Couple of Wiring Harness questions (Page 1/1)
fierocarb MAR 17, 10:36 PM
First, what is the difference between a 86 SE V6 automatic engine wiring harness and an 88 V6 manual engine harness.

Secondly, what is the difference between a 88 V6 manual engine harness and a 88 2.5L automatic engine harness?

The car is an 88 Formula with manual V6 in it running a transplanted harness from a 86 SE V6 automatic. But the alternator is having trouble charging with anything on (lights or fan or really anything) at idle (does charge with rpm) Wiring was converted to a CS alternator. The car is Carbed and at one point all wiring plugs that were not needed were cut out thinking possibly i cut out something that was needed after all or the pins in the C500 are not lining up right. I have a 88 2.5L automatic with a blown engine, so trying to determine path or least resistance to check.

Yes I checked grounds, yes I tested the battery while the car is running and with load and the gauge is reasonably accurate, yes the lamp comes on with key turn and the battery holds a charge fine when it gets it, the belt seems tight and the pulley is 2 3/8 diameter.

This has been this way for years. It's a summer, sunny day car and I live in the country so not a lot of idling so it was livable. But with everything closed down I have some time on my hands so I'm looking to fix it. Please no crap about going carb.
olejoedad MAR 18, 07:55 AM
There are too many differences to list between the harnesses.

To check your charging issue, be sure that you have 12 volts with key ON to both wires on the small plug on the alternator.
theogre MAR 18, 07:21 PM
Lets assume Alt and Battery are good... (Likely not but say so for now... Have alt tested at auto part store.)

If some fool put a "power pulley" on the crank then can spin the alt too slow cause low amps regardless volts @ battery even w/ stock alt pulley.

Alt mounts are ground for the alt. crap/paint on alt, bracket and engine can F'd that ground. Chrome on any of that doesn't help.

See my Cave, Watt Story and rest of alt pages then read more electrical if needed.

Check w/ Ω meter won't help much if any. Wire sizes are too big to use standard meters including "Pro" meters like Fluke 77 etc.
Look up "voltage drop test" instead.

Should see ~ 14.7v anytime the engine runs but if belt slips or have power pulley the alt won't make Amps even is get right volts.
Full Charge battery should be 12.6 - 13v after running the engine.

You likely need a AC/DC Amp Clamp or other method to read high amps. You will blow the fuse or fry most standard meters w/ 10 - 20a range.
Example: https://www.amazon.com/Tool...icator/dp/B07H7BN6L8
these cheap options have guide/marks on the back so can read just by holding wires on the marks
Can test HL loads and others but might not read loads < 10a.
May not be best but give you ballpark to show problems.

Don't bother getting Used Amp Clamps... almost always they are AC only clamps use by Building Electricians dealing 120vac and high and won't work.

Notes:
High Watt HL eat a lot of Amps. If Alt has issues, this only make more problems.
If Rad Fan and other E-motors see low volts for any reason them will try to pull more amps to makeup for this. See my Cave, Electric Motors

------------------
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(Jurassic Park)

The Ogre's Fiero Cave