What can cause a no spark on an old car?
Discussion
Got an Audi 80 B2 1981, with carburettor.
Got an issue with no start.
The car cranks, fuel and air is fine but no spark at all.
When you turn the key twice to just before "start" no lights show on the dash at all, ment to have battery symbol, cold temp and hot temp lights, fuel level needle ment to move but nothing.
Everything else is fine, interior lights, hazards, turn signals, radio etc etc
I've replaced the following, battery terminals, all grounds checked cleaned etc, ignition leads, coil, ignition switch, ignition control module.
The issue is confusing me as Ive connected the main pin on the coil direct to the battery (unplugged the harness first) and hard wired the starter to the battery, still no spark, but all the lights then come on like it should do and the fuel level shows correct, so I can rule out any part of the ignition system from key to ignition module surely?
I've checked multiple wires on the ignition system with a multimeter too, all seem ok.
I'm completely at a loss with this one.....
I even tried disconnecting the ignition switch and connecting 15 35 and 50 with a 3 way wire to essentially hot wire my own car, nothing.
Anyone got any ideas?
Got an issue with no start.
The car cranks, fuel and air is fine but no spark at all.
When you turn the key twice to just before "start" no lights show on the dash at all, ment to have battery symbol, cold temp and hot temp lights, fuel level needle ment to move but nothing.
Everything else is fine, interior lights, hazards, turn signals, radio etc etc
I've replaced the following, battery terminals, all grounds checked cleaned etc, ignition leads, coil, ignition switch, ignition control module.
The issue is confusing me as Ive connected the main pin on the coil direct to the battery (unplugged the harness first) and hard wired the starter to the battery, still no spark, but all the lights then come on like it should do and the fuel level shows correct, so I can rule out any part of the ignition system from key to ignition module surely?
I've checked multiple wires on the ignition system with a multimeter too, all seem ok.
I'm completely at a loss with this one.....
I even tried disconnecting the ignition switch and connecting 15 35 and 50 with a 3 way wire to essentially hot wire my own car, nothing.
Anyone got any ideas?
samoht said:
Does it have a distributor? Have you replaced that?
It's also possible that one of the replacement parts you've fitted might itself be faulty or the wrong one for the car, hence you could have replaced a faulty part with another faulty part and thus no change in the problem.
No not yetIt's also possible that one of the replacement parts you've fitted might itself be faulty or the wrong one for the car, hence you could have replaced a faulty part with another faulty part and thus no change in the problem.
The only issue is if it's the distributor/condenser/rotor arm, it wouldn't explain why the lights on the dash don't show.
A while back it did this for about 2 days all the same symptoms, no start unless lights are on dash It eventually started, but only when the lights on the dash came on. It's almost like it needs to have that circuit complete to start.
A while back it did this for about 2 days all the same symptoms, no start unless lights are on dash It eventually started, but only when the lights on the dash came on. It's almost like it needs to have that circuit complete to start.
Rawsox said:
The only issue is if it's the distributor/condenser/rotor arm, it wouldn't explain why the lights on the dash don't show.
A while back it did this for about 2 days all the same symptoms, no start unless lights are on dash It eventually started, but only when the lights on the dash came on. It's almost like it needs to have that circuit complete to start.
^^^^You need to sort this issue out.A while back it did this for about 2 days all the same symptoms, no start unless lights are on dash It eventually started, but only when the lights on the dash came on. It's almost like it needs to have that circuit complete to start.
No 'almost like it needs to have that circuit complete to start' about it, it obviously does.
If you can't find the problem it might be worth finding a competent auto electrician to have a look.
Sounds more and more like a problem with the switchset but can also happen if a multiway connector joining the front loom to the cabin electrics has a bad contact, depending on the car. Don't know if Audis have them but they were a common failure on Fords and (occasionally) BMW.
Look for a big plug/socket ensemble under the bonnet where the wiring goes through the bulkhead.
Look for a big plug/socket ensemble under the bonnet where the wiring goes through the bulkhead.
I think vws and Audis of this age used a feed from the coil to power the tachometer and fuel pump relay so a problem with the cluster can affect the spark.
Have heard of dodgy connections on the cluster plug causing running issues in old golf’s.
I expect your Audi will be similar to something on here as it pretty much the same as a b2 Passat :
https://clubgti.com/forums/index.php?threads/fuseb...
Might be worth a read. Guy on there called Rubjonny who has vast knowledge of old vw electrics.
Have heard of dodgy connections on the cluster plug causing running issues in old golf’s.
I expect your Audi will be similar to something on here as it pretty much the same as a b2 Passat :
https://clubgti.com/forums/index.php?threads/fuseb...
Might be worth a read. Guy on there called Rubjonny who has vast knowledge of old vw electrics.
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