Non Starter

[SteveSpit]

Well the time of year is approaching again, and again the Spitty is deciding she doesn't want to play.
She didn't run much last year at all as on both occasions I took it to be MOT'd it kindly broke down on me after about three hundred yards and required pushing home. It seemed to struggle whilst under load. When I could get it started it would idle over fine, try and drive it and it would just cut out. Not really having the time to look in to it she was put back in the garage and forgotten about.

Today, I decided, was the day to have a tinker and get hot MOT ready. I've just fitted a brand new 45A battery and have a new fluids and filters (new plugs were fitted last year). Now, I fitted the battery, checked free movement of the engine and attempted to fire. I'm pulling fuel in to (and out of, another job for tomorrow) the fuel filter and she's turning over lovely, have fuel in the carbs and the float valves don't appear to be stuck and move freely. However, I cannot get her to fire up. I have voltage to the starter solenoid and to the coil and can feel the starter is engaging as it's warm. I tested the voltage output from the coil, which is where I'm non too sure. For the most, it wasting 7v and intermittently reading 17.7v. I pulled the king lead from the dizzy and observed the spark against the chassis (after cleaning up the fuel) and to be honest, it looked a tad pathetic. I don't for a second expect sparks as you would see doing a similar test on a modern car but did expect more than one spark per second and a definitive "arc" sound which was't there.

Now, the question is. Do I replace the coil, the starter solenoid or both? Looking at Rimmers they list a 6v and 12v coil for the 1500. I can't see anything that resembles a ballast under the bonnet or near the solenoid so am assuming it's the 12v coil I'm after.

as always, help greatly appreciated.

[SteveSpit]

Update. Had another look and found that I'm only getting a 7v output from the coil despite having a 12v feed, traced through and found the points were high resistance at 70ohms. Popped them off and cleaned them up, retested the resistance and now at a perfect 0.1ohm. However, car still will not fire. I can't help but wonder if the high voltage windings on the coil have burnt out?

[SteveSpit]

Pulled the three most accessible plugs. No spark to either plug 2 )right of alternator) wet, plug 3 dry and plug 4 wet

[1300dolly]

did you check  dizzy cap and that you had a spark from the HT leads onto the plugs , have you changed the points and condenser?

[Kyp]

I'm no electrical expert but just thought I throw this in.

I had trouble getting a spark not so long ago, despite getting good power to the coil. Changed points, leads, dist cap to no avail, eventually figured out that one of the leads at the points was just coming into contact with the side of the distributer casing and causing a short so that the distributer was asking for current all the time, which the coil couldn't manage as it had no time to build up enough whack. It was a while ago but I think i diagnosed it by bypassing the distributer straight to an earthed plug.

Don't know whether this is any help but took me ages to get to the bottom of and your original symptoms of dying under load sounded like points or coil related to me.

Trevor

[RobPearce]

I had a weird one that brought my GT6 to a stop some years back. Ran fine at light load, died completely on throttle. When I pulled onto the hard shoulder it stalled and wouldn't restart.

Turned out the little wire inside the dizzy (that connects the breakers to the coil) was broken. With vacuum advance on, the rotation of the base plate re-made the connection and all was fine. Take away the vacuum and the wire opened up!

[SteveSpit]

Well I've just fitted a new coil, new points and a new dizzy and still it won't fire. Pulled the plugs and have spark.

The only thing left I can do now is some new plugs, leads and try some fresh fuel. After that, I'm stumped.

Also does anyone have the link to or a part number for the condenser that connects on to the neutral side of the ignition coil? I've had a look on the Rimmers site but doesn't show or list the coil etc

[Chasj]

How old is the fuel?

Went around to try to start a neighbours Porsche 356, seems it hadn't run since the owner passed away 6 months before.

After trying everything asked if there was a can of petrol, the gauge almost on empty, the gardener had a can in the shed, put in and pumped it through, the car started.

Chas..

[DougBGT6]

Did you fit a 12v or 6v coil? I have a 6v, no ballast resistor but a ballast wire.

I'd get a can of easy start or similar and squirt it in your carbs. If the engine tries after that your sparks OK.

I had similar problems after a winter lay off, turned out to be the manifold gasket completely shot. Put your hand over the carb air intake, turn the engine over, is there suction? If there's no vacuum the fuel can't get into the bore. Are your plugs wet with fuel?  If not the manifold is letting air in rather than the carb letting fuel in.

Also check compression with a meter, they're quite cheap if you haven't got one. You're looking for all pots to be roughly the same, not zero obviously but about the same.

[bennygoodman]

I'd start again at the beginning, turn the ignition on, make sure there is power at the points, just open them slightly and if you get a spark you have power, turn the ignition off to stop the coil overheating.
Make sure you have the firing order correct at the distributor cap.
Make sure plugs are all dry with the correct gaps, make sure the points gap is correct as well.

Then, get some easy start, take your air filters off, spray it in the carbs and give it a whirl, if you have a spark at the plugs and easy start in the inlet manifold you must get some kind of engine response.

Just one other thing to do if it doesn't start, turn the engine over in the dark to see if there is a short anywhere, you will see a blue spark if there is, you won't notice it in daylight though.