Not 1 but 2 problems

Technical MGB discussion
Steven collins
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Joined: Fri Oct 31, 2014 5:20 am
Forename: Steve
Surname: Collins

Not 1 but 2 problems

Post by Steven collins » Fri May 01, 2020 3:56 pm

First problem,
Since engine and gearbox put back in car it will not turn over via the ignition key, however, it turns over using the starter solenoid, the fuel pump is also not working/pumping.

Second problem - no oil pressure

Any thoughts or ideas On what’s wrong and how to fix it would be gratefully received.
1966 MGB

Found the answer myself ———— flat battery 🥴😳🙄
Mind you not started it up yet but oil pressure went up to +70psi

Dave Wheatley
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Forename: Dave
Surname: Wheatley
Location: SW Scotland

Re: Not 1 but 2 problems

Post by Dave Wheatley » Fri May 01, 2020 5:44 pm

The fact that the car would turn over on the solenoid, but not on the key suggests that the battery was OK.

Let us know when you find the real reason ;) for failure to proceed.
1978 MGB GT
1931 Austin 7 RM
1955 Standard 10
1972 Ford Cortina
No modern!

Vic Butler
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Location: North West Hampshire

Re: Not 1 but 2 problems

Post by Vic Butler » Fri May 01, 2020 5:57 pm

It could be a wiring problem or a faulty ignition switch. Disconnect the small wire from the ignition switch, connect a voltmeter to the wire and turn the ignition switch to the start position and see if there's any power to the wire. If not it's either a break in the wire or a faulty switch.
The solenoid feed wire is white with a red trace connected to terminal 1 on the switch. The fuel pump is one of the white wires connected to terminal 2 and the brown wire on terminal 3 is the main feed.
This assumes that it's a 1966 on positive earth.
1977 Stage 2 MGB GT
1975 SWB Series 3 Land Rover with a later 2.5 petrol engine

Steven collins
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Forename: Steve
Surname: Collins

Re: Not 1 but 2 problems

Post by Steven collins » Fri May 01, 2020 6:13 pm

Dave,
It did turn but very... very slowly on the solenoid put battery on charge, now no problem in turning on key, however, it would appear that the fuel pump has decided to remain asleep so further investigation is required before fuel will flow...

Vic,
1966 negative earth.

Vic Butler
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Forename: Vic
Surname: Butler
Location: North West Hampshire

Re: Not 1 but 2 problems

Post by Vic Butler » Fri May 01, 2020 6:35 pm

Then it could be the points in the pump, assuming it's a standard one. Give it a sharp tap with the ignition switched on once you've got the battery charged. If it starts ticking then, it's best to replace it as it can fail at any time. As your MG is negative earth then an electronic one can be fitted. They still tick.
Do the indicators and wipers work? They are wired to terminal 2 on the switch like the fuel pump except they're fused which the pump isn't.
1977 Stage 2 MGB GT
1975 SWB Series 3 Land Rover with a later 2.5 petrol engine

Steven collins
Posts: 35
Joined: Fri Oct 31, 2014 5:20 am
Forename: Steve
Surname: Collins

Re: Not 1 but 2 problems

Post by Steven collins » Fri May 01, 2020 7:03 pm

Right, time to put my hand up and admit that I have a fuel cut off switch and when I started to strip the engine and gearbox out I switched it off (belt and braces don’t you know) forgot to switch it back on 🙄 😳 surprising what a little spurt of electricary can do!!
Fuel now flowing as it should.....

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Paul Scott
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Surname: Scott
Location: Milton Keynes

Re: Not 1 but 2 problems

Post by Paul Scott » Fri May 01, 2020 7:13 pm

:D
1975 MGB Roadster
Webguru for MGB Register

Dave Wheatley
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Forename: Dave
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Location: SW Scotland

Re: Not 1 but 2 problems

Post by Dave Wheatley » Fri May 01, 2020 7:32 pm

I'm glad it wasn't anything more complicated!

Is the engine running?
1978 MGB GT
1931 Austin 7 RM
1955 Standard 10
1972 Ford Cortina
No modern!

Steven collins
Posts: 35
Joined: Fri Oct 31, 2014 5:20 am
Forename: Steve
Surname: Collins

Re: Not 1 but 2 problems

Post by Steven collins » Fri May 01, 2020 8:24 pm

Briefly, as at the moment I do not have the choke connected (waiting for trunnions and skrew to turn up so I can secure the cable)
Skrew = evidently a naughty word when spelt correctly 🤣

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Peter Cresswell
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Location: Stone, Staffordshire

Re: Not 1 but 2 problems

Post by Peter Cresswell » Fri May 01, 2020 9:42 pm

Hi Steven,
Have you fixed the oil pressure?
Did you fill the oil pump with oil when you reassembled the engine? They don't self prime!
If not try disconnecting the oil cooler pipe that runs from the cooler to the filter head - at the cooler end and using a funnel pour as much oil into the pipe as you can. Hopefully this will find it way down through the filter and into the pump itself. Then remove all the spark plugs and turn the engine over to see if the pressure comes up. The engine will spin over quite quickly as it has no compression and also it will have no loading that might damage the bearings.
Hope this helps!
Pete

EDIT - Just seen the bit at the bottom of your post. All is OK! Phew.
Pete
1969 MGB Roadster
2011 MG 6 TSE Magnette
2007 Mercedes SLK
Plus 32 other cars since 1965

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