no spark, 2.25 Petrol 1975

Landyfella · Feb 23, 2021

I am restoring a 75 series 3 2.25 petrol and have a problem starting. It was working before I started dismantling the panels for paint. DOH!

I am getting 12v to the + side of the coil from the ignition.
I have changed the coil, but the problem occurred before changing it.
also a new solenoid
I haven't touch the points or dizzy, but they look fairly new and again worked before.
I would appreciate any ideas.

Colthebrummie · Feb 23, 2021

Have you taken a spark plug out and turned the engine over to see if there is a spark? If there is and its sparking at the right time, you need to see if there is any fuel getting through, a wet plug will tell you this. Also check to make sure all the HT leads are connected securely.

Col

Marmaduke · Feb 23, 2021

Also take coil ht lead out of the top of the dizzy and try the same as above

wireman · Feb 23, 2021

Are the plug leads on in the right order and right place? Have you had the dizzy out? If so did you put it back the right way round? It can be 180 degrees out.

rob1miles · Feb 23, 2021

Check the condenser and clean the points too.

Europa486 · Feb 23, 2021

rob1miles said:
Check the condenser and clean the points too.

And at least check the points are opening, the points heal to the cam wear down so worth checking,

Landyfella · Feb 23, 2021

thanks all. Yes fuel getting to carb. Plugs in correct order. No spark when turning over engine. I did replace the plugs so may put old ones back in. TBH i didn’t check the gaps so could be that. I’ll take a look at the points gap.
Also invested in an in-line ignition/spark plug tester. So will try that tomorrow.
Thanks for all the advice.

kermit_rr · Feb 23, 2021

I'd be looking at the points gap first.
You have power to the coil and a wire from negative to one side of the points and earth on the other side.
When the points are closed, the coil energises and as the points open, the field collapses and make spark at the HT connection. If you put a plug in the end of the ht lead you can check for a spark at that point

TheMegaMan · Feb 23, 2021

[QUOTE="Landyfella, post: 5099629, member: 165488"
Also invested in an in-line ignition/spark plug tester. So will try that tomorrow.
[/QUOTE]
Something like one of these https://www.ebay.co.uk/itm/IN-LINE-...524739?hash=item4db219eac3:g:T0kAAOSwvqde12hU ?

I would certainly recommend one. I used one when trying to get my engine running again, and really helped prove I was getting sparks at the right time. One of those things you use once or twice, but really helpful.

As to the cause...if your coil is good, it does suggest your points aren't working correctly. Might be dirty or welded shut, or the condenser has failed (very common). A multimeter/DVM on the 'other' coil terminal (the one to the points) when turning your engine over very slowly, should see it bounce between 12V and 0V (twice per engine revolution). If it's stuck at one level, that's the problem.

Landyfella · Feb 24, 2021

looks like I am getting an intermittent spark. I have ordered never ht leads and point/condenser, etc

Thx

Colthebrummie · Feb 24, 2021

Landyfella said:
looks like I am getting an intermittent spark. I have ordered never ht leads and point/condenser, etc

Thx

Let us know if that cures it, we love a success story.

Col

Landyfella · Feb 24, 2021

will do.

Mark Frewin · Feb 24, 2021

Have you checked the earth terminal for the coil, you say you have been removing panels you may have disturbed a connection somewhere.

Landyfella · Feb 25, 2021

Mark Frewin said:
Have you checked the earth terminal for the coil, you say you have been removing panels you may have disturbed a connection somewhere.

how should the coil be earthed? Through the mounting bracket?

Colthebrummie · Feb 25, 2021

Landyfella said:
how should the coil be earthed? Through the mounting bracket?

Yes, there is no separate earth, one wire from the coils spade terminal goes to the ignition switch and the other terminal goes to the contact breaker points in the distributer. Sometimes, one or both of these wires can break somewhere and cause an intermittent fault.

Col

TheMegaMan · Feb 25, 2021

That's a good question. I thought the only connection to ground that the coil needed, was via the points. Certainly won't do any harm to ensure the coil body is earthed, but I'm not entirely sure it's actually needed.

kermit_rr · Feb 25, 2021

definitely no need for a coil body to be earthed but its a good idea for the coil LT contacts to be wired correctly. if its been converted from +ve to -ve earth, then the connections should be swapped

Landyfella · Feb 27, 2021

Yes there is the lead from - to the points.

Colthebrummie · Feb 27, 2021

kermit_rr said:
definitely no need for a coil body to be earthed but its a good idea for the coil LT contacts to be wired correctly. if its been converted from +ve to -ve earth, then the connections should be swapped

It's a 1975 landy so it will be negative earth.

Col

Colthebrummie · Feb 27, 2021

It's not unknown for coils to develop an intermittent fault, usually when they get warm. Coils are not expensive and if it is the original I would recommend getting a new one but get the right one. For the price, it's always worth having a spare.

Col

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