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mcvicar 20 December 2009 05:08 PM

Electrical problem please help
 
Hello allhttp://www.surreyscoobies.co.uk/foru...smilies/hi.gif.
Yet another chapter to this cars line of problemshttp://www.surreyscoobies.co.uk/foru...s/censored.gif.
Car will run fine but as soon as you put your foot down (put on boost) the main fuse will blow. The car starts to judder, then pop. Its the fuse box in engine bay, centre of the three 45amp fuses. If you drive the car like an old granny it seem's to be ok in the main, although it did blow once at low speed. No electrical componants have been changed recently and I have checked all round the engine for loose/broken or chafed wires. Any help would be appreciated, as I have only just got this car back on the road and its sending me round the bendhttp://www.surreyscoobies.co.uk/foru...ilies/loco.gif.
Cheers
Del

jimes 20 December 2009 05:24 PM

Mine melted the loom across the front by rad as the headers were so close. Check earth strap to engine?

mcvicar 20 December 2009 05:48 PM


Originally Posted by jimes (Post 9110009)
Mine melted the loom across the front by rad as the headers were so close. Check earth strap to engine?

Thanks for the reply. Checked the earth straps and even fitted another with no joy.

Jolly Green Monster 20 December 2009 08:47 PM

I would say it has to be ground related.
Try jump lead from neg bat to block?

Jolly Green Monster 20 December 2009 08:50 PM

Also check the voltage at bat terminals and alternator.
The invertor may have gone and you are seeing higher voltage or current?

mcvicar 20 December 2009 09:15 PM


Originally Posted by Jolly Green Monster (Post 9110385)
Also check the voltage at bat terminals and alternator.
The invertor may have gone and you are seeing higher voltage or current?

Hello Simon, hope you are well. Have run a seperate earth lead from battery to block and still the same. Voltage on the battery terminals are 13.7v off and 14.1 running.

jimes 20 December 2009 09:33 PM

if its blowing a 45a thats quite a short somewhere. Unfortunately it may be a case of stripping off some of the black tape on parts of loom and looking for short, had to do this on a granvia last week but got lucky and found it by the diesel pump almost straight away. Did have a wiring diagram on disc but cant find it, seem to remember one of those fuses being the fuel pump. Strange that it does it under load but weird things can happen with wiring faults!

jimes 20 December 2009 09:57 PM

think the other 2 are for the rad fans so maybe check there......

mcvicar 20 December 2009 10:16 PM


Originally Posted by jimes (Post 9110576)
think the other 2 are for the rad fans so maybe check there......

Ok will do. Thanks for the feedback:thumb:

Jolly Green Monster 21 December 2009 04:08 PM

13.7 with engine off!!!!

mcvicar 21 December 2009 10:46 PM


Originally Posted by Jolly Green Monster (Post 9111598)
13.7 with engine off!!!!

Yep checked it several times. Just wondering if it may be the alternator, over charging under load causing the fuse to pop and putting to much juice in the battery?

jimes 21 December 2009 11:42 PM

put a meter on it whilst running and see how high it goes......

Jolly Green Monster 22 December 2009 12:12 AM

13.7v with engine off is too high.. you have issue with alternator I suspect..

mcvicar 22 December 2009 08:19 PM


Originally Posted by jimes (Post 9112437)
put a meter on it whilst running and see how high it goes......

Yeah did that fella and the highest was 14.1v. But thats static. Will extend the wires from the multi meter to inside the car and take it for a drive and see what happens.

mcvicar 22 December 2009 08:22 PM


Originally Posted by Jolly Green Monster (Post 9112456)
13.7v with engine off is too high.. you have issue with alternator I suspect..

Me thinks this too!!. Will try the above and see what happens

Brett_555_Sti 22 December 2009 10:15 PM

Have you identified exactly what the fuse controls ie:which wires and circuits are associated with the fuse?

I somehow doubt the battery or the altenator is at fault from what i have read, so the following is just basic checks as you have done.

Have you checked the bolted connector/terminal under the fuse box in the engine bay ie: clean and dry?

Although the altenator is charging, have you checked that the altenator belt is tight?

If you test the voltage of the battery immediately after turning the engine off, the voltage in the battery will be as high as 13.7V very easily, If you want to get a true reading from the battery do it in the morning before you start the car, as the battery will have had a couple of hours to stabilise.

The trip out(maximum voltage) for the altenator will be 14.4V but no higher than that, but as you say check it while driving as you might be getting a voltage spike.

You also need to check what the amperage is at maximum charge voltage with and without the loads on (lights, fans,etc). You will need an amp guage to test this, which you most likely wont have.

mcvicar 23 December 2009 07:40 PM


Originally Posted by Brett_555_Sti (Post 9113820)
Have you identified exactly what the fuse controls ie:which wires and circuits are associated with the fuse?

I somehow doubt the battery or the altenator is at fault from what i have read, so the following is just basic checks as you have done.

Have you checked the bolted connector/terminal under the fuse box in the engine bay ie: clean and dry?

Although the altenator is charging, have you checked that the altenator belt is tight?

If you test the voltage of the battery immediately after turning the engine off, the voltage in the battery will be as high as 13.7V very easily, If you want to get a true reading from the battery do it in the morning before you start the car, as the battery will have had a couple of hours to stabilise.

The trip out(maximum voltage) for the altenator will be 14.4V but no higher than that, but as you say check it while driving as you might be getting a voltage spike.

You also need to check what the amperage is at maximum charge voltage with and without the loads on (lights, fans,etc). You will need an amp guage to test this, which you most likely wont have.

Can't seem to find what the fuse is for entirely as the fuse lid and the workshop manual on CD just say that the 3, 45amp fuses are SBF?
Checked wires going to fuse box and all seem ok.

HOWEVER A CONFESSION FROM MY SON!!!!!!!!!!!!!!!!!!!!!
He used my car while I was at work to jump start his mates car. They connected both leads to the other car and then when connecting to mine, which was running apparenly, they put them on the wrong terminals.
Apart from the alternator is the anything else in the charging circuit, that controls the amount of power output??? and what other damage is possible?
Cheers
Del

Jolly Green Monster 23 December 2009 08:55 PM

Reg in alternator

mcvicar 23 December 2009 09:25 PM


Originally Posted by Jolly Green Monster (Post 9115352)
Reg in alternator

Ok thanks Simon, will put another one on which will hopefully cure it.
Thanks to everyone for their help and advice.:thumb:
Cheers
Del

mcvicar 26 December 2009 07:50 PM

Still doing it
 
Changed alternator today for a known good one and the problem persists.
Drove the car for around 5 miles gently with no problem, as soon as i put my foot down (in second about half throttle) pop fuse gone again.
Any mor ideas?

Turbotits 26 December 2009 08:23 PM

I suspect a main live has melted> posibly the starter cable> and as your accelerating the engine rock is causing it to short to earth.

I suspect accelerating hard in any gear will cause this.

Check all the main live feeds to starter fuse box etc< check theres nothing bare and nothing able to eath out.

jimes 27 December 2009 12:24 AM

help, my car is possesed - NASIOC

mcvicar 27 December 2009 10:37 AM


Originally Posted by jimes (Post 9119024)

Thanks Jimes, looks like i'll have to do a bit more hunting over the wiring system. Electrics not my thing. Happy days!!!

jimes 27 December 2009 12:47 PM

shame your not a bit closer, love finding electrical faults! try moving the loom around where you can to simulate engine moving to see if you can get the fuse to blow which would narrow down a problem in the loom. it goes right across the front from fuse box under bonnet to drivers side inner wing then into car. When mine melted at front due to headers it did some weird and wonderful things! does it do it everytime you boot it? does it do it if you rev high but slowly if you see what i mean?

jimes 28 December 2009 06:44 PM

any joy?

mcvicar 29 December 2009 08:16 PM


Originally Posted by jimes (Post 9121423)
any joy?

Been all over the car. checked wires, none bare/earthing out that I can see. With engine running at idle car is fine. Moving all wires fuse still intact. Take revs up to around 5.5-6k still no probs. Back at idle, handbrake on, select first gear and rock the engine, fuse still intact. As soon as I drive it and boot it pop it goes. Drive normal keeping under 3k and shes fine.
If I didn't know better I would have thought that there was a camera filming me somewhere as this is getting rediculous.:brickwall

jimes 30 December 2009 12:15 AM

Guy with a small hand called Jeremy?! That is weird. Try removing fuse 12 or whatever the fuse was that's fed by the 45a one. Would at least narrow it down a bit

merlin24 30 December 2009 11:07 AM

Fault could be on the Boost Control side of things - pressure exchange/wastegate control solonoids ??

Mick

mcvicar 30 December 2009 06:36 PM


Originally Posted by merlin24 (Post 9124801)
Fault could be on the Boost Control side of things - pressure exchange/wastegate control solonoids ??

Mick

Was wondering if this may be a possibility. Strange how it only pops on boost. Any clues on how to check them out without changing them?

mcvicar 30 December 2009 06:37 PM


Originally Posted by jimes (Post 9124417)
Guy with a small hand called Jeremy?! That is weird. Try removing fuse 12 or whatever the fuse was that's fed by the 45a one. Would at least narrow it down a bit

Will give it a go. Cheers


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