126 replies to this topic

[Captain Mainwaring]

Something odd very odd as Steve said above going on with those voltages, the electronic distributor some how appears to be set up correctly then when cranking advances the timing so the engine kicks back and turns over slowly. would it have done that with a temporary 12v supply straight to the coil + ? we'll never know now.

 

I would try one of the aftermarket electronic kits in it as that might shed some light on whats going on, as the electronic distributor kits are only a reproduced mechanical item with one of those trigger heads in it, now if it were to do the same again ..........................

 

As above - if the OP swapped the giblets over and just took the trigger from the new kit, I'd pretty much guarantee the problem would travel across from the new to the old. 

Before you do that - just push start the car

[The Freak]

Morning all,

 

Sorry about the delayed repsonse,.  I am not bored with the problem, just very confused.  My understanding when looking at volt drop on starting is that (certainly on an older vehicle like this one) a drop to about 9.5-10.5 is to be expected, that is what I was taught as a mechanic 23 years ago (I have not been a car mechanic for a long time though, 18 years). 

 

When we first fitted the new kit at Powerspark on sat, the engine cranked normally on the first turn of the key, it fired up and ran sweet.  The tech guy said 'no problem here' and I looked like a fool.  I stopped the engine and went to crank it again.  The engine then refused to rotate.  It then rotated slowly or not at all as we tried different set ups.  Some times there was just enough turning for it to fire and it ran fine.  However, the tech tried to set it up by ear (he needs to work on calibraing his ears) and we checked it using the strobe.  It was showing 60 degrees advanced, way to much.

 

When we tried to turn it it wouldn't spin.  We turned it back to 5 degrees static and tried to turn it over, still none or very slowly (like a very flat battery). He said the battery was knacked.  That is impossible, it is only two weeks old and when we checked the voltage it was 12.7 (that is almost 100% charged). 

 

He pulled the king lead from the top of the dizzy and checked for a spark, which we got as the engine span freely.

 

I have a spare battery, can I use that to connect to the + of the coil and check for opperation of the system, using the car battery to power the starter.  However, if something is casuing the massive volt drop, wouldn't connecting a second battery possibly cause a further problem? or damage the battery in situ at present?  I haven't been able to call powerpsark yet.  I will do that later today if I get 30 mins or so.

[The Freak]

When I first encountered this problem, i push started it and it jumped perfectly, off I went.  However, I can't get th ewife to do that every morning..

[lrostoke]

 

He pulled the king lead from the top of the dizzy and checked for a spark, which we got as the engine span freely.

 

 

When he pulled the king lead was this at a point when it was cranking slowly ?? and once lead removed it span freely ..

 

60 degrees advance is almost as if the HT leads are on wrong ??

 

How are you finding the 5 degrees static timing position ???

Edited by lrostoke, 02 July 2013 - 10:13 AM.

[KernowCooper]

From what I gather reading its fine setup at 5degs and when switched off and a restart tried there is to much advance ? I would put a kit in the OPs distributor and try that, if the problem returns then run a new temporary 12v feed to the coil and see if it reacts the same

[Captain Mainwaring]

When I first encountered this problem, i push started it and it jumped perfectly, off I went.  However, I can't get th ewife to do that every morning..

 

 

You've found your answer.

 

Morning all,

 

Sorry about the delayed repsonse,.  I am not bored with the problem, just very confused.  My understanding when looking at volt drop on starting is that (certainly on an older vehicle like this one) a drop to about 9.5-10.5 is to be expected, that is what I was taught as a mechanic 23 years ago (I have not been a car mechanic for a long time though, 18 years). 

 

When we first fitted the new kit at Powerspark on sat, the engine cranked normally on the first turn of the key, it fired up and ran sweet.  The tech guy said 'no problem here' and I looked like a fool.  I stopped the engine and went to crank it again.  The engine then refused to rotate.  It then rotated slowly or not at all as we tried different set ups.  Some times there was just enough turning for it to fire and it ran fine.  However, the tech tried to set it up by ear (he needs to work on calibraing his ears) and we checked it using the strobe.  It was showing 60 degrees advanced, way to much.

 

When we tried to turn it it wouldn't spin.  We turned it back to 5 degrees static and tried to turn it over, still none or very slowly (like a very flat battery). He said the battery was knacked.  That is impossible, it is only two weeks old and when we checked the voltage it was 12.7 (that is almost 100% charged). 

 

He pulled the king lead from the top of the dizzy and checked for a spark, which we got as the engine span freely.

 

I have a spare battery, can I use that to connect to the + of the coil and check for opperation of the system, using the car battery to power the starter.  However, if something is casuing the massive volt drop, wouldn't connecting a second battery possibly cause a further problem? or damage the battery in situ at present?  I haven't been able to call powerpsark yet.  I will do that later today if I get 30 mins or so.

 

 

You're getting closer.

What you need to do is pull the +ve feed off the coil and ensure that the coil and the distributor electronics get a separate feed off the spare battery - Just link the -ve grounds across - it is imperative that you DO NOT link the +ve's - just feed the ignition alone from the spare supply.

 

I've got a pint of cider on it being fine, but can't cope with low voltage.

 

Whoever told you that you could look at a battery voltage off load and determine the condition was talking out of their hat - just because you see 12.7 V you could have all sorts of battery issues, not to mention high resistance at the body earths, through the main battery cable terminations at starter and battery terms, none of which will show up until under load.

[Captain Mainwaring]

From what I gather reading its fine setup at 5degs and when switched off and a restart tried there is to much advance ? I would put a kit in the OPs distributor and try that, if the problem returns then run a new temporary 12v feed to the coil and see if it reacts the same

 

I wouldn't yet - first try a separate supply - Captain's first rule of fault finding and PID loop tuning - only ever change one thing at once.

If the OP can prove that the low voltage is the issue, no need to swap things over - cure the low voltage first.

[lrostoke]

But surely if he's getting 10.3v when the engine is cranking he's not got low voltage...that sounds like a normal drop in voltage when an engine is cranking.

 

Yes connecting a seperate 12v supply may make it work, but is it not then operating under artificial conditions which won't be achieved when the engine cranks with just the normal battery connected.

 

Although I guess such a test may indicate the module is over sensitive and a replacement may be the answer.

Edited by lrostoke, 02 July 2013 - 11:34 AM.

[Captain Mainwaring]

But surely if he's getting 10.3v when the engine is cranking he's not got low voltage...that sounds like a normal drop in voltage when an engine is cranking.

 

Yes connecting a seperate 12v supply may make it work, but is it not then operating under artificial conditions which won't be achieved when the engine cranks with just the normal battery connected.

 

Although I guess such a test may indicate the module is over sensitive and a replacement may be the answer

 

He is getting an indicated 10.3V which for what it is worth would not be enough for a Boyer bike unit unit.....

More importantly you'll not see the peaks and troughs that occur every time that a pot starts compression. 

There are probably 4 or 5 compressions a second, and every one will cause battery voltage to dip.

 

The only way to test the module scientifically (because it sure as hell has never been in the past) is to use a lab powersupply and set up a sychro'ed drive and use a scope to see the module output vs a known good sync, while dropping supply voltage.

Edited by Captain Mainwaring, 02 July 2013 - 01:44 PM.

[KernowCooper]

Getting out of lab for a min if the OP poster has a known power supply of 12v setup on a temporary basis and it does start every time without these over advanced symptoms, than its fault finding time on the car to trace the low voltages experienced on the coil.

 

Me I would try another trigger unit in the standard distributor and if he gets the same results its not a rogue powersparks distributor.

 

may have missed this in all the posts? was it a new distributor powersparks tried in the OPs car on Saturday or the one he brought with him ? If powersparks didn't try a new unit it was a wasted trip and there mechanic needs a course in fault finding.

[Captain Mainwaring]

Getting out of lab for a min if the OP poster has a known power supply of 12v setup on a temporary basis and it does start every time without these over advanced symptoms, than its fault finding time on the car to trace the low voltages experienced on the coil.

 

Me I would try another trigger unit in the standard distributor and if he gets the same results its not a rogue powersparks distributor.

 

may have missed this in all the posts? was it a new distributor powersparks tried in the OPs car on Saturday or the one he brought with him ? If powersparks didn't try a new unit it was a wasted trip and there mechanic needs a course in fault finding.

 

 

I think it's fault finding time on the car anyway - 8 V sounds a bit too low. 

 

Temporary power supply first will at least narrow down the root cause. .

 

I think their mechanic only messed around with the troublesome unit.

 

Taking the distributor body at starting speeds as just a means of turning the rotor arms and the trigger, can there actually be anything happening inside the body to cause the timing to advance at starting then go back to a normal condition?

 

And yes....the mechanic really needs a course on faultfinding -

[KernowCooper]

Quote- Taking the distributor body at starting speeds as just a means of turning the rotor arms and the trigger, can there actually be anything happening inside the body to cause the timing to advance at starting then go back to a normal condition?

 

Only thing I can think off is the advance weights not returning fully? poor machining high spots ?

[The Freak]

Morning,

 

I'm off work today but have some I have some other things to do.  If I get chance, I will try the separate feed and report back. 

 

When we tested it on sat, we used the dizzy I bought from Powersaprk, he didn't try another one.  However, we did swap in a new module, which is sat in the dizzy at the moment.

 

As far as the battery voltage under off load conditions is concerned.  The 12.7v shown at least proves the alternator is working, which the mech tried to suggest was at fault. 

 

If I was getting low volts under starting conditions, wouldn't that show up under all starting conditions not just no turn over with dizzy advanced?  For there to be a volt drop wouldn't something have to be using that voltage? another component or a bad earth perhaps?  When my alternator was packing up, I thought it was a bad earth so I went mad and fitted three new earth straps (as well as the remaining straps) Plus there are only a handful of electrical systems running on this car (it is only a mini don't forget) what could be causing the drop?

[lrostoke]

If your going to play today, I think taking off the baseplate of the dizzy and looking underneath at the springs and weights is a place start.

 

It's been mentioned if the fly weights are sticking this would explain why sometimes it feels to far advanced and won't turn over.

 

See if they move freely with no notchiness.

 

try it without the vac advance tube connected...wonder if thats sticking on

 

probably worth just checking all battery and earth connections before you do anything make sure all clean and tight

Edited by lrostoke, 04 July 2013 - 07:57 AM.

[Yoda]

Also, with the engine running, you should be seeing about 14.5 volts at the battery.from the alternator!!!