after replacing a bad starter motor on my 83 e21 i ran into some serious electrical issues.
i got all everything back on except for the brake booster. i hooked my battery up to test the new starter motor but when i touched the the positive terminal to the battery. sparks flew and the grounds near the driver side fender glowed red hot then bursted.
i got my grounds situated again and rans some tests and found that when the batteries positive lead to the engine is connected, i get the violent reaction for earlier. when i take that lead off the block i get my normal relay clicks and buzzing with normal and strong lights but no crank. i suspect there's no crank because of the new starter motor, i have suspicions that it may bad as well. i tried testing it by crossing the terminals to engage the motor with no results.
if anyone has any suggestions about the grounding issue im open them because ive exhausted my knowledge on it
First test I do with a starter replacement is test it off the car with jumpers to the battery, to test its good with an insulated thick screwdriver. Battery Positive Red Cables goes to the start solenoid and fuse box(smaller red wire), and the Alternator B + Positive terminal is connected to the start solenoid via a smaller red wire. Battery Positive terminal does not ever connect to the engine,,the engine is ground and is connected only to negative sources--battery negative terminal , alternator-it casing and the chassis to engine ground, the negative battery post has one more connection to the battery box.
Randy
Last edited by 320iAman; 11-17-2017 at 01:25 AM.
hey thanks for that ill test it. if you have any pictures of how your grounds and leads look id appreciate it if could see them because it sounds like i've got it right but maybe if i had something to compare it to i might find figure something out.
With sparks jumping there is a negative wire connected to a positive source or a positive wire connected to a negative source--a short. Someone here may have a wiring diagram that you can download.
Randy
Here's a copy of the wire diagram for 1981-1983
http://www.findmymerchant.com/images..._1981-1983.pdf
Be sure to save a copy.
Tbd
You dont need to take out the brake booster to change the starter, remove the support bar to the throttle body and remove the rubber hood that connects the volume air box to the throttle body, the starter motor and solenoid then slides in and out with enough room.
Randy
Last edited by 320iAman; 11-17-2017 at 11:09 PM.
you have your battery connections reversed or maybe the positive cable connected to the starter is not isolated and is shorting on the starter housing.
Tom D
77 e21 - m42
88 e30m3
04 330 dinan3
84 r1000rt
02 r1150rs
all of them gray
14 f800gsa - red headed stepchild!
Use this electrical troubleshooting manual to diagnose your problem. The original link was dead so I had to use archive.org to find it. https://web.archive.org/web/20161231..._1981-1983.pdf
thank you all for replying, i did find the issue it was a simple error, i had put the positive battery lead that goes to the starter on a ground. i don't know how i got them mixed up but it was an easy fix. now i'm encountering a new problem. it turned over, started, then died. now it only cranks. i believe there's no spark. any new suggestions?
Sure do! Compliments to the originators.
http://www.findmymerchant.com/images...l/ETM_1979.pdf
Tbd
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