Post Number: 236
|Posted on Sunday, 08 July, 2018 - 03:31 am: |
I took my Shadow 1 into the paint shop to touch up some nicks and scratches. When I picked it up, the gen light would not extinguish, and as I was travelling back home, it was misfiring, and getting worse.
I know they did some welding without disconnecting the battery. I presumed that this had fried my regulator, and hoped that changing it might fix the misfire.
I have replaced the regulator, but the generator light has not extinguished, so I presume the problem lies deeper.
Also the misfire is still there, so I am sure that the Powerspark is also fried.
I have not started digging yet, but before I do, does anyone know what else could have blown, apart from the regulator which I have replaced. I know modern alternators have the regulator as an integral part with some big diodes that can blow. Does the Rolls also have those, or is everything controlled through the regulator?
I am waiting for an answer from Powerspark as to whether their units can misfire when damaged, or that they either work or not. Any suggestions on what I should check in the meanwhile would be welcome and appreciated.
Thanks as always....
Post Number: 1988
|Posted on Sunday, 08 July, 2018 - 04:11 am: |
The alternator does contain diodes. Section M5 of the manual is very comprehensive and gives procedures for testing the alternator.
I had a quick google of welding cars and disconnecting the battery. As often happens on the net, opinion is divided. Some people say they have welded many cars with no problems, others who say they always disconnect the battery. One person mentioned that exhaust shops never disconnect car batteries and often carry out welding - I suspect most would be using oxy-acetylene however.
Post Number: 1989
|Posted on Sunday, 08 July, 2018 - 04:17 am: |
BTW - when my Powerspark failed it did so gradually with misfiring. This was confusing as I thought it would either be on or off. I therefore replaced the other ignition parts (coil, rotor, leads) before reverting back to points, when the engine ran ok again.
Could you let us know Powerspark's response - it would be interesting to know.
Post Number: 1916
|Posted on Sunday, 08 July, 2018 - 05:56 am: |
Have used arc and mig tig etc and for the last 20+ years have never disconnected the battey,
have always used one of these to stop spikes etc.
Post Number: 1990
|Posted on Sunday, 08 July, 2018 - 06:07 am: |
Hi Patrick (L) - I assume the Sykes Pickavant device is a large smoothing capacitor. So, logically, we can assume that car electrics are prone to spikes from MIG/TIG welders, else there would be no need for such devices.
Vladimir Ivanovich Kirillov
Post Number: 1017
|Posted on Sunday, 08 July, 2018 - 06:35 am: |
Apart from oxy welding I always disconnect the battery. I mean really how much effort does it take to disconnect the battery?
I have heard mig welding will not blow diodes in alternators. I do not care. I always disconnect the battery.
This thread is another reminder to me why I simply will not let any workshop near my cars.
Post Number: 1917
|Posted on Sunday, 08 July, 2018 - 06:48 am: |
Cripes Vladimir, hope you never disconnect some moderns can be a costly time consuming job to re programme with lost codes etc.
Battery disconnect went out years ago.
How is the super Camargue engine coming along.
I need one to put an engine in, if you need to sell at any time give me a bell.
richard george yeaman
Post Number: 983
|Posted on Sunday, 08 July, 2018 - 08:25 am: |
Patrick F I would start with the alternator, a half charged battery isn't helping your chance of a good sparking plug, order up a new power spark and also a spare one.
Post Number: 1918
|Posted on Sunday, 08 July, 2018 - 05:33 pm: |
May be beneficial to know what parts have been welded. Could be burnt loom etc.
Maybe a nothing more than a fuse blown during the operation if fitted.
Connection left off if removed.
Post Number: 842
|Posted on Monday, 09 July, 2018 - 11:32 am: |
As to the welding thing, I've welded a lot of metal on a lot of vintages of cars. If it's someone else's I disconnect the battery, on mine it's cables on. Never had a problem. Of course I ground correctly so there's less chance of electrons going where they shouldn't. In both cases, never a problem. And in all the car welding I have direct knowledge of, no mig / tig induced problems.
Could you get massive current flow somewhere you don't want it or induce current in something electromagnetically or create some high voltage spikes,.. sure.
Even with the "running fine before shop" / "running badly after shop" clue, I would still diagnose this the same way I would any misfire.
If you are more comfortable with replacing stuff, testing the Pertronix would seem easy enough, put the points back in, time them and see if the goes away.
Three days ago I welded front clip back on my new mini, 1.5 hours straight welding.
Battery on, no problems.
Two days ago I welded in metal to fix rusted out drivers and passengers door sills on Ford truck. 1 hour welding time ( job time four hours)
Battery on no problems.
No pictures, but today I welded an exhaust on a Ford Festiva battery on, no problems except I cannot get the dignity back I lost working a Ford Festiva.
Post Number: 238
|Posted on Sunday, 12 August, 2018 - 11:23 pm: |
So sorry that I haven't managed to thank you all for your advice and help as usual, but a combination of work and various other factors has meant that SRH 17968 has been a distant memory for a while.
Geoff, I contacted Powerspark, and these were their answers:
1. Would the failure of the Powerspark unit cause my GEN light to go on?
In answer to question number 1, no, failure of the kit won't cause the GEN light to come on.
2. If the Powerspark unit is damaged, could it cause a misfire, or would it just stop working altogether?
In answer to question number 2, generally, if damaged, the kits would just stop working completely.
Patrick L and Ross
I have also done a lot of welding without any problems, but knowing how delicate Powersaprk ignitions are to electric overloads etc, I would recommend disconnecting the battery as Vladimir suggests.
I have removed and checked the alternator - working perfectly with NO blown diodes. I have replaced the regulator. I have charged the battery. I still get a misfire and a permanent GEN light.
I have not replaced the electronic ignition unit until I can identify the reason that the GEN light will not extinguish.
I should have more time in a couple of weeks and so will start a methodical process of elimination. You will be down this part of the world around that time, so we will have a topic of discussion!!
Thank you all again, and I will report back with any progress!
Post Number: 247
|Posted on Wednesday, 19 September, 2018 - 10:17 pm: |
Richard (Yeaman) - great to see you again the other day, pity we didn't have time to battle this out together!
Thanks to Alan Dibley for his reply to my "condensers" question.
So, trying to get to the bottom of this problem - Generator light stays on, and car misfires to the point of nearly cutting out.
I originally thought it was a welding problem when some bodywork was being done, but they used gas.
So the possibility was a red hot rod puncturing the loom under the front wing where the welding was done. -not the case_
I tried all the fuses and connections, but all seemed OK.
Checked the alternator and replaced the regulator box.
In the process of elimination, I tried replacing the coil, and suddenly the Gen light went out and she ran smoothly.
She was running smoothly on a 1.5ohm coil instead of the 3 ohm electronic ignition coil, even though I had no ballast resistor.
So I changed electronic ignition and coil (borrowed from another car) - but it started misfiring again.
Since she was running fine on the 1.5ohm coil (designed to run on 9v through a ballast resistor), I presumed that she was getting a dropped voltage at the coil due to resistance or a bad connection somewhere.
So I ran a clean lead from the +ve of the battery, straight to the coil.
She ran well for a short while, but then, again, bad misfiring, gen light on and sooty plugs!
So I put the 1.5ohm coil back on and she ran like a dream for a few miles and then really started coughing badly, misfiring and the gen light came back on!
The love hate relationship with the old girl was running out of love!!
She finally stalled and wouldn't start!
I opened the bonnet and noticed a whiff of smoke from the alternator area, and on closer examination, found one of the condensers under the compressor had a melted cable.
On disconnecting it, lo and behold she started an ran like a dream!!
I ran her for about 60km, and during the journey she hesitated and started misfiring a couple of times, especially towards the end of the journey, but otherwise ran well. I have not done the timing since swapping the electronic ignition pickup, so part of that may be due to that, but I suspect that it may also be the second condenser under the compressor, but I have not had time to check that.
My question is, does anybody have a similar experience with these failing condensers? If they fail, does that mean a +ve is earthing and causing these multitude of problems, or is it just a coincidence?
Alan says there may be many condensors around, but I presume these two that are attached to the alternator would be the ones more likely to interefe with the ignition.
I am downloading the circuit diagram to see if I can make sense of it. I am a bit puzzled as to whether I have located the problem, and electrics befuddle my brain!!