30 replies to this topic

[snuff1966]

Hi everyone. I'm pulling my hair out, I can't get my car to start, winds over fine has fuel, checked the timing a hundred times but seems to have a weak spark. Have replaced everything with new, coil, plugs, plug leads, reco dizzy, points gap seems fine. New condenser (twice) new lighting and engine harness and battery leads from Aaron at All Auto Recreations but still it seems to have a week spark, could it be an earthing problem? All the lights and blinkers, horn, radio work fine. Got me buggered. Any suggestions most welcome. Dave

[snuff1966]

Sorry, should add 202 LH



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[hanra]

You’ve got points. That’s the first problem. Pull them out and fit a Pertronix module. How’s your rotor arm? Ive had one go conductive and ground the current straight to the Dizzy shaft.

[rexy]

Cranks ok?

12 v at the coil?

Plugs clean?

Spark at the plug? Pull one out and crank with the plug earthed and see what it looks like.

 

Lots of things to check.

 

Nothing wrong with points for a stocker.

Edited by rexy, 27 September 2020 - 11:31 AM.

[S pack]

Try disconnecting the noise suppression capacitor.

Dizzy not installed 180 degrees out of time with the crankshaft?

[arrimar]

Which coil did you buy?

When clipping the new engine harness to body loom has the pink and yellow wire been pushed out of the back of the old plug?

[gtrboyy]

Voltage drop or faulty ignition...is it better going from batter to coil instead?

 

If balancer is old or unknown history balancer marks can be way off if outer piece has spun.

 

Agree with others hei dissy is much better.Just needs to bridge 2 wires at ignition it's good to go.

[UCSLE]

are you still using the original resistance wire ?

[RallyRed]

Main earth cable to front of block?

[snuff1966]

Main earth cable to front of block?

New and tight

 

are you still using the original resistance wire ?

New

 

Try disconnecting the noise suppression capacitor.

Dizzy not installed 180 degrees out of time with the crankshaft?

Have'nt tried taking off the capacitor yet, tried the dizzy at 180. Thanks for all the replies, a couple of things I have'nt tried yet. Other than that I will have to call in an auto sparky as it is not my strong point. Just annoying as the bloody thing was running before I pulled it apart and just about everything on the car is new

[rexy]

How did you go?

[snuff1966]

  No good, she winds over but just won't fire

[I'm a Red Motor fiend]

Try another coil. First hand I've seen new coils fail.

[Dr Terry]

I notice the new coil has a red case. What brand & type of coil is it ?

 

Are there any numbers on it.

 

What voltage are you getting at the coil +ve while the engine is cranking ?

 

Dr Terry

[rexy]

Multimeter time.

[claysummers]

Bought a new coil when I put electronic dizzy in my 186 and it ran fine. After sitting idle for a year there was very weak and erratic spark. Swapped for original factory electronic ignition coil, strong spark and ran well.


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[snuff1966]

I notice the new coil has a red case. What brand & type of coil is it ?

 

Are there any numbers on it.

 

What voltage are you getting at the coil +ve while the engine is cranking ?

 

Dr Terry        The new one is a Fuelmiser with C80R on it use with external resistor, the one that was in it was an Echlin GX80R. Where is this external resistor supposed to be and what does it look like? Going to borrow a multimeter from a mate this arvo and try and check but as I said electrical stuff is not my go

[S pack]

I notice the new coil has a red case. What brand & type of coil is it ?

 

Are there any numbers on it.

 

What voltage are you getting at the coil +ve while the engine is cranking ?

 

Dr Terry        The new one is a Fuelmiser with C80R on it use with external resistor, the one that was in it was an Echlin GX80R. Where is this external resistor supposed to be and what does it look like? Going to borrow a multimeter from a mate this arvo and try and check but as I said electrical stuff is not my go

The external resistor is the pink resistance wire that runs from the ignition switch to the cabin wiring harness bulkhead connector at the firewall. The pink resistance wire joins to the yellow ignition wire at the cabin harness connector and then a single yellow wire runs from the connector of the engine bay harness to the coil +.
 

Edited by S pack, 04 October 2020 - 12:27 PM.

[Rockoz]

Have you played with the interior wiring at all?

Kind of reminds me of a problem I had when I replaced the fuse panel on my LC many moons ago.

The main centre plug on the fuse panel wasnt in the right place.

 

If you havent already got a multimeter I would suggest that you invest in one.

I bought a relatively cheap one from Jaycar many moons ago.

It was also a clamp meter for AC and DC.

Great for checking alternator charge rates as well as everything else you need on a car.

About 8 years ago they were about 90 bucks.

If you are playing with electrics you really need to have one.

 

The next advice is to follow the instructions of a single helper.

In my case I guide people through a step by step process, which if followed will find the problem quickly/

If you go off doing other things it just makes it too much of a confusing situation to find the problem remotely.

 

 

Cheers

 

Rob

[CI 0308]

Maybe for fault finding simplify the ignition circuit, direct from battery to coil +, then - to distributor. Dont leave it on for long and damage coil with full 12v.

[Dr Terry]

By using a simple 12V test lamp or a multimeter, do you have any voltage at the coil +ve when you are cranking the engine ?

 

Dr Terry

[Dangerous]

Lots of good tips to try here already. Have you replaced the condenser inside the distributor as well as the suppression capacitor on the coil? If either of these are "leaky" they will cause a weak spark. Definitely check the coil +ve voltage. It should be roughly 8 or 9 volts with the ignition on but not cranking the engine. If it is around that, take the distributor cap off, manually turn the engine over until the points are definitely closed,  hold the distributor cap side of the coil lead near the head or another earth (near enough so that it will spark if the coil is fired) - or plug it into a loose spark plug with the body of the spark plug earthed (overkill, but you can do that with a jumper lead clamping the spark plug thread, and the other end on the battery negative), and open the points up with eg a flat blade screwdriver, being careful not to touch any earths with the shaft of the screwdriver. This will cause the coil to spark. You should be able to gauge the strength of the spark from its colour and the sound.

 

This is a good test to do as the engine doesn't need to be cranked (only need to have the ignition on) and it bypasses the distributor cap and spark plug leads - the spark you see is the spark straight out of the coil.

 

For weak spark, I'd be looking sideways at the condensers and the coil itself as culprits first and foremost.

[VIXL34s]

I had a harmonic balancer that had moved ( on a v8 ) but it did throw timing way out, as was in process of resetting everything. It used to run ok beforehand then afterwards it would not. Maybe no help to you but good luck

[snuff1966]

OK  a mate bought his multi meter over.  We got about 4.5 volts at the + side of the coil with the ignition on and it went to 6 when turning it over. So something is not right?

[S pack]

Drop the steering column down and test the voltages at the pink and yellow wiring connectors at the ignition electrical switch.