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77 MGB wont turn over

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Bassist1053 Justin W
Lexington, KY, USA   USA
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Hey guys, new member needing help. I've searched the forums and can't seem to find an answer.

So I have a 1977 MGB that has been sitting in the garage for about six years. Prior to that the car ran just fine. I finally got it out the other day and went to start it and nothing. Charged the battery, swapped the battery, nothing. It's always had a vampire draw so I figured it was just a bad battery. Tried jumping it and nada. The fuel pump is clicking but the thing will not turn over. Figured it may be the starter that went bad so I pulled it and bench tested it... Thing runs just fine...
Honesty I'm a pretty mechanically inclined person, swapped the motor on my 2000 S4 myself last year but I never really did any engine repair on the MG and what should be (I thought) pretty simple in comparison has me dumbfounded. There is a slight gas leak that I can see and smell coming from the carberateur (guess I'll be rebuilding that asap) but that is a different issue since I don't see any reason it would prevent the car from turning over.

I have a pretty steep driveway and I attempted to start it by rolling down in gear and dropping the clutch. Well nothing happened there, barely even slowed the car down when I did it, I figure the clutch is probably in need of replacement as well.

I guess my big question is whether or not you guys think the engine in seized or whether it could be something else? If it's seized what is my next step? I'm not at all scared to pull the motor (will have to do so for the clutch anyway) but I would like to at least get it running before I dive into that....

Any assistance is greatly appreciated!

Thanks!

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calsunshine Paul R
The Valley, CA, USA   USA
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1979 MG MGB
I would suggest as a starting point to review the following article about "Awakening a Sleeping MG" from the tech library.

http://www.mgexp.com/article/awakening-sleeping-mg.html

With a car that has sat for a long time there are many possibilities as to why it will not start, but as a starting point you want to make sure you have fuel and a spark.

So first remove the fuel hose from the carb and place the hose in a container, turn on the ignition and see if you are actually getting fuel to the carb.

The second thing to check is to check you are getting a spark from the distributor, and the easiest way is to remove a spark plug from the engine, recconect the ignition wire to the plug and ground the plug to the engine and turn the engine over. If you get a spark then you are half way home.

if either check fails then you now have a starting point to look for the failure or problem.

Good luck

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Bassist1053 Justin W
Lexington, KY, USA   USA
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Thanks for the help, I'll try those. Engine definitely not seized as I was able to turn the crank easily via the belt by rotating the nut on the alternator...
I understand fuel and spark but my main question is why does it not even feel like the engine is turning at all when trying to start it? Fuel and spark would prevent it from actually starting but I should at least be able to feel the rotation of the cylinders just from the starter turning them over... Right?

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calsunshine Paul R
The Valley, CA, USA   USA
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1979 MG MGB
The starter has a solenoid that causes the drive gear to engage the ring gear on the flywheel. If the solenoid is bad or there are missing/damaged teeth on the ring gear then the starter would turn but not turn over the engine.

Easy check is to make a chalk mark on the drive belt, run the starter and see if the chalk mark has moved. If it has not moved then you need to examine the starter and also the wiring to the starter to make sure the solenoid is engaging.

If you do not have an electrical diagram one can be found here:

http://www.advanceautowire.com/mgb.pdf

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Bassist1053 Justin W
Lexington, KY, USA   USA
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Not sure what exactly I'm looking for on the diagram... The wiring on the car is a mess, although it's been in the family since new my dad took it to some pretty inept mechanics over the years, wires are spliced here and there, disconnected etc... Not ever sure where to start

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ohlord Avatar
ohlord Platinum Member Rob C
A tiny Island off the coast of Washington State, N.W., USA   USA
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1957 Land Rover Series I "EYEYIYI"
1957 Land Rover Series I "OVRLND"
1971 MG MGB
1971 MG MGB "Bedouin 2"    & more
You won't get spark if the starter isn't spinning.
You know the starter works because you bench tested it.

Check battery 12.7v
Check terminals clean and tight
Check ground to frame cable
Check transmission to ground cable on your rbb mgb
Bypass starter relay and see if it turns over
Fix the ZS carb leak. Before starting
6 years of ethanol fuel is all bad gelled and need to be cleaned from tank and carb

Fast forward to your model years

Join you local mg club. And enlist help
Post a picture of your engine bay so we can see if its stock or been modified



LNDRVR4X4.COM
Home of Project "INCARN8'


1957 Series 1 Land Rover electric VEHICLE CONVERSION

FIXITUPCHAP.COM
FIXITUPCHAP INCORPORATED

RD3 Radar/ Electronic Warfare Technician
VIETNAM 1969-1972

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Bassist1053 Justin W
Lexington, KY, USA   USA
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Thanks, I've done most of those already but not bypass the relay...
Also, does anyone know if the od model used the same wiring harness as the non od? There's a single green/blue wire but attached to anything and I can't seem to find anywhere it would go, as well as a three sure connector-yellow, yellow/blue, yellow/black... Would surely be concerning if they have somewhere they are supposed to go

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Bassist1053 Justin W
Lexington, KY, USA   USA
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Followed he video and got a click and a buzz sound coming from the starter area... Does that mean bad solenoid?

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ohlord Avatar
ohlord Platinum Member Rob C
A tiny Island off the coast of Washington State, N.W., USA   USA
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1957 Land Rover Series I "EYEYIYI"
1957 Land Rover Series I "OVRLND"
1971 MG MGB
1971 MG MGB "Bedouin 2"    & more
Check battery connections
Check charge
12.7
?
If so try 12v directly to starter
Car in neutral
Wheels chocked
Work safe
You said the starter bench tested good
Still sounds like you don't have enough juice to the starter or a bad connection along the way.

The wire harness is common od or non
Look at the wire schematic for your non used wires.



LNDRVR4X4.COM
Home of Project "INCARN8'


1957 Series 1 Land Rover electric VEHICLE CONVERSION

FIXITUPCHAP.COM
FIXITUPCHAP INCORPORATED

RD3 Radar/ Electronic Warfare Technician
VIETNAM 1969-1972

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Defender405 Avatar
Defender405 Chris B.
Des Moines, IA, USA   USA
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1975 MG MGB
If the starter isn't doing anything but bench checks good, then it probably is the relay. Locate the relay along the inside of the passenger side fender, it should be kind of above and aft of the coil. Try lightly beating the coil with the handle end of a 1/4" drive ratchet and see if that helps it to cycle. My relay reacted similar to your issue and I was able to temporarily fix the issue (and narrow it down to the relay) by whacking it a few times.



Chris AKA "Defender405"
1975 MGB
1979 Porsche 924
1999 Porsche 996
1987 Nissan 300ZX

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dickmoritz Avatar
dickmoritz Platinum Member Dick Moritz
Philly 'burbs, PA, USA   USA
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There are two large lugs on the starter solenoid. One has the battery + cable and other brown wires attached to it, the other connects directly to the starter motor.

The solenoid on your car performs two tasks. First it pulls the small starter pinion gear into mesh with the ring gear on the flywheel. Only after this has happened does it set the starter spinning. You can (carefully, please...) use a large nasty screwdriver to bridge across the two large lugs of the solenoid. This will apply battery voltage directly to the starter motor, which should set it spinning. Since you're bypassing the other function of the solenoid, the small pinion gear may engage the flywheel ring gear, spinning the engine, or the starter motor may just spin freely. Either way, if the starter motor spins when you jump across these two large lugs, then the solenoid is not properly completing this connection inside, which demonstrates either a faulty electrical supply to the large terminal with the B+ cable attached, or a faulty solenoid.

It's not practical to replace just the solenoid, since a new solenoid costs almost as much as a replacement remanufactured starter motor, which comes with a new (or remanufactured...) solenoid attached...

Dick



In reply to # 3476091 by Bassist1053 Followed he video and got a click and a buzz sound coming from the starter area... Does that mean bad solenoid?



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

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rdmgb77 Avatar
rdmgb77 Robert Davidson
Grand Rapids, MI, USA   USA
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1977 MG MGB
The starter relay is just a standard 4 post relay that is rather inexpensive purchased from any auto supplier. Buy one and keep it in your tool box. It is also the same as the ignition relay which is in front of the fuse box. Try swapping out a new relay for your old starter relay to see if that solves the problem. I so you are good to go. If not you have a spare if one of the other goes bad. If the ignition relay goes bad you will simply die on the side of the road. Turn signals and anything else that runs through the ignition circuit will not work. If you want originality then pruchase the round can style relay from Moss.



"The problem with the world is that everyone is a few drinks behind."

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grahamts Avatar
grahamts Graham Prosser
Chelmsford, Essex, UK   GBR
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There is also the possibility that you have a poor earth connection to the engine. First check the battery earth connection, remove it and clean the connection to the body, refit and coat with vaseline or silicone grease, next check the connections on the engine earth strap, which is probably between the body and one of the bell housing bolts, again clean and refit, if this connection is poor you can actually set fire to the throttle or choke cable which act as very poor earth connections and overheat eye popping smiley I tend to fit an extra earth strap across the engine mount where it is easy to get at and maintain.
Good hunting, Graham.

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ohlord Avatar
ohlord Platinum Member Rob C
A tiny Island off the coast of Washington State, N.W., USA   USA
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1957 Land Rover Series I "EYEYIYI"
1957 Land Rover Series I "OVRLND"
1971 MG MGB
1971 MG MGB "Bedouin 2"    & more
See #6



LNDRVR4X4.COM
Home of Project "INCARN8'


1957 Series 1 Land Rover electric VEHICLE CONVERSION

FIXITUPCHAP.COM
FIXITUPCHAP INCORPORATED

RD3 Radar/ Electronic Warfare Technician
VIETNAM 1969-1972

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Bassist1053 Justin W
Lexington, KY, USA   USA
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Ok, update... I managed to fix the carb leak with a new o-ring... it was on the bottom pop in yellow piece (if that makes sense)
Went ahead and purchased 2 new relays to swap out the ignition and starter relays since that was the easiest an quickest thing to do. I think the starter relay may have actually been bad because now instead of just a click when I try to start it I get a grinding sound (the starter motor itself is definitely working and I'm guessing its partially touching the flywheel causing the grinding sound)... so I pulled the starter again. You were talking about the solenoid somehow moving the starter gear into place against the flywheel. I disassembled the solenoid from the motor in order to see if there was any type of movement from the gear but nada.
Before I order a new starter I just want to make sure that I understand correctly (more for my own curiosity) but when the solenoid is working correctly it somehow pushes the starter gear out about an inch so that it may engage the flywheel and then turn the engine over? Main reason I ask is that now that I have the starter on the workbench I cannot seem to make the gear itself move forward at all.

Like I said, I am pretty much sure that you were correct about it being the solenoid but any more info would be greatly appreciated.

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