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1980 mgb not starting

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1980 mgb not starting
#1
dgpw54 Dave White
pittsburgh, PA, USA   USA
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the engine cranks, it is getting fuel and there is spark, although I'm not sure if the spark is trong enough. I've replaced the plugs, coil, distributor cap and rotor. I also have new wires to put on. A mechanic said the distributor amplifier boxes get fried and that was most likely the problem. A new Petronix distributor is $200 and I found a Petronix amplfier for about $150. I hate to order not knowing if that's the problem. Could it be the ignition switch?

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Re: 1980 mgb not starting
#2
ClayJ Avatar
ClayJ Silver Member Clay Johnston
Mt. Olive, MS, USA   USA
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1972 MG MGB
Dave,
Your 1980 model in stock condition will have two paths to provide ignition voltage. +12VDC thru the cranking circuit and 6-8 volts thru a ballast wire circuit with the ignition "On". Check voltage at cranking and at the "On" position.

The coil you have replaced should be a 1.5 ohm unit in conjunction with the ballast wire. If your ballast circuit has been bypassed you would use a 3 ohm coil. The correct combination is important.

Many of the later cars with the OPUS type ignitions tend to get replaced or modified.

Are you getting any popping or backfiring?

After cranking without starting, what is the condition of the sparkplugs? Are they wet with fuel? If dry, you may have a carb issue.

What carb(s) are on the car?

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Re: 1980 mgb not starting
#3
rocannon Avatar
rocannon Gold Member rocannon L
Comanche County, OK, USA   USA
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1967 MG MGB GT "GT From Hell"
Dave,
Can you post a pic of your coil, the box under it, and distributor?


Pogo is right.
—————————————————————-
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Re: 1980 mgb not starting
#4
glbishop Avatar
glbishop Gary Bishop
Spring Hill, FL, USA   USA
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1980 MG MGB MkIV
1984 Kawasaki Z550
Make sure that it's actually the ignition box. The OPUS system attaches to the side of the distributor. The newer CEI box sits under the ignition coil.

If your CEI ignition box sits under the coil then you can replace the GM (or aftermarket) 4 pin ignition module inside it for about $20.

Here's a look inside the CEI box.

P.S. The GM style module is not likely to go bad.



Edited 2 time(s). Last edit at 2014-10-30 01:18 PM by glbishop.


Attachments:
CEI igntion.jpg    50.8 KB
CEI igntion.jpg

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Re: 1980 mgb not starting
#5
jjgerding Avatar
jjgerding Silver Member Jay Gerding
Spring Hill, FL, USA   USA
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Any chance you might have a buddy or fellow club member around who happens to have a spare 25D dist. laying around? If so, pop it in and see what happens. If it starts, then it is likely your electronic dist. is fried. If not, it's something else.

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Re: 1980 mgb not starting
#6
RAY 67 TOURER Avatar
RAY 67 TOURER Ray Marloff
Fort Bragg, CA, USA   USA
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1967 MG MGB "My Girl"
If your car has the original ignition system it is basically the same unit that was used by GM. It' a very reliable system and the most common fault, after many years of use, is a failure in the module as pictured above. Avoid replacing your ignition system with the Pertronix unit. They are made in China to a very low standard. RAY

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Re: 1980 mgb not starting
#7
lewisrn Avatar
lewisrn Gold Member Bob L
Danville, IN, USA   USA
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1980 MG MGB "The "B"
In reply to # 2838459 by RAY 67 TOURER Avoid replacing your ignition system with the Pertronix unit. They are made in China to a very low standard. RAY

Yeah, my Pertronix only has 40k trouble free miles on it so I'm sure it will fail sometime.

C'mon Ray, what did you use to form your negative opinion?


“Ideological certainty easily degenerates into an insistence upon ignorance". Daniel Patrick Moynihan

In any debate, the side which strays from civil discussion is usually the side that lacks confidence in its debate position or in the merit of their arguments. Making personal attacks on the opponents instead of staying on the subject is also a sign of weakness.

Anyone who feels compelled to respond in kind to any perceived slight is often suffering from narcissism.

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Re: 1980 mgb not starting
#8
dgpw54 Dave White
pittsburgh, PA, USA   USA
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Gary, Thanks for the reply. It is the CEI type mounted under the coil. Is there a specific GM make and model I would use to search for the part on RockAuto, Moss or other sources?

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Re: 1980 mgb not starting
#9
dgpw54 Dave White
pittsburgh, PA, USA   USA
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Thanks Ray. I found a GM unit on Rock Auto. Do you know where I can get a distributor cap clip? As bad luck would have it, I dropped it and of course cannot find it anywhere in the engine bay. It is not on the garage floor. I checked all parts outlets including ebay and can't find one. Thanks. DAVE

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Re: 1980 mgb not starting
#10
dgpw54 Dave White
pittsburgh, PA, USA   USA
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Yes, that is exactly what I have. I found a GM unit at Rock Auto. I can drill out the rivets and attached the new one. Do you know if I'd need to replace the resistor (cylinder shaped unit in box)? Also, as dumb luck would have it, I dropped a distributor cap clif and can't find it. Not on the floor and have looked all over engine bay. Do you know where I can get a replacement? I've checked all the normal parts sources. Thanks Dave

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