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Righto, just been trying to start the desoto and as far as I can tell, it's not making a spark (I'm on my own so I'm trying to see/spot a spark from the drivers seat) but I'm 95% sure it's not making a spark, it's getting fuel (this I know because the carb leaks a bit lol and the plugs are wet) and compressions good. The points are opening and closing fine and most on the ignition parts are fairly new as it was converted to 12v less than a year ago.
I've not done anything to the engine between it working fine (Tuesday) and it not working (today).
Now first things I thought were coil and condenser. Which I'll change when I get to the motorfactors. but electronics is my biggest downfall and tracing/diagnosing faults is a but of a headache for me! Voodoo I tell ya! It's all voodoo!!
So, what I'm asking is, after the coil and the condenser, if I still have no spark, what else should I look at?? And I mean look, anything electrical I just tend to stare at it, give it "the evils" and just will it to work again...
Cheers,
Coops
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Last Edit: Oct 15, 2011 8:06:02 GMT by cairyhunt
Remember the days when sex was safe and motorsport was dangerous. Vintage bling always attracts pussy.  |
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If it's really annoying you, I'll take it off of your hands to get it out of the way  If you pull the king lead off the dizzy, do you get a spark from that? Since it was working the other day, and not at all today, and you have soggy plugs, could it be that you've just flooded it [/optimistic] |
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...proper medallion man chest wig motoring. |
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Lol
Possibly, but the electrodes were dry, an I had the plug out for quite a while which dried it off. And I'm fairly weary of flooding it, 3 pumps of the throttle before I turn it over and it normally starts straight up, it's a very good starter normally (when cold) and has never failed to start. nice tip with the king lead, I'll give it a go.
I do think it's the coil tho, ive had a coil do the same thing before on a bug, drove to Blackpool in it for a holiday and a gig, ran fine on the way there, left parked for 5 days and came to drive home and it had a very weak spark, wouldn't rev and had to nurse it home.
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Remember the days when sex was safe and motorsport was dangerous. Vintage bling always attracts pussy. |
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Right, just tested it with a friend, hardly any spark at the plug and a weak red spark coming off the king lead.
Guess that's the coil kaput! Should I change the condenser as well??
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Remember the days when sex was safe and motorsport was dangerous. Vintage bling always attracts pussy. |
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Id change the condensor too.. For the sake of a couple of quid.
Chuck a decent coil on there... Again. don't cost much.. Can fit and forget then and you know they are good.
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Copey
Posted a lot
Posts: 2,845
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may as well do it all at once Coop |
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1990 Ford Sierra Sapphire GLSi with 2.0 Zetec
1985 Ford Capri 3.0 (was a 2.0 Laser originally)
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Yeah, may as well like you say. Prob gonna get a Bosch blue, new engine going in soon anyway  Cheers guys ;D |
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Remember the days when sex was safe and motorsport was dangerous. Vintage bling always attracts pussy. |
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Dez
Club Retro Rides Member
And I won't sit down. And I won't shut up. And most of all I will not grow up.
Posts: 11,790
Club RR Member Number: 34
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i doubt very much its the coil (unless youve left the ign. on for a long period of time by accident).
9 times out of ten the symptoms you describe will be a duff condensor. they're prone to buggering up all the time for no reason, unlike coils which rarely do unless you leave the ign, on like mentioned above.
id change the condensor first as itll only be about 2 quid. id always carry a spare in the car (As well as points) too.
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ChasR
RR Helper
motivation
Posts: 10,307
Club RR Member Number: 170
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Oct 10, 2011 10:28:29 GMT
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Keep your old condenser. Finding a good new condenser these days is as hard as finding a good woman. I have seen a few new condensers go bad and cause endless amounts of grief.
You could try a cheapo electric ignition kit on it (Accuspark) on it see what that does.
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Oct 10, 2011 12:11:51 GMT
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Right, just tested it with a friend, hardly any spark at the plug and a weak red spark coming off the king lead. Guess that's the coil kaput! Should I change the condenser as well?? If the spark at the king lead is weak it does sound like a low-tension circuit problem. As a quick check of the condensor, take the dizzy cap off and turn the engine until the points are closed. Turn the ignition on, and open the points with a screwdriver, being careful not to short them out. You should see a small spark in the points gap. If the spark is big, then the condenser is dead. I would put money on it being the condenser - it sounds just like the symptoms that Ben was experiencing with his fiesta (no starting, very weak spark). Connecting a known-good condenser between the coil (points side) and earth (we didn't have a Fiesta-specific one, so used a Lucas one for testing) was enough to get it running. Also, have a close look at the points - if the condenser is faulty they will probably be quite burnt, with one face being eroded away and the other being built up. As has been said, finding good condensers now is quite a challenge - most reproduction parts are of poor quality, and NOS is hard to find. The distributor doctor sells a supposedly good quality Lucas style condenser which would be added outside your distributor if it won't fit inside. What brand of distributor does the DeSoto have? |
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Oct 10, 2011 14:54:31 GMT
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Cheers guys, Not sure what make the dizzy is, it looks to be stock and quite possibly original, the condenser is already outside of the dizzy and looks new, but if as you say most new condensers are curse word that that could well be it. The points looked and I didn't notice any corrosion, but then I wasn't really looking for it so could have just not noticed it. I'll check the points and check the spark there too. I understand the condenser does low tension and the coil does high tension (I think??) and that the HT (coil) give the "kick" but what's the LT condenser for?? I don't really understand what the physical differences they make to the spark and where the spark is?? If that makes any sense? Right now I have a very weak, dull but White spark at the plugs and a dull red spark at the king lead. Cheers again guys, I've tried to learn elec's, I've bought books and even did aircraft electrical theory at collage, but still can't get my head round it  |
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Remember the days when sex was safe and motorsport was dangerous. Vintage bling always attracts pussy. |
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Oct 10, 2011 17:25:15 GMT
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Very briefly:
The coil has both LT and HT parts. The LT is controlled by the points, and the HT produces the very high voltage needed for the spark.
The LT side of the coil stores energy when the points are closed and current is flowing. When the points open, a voltage spike is produced using this stored energy, and the voltage seen at the points gap during this peak can reach 400 Volts. The HT side of the coil has more wire in it than the LT side, so it produces a lot more voltage - around 10,000 volts if all is well. This then fires the plugs.
The voltage in the points gap just after opening is high enough to cause sparking there, which 'steals' some of the stored energy, reducing the amount that can go to the HT side of the circuit, making the spark at the plugs much weaker.
The condenser stores a little of this spark energy when the points open, and significantly reduces the size of the spark in the points gap, improving the spark at the plugs. The energy stored in the condenser might help to extend the spark duration a little as well.
Reducing the size of the spark in the points gap also means that the points last longer.
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Oct 10, 2011 17:34:10 GMT
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Right, a few things. I've done the points spark check thing and I've got quite a big spark at the points, enough to cause a flash, so I'm guessing that points to the condenser? But...might be a strange one this...which condenser??? This is what I've got.  One condenser next to the coil  And another in the dizzy??  Is this normal?? The one next to the coil is wired to the negative side of the coil. I have just managed to get it started and revving. But it then stalled and wouldn't restart  |
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Remember the days when sex was safe and motorsport was dangerous. Vintage bling always attracts pussy. |
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Oct 10, 2011 17:38:07 GMT
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Swap the king lead with one of the plug leads if you can and see if the spark changes...
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Oct 10, 2011 18:07:21 GMT
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Having two is not really normal. I suspect that the original failed and a replacement couldn't be found, so that was added as an alternative. I'd be tempted to remove both and fit a new one next to the coil. I would strongly suggest avoiding Intermotor condensers (which is probably what your motor factor will serve up). Reproduction Lucas stuff (green box) doesn't have a particularly good repuation, but I have no direct experience of it. Maybe one of these: www.ebay.co.uk/itm/150476322067NOS and made in germany - probably a reasonable bet. Or a New Bosch one: www.ebay.co.uk/itm/270831379952(both of those would need re-terminating, but that's not too hard I'm sure.) Or one of these: www.distributordoctor.com/distributor_condensers.htm |
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Oct 10, 2011 18:18:33 GMT
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Having two condensators/capacitors is not a problem in itself (placed parallel the capacities will simply add up), but if one of them fails it'll be hard to diagnose, since one will have a short circuit the other one will work only partially or not at all.
So my advice would be to check how it runs with either one of the condensators fitted and see if there is a difference (position in distributor/at coil does not matter).
Sparking between the points does point (hah!) to a faulty condensator.
It's also worth to check if the wires inside the distributor don't rub against the housing since that would short out the ignition! I once heard/read of a story of someone who had the points wire only touching the housing when the vacuum advance kicked in, that sure caused some head scratching!
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Oct 10, 2011 19:05:04 GMT
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Cheers for the links and explanations thing is, both condensers look new and are identical??? I'm confused I think I'm gonna get two new condensers, replace 1, see if it makes any difference, if same I'll replace the other and see how that goes. After all, they don't cost much, but I'll be weary of intermotor stuff. My head hurts and I've got to go to work now Cheers again guys. |
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Remember the days when sex was safe and motorsport was dangerous. Vintage bling always attracts pussy. |
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andyf
South West
Posts: 415
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Oct 11, 2011 14:22:32 GMT
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You will probably find that the one on the coil isn`t a condensor but a suppressor for the radio. Concentrate on the one inside the dissy cap, that`s the one to sort.
It may be worth removing the one on the coil and trying again. If the symptoms are identical then I am sure it`s a radio suppressor, nothing more.
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1980 Triumph TR7.
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Oct 11, 2011 14:27:03 GMT
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You will probably find that the one on the coil isn`t a condensor but a suppressor for the radio. Concentrate on the one inside the dissy cap, that`s the one to sort. It may be worth removing the one on the coil and trying again. If the symptoms are identical then I am sure it`s a radio suppressor, nothing more. But it's connected to the -ve (dizzy/ponts) side of the coil. If it were a radio supressor then it would be on the +ve side. It looks to me like a later bodge to get it running - it's certainly not original. I'd be tempted to remove both and fit one good one at the coil (unless you can find a good replacement to fit the distributor - difficult without knowing what it is). That way you know what you're dealing with. |
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Oct 11, 2011 18:25:59 GMT
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Cheers guys, well I've ordered 2 condensers just in case, pick them up in the morning.
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Remember the days when sex was safe and motorsport was dangerous. Vintage bling always attracts pussy. |
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