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greetings All,
i must have way too much time on my hands in the current environment, cut a long story short i was installing another tachometer, and i shorted something out, the net result is that i have no spark.
What i have done so far:
1. replaced #3 and #4 fuse in the box as they were blown
2. replaced condenser as i thot i had open circuit
3. replaced cap, button, coil with old items i replaced 3 years ago, known to be working when removed.
I still have no spark, and no spark at the coil lead at block when engine is cranked. Electrical checks so far, everything works so far except turn signals, probably because i did not replace tach, its still out of the car, hopefully i have provided enough info, i looked thru haynes manual i have, i think i am missing a relay or something, hoping i did not fry control unit,
Thanks for your input in advance,
Rob
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A sad tale.
Whenever I work on my old cars, I disconnect the battery - this is easy because I have a disconnect switch on the battery post.
Once, when I had a '39 Ford for sale, I called a restorer in town to see if he wanted to buy an old car - he said no, but what brand it is - when I told him that it was a Ford, he told me that he would come and look at it.
He came over in an old Buick - there was a large fire extinguisher on the front seat.
When I asked about it he told me that a lot of old cars lose their lives by fire.
Everyone should have a battery disconnect switch.
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The wire from the negative coil lug to the distributor routes through the tach via a red wire and a white wire, both with round connectors where they plug into the tach. If they are disconnected from the tach the car won’t run.
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Thanks Chris,
i thought this was the case when i was dead with no juice!
Ron,
thanks you for the wiring diagram references, this makes it clear now. Actually what i did was to try to wire the tach externally out of the car to confirm it was working, when i cranked the motor sparks flying everywhere and burn smell. The first place i went to was fuse box to check all of them, 3 and 4 did not look fried, i would say more old and corroded, so i replaced for good measure.
with regards to the condensor, i believe i should have said open resistance, not as you quite rightly pointed out open circuit
next steps:
will add a wire to complete the circuit to test i have spark and nothing else has been fried,
step2 - wire in new tach permanently, hopefully in my test i only fried the old tach and of course my new to me tach works!
thanks so much all for your valuable information as always
Rob
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Rob;
There is no reason why your Tach, correctly connected but out of dashboard, shouldn't work or disable Ign...
Tach may not be "fried"...you may have had it wired wrong, which was enough to cause sparks, but did not damage it internally...I'd double-check, now that you have info with which to connect it correctly...also, if it is indeed toast, you can send it to me and I'll do a post-mortem...it might even be repairable.
Good Hunting
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thanks Ron,
your diagram and pics of the tach really helped me! so new tach is in, but alas running rough and not idling. So now i checked each lead for spark, changed out button and cap - actually back to the original items, and still running rough with no idling unless i give her gas in which she still sputters to a stop. Replaced condenser with a new one and shes purring like a kitten; i think all the sparks flying around spoilt it, not sure of the diagram i couldnt explain root cause if i tried, but anyhow a happy ending thanks to the fabulous technical help and the parts this time provided by Nick T in michigan,
once again thanks so much all!
Rob
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Rob;
Thanks for the follow-up to let us know what the root-cause and solution finally were...and kind words!
I don't think it was " all the sparks flying around spoilt it,"...I think it was more a chinashit* condensor to begin with... There has been a rash of these probably counterfeit(!) condensers, Bosch labeled, not being able to stand up to their function...I too have had one fail with similar symptoms...
* (...those guys could F up a junkyard...and cheapening up products to the point of premature failure, or producing counterfeits or just plain non-functioning to begin with, now they have taken to exporting disease...I hate those pricks! ...ask me how I feel!)
Cheers
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hey Ron,
i did speak to planetman the other night regarding the quality or lack of Bosch parts of recent vintage. I had my first 1971 car in UK cold and damp and we swore by Bosch parts, changed the cap, leads plugs, button and points at the onset of winter and drove year round with spare points cap and button with tools to put them on in the trunck. Recently on trips to well known autostore, i m noticing they are ordering Bosch equipment from Worldpac and parts come in very quickly, i can only surmise parts are coming in from mexico. I had long heard of this and maybe this is why this part failed??? i wont say prematurely as i dont know how long they are supposed to last; its like the points, they are like tires you dont run them down until theres nothing left,
Thanks once again all for another little project completed, if covid goes on any longer, i have either a car in complete pieces or one where everything works like the day it left the factory :)
Rob
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Rob;
...a bit sparse on info!
1. Why were fuses blown? They don't blow without a good reason, and that may be part of the problem...indeed Tach is powered by F4 in a 73 1800ES. Ref Wiring Diagram: https://www.sw-em.com/1800ES_73_Wiring_Diagram.jpg
...and unclear!
2. "condenser as i thot i had open circuit"...a condenser is ALWAYS and supposed to be, an open circuit!?!? Ignition troubleshooting info: https://www.sw-em.com/Volvo%20Ignition%20from%20Scratch.htm#Troubleshooting%20IGNition%20System
Tach wiring info (see Gen 3): https://www.sw-em.com/Smith's%20Tachometer.htm#Smiths_Tachometers_Gen1_vs_Gen2_vs_Gen3
"i did not replace tach, its still out of the car," Tach is in the Ign primary circuit, and without it wired in-place to complete circuit, Ign will not function...
Good Hunting
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The tach almost certainly needs to be in the circuit to complete the low tension circuit. You might have fried something internally. Add a wire at the dizzy end to complete the circuit as if there was no tach.
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Not sure if this will help, but many years ago while trying to install a tach in my nearly-new 544, I fried the voltage regulator. I remember a new one set me back a whopping $16. I never did try to hook it up again. Good luck.
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Hello Rob,
Are you still running points and condenser or do you have an electronic ignition?
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com
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hi Planetman et al,
still running points & condensor,
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