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Help Please with ECU Fuse Blowing

Andy Checkley

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My friends 1800 K series Roadsport has started to blow ECU fuses. The first time the engine didn't restart after stalling the car. We aren't sure whether the fuse blew and caused the stall or whether the fuse blew when he tried to restart the car. Once the blown fuse had been discovered and replaced, it seemed ok. We think it may be related, although we arn't sure, but one of the connectors on the battery cut out master switch had come loose.


The fuse blew again the other day when he started the car after filling up. He checked the fuse straight away and it had again blown, so he replaced it and it blew again four or five times before the problem cleared and the car started ok without a problem.


Has anyone any ideas that may help us with this one?


Thanks in advance.

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I've seen them blowing 30 amp fuses also and this shouldn't be happening at all. 30 amps is 360 watts, which is a lot for the electronics, low tension ignition and fuel pump.


The one I've seen doing this also had a loose connection on the battery master switch.



253 BHP K-seriesteeth.gif, no gearboxbum.gifid=red>

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Mine did this too. Like Peter I can't understand where the current is being drawn. But I had to get mobile and had run out of 20amp fuses so changed to a 30amp which did the trick. Hasn't blown since. Once I cure my hot starting problem I will switch back to 20amp though.



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Thanks for the advice.


I think like all of you, I am also unhappy fixing this type of problem by simply uprating a fuse so I have just spoken to the factory and aparently they are now fitting 30amp fuses as standard to all cars leaving the factory. This is because they have discovered that the 20amp fuse is right on the limit which can lead to this type of itermitent failure. I am assured that there is no risk to the ECU by fitting the 30amp fuse.


I think I will be changing the ECU fuse in mine as well.


Thanks everyone.


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I had a similar problem last year and it always seemed to occur after the engine had been switched off for a few minutes, say the time taken to fill up with petrol.


I thought that it might have been something to do with the immobilisor as I found that switching that item on and off seemed to stop the repeated blowing of the fuse.


I got fed up with divesting seat belts, undoing side screens, getting out of car, pushing it away from petrol pumps, rummaging in boot for spare fuse and then performing contortions under the dashboard. I fitted a 20 amp circuit breaker that plugged into the fuse holder, so that it can be re-set from the driver's seat.


It hasn't gone wrong since........ confused.gif

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Pete, thats interesting. The way in which the factory explained the problem, it seems that the the 20amp fuse is right on the limit and any surges created by perhaps the starting procedure, would be just enough to blow the fuse. Perhaps the circuit breaker you have fitted is a bit more tolorent on surges than a fuse would be.


We will replace the 20amp fuse with a 30amp as per the factory recommendation and I will post back in a few months to let everyone know whether it has cured the problem.



Edited by - Andy Checkley on 15 Jun 2002 17:05:17

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