TR2/3/3A TR3 No Start...Again. Help?

[curdy]

Hi everyone, I'm having a bit of trouble with my 3 and was hoping to get some help here. Here's a little recent history.

We moved to NC last summer. While packing and all during the spring the car didn't get used much. Late spring I took it out and had a stall issue and then a no start while out. Eventually got it started and then stored at a friends. It wasn't until a few weeks ago that I finally got the car down here. Discovered a leaky fuel line between carbs and realized that was causing a loss in prime and the reason for the no start. Replaced and the car was starting well.



Changed the oil on Friday and now she won't start. Verified fuel in carbs and verified spark by pulling a wire and using a screwdriver to jump gap to car body. Shot some starter fluid in and still no fire. I'm guessing by that there's an ignition issue. Why after I changed the oil though? I don't see anything loose that I might have disturbed while changing it.


I am determined to get to the bottom of this today. Thanks in advance for any help. Who's first to take a crack at it?

 

[John_Progess]

I would do the simple things first. Check that it is firing on No 1 cylinder when it is supposed to, change out the distributor rotor, check the distributor cap for cracks, swap out the coil and make sure you have 12 volts at the coil. You might also try to start the car in the dark so you could see any errant sparking.

John

 

[Marvin Gruber]

I'd start with removing distr cap and rotor button. Have someone crank the engine while you watch points. No fire then points needs cleaning or replacing.
Marv

 

[curdy]

Hi John and Marv, thanks for checking in. I should have mentioned in the op that I'm a novice with car work, so I'm really learning as I go here. I thought I had posted an into thread a while back, but guess I didn't. I'll post my story soon, so others can understand where I'm coming from.

Cap is in great shape. Only thing I noticed yesterday was that the coil wire (going into the top of the ignition coil) appeared loose. I pulled it for inspection and the tiny brass screw holding the threaded plastic fitting was loose. Electrical systems are not my strong area, but I don't actually see any wire material in there. Does that connection actually serve a purpose?

 

[sp53]

It looks like you have “carbon” wire-- not solid wire for your spark plugs and coil. Many and most auto parts stores still have metal wire for sparks plugs; if not you can order it easily from Moss Motors. Get some of that and strip a ½ of the insulation off then fold that ½ into the little hole and push or screw the coil wire down into the coil and naturally hook up the other wires with solid wires also, and the car should run. Many solid wire kits have the plug end made, so cut the other end as needed. Marv makes a good point also that any oxidation on the points will stop the ignition also. IMHO having solid wires makes a big difference anyway so even if that is not the problem you have gained a big part of a tune up.

 

[curdy]

Cleaned the points with some light sand paper. With the distributor cap off and the engine cranking I can see sparks between the breaker points. Is this normal?

 

[charleyf]

Yes.
Charley

 

[Marvin Gruber]

Put it back together, it might just crank now.
marv

 

[curdy]

Still no start.

 

[Frank_D]

Have you tried the condenser? Might be the last item to check. Good luck.

 

[NutmegCT]

OK - so you know you're getting spark at the plugs (screwdriver test).

Is fuel getting into the cylinder? After you've cranked for a while, pull the plugs and see if they're wet. If there's a spark, the fuel should fire.

Seems that if you've got spark at the plug tips, and you haven't changed timing (or mis-connected plug wires), the engine should fire up.

Tom M.

 

[TomMull]

Cleaned the points with some light sand paper. With the distributor cap off and the engine cranking I can see sparks between the breaker points. Is this normal?

You have spark at the points. Good. Now remove #1 plug, put wire back on it and ground the plug with the wire on it against the head with a stick (so you don't get a shock) and crank the engine. If you have a strong blue/white spark at the plug, it should run. If not, renew the cap, wires, rotor and condenser. (Probably not a bad idea anyway.) If you have spark and it still won't run, then the issue is probably not ignition.
Tom

 

[TR3driver]

Hi John and Marv, thanks for checking in. I should have mentioned in the op that I'm a novice with car work, so I'm really learning as I go here. I thought I had posted an into thread a while back, but guess I didn't. I'll post my story soon, so others can understand where I'm coming from.

Cap is in great shape. Only thing I noticed yesterday was that the coil wire (going into the top of the ignition coil) appeared loose. I pulled it for inspection and the tiny brass screw holding the threaded plastic fitting was loose. Electrical systems are not my strong area, but I don't actually see any wire material in there. Does that connection actually serve a purpose?


View attachment 42478

You've already gotten some good comments on troubleshooting "no start", so I'll focus on a few side issues here. There are a LOT of people on this forum, and speaking for myself, it is impossible to keep track of all of them, what cars they have (especially what modifications), and what their story is. So it's best to condense the relevant points and include them in your post.

Your photo shows what I think is a serious problem. You are looking at the path that the spark current follows; there should be a conductor sticking out from the middle of the wire that gets connected in some fashion to the conductor in the center terminal of the coil. From that looks of things, that connection was bad and there has been a spark inside the wire, which has eaten away the (carbon core) conductor; leaving a gap that the spark might jump sometimes (like when you are doing the screwdriver test), but not others (like having a spark plug under compression).

With the original coil, the wire should be soldered to a brass washer, which a threaded plastic nut clamps into contact with the coil terminal. I'm not sure, but that looks like the threaded nut in your fingers, with some sort of brass piece somehow stuck inside it. (The original washer shouldn't fit inside the nut.) However, the original setup didn't use that big rubber boot, so it appears you have a mixture of old and new parts, including the "carbon core" wire. The original components were designed for "solid core" (ie stranded copper conductor) wire, and in my experience do not work well with the much more common (today) "carbon core".

You need to do something about that bad connection (which may well be the entire problem but might not be all of it). For now, you can strip back the end of the wire (to expose more conductor) and put it back the way it was. But for a long term solution, you should either convert back to solid core wire; or update the coil and distributor cap to properly accept the push-in connectors used with carbon core. (There is a later MGB cap that takes push-in wires and will fit the TR3 distributor.)

Also, with these high voltage components, it is quite possible for a something to look perfect, and still not work. Just to illustrate the point, a friend of mine bought a new rotor at VTR 2000 and installed it, because his TR4A was running poorly. It helped at first, but went downhill rapidly so that only about 200 miles into the 1000 mile drive home, it wouldn't run at all. After an amusing roadside tech session, we found that the brand new rotor was bad, although it still looked brand new. A broken resistor at one of the plugs (similar to your coil wire) was letting the spark voltage at the rotor go a lot higher than normal (he had an aftermarket Lucas 'Sports' coil that brags about it's high voltage output) and the extra high voltage had eventually punched a carbon track through the center of the rotor, shorting the spark to the distributor shaft. We cobbled up the plug wire (by cutting the end and putting it under the nut on the spark plug terminal); cut down a 6 cylinder rotor to fit (amazingly enough, not one of us had a spare 4 cylinder rotor with us), and it ran like a top all the way home.

 

[curdy]

Hi Randall, thanks for the feedback.

Your photo shows what I think is a serious problem. You are looking at the path that the spark current follows; there should be a conductor sticking out from the middle of the wire that gets connected in some fashion to the conductor in the center terminal of the coil. From that looks of things, that connection was bad and there has been a spark inside the wire, which has eaten away the (carbon core) conductor; leaving a gap that the spark might jump sometimes (like when you are doing the screwdriver test), but not others (like having a spark plug under compression).

With the original coil, the wire should be soldered to a brass washer, which a threaded plastic nut clamps into contact with the coil terminal. I'm not sure, but that looks like the threaded nut in your fingers, with some sort of brass piece somehow stuck inside it. (The original washer shouldn't fit inside the nut.) However, the original setup didn't use that big rubber boot, so it appears you have a mixture of old and new parts, including the "carbon core" wire. The original components were designed for "solid core" (ie stranded copper conductor) wire, and in my experience do not work well with the much more common (today) "carbon core".

You need to do something about that bad connection (which may well be the entire problem but might not be all of it). For now, you can strip back the end of the wire (to expose more conductor) and put it back the way it was. But for a long term solution, you should either convert back to solid core wire; or update the coil and distributor cap to properly accept the push-in connectors used with carbon core. (There is a later MGB cap that takes push-in wires and will fit the TR3 distributor.)

I tried cutting back some of that wire after I took that picture and it was hollow other than some black fiberglass material. I figured it wasn't important because of the spark I was getting through the plug wires, but sounds like I am wrong. I do feel I've learned a lot so far in my crash course on the ignition system I've been reading up on. So, no sense in me trying to cut that wire back anymore at this point, let's fix it right.

Called Moss and ordered a new push in style cap, rotor, points, condenser, plugs and wires. This should be a great project for me to tackle with the kids when the parts come in. I will report back with the results when complete.

 

[TR3driver]

That "black fiberglass material" is the conductor! Literally carbon impregnated fiberglass strands. It's main advantage is that it's cheap to make, but the carbon also acts as an RFI suppression resistor, so it's pretty much standard on more modern cars. The original setup used discrete resistors at each spark plug, plus the contact in the center of the distributor cap was a resistor.

 

[curdy]

That "black fiberglass material" is the conductor! Literally carbon impregnated fiberglass strands. It's main advantage is that it's cheap to make, but the carbon also acts as an RFI suppression resistor, so it's pretty much standard on more modern cars. The original setup used discrete resistors at each spark plug, plus the contact in the center of the distributor cap was a resistor.

Interesting. I did have to cut back a a good 1/2" to get to the material so obviously there was some sort of issue. Either way, that didn't solve the overall issue and is still getting replaced!

 

[NutmegCT]

I'm really hoping the new wires solve that problem! But I'm puzzled by something you wrote in the first post:

"It wasn't until a few weeks ago that I finally got the car down here. Discovered a leaky fuel line between carbs and realized that was causing a loss in prime and the reason for the no start. Replaced and the car was starting well. Changed the oil on Friday and now she won't start. "

If that ignition wire is in such bad condition now (you had to dig in to it to find the damaged conductor), seems it was in that same condition before you changed the oil on Friday. But before you changed the oil, "the car was starting well."

Anyway, good luck with the new parts. Please do let us know how this turns out.

Thanks.
Tom M.

 

[curdy]

I'm really hoping the new wires solve that problem! But I'm puzzled by something you wrote in the first post:

"It wasn't until a few weeks ago that I finally got the car down here. Discovered a leaky fuel line between carbs and realized that was causing a loss in prime and the reason for the no start. Replaced and the car was starting well. Changed the oil on Friday and now she won't start. "

If that ignition wire is in such bad condition now (you had to dig in to it to find the damaged conductor), seems it was in that same condition before you changed the oil on Friday. But before you changed the oil, "the car was starting well."

Anyway, good luck with the new parts. Please do let us know how this turns out.

Thanks.
Tom M.

I share the same thought Tom. I figured for less than $100 I can replace all previously mentioned parts. If it starts then, well it was one of those parts. If it doesn't, then at least we can rule out several things. Plus, it's a good time to tune the car up.

I pulled the distributor cap screw holding the coil wire in and it was corroded. I cleaned it and cut the wire back some to a fresh spot and reinstalled. No start. Then I pulled the plugs and they were wet, so I know fuel is getting there. Cleaned them and re-installed. Still not starting.

I'm out of ideas and will just have to wait for the UPS man to show up.

 

[BobbyO]

I would check where the condenser connects to the points post. It should not be grounded. If grounded it won't start. Could have been OK initially but shifted during all the other trouble shooting. Worth checking.

 

[bnw]

I don't know if this has been mentioned, if not, try this. Put some water in a spray bottle. Add a little alcohol as a wetting agent. Spray the whole secondary ignition system, wires, plugs, coil tower, dist cap with the mixture. Turn out the lights, turn the key on and crank from the underhood solenoid. If it lights up like a Christmas tree, you've found the problem. Pay close attention to the coil tower and watch for sparks running down the tower. The spark will take the path of least resistance. You can get a good looking spark with a plug out of the head, but once the plug is under compression pressure, the spark may want to go elsewhere.