Cuts out when hot at idle and difficult to restart.

[simon.williams]

I’m going bit further afield now, but this confirms that once it is hot the car is cutting out, first when « idling » (as it revs quite high even at idle) and then it is difficult to restart / have to give it some choke to keep it alive.

The fuel pump makes an intermittent mewling noise as well, much to the amusement of my wife…

I got back after an hours run, but it was touch and and go at the end.

Does this sound like fuel pressure? I don’t think its electrical. Might it be slightly out on timing? Or could it be the set up of the air bodies?

Might have to go to a pro…but any thoughts based on the symptoms ?

[Firewatcher]

Hi Simon - not enough clues, what is the lead up and a bit of background. Has it been OK and just started happening or have you had any work done recently that might have triggered it? Also what fuel pump and ignition do you have, presumably you are also losing power if getting back was 'touch and go'. Timing and carb' settings don't tend to wander out enough to suddenly cause the symptoms you describe, so looks more like something failing on the face of it.
Pete

[simon.williams]

Hi Pete, got it on the road after 20 years in a garage. Motor starts and runs well, but these are its first bedding in trips, and always when it gets hot it will cut out. It has a newly reconditioned lucas pump. Metering unit was jammed solid but I managed to take it apart, free it, and put new seals. Injectors are original but seem to spray OK. Coil & distributor are original set up and at least 20 years since touched.

Air bodies/intakes move freely, have been cleaned and I have an extra spring to try and have them close when at idle.

I’m not 100% sure the metering unit set up is 100% right, the hole in the metering unit is not « just appearing » when it is at TDC, but it runs well enough initially so seems odd if its this.

[Mike Stevens]

Coil overheating perhaps? Have you another one you can try?

[simon.williams]

Thanks Mike, they are not so expensive so will get one and see. Might well be that, or a dodgy connection given the time this car was stood for. Will find the fault eventually !

[Mike Stevens]

Make sure you get the right one. If you have a 'ballast' resistor, it should be a 6V coil, if not a 12V one.

Cheers,
Mike.

[simon.williams]

Ooops, now you’ve got me, no idea what I have….will look tonight.

[triumphman]

Sounds like it could be a number of different problems. Fast idle / difficult to start without choke is probably that the inlet manifold butterflies are not synchronised. If it's a 1973 car then you may well have the later type of manifolds (2 balance pipes between each) which are a real pig to set up correctly. It's also definitely worth checking that the fuel pump is producing 110 psi. Check that the pressure release valve is set up correctly. If not, that can lead to low pressure. And finally, the mixture might be a bit weak if you've had the metering unit to bits. In the control unit, underneaththe side cover, the gap between the rollers and the end stop should be 0.057" with the engine off, rollers at the bottom of their travel, and you should just be able to get the rollers out past the top of the datum track if you take the top off and withdraw the diaphragm assembly. Good luck!

[johnnydog]

It's hard to see but it looks like you do have a ballast resistor fitted and wired up. Owner often remove / bypass them and fit a 12v coil. My 1973 PI definately still has a ballast resistor fitted.

[simon.williams]

Is it too late to buy a Tesla instead?

Golly. So I have the 2 pipe intakes. I kind of think they are set up OK. But the balance pipes don’t have hose clips on them so some might have air leaks…I didn’t get new ones.

I will send a close up of my coil tonight, it has capacitors and resistors all over it. Think the PO must have had shares in an electronics factory.

My only choice of new coil from Moss is 12v ballested, or 12v unballasted…if i get the ballasted can I do away with any additional resistor?

The PRV, how can I test it please? I have seen the inside & screw, but no clue how to set it!

Is there a simple pressure guage set up I can make or buy?

I will not be defeated having come this far!