changed the condenser in a cold windy parking lot 40 km from home with intermittent rain showers never far away that I found a plastic part on the ground afterward. I saved it even though I didn't know where it came from or even if it came from my car. When the next heavy shower hit, in the race to get everything packed up, I must have lost the part. Tonight, when I got home, I went out with a drom lamp in the dark and changed the coil. Then I cut a small piece of scrap plastic and inserted it between the points spring and the tab on the distributor. I turned on the ignition and separated the points and, wonder of wonders, got a spark. Next I put the cap back on the distributor and the engine fired immediately! I've taped the plastic to the post temporarily but will need to source a proper replacement for the missing insulator.

Root cause of the initial failure was a bad coil. Secondary cause was my own ignorance of the guts of the distributor!

I love these forums! Now I can try to resolve the ignition problems on my Lotus!

A big thanks to all who replied and especially to Keith who kept offering suggestions until the issue was resolved.

[city998]

Hopefully the last update on this. I found the plastic insulator today and reinstalled it. I'll get a new coil as the one I've installed is over 40 years old! It's good now but for how long?!