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Ignition switch, or something else?

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Ignition switch, or something else? #1
curtis7420 Curtis Wright University City, MO, USA Sign in to contact 1975 MG MGB "The "B" 2003 Toyota Highlander 4WD 2010 Jeep Wrangler	Topic Creator (OP) Oct 7, 2015 11:15 AM Joined 13 years ago 4,032 Posts

With the weather being unbelievably nice my B has been my daily driver. The past couple of days I've noticed some strange things. First, my tach was acting screwy while starting the car (jumping up and down), but would quickly return to normal when the car started. Next/now, when I turn the key to the 2nd position there's no power showing - no ignition light glowing, not HEARING the fuel pump.. But, it will crank/start as usual. I'm not sure these two issues are connected, but could the second issue be the start of my ignition switch failing? What else should I be looking for? Loose connection somewhere?

TIA

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Re: Ignition switch, or something else? #2
rntanner Roger N. Tanner (Disabled) Oxnard, CA, USA Sign in to contact 1970 MG MGB 1977 MG MGB	Oct 7, 2015 02:53 PM Joined 15 years ago 4,348 Posts

Your strongest statement:

"Could the second issue be the start of my ignition switch failing?"

If you or your family intend to keep that car a long time, I would order a new Ignition Switch and install it.

If the remainder of your "old" wiring harness is in less than great shape, I would consider these folk's Wiring Harness.

Look on the black bar on the left. "WIRING HARNESS."

http://www.advanceautowire.com/

Yes, it is a lot of money. Yes, I have installed it on my 1977 MGB

Roger N. Tanner, Professional Engineer, Retired
Oxnard, CA USA
roger.n.tanner@gmail.com

Roger N. Tanner
Professional Engineer, Retired

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Re: Ignition switch, or something else? #3
ErnieY Ernie Y Albatera, Alicante, Spain Sign in to contact 1976 MG MGB GT	Oct 7, 2015 03:22 PM Top Contributor Joined 12 years ago 19,528 Posts

Loose wire or ignition switch seem favourite.

Personally I'd start with the 4 way white wire connector in the bundle under the bonnet.

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Re: Ignition switch, or something else? #4
Ex-Calif Dan D Dayton, OH, USA Sign in to contact 1968 MG MGB GT "Bart - Yellow And Naughty" 1977 MG MGB "Red Betty" 2006 Suzuki Grand Vitara "Suzi Q" 2012 Jeep Liberty "Tommy The Tank"	Oct 8, 2015 05:39 AM Joined 8 years ago 8,992 Posts

Agree with Ernie. I would also remove, clean and reconnect the ignition switch plug under the dash.

For the tach I would remove the connector at the tach, clean reainstall and remove clean and reinstall all the connecitos on the coil.

My tach was getting intermittently jumpy at steady state around 3700 rpm. It would hunt from like 32-4200. Cleaned hte connecitons and has been good for about 1,000 miles.

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

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Re: Ignition switch, or something else? #5
curtis7420 Curtis Wright University City, MO, USA Sign in to contact 1975 MG MGB "The "B" 2003 Toyota Highlander 4WD 2010 Jeep Wrangler	Topic Creator (OP) Oct 8, 2015 09:32 PM Joined 13 years ago 4,032 Posts

UPDATE

So after doing quit a bit more driving and really taking notice to what's happening, I observed:

Initially turning the key to the second position still won't show power. However, after turning the key to crank the motor, if it doesn't start, when it returns to the 2nd position, everything is normal. So, I'm gonna guess my ignition switch is starting to fail.

Secondly, I stopped for gas on my way home from the pharmacy. Started the car up and I had no tach, as well as other things on that circuit. I went under the hood and played with the third fuse, jiggled some wires, and all came back to life. So, looks like I'll need to do some cleaning at the fuse box. But, I will probably just purchase a new one because this is a reoccurring issue. Any known quality issues with new fuse blocks? I thought about picking up one of Limey's (sp?) but I already have an up-rated wire harness for my lights.

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