MGB & GT Forum

I'm going to cry...

Simple background:
Chrome Bumper Early 1974 MGB
Have been using it 2-3 times a week for the past few months... has been running great. Not a single issue.
Pulling up the driveway tonight, engine dies (radio is still on, as is ignition light). Think I must have stalled it in reverse, no?
Try restarting, "CLICK" then nada. Electric still working.

Push it into the garage... check battery, voltage is fine. Try to start car while hooked up to charger... "CLICK" :nope:
Wait an hour... "CLICK" :nothing:
Check grounds (I just rewired last year)... look perfect.
Pop hood and turn key in ignition and get out to check voltage across solenoid... it's good. Ooops... fuel pouring out of carb overflow. Turn off key.

Tap carbs... nothing. It can't be a float, came out of nowhere.
Can't be the altenator, other electric working fine
Can't be spark plugs... why would car die... and again, no problem all summer and then just BAM?

Any ideas... I can't bear the thought of this being something I can't figure out and fix easily.

UPDATE: Resistance across coil is reading 1.6 Ohms
Tried manually touching wire from starter relay to wire in the fuse box to turn it over, still wouldn't turn over (so it's definitely not a solenoid or relay issue)



Edited 1 time(s). Last edit at 2015-07-29 11:39 PM by Nyiballs.

Wild guess, you might have a coil that has gone bad. If you have a volt meter, check the voltage across the + and -. You should have 3.5 ohlms. Then try it using the - and the wire going to the dizzy. If I remember correctly, that should be about 8, but I can't remember if that is ohlms or volts. I had to do this last fall, and unfortunately, I did not write it down. Sometimes when the coil gets hot, it shuts itself off.

Does your fuel pump tick? You might want to ensure that you are getting fuel to the carb, too.

Forgive me if this is dumb... but if fuel was pouring out of the carb overflow, would it be safe to assume that fuel is getting to the carb.

I'll give the coil a check and see... do I need the key in and/or turned in order to get a charge across it?

It probably died because of the overflowing carb and if it's clicking but not cranking then it may be the solenoid contacts.

Tapping an overflowing carb may on a rare occasion fix a stuck float valve but TBH if it's done it once I wouldn't trust it and would plan on replacing both, unfortunately with the HIF carb that means taking them off the car.

Don't be fooled into believing you can do it with them in place, try it and I'll guarantee you'll regret it and end up taking them off anyway.

If you do replace them make sure you only buy Viton tipped ones, do NOT buy the Grose type !

Does anyone happen to know the correct coil readings so I can either confirm or throw away that diagnosis?

I got 1.6 Ohms on the sides, and 7680 on the center...

EDIT: Even though I'm chrome bumper, I'm a '74 with a ballast resistor, which I have read should be 1.5 Ohms... so this would indicate it's NOT the coil, correct?



Edited 1 time(s). Last edit at 2015-07-29 11:17 PM by Nyiballs.

Click, nothing is starter solenoid ir starter relay. It is still pissinle to have bad ground or pos cable connection and still pass low current for radio etc


With lights on try starter. If lights dim almost surely bad ground.

No reason to suspect coil until it cranks and wint fire. Leave ign on for 3-4 minutes and feel coil. Warm coil is getting power.

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The goal - Reliable summer driver interspersed with mechanical tinkering...
Motto - "Driving fifty in the twisties..."
On Mods - It's your damn car - Do what you want. Haters gonna hate...
On SUVs - Drive your B like a soccer mom is texting her friends about how she wants to kill you...
Red Betty - http://www.mgexp.com/registry/GHN5UH418165
Bart - http://www.mgexp.com/registry/GHD4U146898G

Just checked my, "The Complete Official MGB" copyright 1968, 1970, and for 18G, 18GA, 18GB, 18GD and 18GG engines, it says that primary resistance should be 3.1 to 3.5 ohms at 68 degrees F.

And, yes, if you have fuel coming out of the overflow pipe, you got fuel. One question, though, what do you have for a fuel pump? I had an aftermarket fuel pump that was over enthusiastic and tried to dump too much fuel into the carbs. I replaced it with a SU, which fixed that problem.

So I tried the Twist method of hotwiring to see if it was the starter...

Brown/White wire disconnected from relay and touched to brown contact in the fuse box... supposed to turn it over... instead: CLICK

Connected Brown and White fuses and touched brown/white wire from relay to the fuse... supposed to fire it up... :rapid clicks: then nada.
(Other than the sparks while I have gasoline on the floor from the carb overflow)

Rapid clicks. Low battery, bad grounds. Maybe bad solenoid.

What is battery voltage?

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The goal - Reliable summer driver interspersed with mechanical tinkering...
Motto - "Driving fifty in the twisties..."
On Mods - It's your damn car - Do what you want. Haters gonna hate...
On SUVs - Drive your B like a soccer mom is texting her friends about how she wants to kill you...
Red Betty - http://www.mgexp.com/registry/GHN5UH418165
Bart - http://www.mgexp.com/registry/GHD4U146898G

Larry... it's a ballast coil, so I believe it should be 1.5 Ohms and 6 Volts, as opposed to the non-ballast ones that are 3 Ohms and 12 V.

Dan, Battery is reading 12.4 Volts, but I have it plugged in to the charger and I am still not getting anything. The rapid clicks only occured when I tried to hotwire the engine... otherwise I'm dealing with a single click.

EDIT: It's a COL202 12V Ballast coil... can't find anywhere what the resistance should be.



Edited 1 time(s). Last edit at 2015-07-29 11:52 PM by Nyiballs.

Taking stabs in the dark...

What would happen if you disconnected the ballistor and biased it, then getting a reading? Or trying to start it with it bipassed?

Have you checked your connections at the starter? I had a red (?) wire that used to come loose and wouldn't allow me to start the car. I also found a small break in a brown wire once.

Is there a way to check the ignition relay?

Could it be the key ignition, under the dash wiring?

Again, just complete guesses that may or may not make sense, but hopefully might trigger a thought

Good luck

So your car is actually a 74.5 RB then ?

Proof conclusive that it's the solenoid contacts.

This is what they can get like, you can buy a whole solenoid or you can get a repair kit which requires some work with a soldering iron.

EDIT: forget about coil resistances, 1.5 ohms is right but that is not your problem.



Edited 1 time(s). Last edit at 2015-07-30 01:34 AM by ErnieY.

To summarise

not coil
starter solenoid suspect
needles and seats very suspect ~ overflow ~ should never happen.

Order of repairs

New needle valves and seats
Starter solenoid ~ repair or replace

Herb

You have mutiple problems. Fuel pouring out of the carbs has nothing to do with the no-start. You have stuck needle/seat valve or a float that's full of fuel. Check the floats and the needle valves in the carbs.

The no-start is a separate issue. Hook your charger directly to the hot side of the starter. If it doesn't crank, you have a bad starter. If it does, it's the solenoid of the stater switch itself. Check voltge at the solenoid with the key turned to the "start" position. If the voltage is below 12.5, it's the switch. If it' 12.5 or higher and no start, it's the solenoid. Call, pm or email if I can hep. Basil 707.762.0974 basiladams@yahoo.com

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Basil C. Adams
1956 MGA Coupe (Show Car)
1957 MGA Roadster (Driver)
1958 MGA Coupe (Racecar)
1959 MGA Coupe (unrestored)
1960 MGA Coupe (unrestored)
1960 MGA Roadster (Driver)
MKIII Elva Courier (E1056)
1967 427 Cobra
1972 Alfa Romeo Montreal
A coupla late MGBs
1960 Austin Healy BN7
More Cars than Brains

Would a bad solenoid cause the car to die whilst driving though? It first crapped out mid-use.