TR6 TR6 hard starting

[pdplot]

I'm getting sick and tired of cranking endlessly trying to start after car has been sitting even overnight, plus my 8-year old battery doesn't like it either although it still has plenty of life left. The choke is adjusted ok and it starts instantly from hot. Would a Pertronix ignition help? I still have a Crane but it cut out on me in hot weather and I took it off & put the points back. I think my coil is ok but don't know how to test it. I tried a spare but it made no difference.

 

[TR3driver]

Depends on why it's hard to start. If your points & plugs are fresh, I doubt you'll see much difference with the Pertronix. Where it helps is firing plugs that are fouled or glazed.

Have you double-checked that the float bowls aren't losing fuel for some reason?

 

[Brinkerhoff]

A new condenser might make a difference. Have somebody crank it over while you watch the points snap , you should get a nice strong spark if all is ok.

 

[Gliderman8]

Have you tried giving a couple of pumps with the hand primer? After sitting for some time fuel bowls can become dry. Try the hand primer.

 

[pdplot]

Randall - where would the fuel be going? There are no visible leaks from either carburetor.
Pluga and points aren't new but 5 plugs are grey and one is sooty (from the one bad cylinder). Points appear to be ok, not pitted or visibly worn and re-gapped to .013.
Condenser? Maybe. I have a spare and will try it out.
Hand primer never seems to help.
Car runs perfectly once it starts and revs all the way up to the red line without skipping or missing and has done so for 20 years. Car only needs new left rear suspension bushings and rubber gaiters on the half-shafts and new front motor mounts. I have all the parts. It will need new rings eventually.

 

[trrdster2000]

I'm going with the coil. Are you getting a good spark jump from the coil wire to the block. If your coil has been changed and someone stuck in the later model one which only gives lower voltage after start, but can be a issue on cars that don't need it.

Look for 12V going in and out of the coil, better, spark jump is best indication.

Wayne

 

[crash21]

You asked "where could the fuel be going?.
There are a couple of things..
If the needle is leaking at all the fuel pressure can dissipate overnight. It can also happen if the diaphragm isn't holding pressure or even if the fuel pump isn't holding pressure. The fuel pump has to get fuel pressure back up in the system. It is possible it could siphon back into the tank from the lines.
OR if the needle is leaking it could be a flooding situation. Just because you don't get the black smoke from the exhaust doesn't mean it isn't flooding.
It could even be that the fuel is boiling out once you stop the car and leave it overnight. Empty bowls in the carbs.
You also mentioned the hand primer never has worked well..it is even possible that the primer diaphragm has a pinhole in it and is not getting good pressure to push fuel.
It seems to me like a fuel issue but I have been wrong before.

 

[NutmegCT]

I'd think a simple test for "loss of fuel" would be to look in the carb bowl(s) first thing in the morning.

Tom M.

 

[pdplot]

Assuming it doesn't rain today, here's the drill.
1. Push car out of garage. No room to even open hood in there due to Subaru next door.
2. Check coil. 12V in, 12V out & good spark when wife cranks over and I hold (with insulated pliers) cable near block. I've been shocked too many times. I'm 99% sure the spark will be good.
3. Check points while wife cranks. Probably ok.
4. Swap condenser - although I don;t see how a bad condenser could cause hard starting when cold and not any other time. Remember, this engine runs perfectly when it has run even for 3 or 4 minutes at half-choke.
5. Pull plug and check spark at gap.
6. Try to start.If no action whatever after 30 seconds, then ignition off and fuel line off at front carb. Crank fuel pump ever a few time while wife holds fuel line over bottle. If ok,
6. Check choke cable to see if there's full travel. (I did this a year or two ago and adjusted it so it should be fine).
7. Have assistant wife crank with choke pulled out. If no action at all within 30 seconds, I'm in trouble. HELP!

 

[NutmegCT]

Suggestion: check the carb bowl(s) first. If you wait until after lots of cranking, you can't tell if you have loss of fuel.

Tom M.

 

[TR3driver]

I was thinking perhaps the fuel is weeping from the big O-ring in the bottom of the float bowl; not fast enough to drip but enough to lower the level in the bowls overnight. Kind of a reach, I suppose, but it's a common problem on TR3s. To the extent that the first thing I do when it's hard to start for no apparent reason is rub my finger across the low point and smell it. If I can smell fuel on my finger, one of those dang seals is weeping.

One way to try to sort whether it's ignition or fuel is to give each carb a shot of spray carb cleaner (eg Gumout) down the throat and then immediately crank the engine. If it fires, even if it dies again, the problem is probably lack of fuel for some reason. (Chokes not working, passages clogged, etc.)

 

[pdplot]

OK. Here are the results. Tested coil on car. 12.57V in, 2.8V out. bad coil? replaced with spare coil. 12.57V in, 3.8V out. Good spark from tower wire to block, good spark at points. Cranked over & engine started in about 28 seconds and ran fine. Warmed up because I don't like to shut off cold engine because of condensation. Tested old coil downstairs on bench with 12V power supply. 13.57V in, 13.57V out. Huh? Maybe my bad ground on car? But this wasn't a real good test because car only sat overnight and temperature here was 50F. I'll let sit for a week and try it again.
Carbs? The front one did weep a bit one time two years ago but I rapped the float area with a wooden screwdriver handle, wiped off the bottom of the bowl and no leak since. If it is a carb problem, it would be a first for me since I first fiddled with an SU carb way back in 1954 and have found them trouble-free ever since provided oil is kept in the dashpots and you don't mess with them too much except for a seasonal touch-up of the idle speed.

 

[Sumton]

simple test - spray some starter fluid into the filters. if it starts right up then you have a fuel problem. if not, then its spark or compression. btw, have you done a compression test?

 

[TR3driver]

OK. Here are the results. Tested coil on car. 12.57V in, 2.8V out. bad coil? replaced with spare coil. 12.57V in, 3.8V out.

Was that with the points open, or closed? If they were open, you've got a short somewhere else that is drawing current through the coil. If they were closed, there is a high resistance in the circuit causing the coil current to be lower than it should be.

Evidently you don't have a ballast resistor in the circuit (which is correct for early TR6). Do you have a 3 ohm coil or 1.5 ohm?

 

[pdplot]

1. I'll take Sumton's suggestion & spray some starter fluid in, then try to start after car sits a few more days. BTW, it's 42F now - more seasonal.
2. Randall - how can I tell how many ohms the coil might be? I have a Radio Shack multi-meter.

 

[TR3driver]

2. Randall - how can I tell how many ohms the coil might be? I have a Radio Shack multi-meter.

Set your meter to ohms x1. Short the probes together and either adjust the meter to read zero (if it has the ohms zero adjustment, usually only found on analog meters) or note the reading.

Pull one of the low tension wires off the coil, then probe the two low tension terminals. Subtract the reading noted above from the new meter reading. Since you have no ballast, the result should be close to 3.0 ohms.

My thinking is that if you have a 1.5 ohm coil (which would be correct for later TR6 with a ballast), the points may have gotten overheated and be damaged.

 

[pdplot]

Thanks. I'll give it a try. This is a no ballast coil - so is my spare.

 

[NutmegCT]

hmmm - did you ever check the fuel bowls, after the car sat overnight?

That would go a long way to knowing if the starting problem is due to no fuel in the carbs.

 

[pdplot]

Randall - the ohms jumped between .2 and .3 when I touched the leads together. The (original) coil read 3.1 on average. I guess that's a 3 ohm coil.
Tom - how do you check the float level without taking the carbs apart? Outside of the dashpots, I've never had any occasion to dismantle either SUs or Strombergs. I always left well enough alone.

 

[TR3driver]

Randall - the ohms jumped between .2 and .3 when I touched the leads together. The (original) coil read 3.1 on average. I guess that's a 3 ohm coil.

Yup, good enough. Sorry for the wild goose chase, it was just a thought.