Fuel pump fire!

[doffo25]

I went to start my V12 for first time in 6months and had to jolt fuel pump to activate it(don't know if this is relevant)
Then after running engine for 5mins I ,,,,fortunately......had walk around to check all looked OK and noticed wisp of smoke from boot and rear arch paint bubbling. FIRE!
Fortunately I had an extinguisher to hand....

Any ideas how I should find cause or what should I check?

David

[christopher storey]

David : if these are a modern electronic replacement for the original points type pump, then fires, I am afraid, are not uncommon

[MarekH]

Why? How? Please explain. The opposite should be true.

In any case, the first thing that has to happen is that you have to have had a fuel leak such that combustible vapour reached the points. I would check the rubber parts for a split or crack. The old style points present a greater fire risk than a modern low current switching circuit where no arcing occurs.

kind regards
Marek

[cactusman]

May not have helped but a fuse in the supply may have cut the supply. Not sure if V12 cars have a fuse in the pump feed as standard but seems a pretty good idea to fit one...5 amp should be sufficient!

[myJagV12]

I am with Marek and the design of the pipes let's me assume they are original fit just as mine were. And though they looked quite nice from the outside they were done. I hope the damage to your car is not too bad.
BR, Tom

[MarekH]

Once you have all of that out of the car, with those pictured hoses still attached, use a track pump to pressurise the hose and try to find out where the leak might be.

Without a fuel leak, there couldn't have been a fire. The rubber hose pictured may be hard and brittle and not seal to the banjo bolt as a starting guess.

The 12v wire that looks to have shorted against the banjo bolt may be the ignition source, but it's not obvious what is cause and effect from just an internet picture.

Given that you have survived this, it'd be a reasonable guess that the fire source was always outside the fuel supply and fuel pump, as if the fire had access to what was inside the fuel line and the pump was still pumping, it'd only be a step away from the tank. It might be a good time for people with 50 year old hardened rubber hoses to start worrying.

kind regards
Marek

[christopher storey]

Marek _ all I can tell you is that when I was rebuilding my FHC, now more than a decade ago , and a regular visitor to Hutsons , they had experienced several cases of fires with electronic pumps and had the evidence to show in the shape of damaged pumps . I have never , in now more than 60 years of having cars with SU pumps , heard of a fire with the points type

[doffo25]

Damage limited to a 4" ring of blistered paint.....fortunately car due to be resprayed later this year.

The pump is original points type and inside points casing there is no damage .....in fact I reckon pump may still work. The fire was gentle burning of wire casing and the pump insulation......not sure if petrol was involved at all......

If there was a simple short couldn't that be enough to start fire......maybe with a weep from the green tube....what ever that is....?.....but then why didn't fuse blow?

One thing I do know if I had driven anywhere on road I would not now have a car as I never carry extinguisher....

BUT I WILL NOW!

[johnetype]

If there was a simple short couldn't that be enough to start fire......maybe with a weep from the green tube....what ever that is....?.....but then why didn't fuse blow?

A simple short as you describe it certainly can and has caused your fire. There is no fuse in the feed to the fuel pump.

[MarekH]

So what you are saying is that you have had a simple electrical fire with no link to the fuel pump or petrol in any way.

A short circuit will draw a high current along that wire and heat any connector and wiring along its length. The white sleeving will likely be brittle in other places and there is another connector under the dash at the A post and again behind the right hand speaker at the B post. The ignition switch will also have seen this high current.

The fusing on the etype is a hangover from the xk120 design from 1940s. The white wire is simply ignition switched brown wiring with a 35amp fuse for the white/pink circuit. The fusing protects the wiring loom but is woefully inadequate compared to modern standards.

The fuse to the fuel pump was removed when the change from a submersible pump was made.

kind regards
Marek

[doffo25]

OK that's really helpful thank you all for your replies.....Ill replace the wiring, insert a new fuse for the pump and hope for the best

regards

David

[myJagV12]

.. and please get rid of the old fuel pipes. I used 8mm but i guess 8.5 would be the right diameter ?!

[cactusman]

A salutary tale indeed....I replaced all my lines with new Cohline ethanol resistant lines last summer....and do fit a fuse! Fuses are good...they won't protect against every type of failure but a complete short and they should pop...for a fuel pump 5 amp continuous is more than sufficient. Remember that a fuse only protects the cable AFTER the fuse so find the fuel pump feed wire in the dash as put it there and not next to the pump!

[doffo25]

"Remember that a fuse only protects the cable AFTER the fuse so find the fuel pump feed wire in the dash as put it there and not next to the pump!"

Oh....thanks for that!! (I always anywhere in the circuit would work)

[cactusman]

If the short occurs in the side feeding the fuse the fuse won't fail...big short....smoke...ideally all the fuses should be as close to the electrical supply as possible....right next to the battery. In most cars this is physically inconvenient but it makes sense to add the fuse as near the battery as feasible...most wires in the e type run back to the centre dash console...the fuel pump feed will be a white wire there somewhere probably...not 100% certain about V12 cars...