Car won't start and fuse confusion

[Terry Field]

So with the sun shining I try to start the car. Switch on, fuel pump turns merrily, but when I try to start it, everything goes dead - no ignition light - nothing!

 

Checked the fuses thinking that might be the problem, but they all seem intact. However, the Brown Book says all three fuses should be 35amp, but I have a mixture of 35 and 20 amp in place.

 

So: What fuses should I have and why has everything died?

 

Many thanks

 

Terry

[Mike C]

Could be a dead battery.

 

If the battery's OK and the fuses didn't blow I'd check the engine earth, even to the extent of running a booster cable lead directly from the battery -ve terminal to a starter motor mounting bolt as a test.

[TR NIALL]

All Fuses on a 6 are normally 35amp.

[TR5tar]

I'm a long way off being being an expert Terry, but if you are sure the battery is good and there's no issue with fuses, then I'd check the earth like Mike said. I had a similar issue with my daily driver a few years back and on that occasion it was a corroded earth strap.

 

Hope it's an easy fix for you.

 

Cheers, Darren

[Geko]

if the fuel pump turns on ignition then power goes off on cranking then it's not the battery itself but rather the connectors/leads to battery terminals or earth to chassis or +ve to solenoid /starter.

[Terry Field]

Thanks Chaps. I'll have a dig around with earthing. And some uprated fuses!

 

Terry

[Steves_TR6]

It could be the battery is dying but can produce just enough power to run the pump, but not enough when the starter engages.

 

The original starters can take a LOT of current, so any weakness in the battery will be exposed.

My last tr6 would flatten its healthy battery in a few starting attempts, new starter and it would crank for ages and not flatten the battery.

 

Current car with reconditioned original starter also kind to the battery.

 

A metodical testing approach is called for , or replace the battery and starter !

 

Steve

[Alfrom]

Given that all lights go out when attempting to start, another tack could be to check the ignition switch . . . . . . .

[ChrisP]

Check that your battery terminals are clean and the clamps are tight on the posts, they may look ok but thats the same as happened to me before.

 

Chris

[Mike Collins]

There is a short wiring loom from the switch to three? bullet connectors above the column, very prone to corrosion and poor contact.

 

Mike.

[Peter Cobbold]

Give the starter solenoid on top of the starter a thump.I carried a stick for the job as it only happened sometimes. Eventually a clean-up of the terminals cured it.

[Will]

Terry,

Is that Wellington NZ? If so, are your available fuse ratings the same as the old Lucas brand? You may need to be careful of “upgrading your fuses”.

Don’t want to get into too much detail cos I am not a sparky, but I do respect what what Dan Master’s has to say in his book - Triumph TR250 - TR6 Electrical Maintenance Handbook. Really useful to owners.

The difference between North American and Lucas fuses comes down to time/current characteristics.

It seems that a Lucas 35 amp fuse may be 17 amp current rated which may take a while to blow at 35, whereas the 35 amp NA fuse will handle current very near 35 amp indefinitely and would take a lot more than 35 amp to blow, which may not be good for the circuits.

Masters recommends the following North America Fuses, which I have been using without issues:

10 amp red fuse.

15 amp purple

20 amp green.

Don’t know what type of fuses you have but basically they should be just over the mamimum current draw for all loads fed by a given fuse.

[AarhusTr6]

Hi

 

Is this book, Dan Master’s - Triumph TR250 - TR6 Electrical Maintenance Handbook only available from Moss and is it recommended?

Edited April 21, 2018 by AarhusTr6

[Will]

The Dam Masters book is the go to for many TR250-6 owners in America and Canada. As you say, Moss carries it plus TRF and electrics specialists.

It’s very detailed by model year and covers all the electrical components with trouble shooting and repair or modification instructions with schematics

[Terry Field]

Finally got out to the garage again.

 

Removed, cleaned and replaced (with a touch of Copperslip), battery earth to chassis, chassis to engine, and both battery terminals. Have not checked the +ve to the solenoid simply because of the difficulty of getting to it, but it 'looks' clean enough.

 

Fuses now all new 35amp, and battery reading 12.6 across the termimals.

 

But still no light on the dash, no fuel pump, nothing.

 

I'll try again with the solenoid, but apart from that, where to go next?

 

Thanks

 

Terry

[RogerH]

Hi Terry,

have you got a multimeter and know how to use it. Have you got a decent wiring diagram?

http://www.advanceautowire.com/tr2506.pdf for US cars but gives an idea.

 

Somebody previously mentioned trying to start it with the headlights on - and seeing what the lights do.

They should dim but not extinguish. If they do then the battery is either very flat or a dead cell.

 

Is the multiway connector that connects the battery/starter to the car clean and working (assuming you have one).

Does the horn work and other non-Ig switch circuits.

 

Roger

[RobH]

So the symptoms have changed (?) as in your first post you said the fuel pump ran - but now it apparently doesn't so if that is true perhaps due to something you have done.

 

I'm not sure about using copper-grease on electrical connections - the grease itself is not electrically conducting and its not really intended for electrical use (not enough copper in it for the particles to touch each other consistently and the grease/thickener film will reduce the contact area of the connection). I would clean that off and ensure there is good dry metal-to-metal contact everywhere. If you want to coat the outside of the connections once fitted and tightened, to stop external corrosion, then vaseline is fine and less messy than copper grease.

 

Can you hear the solenoid click when you turn the key ?

[Mike C]

Given that all lights go out when attempting to start, another tack could be to check the ignition switch . . . . . . .

+1 for the switch.

[Terry Field]

Rob, nothing has changed. When I very first tried to start it a few weeks ago the petrol pump kicked in properly, but as I turned the key further to start the engine, everything went dead.

 

It is still absolutely dead. No ignition, no tell tale clunks, no headlights, indicators, washers, horn, wipers, nothing apart from the light in the cubby hole! I take your point about the grease though - thanks.

 

Hi Roger,

 

my electrical skills in the automotive dept are very limited! And I wouldn’t know where to begin on something like this, which I appreciate is a bit of a problem!

 

Cheers

 

Terry

[RobH]

If the light in the glovebox works that is a start as it shows there is some degree of life in the battery and that it can at least supply a very small load. The easiest thing to do first would be to swap to another battery if you have one available, or jump leads from another car would do (make sure of getting the polarity right) just to show that circuits are actually working. If everything functions then, you have a dead battery despite the open-circuit volts being reasonable. If still nothing works there is obviously a connection problem somewhere.

[Terry Field]

Just been out again, this time into a dark garage and noticed that the headlights are working a little. Not a lot more than a bright glow, which fades pretty quickly after switching them on. Does this indicate a duff battery, despite the reading across the terminals?

 

Terry

[Terry Field]

Sorry Rob, I didn’t read your post first - I think you have answered my points.

 

Terry

[peejay4A]

What’s the voltage across the battery terminals with the lights on?

[RobH]

Just been out again, this time into a dark garage and noticed that the headlights are working a little. Not a lot more than a bright glow, which fades pretty quickly after switching them on. Does this indicate a duff battery, despite the reading across the terminals?

 

Terry

That's pretty conclusive Terry. Dead battery.

 

The open-circuit voltage doesn't really mean a lot. Its the voltage on-load that counts as Pete is asking. A battery which has gone high impedance can still have a reasonable o/c voltage but cannot supply a load and your headlamps show just that happening.

Edited April 30, 2018 by RobH

[Mike C]

Are you in a position to try starting with another battery and jumper leads?