HELP! Ignition Failure
Discussion
I am now a fully fledged TVR owner having suffered the indignity of breaking down in heavy traffic and having to trailer the car home.
After an hours perfect running the engine cut out dead leaving just the dashboard warning lights on. A quick turn of the key and the engine spun merrily but didn't catch at all.
Pulled off the kinglead to find no spark on turnover as expected. To check the coil we took a wire from the battery positive to the coil which only seemed to worsen the problem as there now seems to be some sort of arcing out at the starter motor.
Most importantly when the key is turned to position 1 the tacho and speedo normally zero themselves, instead the tacho stays at around 7000rpm (it's normal resting place) and the speedo is at 40 mph (even though I was stationery when the engine cut out). However the fuel pump does prime as it should.
Does anybody have any similar experiences or suggestions?
How about the notoriously dodgy 4 pin ignition block?
>> Edited by burblev8 on Friday 16th December 00:10
After an hours perfect running the engine cut out dead leaving just the dashboard warning lights on. A quick turn of the key and the engine spun merrily but didn't catch at all.
Pulled off the kinglead to find no spark on turnover as expected. To check the coil we took a wire from the battery positive to the coil which only seemed to worsen the problem as there now seems to be some sort of arcing out at the starter motor.
Most importantly when the key is turned to position 1 the tacho and speedo normally zero themselves, instead the tacho stays at around 7000rpm (it's normal resting place) and the speedo is at 40 mph (even though I was stationery when the engine cut out). However the fuel pump does prime as it should.
Does anybody have any similar experiences or suggestions?
How about the notoriously dodgy 4 pin ignition block?
>> Edited by burblev8 on Friday 16th December 00:10
I think you need to check all the ignition components.
I had a similar problem but I was travelling at about 50mph at the time!
Called the RAC and despite him trying for 30 minutes to get it started he couldn't and had to tow me home.
Turned out the rotor arm had disintegrated in the dizzy. So my lesson was not to ignore the basics.
Colin
I had a similar problem but I was travelling at about 50mph at the time!
Called the RAC and despite him trying for 30 minutes to get it started he couldn't and had to tow me home.
Turned out the rotor arm had disintegrated in the dizzy. So my lesson was not to ignore the basics.
Colin
Now all the starting circuit is checked and ok.
Replacing the coil/ign fuse and the instruments zero themselves ok on position 1but the fuse blows on cranking. Bear in mind the original breakdown occurred whilst driving, this doesn't make nuch sense.
If the ign switch is isolated and the engine is cranked by bridging across the starter motor the result is ths same - fuse blows.
Any thoughts?
Replacing the coil/ign fuse and the instruments zero themselves ok on position 1but the fuse blows on cranking. Bear in mind the original breakdown occurred whilst driving, this doesn't make nuch sense.
If the ign switch is isolated and the engine is cranked by bridging across the starter motor the result is ths same - fuse blows.
Any thoughts?
burblev8 said:
If the ign switch is isolated and the engine is cranked by bridging across the starter motor the result is ths same - fuse blows.
Not sure what the first part of this means, could you clarify?
The other symptoms might indicate that you have ballasted ignition with the non-ballasted starting circuit shorted to earth.
It Runs!
Replaced one of the ignition relays (checked and isolated just about everything else)
item no. 14 on the wiring diagram in Steve Heath's bible...
...if anyone's interested.
Do I win a prize for posting more than 90% of my own thread?
Green V8S - I think it is a ballasted system - 2 black fuse type boxes on the front chassis earth. I don't understand the principle of the ballast resistors yet but we did disconnect them to see if they were causing the problem.
>> Edited by burblev8 on Tuesday 20th December 17:56
Replaced one of the ignition relays (checked and isolated just about everything else)
item no. 14 on the wiring diagram in Steve Heath's bible...
...if anyone's interested.
Do I win a prize for posting more than 90% of my own thread?
Green V8S - I think it is a ballasted system - 2 black fuse type boxes on the front chassis earth. I don't understand the principle of the ballast resistors yet but we did disconnect them to see if they were causing the problem.
>> Edited by burblev8 on Tuesday 20th December 17:56
Still got problems.
Having replaced the relay yesterday and fired it up for the first time, it blew the fuse again after 2 miles driving normally. This time simply replacing the fuse allowed the engine to fire up again.
After a further 50 miles the fuse blew again - replaced it and off we go again for about 45 miles before it ate another. This last time replacing the fuse was not enough, it blows as soon as the ign circuit is live.
What would be causing random overloading of this circuit?
Having replaced the relay yesterday and fired it up for the first time, it blew the fuse again after 2 miles driving normally. This time simply replacing the fuse allowed the engine to fire up again.
After a further 50 miles the fuse blew again - replaced it and off we go again for about 45 miles before it ate another. This last time replacing the fuse was not enough, it blows as soon as the ign circuit is live.
What would be causing random overloading of this circuit?
GreenV8S said:
1) It sounds as if you may have a wiring fault causing an intermittant short circuit.
2) Resettable circuit breakers are your friend.
A nice pile of blown fuses are a testament to that!
Having read some of the archived threads I am now going to check the fuel pump feed/circuit and the earthing of the immobilizer as sometimes the central locking chatters to itself while I'm driving!
check the main loom on the nearside of the engine bay as , i had a problem where the loom had worked loose and fell onto the exhaust and burnt through the out covering so it was shorting on the exhaust,
i broke down on a roundabout just outside Le Mans on the way back couldn't find the fault their ,so low loaded all the way back DOH!
once i found the problem took 2 minutes to fix
i broke down on a roundabout just outside Le Mans on the way back couldn't find the fault their ,so low loaded all the way back DOH!
once i found the problem took 2 minutes to fix
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