Technical 500L - Won’t start!

[Gonein60seconds]

Hello All,

I’m at the end of a slow home restoration of a ‘71 500L, prior to putting the car all back together it was running nicely.

I just can’t get it to start and positive it’s down to spark. In past week I have checked;

That there is 12v to +/- points of the Coil
I checked OHM across coil in isolation it’s was OK but slightly low so I have brought and fitted a new one.
I have replaced the HT leads
I have replaced the condensor
I have replaced the disti cap
I have replaced the points and mount and set the gap to .5
I have checked and cleaned the plugs
I have replaced the wire between the coil -ve and the disti
I have fuel at the carb
The battery is good.

As you can see I have tried all the obvious. I haven’t checked since replacing all these items the spark at the plug again but it wasn’t their prior.

I’m just struggling having done and replaced all the basics what can be left.

I’m open to advice please! I’ve been thinking about doing a face time for any home mechanics in isolation who fancy having a look ?

Advice much appreciated - I just want to hear it start again - clearly not able to go for a drive but be chuffed to know it’s back and ready.

A photo for interest

 

[Toshi 975]

So have you actually checked you have a spark at the plugs? If you have the the most common problem is the distributor being fitted out of position. If the timing is correct an easy check is to reverse the plug leads on the distributor cap.

 

[Gonein60seconds]

Re spark, I checked prior to replacing the ignition parts in the week, I haven’t yet been able to check again since as needed someone to do the starting bit in the car whilst I check spark at rear. Job for tomorrow. But it sounds and feels exactly as it did before all the new bits so pretty sure I’m going to still be missing a spark. Will update tomorrow..

 

[F123C]

^^ :idea: Can't you reach around the engine and operate the lever on the starter motor, (if necessary using a stick), if you have no one to help you?

(I seem to remember doing this a long time ago, also vaguely remember the engine tried to repeatedly squash my arm as it rocked while being turned over ).

Al.

 

[Gonein60seconds]

Just to confirm no spark (and a dog lead is perfect to operate starter whilst at the engine!).

No spark at the plug. I tried putting a test light connected onto the -ve of the coil and the positive onto the top of the coil tower (removing the HT cable) and nothing. not sure but assumed I’d see voltage there. The coil is brand new and I didnt really doubt the old one. Has 12 volts between the + and - terminals on the coil. Confident power isn’t being sent from that to the distributor just don’t know why or how to test further?

 

[Toshi 975]

With the ignition on and the wiring in place on the coil you should get 12v down to the distributor then with the points closed you can flip the points open with a screwdriver tip, not shorting out the points, and get a spark across the points. If that is ok it would suggest a problem on the ht side.

 

[Gonein60seconds]

Sorry to be thick but with the disti cap off where should I put the volt meter rods to check for 12v?

 

[Toshi 975]

You can check the 12v where the low tension wire is connected to the connection at the outside of the distributor when the points are open. The screwed connection on the distributor passes through an insulator on the metal body and in turn clamps the sprung part of the points in place plus carries the circuit through the spring to the points. So when the points are open you should get 12v on any part of that circuit including inside the distributor. If you don't get that then you have a short somewhere. Most likely candidate would be the insulator or points fitted incorrectly. You can test for this by disconnecting the low tension wire at the distributor to see if that gives you the 12v at the lug/far end of the lead. If the points are closed the 12v will go straight to earth so you won't get a reading. Not a case of being thick these things have a habit of scrambling your brains when you feel you are going around in circles

 

[Gonein60seconds]

Toshi - you’re a hero I would of never found the issue without the advice given. I tested the LT cable and was 0v so shorting. Tested lots of areas. Fiddled about and took the condensor away and it gave 12v so thought condensor was failing, tested again with condensor in place and it wasn’t shorting still. Looking the live wire from the condensor that goes to the same isolated bolt as the LT cable has a biggish connector, I think in fitting it was just touching the mounting for the condensor and was shorting everything. Careful refit and all is good and I have a spark! I just wouldn’t of found that without the advice to even know how to rest for volts in the right places. Thank you.

Still not starting but happy that’s just down to the disti being out on timing as it’s trying. Will read up and that’s next. But that’s set up not an issue so really chuffed - thank you

 

[Gonein60seconds]

Reset the distributor and running again ?