Alternator Problem? Mira L200S engine

mouse8899

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mouse8899

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Any sifus here willing to help?

Engine is a Mira L200S. Bought a new battery and crank it up. Response on the engine is slow and not revving fast enough. Multimeter reading is around 11-12+ volts.

Revved the engine and the reading stays at 11-12+ volts also. But when I disconnect the battery or the socket at the alternator, either one, the engine revs normally. What I can see here is there is only output for the battery and no input. When I connect the socket/battery back again, the engine idles very low. Positive battery cable gets very hot too.

Any help will be much appreciated.
 

nyantong

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nyantong

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Usually the alternator should have a reading of 13+ volts when revved. Its quite possible the alternator needs to be overhauled. But you should also check the alternator cable's resistance to make sure its the alternator thats kaput and not the cable
 

Supra_Fanatics

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Supra_Fanatics

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Does it matters or will it work if use a fake grounding cables? Like not the ori type?
 

vr2turbo

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vr2turbo

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Does it matters or will it work if use a fake grounding cables? Like not the ori type?
Fake in this situation, probably will not damage anything, except for it being of poorer quality, therefore not getting the full potential of the grounding cables....
 

mouse8899

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mouse8899

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before change battery also same, no charging. today swapped in a working alternator from my friend, there is charge but no the normal reading. grounding terminal should be okay, was using jumper wires.

previously - 11-12+v
good alt - 12-13+v (revving hard)
normal reading - 13-14+v

very suspicious reading so went and splice open wire harness alt>bat/ecu, found the single big wire insulation melted. possible cause of wiring shortage that's draining the power. gonna replace the wire tomorrow and see what happens. hopefully that is the cause... if not i don't know what to say.

will keep you guys posted on updates and thanks for suggestions/help
 

vr2turbo

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vr2turbo

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Oh! wanted to post that something is wrong with your wiring, because the rev drops after hooking the terminal back on, that is why I ask symptoms before battery change, to rule out the battery first. Looks likely that is the problem.
Let us know and if possible some pics of the damaged wire.....
 

mouse8899

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mouse8899

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yup, confirmed the main culprit was the big fat wire. :proud:
replaced wire now with normal engine response, but alternator still need to service.
will upload the damaged wire image by tomorrow

by the way, is there anyone that know of L200S ECU pin-out? was trying to find the tach signal that was taking forever... or can mount the tach signal wire to the 1 cyl on the distributor cap contact point?
 
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