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78 MGB wont start


NowhereFast
09-21-2005, 07:43 PM
hi

i have a 1978 MGB and it ran fine one day and then the next day i went to start it and it wouldnt start. so i jumped it and it ran fine. the next day i went out to drive it agian and the battery was dead so i went and bought a new one. i brought it home got it all hooked up and it wouldnt start. i can hear the fuel pump but nothing is happening. all the lights work and stuff but still no start. i tried jumping it and nothing. i also took the battery back and they said it was fine. i was wondering if anyone can help me or give me some tips as to what might be wrong. thank you very much for anyone that can help me.

KimMG
09-22-2005, 12:34 PM
Make sure all connections at the starter are clean and secure.
Make sure the ground cable connections from battery are clean and secure to the body.
Check your alternator belt.
Check the electrical connections to your alternator.
Is the red ignition light staying on while you are driving?
Check the starter relay.
Can you push start your car?
Using a wiring diagram to help trace the wires, check your ignition switch. Making sure power is going to the starting circuit.
The Bentley repair manual has the best wiring diagram for your car.

Flash75
09-22-2005, 02:48 PM
I assume when you say nothing is happening you mean the starter isn't cranking the engine over. It sounds like you may have a bad start relay or ignition switch. But you should go through the points Kim mentioned as they are easy to do. I don't have a rubber bumper car and don't know the exact location of the start relay. I think it's in the rear of the engine bay on the right inner fender area. It will have four terminals. They a labeled C1, C2 & W1, W2. C1 should have a brown wire and C2 will have a brown wire with a white tracer. You can remove those two wires and clip them together, bypassing the switch and relay. Be sure the shifter is in neutral and the handbrake on because the brown wire is live and the starter should start running when touching the wires together. If if does you problem is probably from the relay toward the ignition switch. If it doesn't turn look for bad connections at the starter solenoid or check the starter. Good luck.

Clifton

NowhereFast
09-22-2005, 03:02 PM
thanks alot for your help both of you. i will try these steps and hopefully it works. if not ill be right back here.

MGBSS63
09-22-2005, 09:35 PM
There are 2 relays on rs upper fenderwell. 1 is starter 1 is cooling fans.Do what flash said.If i remember right the emergency brake is somehow tied to the ignition curcuit.I don't have diagram handy maybe someone else does.mgbss63

imnezrider
03-17-2008, 07:59 PM
Always start with the basics. Make 100% sure you have a good ground at your battery cable. Next, don't "assume" the battery is fully charged. It's super simple to check. Get a good volt meter and take a reading. The following chart will be informative.

Proper Voltmeter Readings State of ChargeMaintenance FreeLead- Antimony100%13.0v12.7v75%12.8v12.5v50%12.5v12.2v25 %12.2v12.0v

If that checks out, go to the starter. Remove it from the engine *not difficult). You can do a simple bench test. Read the following carefully:

http://www.misterfixit.com/starttst.htm

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