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alternator eater

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Sopwith_Camel

Sopwith_Camel

Jedi Knight
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well Shaggy ate two alternator in two days. i have been having starting issues, and i did have an issue a few weeks ago where the radio flicked off on each of the 12 speed bumps to get to my house.

please advise

the long story. big summer rally 8 hours away. I had a breakdown where the point closed up and the brown wires under the dash were hot to the touch. i re ran new white wires out to the coil because im trying to get the tach to work.
first day of the rally full tank gas bright sun car was very wet and it was hesitant to start the starter moter, ran well maybe need the points adjusted a little. about a half hour out i lost power pulled in to a gas station checked the points, the gap was good. the car started so i decide to press on it ran smooth till south of trondheim. i got rattled going through some construction. and the radio cut out. and the gas gauge started to move down quickly. so I pulled off for gas but it only took 16 liters but then it wouldn't start nothing to the starter sylinoid. so I push started it and turned for home. but got about a half mile. when i lost all power. called the tow truck. took the car to a mechanic who diagnosed the alternator. so i hoped on the train home. (five hour wait) got in at 23:15 and realized i had no tools to pull the alternator out of the mgb. texted my buddy down the street and he showed up at 8:00 with a full set of imperial tools.
I pulled the alternator out of the B gaither a selection of imperial nuts and blots. and hoped on the 10:30, i got back to Shaggy at 14:40 and popped in the alternator after swapping the pullys. about a 2 miilamiter offset. but it put out about 11.8 so I headed for home, shaggy ran strong. but at the wait for the construction site it started bucking . but stayed running, long down hill till i found a site to pull over. but the engine lookd to be running smooth the belt looked ok. had the road to my self heading in to trondheim passing along traffic jam heading south. but just north of Trondheim heading up a fast hill i lost power and that was it. flat bedded home.
 
If you are burning up wires you have a short. If things just stop you might have just a bad connection. Ice pick continuity testers are cheap.

Kurt
 
i ordered a new wireing harness. after 50 years its pretty bad under the dash. I have too many replaced wires.
 
Probably a wise decision.
 
just too many wrong coloured wires. patched in. and i think my skill set is up enough to handle it.
 
I agree with Kurt that your car has to have a short somewhere. The brown wires shouldn't get hot in normal use.

11.8V out of an alternator says it is not charging. Does the red charge warning light on the dash work? The warning light is more than just an indicator, it is a part of the charging circuit.
 
ahhhhh. I forgot that mine is North american car and has a different harness on this side of the pond. what is the big plastic block under the dash with a big connector. its on the fire wall. the new harness dosent have any thing for it. I recognizes the rest of the harness. and ive been labeling all morning.
 
thanks yes i have colourd it in photoshop and printed it.
IMG_7499.jpg
 
In the picture some text can be seen behind your fingers. What does that say?

I also see a bunch of (as many as 9?) colored wires going into the plug on the box. Can you list the colors? You may need to clean them a bit to confirm there are no secondary colored stripes on the wires.
 
When you get a chance, do try for a picture where the text on the box is not obscured and one that shows each of the wire colors going into the plug.

Your signature says that this car is a '70 Spridget. I have looked at the diagrams in the PDF I linked earlier. I did not see anything like what is shown in your picture. I was also surprised by all the yellow wires in your picture. Yellow wires are not common. I have usually seen them on schematics where the car has an overdrive which would not be the case with a Spridget. The box's plug also appears to have a purple/black wire. Purple/black is for the horn circuit. That further confuses me.
 
what i know of the car is it has a 67 dash and gauges. the tach is a 72 in the larger can of the 67. the engine is from my 72 but it might not have been original in that since that car had race paint when i bought it.
when i bought my mgb finaly a car that left the factory together wow was i wrong. back to the spridget Im thinking just putting in the european harness and patching to the rear harness. i wish it was june this is not a project for september. ahh with good sunlight and time to do the task, the box says "Pektron"IMG_7514.jpg
 
Sopwith_Camel said:
what i know of the car is it has a 67 dash and gauges. the tach is a 72 in the larger can of the 67. the engine is from my 72 but it might not have been original in that since that car had race paint when i bought it.

...the box says "Pektron"
Click to expand...

Perfect! I was able to Google Pektron and MG and found the thread linked below. In the link, read post #4 by Norm Kerr
https://www.mgexp.com/forum/mg-midget-forum.3/pektron.2059173/
Succinctly, it sounds like you need to change Shaggy's real birthday to 1974 or at least add '74 to his mixed pedigree for the body/wiring.

It appears the Pektron box was also used on the '74 MGB (probably others as well).

I like your idea to use the European harness and splice it into your existing harness as necessary. It doesn't sound like the Pektron unit is something I would want to get operational but that's just me.


EDIT: I also found a BL tech bulletin about the box. If you are really into originality (Shaggy doesn't sound like it! ) you might be able to get the Pektron box working again using the info in the PDF linked below.
https://www.triumphexp.com/article/mgb/TSB/TSB 14 Pektron Seat Belt Interlock.pdf
 
Good work Doug. 1974 was a bad year. Wife's '74 VW had a similar device that had failed when we got it. Fortunately I was able to completely bypass it by moving a single wire on the fuse box. Hope a similar fix works for Shaggy.
 
wow thanks.

yeah i think i should pull it out and put in the simpler european harness.
its going to be a tough weekend.
my next car has to be a matching numbers car.
steve
 
it lives!! ok its running. i can get it to winter storage.
i did a test drive last weekend and made it 30 meters and the wire to the fuel pump died. i hated the speed bumps on my street before now i realy hate them.
ok so I have one speed of winsheilde wipers. and i have no brake lights because the switch is bad......again. and I think the issue with the revers light is at the switch too.
I put the raido on the switch for the dash lights and the light switchs are some jaguar ones i had lying around.
the left right marker reperters . idont know how to hook up they need little cylinders on the back to the dash to clip into. and the dash lightes (leds) arent realy working.
the funny starting issue turned out to be a bad ground strap. engne to body.
yes im done for the season snow is on the mountain on the far side of the fjord.

steve
 
Great !

Hopefully your winter storage space is heated so you can sort out the wiring issues over the winter.
 
nope its just a barn. i stick it in in the fall and I get it out in the spring.
steve
 
nope its just a barn. i stick it in in the fall and I get it out in the spring.
steve
 
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