Cutting out after driving for about a minute.

P

phil

New Member
Hi, my newly aquired v8 cuts out after about a minutes driving. Leave to cool for five mins and it fires up like nothing has happenned.
I have tonight replaced the coil, rebuilt the carbs replaced the fuel.
The blokes who bought it after a 10 year lay up have fitted an electric fuel pump to replace the mechanical one which apparrantly was leaking fuel into the engine. Has anyone any ideas? I have put about 20 litres of fuel in, is this enough?
It seems to run better than it did.. I haven't balanced the carbs yet or set them up correctly as I need to get it to someone who cab but I would have thought it should still run without cutting out??
Could it be the electric pump isn't up to it? It seems to run faultlessly then suddenly it falters out.
Please help, I'm going mad. The points and cap look good.
 
Thinking about it, maybe the electric pump isn't man enough a mechanical one spins faster according to engine speed whereas an electric one spins at one speed.
Are mechanical pumps available from motor factors?
 
could be faulty ignition componants such as the points cap, these are notorious for intermittant behaviour also the coil.

Graeme
 
Hello Phil,

Is this the first time the car has run for some time? Water in the fuel will bring your engine to a halt, so put some methylated spirits in the tank, a good cupfull or two will remove any water present.

You won't be able to buy a new mechanical fuel pump these days, in fact they have been as rare as hen's teeth for many many years. An electric fuel pump delivering fuel in the correct pressure range will have no problem in maintaining the supply to your engine.

When your engine cuts out, has the electric fuel pump already stopped or was it still running? What speed are you doing when it cuts out? Are you braking at this time?

Ron.
 
First observatiion is to try to do your fault finding in the moment immediately after the engine has cut out. I guess first up is to try to eliminate your concern about the pump. Why not have a spanner handy so that you can crack a fuel line joint and verify whether the pump then floods you in petrol? They are supposed to stop ticking when the line pressure is established, so won't do so with the engine stopped - you need to open the line for them to start up again.

Assuming this is OK, the search becomes more general. The only remaining fuel issue would be if the carbs are set really rich, so that as the engine comes up to temperature it then chokes. More likely is an electrical malady. Was the coil a new one? And was it a type suitable to use with a ballast resistor ie it is OK with about 7V rather than 12? The P6 has a ballasted set up which over-volts the coil (ie to 12V) for guaranteed starting whilst the starter motor is cranking and then reverts the supply to going via a ballast resistor to drop the volts in normal running. If you had a standard coil you'd get a very weak spark. Next up would be a duff capacitor in the distributor - I presume it is still on points? Your description would definitely match a capacitor on its way home. Likewise a plug.

Will that do for a couple of ideas to be going on with?

Chris
 
Hi, there doesnt seem to be much of a pattern really. Totally random. The fuel pump fitted is a small in line one that clicks in operation. It appears to click continually. I was wondering if it might be too small. I have already replaced the coil. The coil is a 12v one. It is new. The pump doesn't stop clicking with engine off. When you say duff capacitor, do you mean condensor?
 
Appreciate the coil is 12V Phil, but is it ballasted or ordinary as per above.

Yep I did mean condensor - there have been some duff batches around, so even if new it could be the problem.

Chris
 
The one I've fitted was ordered for Maxi, I honestly don't know. Is there something obvious that I can see on it?

What fuel pressure does the electric pump need to deliver?
 
Hello Phil

Fuel pressure is from memory 3 to 5psi. Is the fuel pump made by Facet?

The primary resistance of your coil will tell you whether or not it is correct. It needs to be in the range of 1.2 to 1.5 ohms. On the coil it should also say that it needs to be used with a ballast resistor. What brand of coil is it?

To be honest I doubt the fuel pump is the problem in terms of not meeting the necessary fuel delivery requirement. What rpm is the engine doing when it cuts out?

Ron.
 
Unlikely that your pump is too small though it could be faulty, my electric pump led me a merry dance for over a year!! I would start as I said earlier with the cap (opps I should have said capacitor) however the smartest move is to just go straight to electronic ignition the fuel savings alone will let it pay for itself within a year or two and in doing so you have eliminated many future potential faults and much hair greying strong words and skinned knuckles. it could well be a water contamination problem or worse crap clogging the pickup filter in the tank, it may pay to visually inspect the fuel filter in the engine bay and see if there is moisture in that.

graeme
 
Cheers guys. Another thought, blockedtank breather? How likely is that?? Making the tank vacuum? When I take the cap off to add not fuel and it starts? I'm away from the car at the mo so cannot do any checks til tonight? Thinking of ordering points, cap arm and condensor. Anyone know what type I need as the factors look at me like I'm stupid when I ask for them as apparrantly there are loads of different types.
 
Phil, seriously look at an electronic ignition upgrade, there is a ton of info on here, you will probably find the majority of P6 owners on here have converted or are in the process of going down that track.

Graeme
 
I've rang them. I need to check some thing about my base plate in the dizzy. Unless anyone knows the answer to speed things up? 1971 j reg.
 
phil said:
I've rang them. I need to check some thing about my base plate in the dizzy. Unless anyone knows the answer to speed things up? 1971 j reg.
Click to expand...

Hi Phil,

Your distributor will (more than likely) be a Lucas 35D8. There are 2 styles - one with a triangular baseplate, the other circular.

Have a look just over halfway down the page >here< to see the difference, and then check against yours.

I fitted a Pertronix LU-181 Ignitor some time ago and haven't looked back, but I know the simonbbc kits are very well regarded.

Good Luck!
 
Hi, I've found the problem. My electric pump doesnt seem to suck. I think it is mounted in the wrong place. Behind n/s headlamp. I have checked the line is clear and have syphonned fuel up to the pump so it is continually pushing fuel to the pump and so far, ticking over on the drive, it appears ok. I think I need an anti siphon valve possibly? Or could it be low fuel level? As im watching now, I see the fuel level in the filter fall.
 
phil said:
Hi, I've found the problem. My electric pump doesnt seem to suck. I think it is mounted in the wrong place. Behind n/s headlamp. I have checked the line is clear and have syphonned fuel up to the pump so it is continually pushing fuel to the pump and so far, ticking over on the drive, it appears ok. I think I need an anti siphon valve possibly? Or could it be low fuel level? As im watching now, I see the fuel level in the filter fall.
Click to expand...

Hi Phil another problem that may cause your electric pump issue could be a leaking reserve tap, introducing air into the system leting the pumpm siphon back.

Graeme
 
on the bell housing flange drivers side, they have an o-ring which forms the seal, there are a few pics and info if yuo do a search for them.

Graeme
 
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