djkeenan

Thanks for confirming that David. I'm glad I correctly read the diagram.

Checked continuity across fuse 23 and its golden. Getting 12v on the purple line so i'm assuming this is a component [fuel pump] problem not a power/wiring problem. Ordering a new £50 fuel pump off the ebay.

@Notanumber My post is very confusing and could use some more detail: The cars been pumping fuel to the engine. Last month I'd seen it pump fuel into a jug and had the injectors out to check spray pattern. What I didn't have was a fuel pressure gauge which [and this is a theory] would have told me the fuel pump was slowly dying [not providing enough pressure]. I dismissed the pump as an issue cuz I found it hard to believe as pump was only 2 years old BUT I did have a faulty alternator in the summer which caused odd behavior with the lights and radio. Maybe that's caused its death?

Its good to hear from Cobber that a failing fuel pump can cause all sorts of problems. I'd, again, dismissed it as an issue thinking: "its either working or broken as its only a motor". I now guess the commutator could have burned out a bit but not completely causing a slowly dying pump leading to lower and lower fuel pressure .

Anyway, currently the car doesn't start (only cranks with sparks) and that's definitely partly or fully caused by no fuel going from the fuel pump. This post was to establish if its just the fuel pump or it could be multiple things. I'm going with a replacement pump and seeing what happens.

You guys, as always, have been stupid helpful and patient and appreciate that tremendously.

sworkscooper wrote:

Well I think that you might have diagnosed the problem and it really does not need a speculative answer to A or B.

In this rather odd case I do need a speculative answer. I've no money to maintain and would like to move it either to the scrap heap or another buyer.

I.e. if its A I've shorted it out (by linking the positive terminal to the purple/white wire) wire and the original issue is something else (and the fuel pump is an extra fix) then i'll scrap it.

If its B then its just a case of the fuel pump slowly dying then I'll get a replacement then I'll get it MOT'd. Then sold.

@Cobber The car has been run (for 30 minutes) every 2 weeks for the entire time its been stored until it fully died last month. It got progressively worse to the point where it would die when you tried to pull away but would happily idle. No stuttering or misfires for the duration. I've kept it on life support until the weather warmed up and now im trying to fix it.

Had problems with engine cutting out (see my post history over last 12 months) or just failing to start when engine hot but not when cold. Now MGF 2001 wont start at all.

Tried hard wiring the positive terminal of the battery to the purple-white wire going into the fuel assembly. Read about this trick from post #24 of this thread. Got a spark so assumed I got a closed/complete circuit. Tried cranking and still would crank but would not start. Attached a photo of the hard wiring job.

Took the fuel out pipe off and tried priming and no fuel comes out (none while cranking either). I think I've either:

A: Destroyed my fuel pump by connecting to the wrong wire/circuit.

OR

B: The fuel pump has been slowly dying (why i've had car trouble this whole time)

Let me know which is which? Thanks guys!

I'm gonna scrap it. Tried all sorts of things to get it going. Its a shame. The engine is new and so is the fuel pump. Tested the engine and the chambers all throw out 135psi exact. Scrap man is gonna get a bargain

Do you mean this? https://rimmerbros.com/Item--i-725414

And will this fault stop an engine from starting when hot? i.e. run the engine, turn off car and try to start and the engine will crank but not start like its missing one of the essentials (air, spark or fuel).

I used caution and only 3/4 clamped it with some mole grips. Did not fix.

Also tried disconnecting the Manifold Absolute Pressure (MAP) sensor and the Idle Air Control (IAC) valve to put the engine into limp mode in case one of these was the problem. No fix. I did note the quiet, high pitched whine when an MG's engine is off (key removed), comes from the IAC valve. Does your engine do this?

Dunno what to do next as I don't think it's a compression problem as engine runs fine once its going. I'm gonna have a look for oil in the combustion cylinder and double check i'm still getting a strong spark when cranking a second time.

I've just had a thought. Clamp the fuel return line (like you would when replacing brakes) and see if that gets the engine to start. I'm gonna try it tomorrow. Maybe not full clamp but enough to artificially increase pressure. You said it doesn't matter where the fuel pressure valve is located so I'll clamp just after the fpr.

"I can’t see any reason for the regulator to work cold but not hot, the unit is little more than a spring acting on a diaphragm & when the pressure is reached the valve opens & fuel is returned to the tank."

I hear what you're saying but maybe this isn't a problem caused by overheating but caused by a certain situation i.e. the fuel system doesn't work properly if its primed after the engine being run recently. Something is not resetting to default causing the fuel to not get to the engine?

What's frustrating is the fuel was spraying every time I cranked the injectors while outside of the engine. I can only presume something is different inside the piston heads. Although I would assume the pressure in the head is very much the same as outside the engine block when first cranking?

My car cranks but doesn't start. I've checked ignition and I've checked fuel pump is supplying by filling up a measuring jug. I've had the fuel rail out today and confirmed the injectors all have the same resistance (15.2 ohms) and they are firing (fired them onto some a4 paper). Put the fuel rail back together and car starts immediatly. Revved it and all sounded good with all pistons firing. Turned car off and back on and is back to cranking with no start.

Thinking an empty fuel rail caused the fuel pressure regulator to allow enough fuel into the car to start it. How can I confirm something is up with the fuel pressure regulator?

Engine is an MGF 1.8 MPI mems3 from 2001

Edit: should add the car starts for a second if I spray easy start spray into the intake.