That awful colour MGB GT

[SiC]

Fuel filter was full when it broke down. I'd expect it to fill the carbs up from gravity as the filter is a fair bit higher. Also all fuel lines, pump, filter and tank are new. Tank was completely clean when it went in. Also I'd expect the fuel filter to have been empty if it couldn't pump fuel up.

[SiC]

Fuel pump.

The carb end was disconnected and it ran for a bit then petered out. Currently has one of those blue Hardi German units on. Apparently gravity isn't enough to fill these carbs, they do need a bit to force them through.

Either the pump or possibly the connections. I suspect pump as it's only pulling 4 amps or so when running. Hardly enough to be too much of a draw on dirty contacts for it to fail on a short run.

Had to be something obvious, there isn't too much that can cause a sudden failure.

[DodgeRover]

Glad it's sorted, was just about to suggest trying to fire it up on ether to eliminate a spark issue.

[SiC]

Getting the garage to replace it for me on Monday. Going to go with another Hardi unit as it'll be an easy straight swap. Did say to check the wiring and any blockages before the pump was completely condemned. Thinking about it, the steel braided hose to the pump was from MSC. I'd hope it was Ethanol compliant, but I bet it's not.

Out of my four cars (if we exclude my wife's Audi A4 which she's using tomorrow), there is only one left which is fully working to get me to Haynes tomorrow. The ever reliable* and trustworthy**...

1a2262328dd173e600cfd320f7bf63c1[1].jpg (149.04 KiB) Viewed 4432 times

[Alf892]

I reckon you should carry on SiC....your fault finding is probably more methodical than the garage.

Starting so well after a while is still indicative of condenser though.

you could run a couple of wires from the coil to a bulb in the car....while the bulb flashes the coil is getting switched. Doesn't totally rule out ignition fault but good check on lt side

[richardthestag]

This is the exact rotor arm that is on it:

https://www.moss-europe.co.uk/rotor-arm ... 101hq.html

I think its a genuine Distributor Doctor item. Certainly had the letters DD on it.

give him a call and ask him, I wasn't aware that he was distributing through other suppliers. I do know that other suppliers #cough powerspark shit started colouring everything red and making them out of French cheese.

If the surface of the points is clean then the condenser is likely good.

Check that then carbon pin is still inside the middle of the dissy cap?

I have had visually perfect rotor arm not allow an engine to run, must have been gap between rotor tip and cap contacts being greater than the spark plug gap

[SiC]

Do keep up Richard! It's looking like the fuel pump/fuel system at fault. Pipe to carbs started fuel flowing and pumping. Then after a few more seconds it went really weak.

Got a blue Hardi on it. Getting the garage to investigate further.

I'd love to investigate and diagnose this, but unfortunately I have too much else going on. The reason I was originally travelling down the M5 yesterday was to talk to the agent we are buying from, was to explain why it's looking like we will have to pull out of the sale. TL;DR right of way issues have come to light on it.

So will be house hunting again shortly. Probably will have to go into rented to ensure our sale goes through ok.

Thus I really need to get on with the Dolomite, as work will grind to a halt very soon. It'll end up getting lobbed into storage until we actually have a house to live in again.

Sorting out all the house stuff and now just getting the MGB recovered has eaten up the two days last week I had off to get on with welding. Weather was good too.

[richardthestag]

posted that ^ before I had got to the end of the thread.

Had a stag that would not start!, pulled fuel line from carb and switch ignition on and fuel flooded out of the pipe, = discounted the pump.

Almost an hour later and only after removing the carbs and finding both float chambers empty we went back to the pump, again it gushed forth.

In desperation I tipped fuel into the carb inlet and of course if coughed and tried to start. fucking thing is haunted.

Turned out to be poor electrics to the pump that caused it to fail when under load. Carb float valves needed 2psi to overcome and fill the float chamber. This just wasnt happening.

My advise? Do not forget that 98% of fuelling issues turn out to be ignition related and vice versa

And to prove? I had a Vauxhall that worked beautifully most of the time except after a brief period of full throttle at which point it would die, but after coasting to a stop it would restart with no issues!

That ended up being a dodgy joint to the coil which was stretched when the engine was on full throttle and shifting on the engine mountings. Only found when I ran a wire to the coil from +ive feed on battery and failed to replicate the fault.

1972 RR did a similar thing last year, conked out after revving it, only it restarted just fine. Bypassing feed to coil had it running sweetly and helped me ID the intermittent cause! dodgy multi connector to the engine loom

[BenHar]

You have now fannied about with so many things that even when it runs again you won't know the cause of the problem.

Ben

What a silly thing to say.

Yep, I'm silly.

But you seemed to be thinking that the oil pressure could be affecting it.

Had oil pressure. Oil pressure when cranking too.

How silly is that?

Ben

[brandersnatch]

That’s helpful Ben.