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Re: No spark until key is released

PostPosted: Mon Jun 27, 2016 10:33 am
by Craven
Consider the possibility of the voltage available to the ignition module being too low during engine cranking.
As known the battery voltage drops under heavy load of the starter, when the key is released the voltage jumps up to full voltage again.
Does the engine crank over with good speed?
Check the voltage at the + terminal of the coil UNDER CRANKING.
Make sure all the chassis earth bonding is good, voltage drop here reduces the voltage available to the ignition module.
A faulty ignition module is possible.
May help.
Ron.

Re: No spark until key is released

PostPosted: Mon Jun 27, 2016 11:59 am
by billwill
When in doubt you should always use a multimeter to find out what your electrics are doing or how they are wired or how they should be wired.

Wire colours are merely a rough guide if you do not know what changes a previous owner made.

If you need to trace the connections to the ignition switch take it out. First disconnect the battery, remove the panel knee trim, carefully unscrew the retaining ring nut and push the switch back through the panel and then hopefully there will be enough slak in the wires to ease out into the knee area where you can get at the contacts.

Connect the battery for a while to use a voltmeter setting find which is the always live terminal (Live when switch is in the OFF position).

On the ignition switch one wire is always live 12v coming from the battery.

Once you know which terminal (lets call it the Supply terminal), disconnect the battery again and use the ohmmeter setting to trace switch actions.

Put one probe of your ohmeter on the supply terminal and use the other probe to determine which other contacts it is connected to for the various switch positions (Aux, Off, Run, Start)

Aux position is twist the key anti-clockwise (it stays there).
Off position is usually with the key vertical
Run position is twist the key clockwise one click (it stays there)
Start position is twist clockwise from the Run position, it is spring loaded to return to the run position when you release twisting the key.

The permanently live contact should have a Brown/blue wire on it

The Aux contact (which should go via a wire which should be white) to the fuse box, is connected in all positions of the key except OFF and START

The Run contact is connected only in the run position AND IN THE START POSITION. It should be connected to a white wire thart goes to the ignition coil. It may (probably) go there via the tachometer sensing loop.

The Start contact is connected only in the START position. It goes to the starter solenoid activate terminal via a wire that should be Brown/Yellow

~~~~~~~~~~~

On my old starter switch (which is no longer in the car) the contacts are not identified by letters or numbers. It is I think a Lucas one. Its type number is 31953H

Viewed from the back near the bottom is a SINGLE-connector contact which is the START contact then going clockwise there is a DOUBLE-connector contact which is the Aux contact, then
continuing clockwise there is a DOUBLE-connector contact which is the SUPPLY contact then
continuing clockwise there is a DOUBLE-connector contact which is the Run contact.


Image from Holden website
Image


~~~~~~~~~~~
edited: add and START to the Aux contact non-connection

Re: No spark until key is released

PostPosted: Mon Jun 27, 2016 2:49 pm
by Flightmate
Power to the coil in the run position is 12.3 and when I hit the starter it dropped to around 8.5. I pulled a bigger battery out of a different car and got 12.7 at the coil in the run position and around 9.6 with the starter engaged. Is 8.5 enough power? It seems to me the engine seems to turn over at a good speed.

Re: No spark until key is released

PostPosted: Mon Jun 27, 2016 3:09 pm
by Flightmate
Also, if I am checking this correctly this is the resistance across the coil.

Image

Re: No spark until key is released

PostPosted: Mon Jun 27, 2016 4:43 pm
by Craven
From your measurements all seems OK, only reservation being, where is your chassis probe. Voltage for the ignition module is between the red wire on coil and the body of the distributor. 3.4 ohms is also OK for a non-ballast coil.
Are you sure there is no spark when engine is being cranked
Ron.

Re: No spark until key is released

PostPosted: Tue Jun 28, 2016 11:43 am
by rgh0
The voltage drop seems excessive when cranking and the electronic ignition may not trigger with this low a voltage

regards
Rohan

Re: No spark until key is released

PostPosted: Tue Jun 28, 2016 12:33 pm
by billwill
Sorry I missed in my tests of my old ignition switch above that the connection between Supply and Aux is discoonnected when the key ir twisted clockwise to the start position.

I've corrected it above, but I'll quote the corrected version here for convenience:
Put one probe of your ohmeter on the supply terminal and use the other probe to determine which other contacts it is connected to for the various switch positions (Aux, Off, Run, Start)

Aux position is twist the key anti-clockwise (it stays there).
Off position is usually with the key vertical
Run position is twist the key clockwise one click (it stays there)
Start position is twist clockwise from the Run position, it is spring loaded to return to the run position when you release twisting the key.

The permanently live contact should have a Brown/blue wire on it

The Aux contact (which should go via a wire which should be white) to the fuse box, is connected in all positions of the key except OFF and START

The Run contact is connected only in the run position AND IN THE START POSITION. It should be connected to a white wire thart goes to the ignition coil. It may (probably) go there via the tachometer sensing loop.

The Start contact is connected only in the START position. It goes to the starter solenoid activate terminal via a wire that should be Brown/Yellow

~~~~~~~~~~~

On my old starter switch (which is no longer in the car) the contacts are not identified by letters or numbers. It is I think a Lucas one. Its type number is 31953H

Viewed from the back near the bottom is a SINGLE-connector contact which is the START contact then going clockwise there is a DOUBLE-connector contact which is the Aux contact, then
continuing clockwise there is a DOUBLE-connector contact which is the SUPPLY contact then
continuing clockwise there is a DOUBLE-connector contact which is the Run contact.


Image from Holden website
Image


~~~~~~~~~~~~~~~~~~~~~~

Taking all this into account it seems clear to me from your symptoms that indeed the two white wires have been interchanged. Your symptoms match no power to the coil in the START position, which is a characteristic of the AUX contact not the RUN contact.

You need to check with your ohm meter that the white with blue tape at the ignition switch is indeed the other end of the white with blue tape at the tachometer. That is the one that should be on the RUN contact.

And you should check (preferably with the battery disconnected) that the other white wire at the switch does indeed go to the fusebox to power the accessories. This is the one that should be on the Aux contact of the ignition switch.

Re: No spark until key is released

PostPosted: Wed Jun 29, 2016 1:56 am
by Flightmate
I still haven't gotten a chance to look at the ignition switch, but I did check for spark again. This time I used a light hooked to the plug wire and shut the garage so it was dark. I did see spark when it was cranking so there is some, but I'm guessing it was to weak to see in the daylight.

It had been running well otherwise the last few days, but today just from me touching only the plug wires and a couple wires on the ignition coil, which all got put back correctly, I went for a drive and it ran horribly. Missing constantly. I double checked that everyrhing was hooked up correctly and it still ran bad. I'm starting to wonder if the bulk of my problems lie in either the wires or the ignition coil.

I plan on buying both and seeing the difference they make. I was thinking of using the Pertronix flame thrower since I have thier ignitor already. I see there are two different ones. One is 1.5 ohms and the other is 3.0. Which one is correct for my application?

Re: No spark until key is released

PostPosted: Wed Jun 29, 2016 8:09 am
by billwill
Ignition switches get corroded & mucky inside and become erratic contacts.

That's why I replaced mine.

Re: No spark until key is released

PostPosted: Wed Jun 29, 2016 10:10 am
by Craven
You need to check the spec of your ignitor, but generally the small electronic modules don?t like the higher current in the low resistance coils. I would stay with a 3 ohm coil.
Inspect all high voltage leads, possible leakage in the distributor cap, rotor arm etc.
May help
Ron.

Re: No spark until key is released

PostPosted: Thu Jun 30, 2016 4:33 pm
by Flightmate
I ordered all the parts, but I figured while I am waiting for them I would check the fuel flow.
I disconnected the fuel line just before the T fitting to the carbs which on my car is right after a fuel filter. I cranked the engine over for 10 seconds and got just over 2 ounces of fuel. It came out in spurts like I would expect a mechanical pump to do. I tried again and got 2 ounces. That seemed a bit low so I tried a 3rd time this time without the filter installed to see if it would change and I got absolutely no fuel flow whatsoever over the 10 seconds. I put the filter back on and tried for a few more seconds and got nothing. The only other thing I did was remove the lead to the coil before doing all this to keep the plugs from firing. Am I missing something? Does the pump need some sort of back pressure to pump correctly?

Re: No spark until key is released

PostPosted: Sun Jul 03, 2016 10:47 am
by vincereynard
Flightmate wrote: Am I missing something? Does the pump need some sort of back pressure to pump correctly?


It's just a simple diaphragm pump. Sucks fuel through a one way valve on one stroke, pushes it out through another one way on the other stroke. If it needed back pressure it could not fill empty carbs.

Check you have a clear tank and fuel line. I had a car which had got some sort of debris floating about. Sometimes it would go for days without a problem, then suddenly interfere with the fuel flow and run terrible.
When stationary the "stuff" floated away and showed no hint of a problem!

Re: No spark until key is released UPDATE

PostPosted: Sun Jul 10, 2016 11:18 pm
by Flightmate
Thanks to everyone for the suggestions and help. I ended up replacing most everything under the hood. New plugs, wires, distributer cap, rotor, ignitor, and a new coil. Whether it was one part or a combination thereof, my car now starts up so fast it'll make your head spin. :D :D I haven't gotten to drive it enough to know if my intermittent poor running problem is also rectified, but so far so good. Thanks again to everyone who helped!

Re: No spark until key is released

PostPosted: Mon Jul 11, 2016 5:36 am
by john.p.clegg
Now is the time to replace every thing back , one at a time , to find the culprit and throw it as far as you can ,all the rest can go back on the shelf...

John :wink: