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Ignition/Engine Problem

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Ignition/Engine Problem
#1
  This topic is about my 1970 MG MGB GT
walkerbob0 Avatar
walkerbob0 August A
Vacaville, CA, USA   USA
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1970 MG MGB GT "Sketch"
I'm having the same problem as this post but still no luck getting it fixed. I've tried all the fixes people recommended in the post and around on the forums with no luck. I've replaced the coil, distributor cap and rotor, plug wires and plugs. I've also retuned my HS4's and the cars timing. The car starts to stutter under load and the tach would go crazy and the ignition light would come on.

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Re: Ignition/Engine Problem
#2
fast-MG.com Avatar
fast-MG.com Dave Headley
Cortez, 4 corners, Colorado, USA   USA
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Condensor?

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Re: Ignition/Engine Problem
#3
jjgerding Avatar
jjgerding Silver Member Jay Gerding
Spring Hill, FL, USA   USA
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Does the condenser have an orange lead? I have had a bunch of these go out. finally got one with a black lead from Advance Auto. Haven't had a problem since.

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Re: Ignition/Engine Problem
#4
lil.red.roadster Avatar
lil.red.roadster Bernie Anderson
Marshfield, Gloucestershire, UK   GBR
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1970 MG MGB MkII "The Beasty"
Easy to check,
Either remove it (Condenser that is!) and see if it gets worse

OR
connect a new one from distributor input to earth and see if it improves


Bernie

"discere mutari est"

Wiring Diagrams: http://www.advanceautowire.com/mgb.pdf
Paul Hunts very useful site: http://www.mgb-stuff.org.uk
Manual for download: http://www.geomatique-liege.be/MGJP/DocumentsPDF/MGB_Workshop_Manual.pdf
UK MoT guide: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/518634/mot-inspection-manual-for-class-3-4-5-and-7-vehicles.pdf
Some basic guides: http://www.howacarworks.com/

1970 Roadster (First Reg July 10 1970). Std exhaust (Bell SS) AFAIK rest is bog standard

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Re: Ignition/Engine Problem
#5
walkerbob0 Avatar
walkerbob0 August A
Vacaville, CA, USA   USA
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1970 MG MGB GT "Sketch"
I put a new condenser and points in today and still no luck. The problem still occurs when I accelerate. Could it be a bad vacuum advance? Is there anyway to check if the vacuum advance is working correctly?

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Re: Ignition/Engine Problem
#6
9146 Avatar
9146 rick dentel
yardley, PA, USA   USA
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1970 Porsche 914
1978 MG MGB
1998 Jeep Cherokee
2001 Jeep Cherokee    & more
Just put a hose on the vacuum unit and suck, remove the dist cap and see it the plate moves.

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Re: Ignition/Engine Problem
#7
Tom Bedenbaugh Avatar
Tom Bedenbaugh
Memphis,Tn, USA   USA
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It doesn't happen very often,but the advance weights in the destributor could be stuck. With a timing light hooked up rev the encine up and see ig the timing mark advances.


http://www.importandsports.com/

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about 1 week and 4 days later...
Re: Ignition/Engine Problem
#8
walkerbob0 Avatar
walkerbob0 August A
Vacaville, CA, USA   USA
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1970 MG MGB GT "Sketch"
Still no luck on finding a fix. I took out the distributor to find that the housing is cracked where the clamp is held and the vacuum advance not moving when tested. I ordered a new 45d and installed it hoping it would fix my problem. The problem is still there. Stumped...

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Re: Ignition/Engine Problem
#9
morris556 Avatar
morris556 Les L
So Cal, SoCal, USA   USA
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1967 MG MGB MkI
I assume you are just using a points system, if so do you have 12.+ volts at the + side of the coil running? What happens if you eliminate the whole positive side of the ignition circuit and run a test lead from a 12v source under the hood to the 12v side of the coil??

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Re: Ignition/Engine Problem
#10
rggavmge Avatar
rggavmge roy gavilan
Williamsburg, VA, USA   USA
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1974 MG MGB MkIII "Ruby"
You can buy a new dizzy from Sports Car Parts LTD for $78.
Sports Car Parts LTD 45D dizzy

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Re: Ignition/Engine Problem
#11
B-racer Avatar
B-racer Jeff Schlemmer
Shakopee, MN, USA   USA
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1950 Willys Jeep Pickup "Ratrod"
1964 Land Rover Series IIA
1971 MG MGB
He already has a new dizzy, so that's not the right direction.
Try leaving the vac disconnected (wrong vac unit for your car), and set the timing at 12-14 degrees BTDC at idle. Use a timing light, not static setting.


jeff@advanceddistributors.com

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Re: Ignition/Engine Problem
#12
lil.red.roadster Avatar
lil.red.roadster Bernie Anderson
Marshfield, Gloucestershire, UK   GBR
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1970 MG MGB MkII "The Beasty"
In reply to # 2918147 by B-racer He already has a new dizzy, so that's not the right direction.
Try leaving the vac disconnected (wrong vac unit for your car), and set the timing at 12-14 degrees BTDC at idle. Use a timing light, not static setting.

And don't forget to seal the carb/manifold port if you disconnect it!


Bernie

"discere mutari est"

Wiring Diagrams: http://www.advanceautowire.com/mgb.pdf
Paul Hunts very useful site: http://www.mgb-stuff.org.uk
Manual for download: http://www.geomatique-liege.be/MGJP/DocumentsPDF/MGB_Workshop_Manual.pdf
UK MoT guide: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/518634/mot-inspection-manual-for-class-3-4-5-and-7-vehicles.pdf
Some basic guides: http://www.howacarworks.com/

1970 Roadster (First Reg July 10 1970). Std exhaust (Bell SS) AFAIK rest is bog standard

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about 1 week and 6 days later...
Re: Ignition/Engine Problem
#13
walkerbob0 Avatar
walkerbob0 August A
Vacaville, CA, USA   USA
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1970 MG MGB GT "Sketch"
This has been the problem for the past 3 weeks. It won't stop doing this. It also starts stumbling and stuttering when I'm driving.

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Re: Ignition/Engine Problem
#14
walkerbob0 Avatar
walkerbob0 August A
Vacaville, CA, USA   USA
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1970 MG MGB GT "Sketch"
Any idea whats causing this to happen?

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Re: Ignition/Engine Problem
#15
Rick Fawthrop Avatar
Rick Fawthrop Gold Member Richard Fawthrop
Langley, WA, USA   USA
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1960 Austin-Healey Bugeye Sprite
1974 MG MGB
1994 Mazda Miata
Do a compression test.

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