My 505 won't go

broomy

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Fellow Frogger
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Oct 10, 2012
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Queensland
I have contributed this as I have watched the pleas of"My 505 won't start" and the parts swapping that accompanies the owners efforts.This, I term rectification by substitution.Also it can be called "Wilfull dismantling".
This hybrid ignition system sorted out the mechanics who were stuck in the EH era--and they stayed there!And things are even more technical now,and as manufacturers make cars more complex[mainly due to legislation and bean counters] its getting worse.
After the engine,fuel pump etc, is checked that its mechanically sound,the diagnosis can begin.If its proven there is no spark,this is a short lesson on trouble shooting the ignition on electronic ignition on such as 505 2.2 litre OHC Engines,once more fuel in tank,clean battery terminals,etc,etc.??
1. there MUST be 12v at the + coil terminal.Key ON
2. the module must be coated--lightly with heat paste on back of module,but not too much as it can cause problems if its covering the brass earthing ferrule in the module or shorting out the push on terminals.
3.the coil [there were about 20 listed--not anymore though] should be less than 1-one ohm resistance thru the primary circuit,Then primary to secondary 5 to 7 K ohms,that doesnt seem very important to Bosch.Jaycar/Repco type DMMs are not sensitive below about 3 ohms,so Fluke is the only way to measure primary windings.
4.Reluctor coil inside distributer-this the most vunerable part of the system IMO,approx 2800 turns very light wire ,2 to 2.2 k oms,can give cold or hot start problems -I've struck both.It puts out AC voltage, 2 to 4 v ac if you spin the dizzy shaft [out of the car] to 100v ac spinning full bore in the engine.
I'll upload some scope patterns, you can only work on these things with a scope---[that's what stuffs our EH blokes] even then you have to know what you're looking at.
5. Module and wiring, and here's a trap --if by chance over the years somebody has managed to plug the cable from dizzy to module back to front--[remember any thing is possible!] or have cut and joined the 2 wires reversed,or if the permanent reluctor magnets get reversed polarity
The the firing of the module would then be on the falling edge of the AC wave instead of the rising edge,this would cause the module to be completely scrambled ,and cook up eventually ,you would have to ask one of the boffins about that!It would run but for how long? The dwell would work in reverse.Or just hang up.
So the module must fire on the rising ramp of the wave.This controls the dwell time.
Also there is light screen over the dizzy to module lead,I haven't bothered to have a good look at one,but I'll bet its earthed one end and acts as a ground loop screen,it would be good fun finding an intermittent misfire caused by a module getting stray spikes!
This is a rough and ready article no mention of cracked dizzy caps coil towers so on,just an indication of why a no start needs some one with a scope and able to use it--it saves you from guessing and from buying heaps of stuff you don't need.And rule one tricky bit out.If you have spark move on.
I also have the ECU scope patterns but if you are in that deep you would have a rare one
Made mistake,the earthing ferrel is on the Holden hybrid module ,505 is in the plugin cable - sorry .
broomy
 

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Let the RACQ get it started :)
 
That's pretty detailed info, Broomy.
Do you happen to know something ?
Some 505s have three wires going from the distributor to the module, and some have only two. Is the extra one an earth ?
 
To be quite honest I haven't looked at one for years but the extra wire should be that screened earth I referred to , that's the earth loop to stop stray spikes ,My experience in this area is not so much automotive-it was building CNC routers and earth loops in the drive motors have to be looked out for when the wiring is plan devised,its really an extra earth in a wiring bundle-earthed at one end only, to each motor.The motor in this case is the dizzy.
. Some one like Robs could explain better than me.
Bet you are sorry you asked.
And - Mr Driven, RACQ is an Insurance Company,subsidiary NRMA I serviced their cars for them from time to time, they were over the road from my workshop in Fortitude Valley---but they do tow cars to the nearest franchisee,then you take your chances,which is what this post is all about.
 
Not sure about that broomy. Perhaps you were thinking of robmac. Since I'm here, I'll have a stab.

Beano, I haven't seen one with three wires, but since you say all three go to the module, here is a note I made about the pins at the module:

7 - RPM out (not connected)
6 - -input
5 - +input
4 - 12V
3 - Ground
2 - Ground
1 - Coil trigger

So you could unplug the module and (if you can get at it) the little plug at the dizzy and use a continuity meter to see what goes to what. I can't think what else it would be but a shield, but that would be a cable -- two cores with shield around them -- not three wires. If it is a shield it should only be connected at one end (as broomy said), so your continuity test would only find connections to pins 5 and 6 above (not sure which way the numbering scheme goes).

Have fun,

Rob.
 
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