Gremlin in the electrics !!!
Discussion
I have owned a few TVR's but today I encountered something new.
I have been trying to get my 4.2 Cerbera started for a while, this resulted in the car turning over but not firing into life. I have checked most things but a week ago the igninition would come on but when I press the black button nothing else. The starter motor wouldn't turn over. I took a live feed to the starter and it works, I have checked both 100amp fuses and all the other problems I've read in previous posts.
Today I noticed a 20amp fuse had blown. I removed the old fuse and put a new one in as I did this the car started to turn over, the shock of this made me smack my head on the boot lid and drop the fuse into the boot.
I tried inserting the fuse again and as soon as it made contact the starter motor turned over???
The ignition was NOT on.
When I looked in the handbook to check what the fuse does it was labelled as No 13 "not used"
Out of 21 fuses this is the only one not in use.
I removed the starter solenoid relay and the Auxiliary igninition relay then put the fuse back in No 13 and the starter motor fired up again !?
Has anyone encountered this?
Any help would be grateful.
Thanks
I have been trying to get my 4.2 Cerbera started for a while, this resulted in the car turning over but not firing into life. I have checked most things but a week ago the igninition would come on but when I press the black button nothing else. The starter motor wouldn't turn over. I took a live feed to the starter and it works, I have checked both 100amp fuses and all the other problems I've read in previous posts.
Today I noticed a 20amp fuse had blown. I removed the old fuse and put a new one in as I did this the car started to turn over, the shock of this made me smack my head on the boot lid and drop the fuse into the boot.
I tried inserting the fuse again and as soon as it made contact the starter motor turned over???
The ignition was NOT on.
When I looked in the handbook to check what the fuse does it was labelled as No 13 "not used"
Out of 21 fuses this is the only one not in use.
I removed the starter solenoid relay and the Auxiliary igninition relay then put the fuse back in No 13 and the starter motor fired up again !?
Has anyone encountered this?
Any help would be grateful.
Thanks
Not sure which manual you're looking at but in the below Fuse 13 is described as being for the Starter & Driver's Door Lock.
http://tvr-cerbera.co.uk/OwnersHandbook/Cerbera-ow...
Maybe you have the later fuseboard design?
If putting the fuse in turns the starter over straight away theres either a wiring issue or possibly a stuck relay/other fault in the ignition control box. The ignition control box on top of the fuel tank has a permanent live feed from the battery and provides 12v to the starter motor solenoid through the immobiliser. As its a permanent live it wouldnt need the ignition to be on for the control box to have power.
Does it still turn over as soon as fuse 13 is inserted when the immobiliser is armed? If it does you have a problem somewhere forward of the immobiliser.
http://tvr-cerbera.co.uk/OwnersHandbook/Cerbera-ow...
Maybe you have the later fuseboard design?
If putting the fuse in turns the starter over straight away theres either a wiring issue or possibly a stuck relay/other fault in the ignition control box. The ignition control box on top of the fuel tank has a permanent live feed from the battery and provides 12v to the starter motor solenoid through the immobiliser. As its a permanent live it wouldnt need the ignition to be on for the control box to have power.
Does it still turn over as soon as fuse 13 is inserted when the immobiliser is armed? If it does you have a problem somewhere forward of the immobiliser.
Is your car a particularly early one ?
I remember investigating an electrical fault when I worked at HHC .. was playing about with fuses in the fusebox and the starter motor started up .. thing is the car was in reverse gear at the time and started pushing me back towards the wall .. fortunately I hadn't really managed to push the fuse in properly and it pulled out really easily. Could have been nasty ..
Wonder if there is a particular version of fusebox and wiring configuration that affects only a handful of cars. It's not exactly a common occurance, but it's something I have experienced .. May be coincidence but then again ...
I remember investigating an electrical fault when I worked at HHC .. was playing about with fuses in the fusebox and the starter motor started up .. thing is the car was in reverse gear at the time and started pushing me back towards the wall .. fortunately I hadn't really managed to push the fuse in properly and it pulled out really easily. Could have been nasty ..
Wonder if there is a particular version of fusebox and wiring configuration that affects only a handful of cars. It's not exactly a common occurance, but it's something I have experienced .. May be coincidence but then again ...
The handbook I'm using is the one provided from the factory. The fuse diagram is in the handbook with all the service history in.
I had put in a new starter solenoid relay.
The igninition is off when the fuse is inserted and it still turns over ?!
Immobiliser is disabled.
I had put in a new starter solenoid relay.
The igninition is off when the fuse is inserted and it still turns over ?!
Immobiliser is disabled.
CerbWill said:
Not sure which manual you're looking at but in the below Fuse 13 is described as being for the Starter & Driver's Door Lock.
http://tvr-cerbera.co.uk/OwnersHandbook/Cerbera-ow...
Maybe you have the later fuseboard design?
If putting the fuse in turns the starter over straight away theres either a wiring issue or possibly a stuck relay/other fault in the ignition control box. The ignition control box on top of the fuel tank has a permanent live feed from the battery and provides 12v to the starter motor solenoid through the immobiliser. As its a permanent live it wouldnt need the ignition to be on for the control box to have power.
Does it still turn over as soon as fuse 13 is inserted when the immobiliser is armed? If it does you have a problem somewhere forward of the immobiliser.
http://tvr-cerbera.co.uk/OwnersHandbook/Cerbera-ow...
Maybe you have the later fuseboard design?
If putting the fuse in turns the starter over straight away theres either a wiring issue or possibly a stuck relay/other fault in the ignition control box. The ignition control box on top of the fuel tank has a permanent live feed from the battery and provides 12v to the starter motor solenoid through the immobiliser. As its a permanent live it wouldnt need the ignition to be on for the control box to have power.
Does it still turn over as soon as fuse 13 is inserted when the immobiliser is armed? If it does you have a problem somewhere forward of the immobiliser.
It's a 1997 .
The car was originally purchased from HHC which is a bit spooky and serviced there until 2002.
Maybe this is the car that pushed you into the wall !
The car was originally purchased from HHC which is a bit spooky and serviced there until 2002.
Maybe this is the car that pushed you into the wall !
spitfire4v8 said:
Is your car a particularly early one ?
I remember investigating an electrical fault when I worked at HHC .. was playing about with fuses in the fusebox and the starter motor started up .. thing is the car was in reverse gear at the time and started pushing me back towards the wall .. fortunately I hadn't really managed to push the fuse in properly and it pulled out really easily. Could have been nasty ..
Wonder if there is a particular version of fusebox and wiring configuration that affects only a handful of cars. It's not exactly a common occurance, but it's something I have experienced .. May be coincidence but then again ...
I remember investigating an electrical fault when I worked at HHC .. was playing about with fuses in the fusebox and the starter motor started up .. thing is the car was in reverse gear at the time and started pushing me back towards the wall .. fortunately I hadn't really managed to push the fuse in properly and it pulled out really easily. Could have been nasty ..
Wonder if there is a particular version of fusebox and wiring configuration that affects only a handful of cars. It's not exactly a common occurance, but it's something I have experienced .. May be coincidence but then again ...
Mines a 1996 and its not don that. I dont think 1997 counts as particularly early but Joolz will have to confirm.
Does it still turn over when Fuse 13 is inserted when the immobiliser is enabled?
Unplug the ignition control box in the boot with the immobiliser disabled, insert Fuse 13 and see what happens.
Does it still turn over when Fuse 13 is inserted when the immobiliser is enabled?
Unplug the ignition control box in the boot with the immobiliser disabled, insert Fuse 13 and see what happens.
nibor said:
It's a 1997 .
The car was originally purchased from HHC which is a bit spooky and serviced there until 2002.
Maybe this is the car that pushed you into the wall !
The car was originally purchased from HHC which is a bit spooky and serviced there until 2002.
Maybe this is the car that pushed you into the wall !
spitfire4v8 said:
Is your car a particularly early one ?
I remember investigating an electrical fault when I worked at HHC .. was playing about with fuses in the fusebox and the starter motor started up .. thing is the car was in reverse gear at the time and started pushing me back towards the wall .. fortunately I hadn't really managed to push the fuse in properly and it pulled out really easily. Could have been nasty ..
Wonder if there is a particular version of fusebox and wiring configuration that affects only a handful of cars. It's not exactly a common occurance, but it's something I have experienced .. May be coincidence but then again ...
I remember investigating an electrical fault when I worked at HHC .. was playing about with fuses in the fusebox and the starter motor started up .. thing is the car was in reverse gear at the time and started pushing me back towards the wall .. fortunately I hadn't really managed to push the fuse in properly and it pulled out really easily. Could have been nasty ..
Wonder if there is a particular version of fusebox and wiring configuration that affects only a handful of cars. It's not exactly a common occurance, but it's something I have experienced .. May be coincidence but then again ...
1997 isn't that early .. first customer cerbs were late 95 of course, and development cars were 94.
However .. whilst at HHC we also had a customer come in with some very light front end damage on his cerb .. he claimed the car started itself up when he pressed the fob to unlock the car and drove itself into the parked car in front.
At the time I think we all dismissed the story as the guy trying to save his embarrassment but with hindsight maybe there was more truth to his story than first given credit for ...
However .. whilst at HHC we also had a customer come in with some very light front end damage on his cerb .. he claimed the car started itself up when he pressed the fob to unlock the car and drove itself into the parked car in front.
At the time I think we all dismissed the story as the guy trying to save his embarrassment but with hindsight maybe there was more truth to his story than first given credit for ...
CerbWill said:
Mines a 1996 and its not don that. I dont think 1997 counts as particularly early but Joolz will have to confirm.
Does it still turn over when Fuse 13 is inserted when the immobiliser is enabled?
Unplug the ignition control box in the boot with the immobiliser disabled, insert Fuse 13 and see what happens.
Would try what Cerbwill has suggested there, a lot of the control circuitry is switched via an active low signal to zero volts rather than souced via an active high signal to plus 12 volts so if a cable or wire is chaffed down to the metalwork or chassis the circuit will activate and behave in a random and unpredictable way, if it was switched on the positive side and a short circuit developed the worst that could happen is the fuse would blow.Does it still turn over when Fuse 13 is inserted when the immobiliser is enabled?
Unplug the ignition control box in the boot with the immobiliser disabled, insert Fuse 13 and see what happens.
nibor said:
It's a 1997 .
The car was originally purchased from HHC which is a bit spooky and serviced there until 2002.
Maybe this is the car that pushed you into the wall !
The car was originally purchased from HHC which is a bit spooky and serviced there until 2002.
Maybe this is the car that pushed you into the wall !
spitfire4v8 said:
Is your car a particularly early one ?
I remember investigating an electrical fault when I worked at HHC .. was playing about with fuses in the fusebox and the starter motor started up .. thing is the car was in reverse gear at the time and started pushing me back towards the wall .. fortunately I hadn't really managed to push the fuse in properly and it pulled out really easily. Could have been nasty ..
Wonder if there is a particular version of fusebox and wiring configuration that affects only a handful of cars. It's not exactly a common occurance, but it's something I have experienced .. May be coincidence but then again ...
I remember investigating an electrical fault when I worked at HHC .. was playing about with fuses in the fusebox and the starter motor started up .. thing is the car was in reverse gear at the time and started pushing me back towards the wall .. fortunately I hadn't really managed to push the fuse in properly and it pulled out really easily. Could have been nasty ..
Wonder if there is a particular version of fusebox and wiring configuration that affects only a handful of cars. It's not exactly a common occurance, but it's something I have experienced .. May be coincidence but then again ...
It is possible a start relay has latched in the control box and is reluctant to unlatch, can you get the top off and have a look in there?
Post up later with an update and good luck !
My 96 car, has fuse 13 (20A) for Starter, Driver’s door lock.
Has anyone worked out the circuit ?
Looks like starter button to ignition control ‘in’
Ignition control ‘out’ to immobiliser ‘in’
Immobiliser ‘out’ to starter motor ?
So where would that 12v supply from fuse 13 be going ?
And what else have I missed ?
Edit.... Immobiliser shows a wire to the fuse box and and wire to the ignition control. I haven’t a clue how that’s working.
But I too agree, go with Cerbwills suggestion.
I’m guessing either the ignition control unit is sending out a permanent positive to fire the starter motor.
Has anyone worked out the circuit ?
Looks like starter button to ignition control ‘in’
Ignition control ‘out’ to immobiliser ‘in’
Immobiliser ‘out’ to starter motor ?
So where would that 12v supply from fuse 13 be going ?
And what else have I missed ?
Edit.... Immobiliser shows a wire to the fuse box and and wire to the ignition control. I haven’t a clue how that’s working.
But I too agree, go with Cerbwills suggestion.
I’m guessing either the ignition control unit is sending out a permanent positive to fire the starter motor.
Edited by RUSSELLM on Tuesday 5th May 18:44
Edited by RUSSELLM on Tuesday 5th May 18:50
RUSSELLM said:
nibor said:
I removed the starter solenoid relay
Out of interest, where did you find that ?Edited by RUSSELLM on Tuesday 5th May 19:00
RUSSELLM said:
My 96 car, has fuse 13 (20A) for Starter, Driver’s door lock.
Has anyone worked out the circuit ?
Looks like starter button to ignition control ‘in’
Ignition control ‘out’ to immobiliser ‘in’
Immobiliser ‘out’ to starter motor ?
So where would that 12v supply from fuse 13 be going ?
And what else have I missed ?
Edit.... Immobiliser shows a wire to the fuse box and and wire to the ignition control. I haven’t a clue how that’s working.
But I too agree, go with Cerbwills suggestion.
I’m guessing either the ignition control unit is sending out a permanent positive to fire the starter motor.
The wiring manual states that the immobiliser is connected to the fuse board and a fuse board output goes to the starter motor. So it goes start button>ignition control box>immobiliser>fuse box> starter solenoid. The fault must be before the fuse board. If it was after it would Crank regardless of the fuse being blown. So its a wiring fault (chafed through etc), the immobiliser, or the ignition control box. As the OP states he's bypassed the immobiliser its wiring or the control box. I'd check the easy thing first and remove the control box.Has anyone worked out the circuit ?
Looks like starter button to ignition control ‘in’
Ignition control ‘out’ to immobiliser ‘in’
Immobiliser ‘out’ to starter motor ?
So where would that 12v supply from fuse 13 be going ?
And what else have I missed ?
Edit.... Immobiliser shows a wire to the fuse box and and wire to the ignition control. I haven’t a clue how that’s working.
But I too agree, go with Cerbwills suggestion.
I’m guessing either the ignition control unit is sending out a permanent positive to fire the starter motor.
Edited by RUSSELLM on Tuesday 5th May 18:44
Edited by RUSSELLM on Tuesday 5th May 18:50
What do you reckon it connects to, in the fuse box though ?
We know that fuse 13 states it does starter and driver’s door lock. So it can’t be wired to that, otherwise you’d press the start button and the driver’s door would fire
So I presume the wires out to “fuse board” are a starter relay in the fuse board ?
Edit.... Even though it doesn’t state it in my owners manual, I seem to recall mine might have a starter relay in the fuse board. I had a none start issue, and seem to recall bridging a relay.
It would seem odd though, putting the relay at the opposite end of the car to where the starter motor’s located.
We know that fuse 13 states it does starter and driver’s door lock. So it can’t be wired to that, otherwise you’d press the start button and the driver’s door would fire
So I presume the wires out to “fuse board” are a starter relay in the fuse board ?
Edit.... Even though it doesn’t state it in my owners manual, I seem to recall mine might have a starter relay in the fuse board. I had a none start issue, and seem to recall bridging a relay.
It would seem odd though, putting the relay at the opposite end of the car to where the starter motor’s located.
Edited by RUSSELLM on Tuesday 5th May 20:22
Edited by RUSSELLM on Tuesday 5th May 20:23
It's about standard for TVR though. The wiring is, in many cases, idiotic. I have no idea why they decided to put the fuse board in the boot and route all (internal, I know the starter motor is powered directly from the battery) power from the battery to the back of the car to then go (in most cases and in all cases of significant power draw) back to the front of the car. Jody Wiles spent ages working out the internal workings of the fuse board to convert a Cerb to the later type, and massively simplify the headlight power arrangement. The multi way plug configuration in the published manuals seems to be wrong.
Getting back to this problem maybe there is a relay. Or maybe Fuse 13 has bugger all to do with the driver's door.
Getting back to this problem maybe there is a relay. Or maybe Fuse 13 has bugger all to do with the driver's door.
CerbWill said:
It's about standard for TVR though. The wiring is, in many cases, idiotic. I have no idea why they decided to put the fuse board in the boot and route all (internal, I know the starter motor is powered directly from the battery) power from the battery to the back of the car to then go (in most cases and in all cases of significant power draw) back to the front of the car. Jody Wiles spent ages working out the internal workings of the fuse board to convert a Cerb to the later type, and massively simplify the headlight power arrangement. The multi way plug configuration in the published manuals seems to be wrong.
Getting back to this problem maybe there is a relay. Or maybe Fuse 13 has bugger all to do with the driver's door.
Cerbwill, looks like you and Russellm have the same type of fuse and relay board, if you can remove fuse 13 and then test by trying the starter button or operating the drivers door lock with the immobiliser enabled, hopefully it wont make a bid for freedom (or start) and this will prove your owners handbook is correct.Getting back to this problem maybe there is a relay. Or maybe Fuse 13 has bugger all to do with the driver's door.
Nibors fuse and relay board looks like a different version and fuse 13 is best left out at the moment as per the owners manual as it is somehow back feeding the starter circuit.
Out of interest what rated fuse did you put in and did it blow?
I would also try to take a voltage reading at the new starter relay you fitted or at the starter solenoid coil itself whilst pressing the start button with the immobiliser enabled, if no voltage present its back to the ignition control box or the immobiliser itself.
Good luck and post up later if you have any more info
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