TC Stopped While Running

[jbcollier]

I think you found the problem.

[surypap3]

Thanks. I hope so. I will be busy over the next couple days but will update you. For confirmation ..... set the points at .016" gap? Also, the other wire coming off the - coil side powers the tachometer? Thx

[jbcollier]

Maybe.  Picture would be helpful, or the wire colours.

[surypap3]

Still struggling with "power on the negative coil side always on". I am setting up a bench test with the ignition system components separated from the car. Does that make sense to rule out component problems?

[jbcollier]

I can't see the need of a test bench myself.  Somehow the power is not crossing the points to ground.  This should be an easy thing to diagnose.

- put the car in 4th gear

- nudge the car until the points are closed

- put the car in neutral

- remove the coil wire from the distributor cap and hook it to a spark tester

- turn on the ignition

- put a test light on the coil negative terminal.  The test light is lit

- connect a "jumper wire" to a bolt on the engine block

- touch the other end of the jumper wire to the coil - terminal.  The test light should go out and the coil wire emit a spark.  If it does, carry on with the test.  If not, report back in this thread.

- Touch the jumper to the WB terminal on the outside of the distributor.  No spark?  Broken wire or bad connection between the coil and the distributor

- Test light out and spark?  Touch the jumper to the connection on the points.  No spark?  Broken wire or bad connection between the external connection and the points (which is what I thought you had already found)

- Test light out and spark?  Touch the jumper to the side of the points fixed the the distributor plate.  No spark?  Dirty or burnt points.

- Test light out and spark?  Touch the jumper to the points plate.  No spark?  Hardly like, report back if so.

- Test light out and spark?  Touch the jumper to the distributor body.   No spark?  Broken or missing distributor plate ground wire.

- Test light out and spark?  Check engine and battery ground connections.  Though hardly likely to be the issue if the engine cranks over.

Would also like to mention that you have not reported back on the wire colours and positions at the coil yet.  I can only help if you answer questions.

Good luck

[surypap3]

OK. I will give this a try today. Back to you soon. Thx

[surypap3]

So the bench test worked (not necessary but I had the dist out to check the points and reset gap). Installed in the car, I get spark. Stopped there because I don't know which side of the coil this white wire (maybe Tach???) goes in the attached picture. Previously it was on the - coil and the dist wire was on the + coil. Not I put back the dist wire to the neg side.

[jbcollier]

That's not stock wiring.  Leave it disconnected for now.  Ignition power to coil positive and wire to distributor to coil negative.

Starts and runs?

Excellent.

Tach working?  You are done.

No tach?  Also hook up the WB wire to the coil negative and see if it works then.

[surypap3]

Well ... I was so happy to get spark that I stopped there. My timing is out of whack. Somehow I was not careful in dropping in the dist and I have the rotor pointing to #2 when #1 piston is TDC. Try clock the dist properly tomorrow. Keep you fingers crossed! Will update tomorrow if I can get back on it. Another set of grandkids are coming and my wife has me doing readiness chores. Thanks very much for hanging in there.

[surypap3]

Worked on it a bit today. Timing light tells me ignition is set at 10 BTC. Should be 5 I see but I had 10 deg stuck in my mind while playing with it. Gas is pumping to the split at the carbs. Getting back fires through the exhaust. Pulled a plug and not really as wet as I thought I might see. WIRES are 1342 in counter clockwise order. Backfires make me think of firing order. Thoughts?

[TCS4605R]

Any chance the position of the distributor on its drive shafts is 180 deg. out.  I had the same problem on my MGA - backfire when trying to start.  I removed the distributor drive , turned it 180 degrees, reinserted the drive shaft and distributor and it fired up.

Tom
74 TCS - 4605R

[jbcollier]

Spark plugs out.  Put in 4th gear.  Finger over #1 spark plug hole.  Nudge it forward until you start to feel pressure under your finger.   Now watch the timing marks.  Nudge it forward until it is at TDC, it should just be a short distance.  Now see if the rotor is pointing to the wire going to #1 cylinder.

[BDA]

I find it hard for me to see where the #1 spark plug wire is. On my distributor (Lucas 23D) the cap has the wires coming out the side of the top (see http://lotus-europa.com/manuals/tcparts/m/tcma.pdf), there is a small line or notch on the edge of the housing of the distributor under where the cap goes and the rotor should point toward that notch when the #1 plug fires.

Alternatively, you can pull the plugs out and ground them, turn on the ignition and you can see which plug fires when you think you are near TDC of #1 using JB's method. The ignition timing is supposed to be set statically and this is one good way of doing that.

[surypap3]

Spark plugs out.  Put in 4th gear.  Finger over #1 spark plug hole.  Nudge it forward until you start to feel pressure under your finger.   Now watch the timing marks.  Nudge it forward until it is at TDC, it should just be a short distance.  Now see if the rotor is pointing to the wire going to #1 cylinder.

Understood. I will try this afternoon. Otherwise, My wife is going to make me send it to a shop ..... so my manhood is in jeopardy! I keep telling her we are very close to solving this.

[surypap3]

I find it hard for me to see where the #1 spark plug wire is. On my distributor (Lucas 23D) the cap has the wires coming out the side of the top (see http://lotus-europa.com/manuals/tcparts/m/tcma.pdf), there is a small line or notch on the edge of the housing of the distributor under where the cap goes and the rotor should point toward that notch when the #1 plug fires.

Alternatively, you can pull the plugs out and ground them, turn on the ignition and you can see which plug fires when you think you are near TDC of #1 using JB's method. The ignition timing is supposed to be set statically and this is one good way of doing that.

Much appreciated! Wish me luck.