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Won't start after tightening the alternator belt

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terri13p Terri P
Wallkill, NY, USA   USA
I have a 1976 MG Midget that won't start after tightening the alternator belt and trying to tighten the second belt. It cranks and cranks fine, but just won't kick over. I've checked for loose wires in case I accidentally loosened something when sticking the bar in to nudge the alternator, but I just don't see anything loose. I reseated the plugs to the distributor and to the core--still nothing. What did I do to my car?



Edited 1 time(s). Last edit at 2018-06-10 04:06 PM by terri13p.

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Kerr Avatar
Kerr Platinum Member Norm Kerr
Ann Arbor, MI, USA   USA
check the wires to the coil and from that to the distributor, most likely one of them came loose

if they are all connected, then suspect that a wire might be broken inside of the connector and take each one off and inspect carefully for that


Look the most closely at anything that is near where you were working.

terri13p Terri P
Wallkill, NY, USA   USA
Hi Norm...I re-seated every cable and wire I could see and still it won't start. It just cranks away. My neighbor took a voltage tester with a light on it and tested the coil, which was fine, and a few other things and found that it just wasn't getting a spark.

We took the distributor cap off to test the points but found that it's electric so no luck there.

Can you tell me how I would test to see if a wire is broken internally? I don't want to keep bothering my neighbor so I would like to learn to do this myself.

This all started because my fan belt was squealing, and we found that both belts were loose. Prior to tightening the belts the car started up with no problem and was running fine with the exception of maybe a little loss of power when starting from a full stop.

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ken472 Avatar
ken472 Ken Petersen
Luverne, MN, USA   USA
I'm guessing the non starting is not related to the belt tightening. Probably coincidence. I think your electronic ignition module died. No good way to troubleshoot it. I would switch back to points. Or borrow a distributor from a friend for a test. Jeff Schlemmer at Advanced Distributors will be a great help.

ken472 Avatar
ken472 Ken Petersen
Luverne, MN, USA   USA
I presume you have a shop manual. If not it's time to get one.

terri13p Terri P
Wallkill, NY, USA   USA
Ken: I think you might be right about the electronic ignition module. I think my next step will be to replace it. I don't think I'll switch back to points though because I am really just learning how to work on this car and I don't want to start something that I won't be able to finish--or that will get me into trouble!

Also, I do have a 600-page manual, but I don't know if it's considered a shop manual.

Thanks guys for all the advice. I'll let you know how everything goes once I replace the electronic ignition.

Kerr Avatar
Kerr Platinum Member Norm Kerr
Ann Arbor, MI, USA   USA
"Can you tell me how I would test to see if a wire is broken internally? "

Take an ohm meter, or wire continuity tester, and check that each end of each of the wires does, in fact, conduct from one end to the other. If you get continuity, even when you wiggle the wire, then it is confirmed good and move on to the next one.


Check for spark: take out a plug and connect its threaded portion securely to engine ground and spin the engine over and confirm if there's a strong spark. If there is no spark then here are some key steps to finding where an electrical problem is in your ignition system:

Step 1) confirm you have +12V at the coil + terminal when the key is in the "on" position. If you do not, then your problem is a broken wire between your battery, IG switch, and coil. I can't remember if a '76 has a ballasted ignition or not. If it does, then the resistor is another thing to check (if the resistor fails the engine will not run).

Step 2) confirm the spade terminal on the distributor, where the - wire from the coil is attached, does, in fact, connect to ground 4 times for each engine rotation. To do this, take out the spark plugs, put the transmission in 4th gear, connect your continuity tester: one lead directly to the engine ground and the other lead to either end of the wire that runs from the - terminal on the coil to the distributor. Push the car forwards (or backwards, doesn't matter) to rotate the engine through one complete rotation. Confirm the continuity tester does register that it is losing contact 4 times (that is the points opening). To do this test with an electronic distributor I think the key will have to be in the "on" position, to power the module. If you get continuity the whole time that you rotate the engine that means your distributor has a fault internally and the points are not able to break the connection to ground as they were meant to.

Step 3) if it passed step 2, then you can move on to the rotor, cap and spark plug wires. If it failed step 2, then your problem is in your distributor.

Step 4) If steps 1 ~ 3 all check out then take off the cap and confirm continuity of each of the spark plug wires (you can also measure the resistance in the wires, it may be a high number which is ok, just confirm they are all alike).

Step 5) confirm the rotor is good: take off the cap and connect your continuity tester between the top of the rotor arm and the engine ground, if there is continuity from the rotor to the engine ground that is bad, the rotor must not be grounded.

Step 6) confirm the continuity of each of the 5 posts in the cap (the center one might have a resistor in it, generally you use either a resistor in the center of the cap OR in the spark plug wires, not both).

If all of the above checks out, but you still have no spark, then check everything again, systematically, but try wiggling each of the wires as you check it. Also, check things in the assembly, rather than just on the workbench (a partial fault will sometimes not show up unless it is in the position with all of its surrounding parts).

Good luck, and let us know what you found!
N

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