Ignition issues/misfire/starting

[spillman]

Hello Friends

 

I have not posted for a while, as my lovely motor has been running beautifully. I thought this to myself a week or so ago after an evening run. Then......the very next day the Boss and I drove to a garden party. (get us!!) About 5 miles in, turned a corner and accelerating out of it, the engine started to misfire. We got to our destination, had a lovely time, and on the journey back the car was still misfiring. Mainly under acceleration. When pootling along at 2500 rpm, it felt OK.

 

Now I am no expert on electrickery, but I sensed it was electrical. I checked plugs, gaps OK, cleaned them up. Checked points OK opening and closing. Checked wiring to and from distributor. Tidied it up a bit, on end of the secondary wiring was messy, could have been shorting? Did not know how to check timing (bit of a newbie on these things!) Checked here and on Google and was able to find TDC and the compression stroke and established that the Distributor was apparently OK. Along the way doing all this I attempted to start the car and it would not start. It has always been a great starter. Eventually on one of the starting attempts, at the moment I stopped pressing the starter/solenoid, the engine kicked in.

 

I fiddled and googled some more, and today (Friday) eventually I started it, as per above, immediately I let go the starter, she kicked in, and went for a test drive. She is running beautifully. Returned home after about 10 miles. Stopped the car. Tried to restart on the drive, and she was very reluctant to get going again, but finally made it just as before, when I stopped the starter! This I feel may be significant. When the starter motor stops drawing power, there is enough energy to energise other bits and pieces, and the residual rotary energy continues to turn the engine for a cycle???

 

Gentlemen, does any of the make sense? I would love to hear your thoughts as always.

 

Many thanks

 

John

 

[BrianC]

I had exactly the same problem recently after my 2yo grandson had been let loose in the car and I had left the key in the ignition as I was in the midst of working on the car when the family arrived. He had obviously turned the key, fortunately without starting the car, but I didn't get back to the job for a few days and discovered the key turned on and a very flat battery. Started OK as you describe for a few trips and then back to normal after an overnight charge. No problems with the battery normally as it is a Yuasa Silver and well within warranty, starter and solenoid and dynamo all good, so in my case it was just a well-flattened battery.

[spillman]

Thanks Brian. The battery is nearly new, and the engine turns over fine. Good thought though, and sorry I did not mention in first post.

John

[Ben Freer]

Distributor cap/rotor arm OK?

 

Carb dashpots got oil in them?

[Richardtr3a]

It could be the starter itself and I feel sure that I have read about this problem on the forum before. Is it an original starter or a modern new one which takes less current. I use a battery from Lincon which is the correct size, has the terminals at the rear and therefore away from the bonnet, and last for years. Once you have full current going to the ignition system the engine fires so it must be straight forward.

 

I left the ignition on all night and burnt out the coil. A new fancy one from Distributor Doctor has made the starting more reliable. I could not blame the grandchildren.

 

Good luck.

[roger murray-evans]

I'd change the coil/condenser and go from there personally.

Cheers

Roger M-E

[Richardtr3a]

if you are changing the condenser buy a racing one for a mini minor ,cost £30.00. which is mounted outside the distributor. This put an end to my hot engine starting. If you are interested I will look up the supplier.

[hpremote]

If it was me, John, l'd change the condensor first, as it's a cheaper fix. Then the rotor arm, as it's next cheapest (get a red one, from the Distributor Doctor). Also check the tightness of the small nut in the distributor, which clamps the left side of the cb points and the lo-tension wire.

Then get a new coil!

Good luck,

Tim.

[Peter Cobbold]

I think its fuel.Check that fuel is not running out of an overflow. A float might have hung up in the corner, leaving you with enough fuelling for light loads but not accleration.

Peter

[ianc]

If the battery spins the starter motor at a decent rate, the fit new condenser & rotor arm from Distributor Doctor.

If difficulty spinning the starter motor, trickle charge the battery.

Ian Cornish

[spillman]

Morning Folks.

 

Many thanks to all contributors so far, and the valuable thoughts and suggestions.

 

I manged to start her yesterday evening, and went for a 10 mile run. She ran beautifully with no misfire. Returned home, stopped the engine. Attempted restart, and she would not start. Weird?

 

I hope this update throws a few more clues out there.

 

With my limited knowledge and experience, I am think replace condenser, rotor arm, and then coil if no joy with first two. I will be on to Distributor Doctor forthwith.

 

Thanks again, have a great weekend in your TRs.

 

John

[Fireman049]

Hi John ~

 

When you come to replace the parts mentioned do them individually so that if the fault is cured then you know which component was faulty.

I take it that you've checked all your earth connections?

 

Tom.

[Paul Down]

John,

 

The fact that it started when you released the ignition key reminds me of a similar fault I experienced.

 

It turned out to be an intermittent ignition switch problem.

 

Easy to check by measuring that the ignition feed is present during cranking

[Graham Harris]

You could try running a seperate wire from the battery to the coil and see if it will fire up any better, if so you have a loose connection somewhere?

 

Graham

[BrianC]

If you have a coil with spade terminals, check that the rivet isn't loose. I have had similar intermittent faults like this twice (on different cars) and a light tap with a hammer and punch fixed both.

[John McCormack]

If it was me, John, l'd change the condensor first, as it's a cheaper fix. Then the rotor arm, as it's next cheapest (get a red one, from the Distributor Doctor). Also check the tightness of the small nut in the distributor, which clamps the left side of the cb points and the lo-tension wire.

Then get a new coil!

Good luck,

Tim.

+1. Having driven TRs for over 40 years the condensor is the usual culprit. Then the coil.

It is very unlikely to be fuel with those symptoms.

It could be the ignition switch although when I have had them fail the engine just won't go.

[ijonsson]

+1, on my recently restored TR2 the coil lasted 600 miles, the condensor failed me today after 1000 miles. You would expect a bit better from new parts. Spares fortunately in the boot.

[spillman]

Hello Gentlemen

 

Thanks again for all your replies and brilliant advice. I have been on to Distributor Doc. and ordered points, condenser, red rotor, and coil, The coil is on sale or return if not needed, although I may keep it for a spare, even if not required. So, hopefully things will be sorted soon. I will let you know.

 

John

[NCS_TR3A]

Listening to the comments and the symptoms it would sound like electrical. From your description once you get the car going it runs well? So it seems to be during the act of starting that the ignition system is struggling?

To me this usually suggests that there is a poor spark under starting conditions. Things to check (as previously mentioned) are the eating of the engine (the earth is used heavily under starting with the starter motor). Battery condition, I have had batteries that seem OK but lacking when it comes to having power for starter and ignition. Plug gap? If this is big it puts a strain on the ignition system which does show up under starting.

I must admit, I find the TR engine very forgiving to set up, it pretty much starts however badly set up it is allowing you to start and then tune it. Fortunately a simple system as well. I tend to carry a full set of spares from coil, distributor, leads and plugs. The last time it stopped, I was on the M62 and just lost all power, it was the LT wire from coil to the distributor, it had parted from the spade terminal. Didn’t have a spare for that but a quick fix jamming the wire under the spare to get me home. I now have that spare as well

Neil

[TorontoTim]

Don't overlook the earth strap from the engine. Make sure it's in good condition and that the contacts (on the strap, the engine and the chassis/body) are nice and shiny. If this is poor, it can be earthing through something mechanical like the choke cable or throttle linkage...

[spillman]

Gentlemen - UPDATE.

 

Have been in touch with Dizzy Doctor, purchased, points, condenser, and coil. Made myself timing light. Fitted the first two this morning, sorted out timing (Thanks to Google and Youtube.!) She started straight away, and ran beautifully for about 10 miles. Re-start is there, but not as quick as it used to be before the problems. Could it be timing? Could it be coil? Happy to fit the coil, although I think The lady at Dizzy Doc, said points need to be 40 thou, as it is a coil used also on electron ignition.

 

Oh, also changed the earth strap, which I had purchased ages ago as the old one was showing signs of corrosion and breaking down. Never got around to it before, not urgent!

 

So overall very happy, managed to do something I have not attempted before. Thanks to you guys!

 

Any thoughts on the starting would be welcome, but at least it starts whilst the engine is turning, NOT when I stop the starter as it were! Incidentally a friend with an old Landrover, had a similar problem, and he reckons it was the ignition that was too far advanced. I have set the timing at 4 degrees before TDC.......

 

Hope you are all well.

 

John

[Ian Vincent]

Hi John,

 

I may have misunderstood you but points at 40 thou would be far too wide I would have thought. Maybe she meant plug gap at 40 thou although I have electronic ignition and mine seem to work fine at 32 thou. The points gap sets your dwell angle and at 40 thou you would have the points only closed for a very short period of time which probably wouldn't be enough to build up a decent spark in the coil, (there are probably others more knowledgeable who will be able to confirm this or otherwise.)

 

Rgds Ian

[RobH]

She was probably talking about the plug gaps though 40 thou sounds excessive even for that.

 

A wide points gap did not ought to work - unless there is something odd about the coil? If its a 'flamethrower' I am running one of those on standard points gap.

 

As Ian says, the 'dwell' time while the points are closed is necessary to fully saturate the coil core at max revs. Setting the gap wide reduces the dwell - it might still work at low revs but could give ignition problems higher up the range as the coil doesn't have time to fully 'charge'. The only benefit of a wide points gap would be reduced heating of the coil at low revs.

[HSM]

_{Set points to 15 thou & then re-set timing.}

 

_{Harvey S. Maitland}

[roger murray-evans]

Good that it now runs!

Dizzy girl misinformed you.

As has been said, points need to be 14-16thou.

The plugs will be happy at anything between 25 and 40 thou!!

 

Roger M-E