Loosing power uphill or under load any ideas?

[Worby876]

Well I cleaned all the connections to the coil and made sure they were all solid and
electrically sound.

Then when  tried to start the motor the battery went flat...so Ive Got it charging now
and will try later this evening when its dark so i can observe if there is any arching over
or such.

here is a couple of pics of the positive and negative side of the coil.


and


I will report later on how I get on and any discoveries or progress I make. 

cheers

Ian

[obsession]

 
I think you may have destroyed the battery as well 

[Worby876]

Naa the battery is ok ,I forgot to connect one of the wires to the negative terminal of the coil and thats why
it wouldn't start.  doh !!!

Anyway ran the motor in the dark and absolutely no sparks or corona or anything to suspect any faulty high tension
leads breaking down.

next i hooked up a brand new multimeter and on ignition 11.9 volts at the positive terminal of the coil rev the engine
to 2 , 3 thousand rpm and the volts stayed the same  it flashed 15 18 but i suspect its breaking down under load.

could it be the condenser? or something inside the HEI dizzy circuitry? Or Just the coil breaking down? H'mmm 

will investigate further more tomorrow.....I just don"t want to buy a new Coil  if its not the problem.

cheers

Ian

[Worby876]

Ive been trying to find out more info on the coil and Bosh HEI combo reading the OLD HOLDEN sites etc

cant find any specific info on the voltage readings I should be getting at the + side of the coil.

Any of you fellas have some more info?

[Mr Whippy]

11.9 volts seems a bit low. Have you checked the voltage across the battery with the engine running? should be around 13-14 volts.

I found some info on the hei ignition system on old holden. even has a troubleshooting guide .

http://holdenpaedia.oldholden.com/Bosch_HEI

[Worby876]

Well taking on board some of the advice and suggestions I measured the Coil as per this website
http://waywardgarage.com/129/testing-an-automotive-12-volt-ignition-coil/

I also measured the voltage and was disappointed to see its below the 13+ volts that I have been told to expect.
heres a video i took with my iphone Im using a brand new auto multimeter.

http://www.youtube.com/watch?v=xF94t0s2r0c&feature=youtube_gdata_player


and it seems my Bosh Coil is not within the specs illustrated see here


So I have posted some pics of the old coil being tested and then the New Coil I purchased from Auto barn  its a high performance
MSD Blaster unit...

Here is the original unit's Primary coil being tested


here is the original secondary coil being tested seems to be low compared to the 10,000 ohms its supposed to be.

So I replaced this unit with a NEW MSD Blaster unit from the USA @ $109.

And to my surprise the new unit didnt read to spec either !!! 


here above is the reading for the Primary coil on the NEW MSD unit. (same as the old Bosh unit)



and above you can see the New MSD unit is even lower than the Old bosh unit and well below the specs of the web article what the ??

The new unit works fine BUT with such low voltage I'm wondering if I have other electrical issues..the battery could be on the way out
although the projectar battery monitor says its OK...

H'mm Could be the alternator is not doing its job properly...will read up on how to test that tonight and look at it tomorrow.. (long weekend so that good)

Other than that I'm thinking that there could be a leak of juice from the battery or maybe the wires from the battery and alternator could be in bad shape and posing too much resistance and thus loosing power at the coil.

The more I look the more I get so many other options as whats causing the problem...sigh owning an old bedford can be stressful eh?

Cheers

Ian

[Jeff]

I think I would try hot wiring it.
A fresh wire from the battery direct to the coil.
Also make sure that the earthing is working well; maybe a wire back to the battery.
That should tell you if the primary circuit is faulty or not.

PS Don't leave it on for long without the engine running, as I don't know if that would do damage or not. (same as leaving the ignition on)

I love these mysteries....when they are someone else's.

[hotrod]

H'mm Could be the alternator is not doing its job properly...will read up on how to test that tonight and look at it tomorrow.. (long weekend so that good)
Cheers
Ian

The old fashioned way is to turn the headlights on and give it a rev, you will see them improve

[Jeff]

I had another thought.
It could be that you have a leak in the inlet manifold gasket.
That may get worse as the engine heats up and the studs stretch.
If using the choke makes it run a bit better, then it is looking more likely.

The manifold nuts need to be re tightened after the engine heats up if the gasket has been replaced.

PS I have just reread the whole thread. Two others have suggested a manifold leak, but there is no mention of any action on this.
I do wonder if we are getting off track by looking for the difficult first.

[Worby876]

G'day Jeff,
Good thought..I'm willing to try anything...I  will check it out tomorrow,
I would have thought that a leaking inlet manifold would have shown up
on the vacuum gauges 
Any ways ...I will retention the studs tomorrow after I warm the
engine and see if it makes any difference.

I will also test the headlights while the motor is running and see if they
brighten with the revs.

Cheers

ian