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starting problem with 1990 mustang please help

941 Views 9 Replies 6 Participants Last post by  Hockeyman48
ive been reading so many old threads all over google.ive trues a bunch of stuff and im getting really frustrated with this now..hopefully someone can help

before i pulled my motor car was fine.
after sitting for a few monthes i finished my motor and the car would start fine..took it for a test drive then it cut out down the street and didnt wanna start it back homeand started messing with has new 3g battery new first i didnt relize i didnt have the ground from the frame to the post so i thought it was that.then i added it and now it still wont start.i took the battery to get charged cuz it was a lil low.when i got it back from autozone i plugged it up and the car started fine about 2 or 3 times.less then 15min and the car wont start..i have 2 gronds stratps from my motor mounts to the frame.i added a ground from my block to the frame also and also added a ground from the negative post to the frame.also has fromneg post to timing chain cover to complet the loop.and still wont start.all surfaces are clean and sanded to bare metal.also have the ground from the fuel inj harness connected to the bell housing..all my wires seem to looknew ..but only when i put a new battery it will start.then after a few starts it will seem will crank really slow and sluggish then just click and i can hear a hummm.soi know it something electrical cuz it works fine with a new bat..please helpany ideas u might have..thanks
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ive also tested all my wires going to and from my alt,my starter and from the coil all have 12.6-7volts
something is getting constant power, and draining the battery fast. leave the battery in the car hooked up to a charger, and leave the key off, and start testing things and seeing what if any has power.
Sounds like a short or you have a vampire of some sort.

Short can be caused by a old, frayed wire or something not being grounded correctly.

A vampire could be something as stupid as some change in your cigarette lighter or an accessory that isn't being shut off with the ignition. One of those things that could take hours, day, and weeks to find and it will be something you will hate yourself for not thinking of earlier.
That sounds pretty reasonable..but how would sonething draining it be able to kill the battery with in minutes..ill try looking into that tho.I haven't touched it in 3 days so ima go checkb the battery and see if its lower.keep em coming
You have to look back on what you have done. So often, and I fall into this category as well, we do modifications and then wonder why our stuff ain't working.

It sounds like you added a ton of ground wiring...I'm wondering why? What was wrong with the stock ground wiring? In any event, it may be a good idea to retrace your wiring efforts and double check for shorts.

If it wasn't doing this before your work, and it's doing it now, I would think it's related somehow to something you did.
it originally had all those grounds..i only added an extra one.i heard the ssp chp coupes came with extra grounds to help with all the electronics they came with..idk if its true or not..i just went out to the garage and it started right up..bat was at 12.75 before i started it and it was at around 14 while it was running..its sat for a few days with the battery connected and over time it will start but after a few start ups with in say an hour it willl give out..idk its really got me:confused:
I only skimmed though your posts so I might be missing something but from what I did read it seems to me that the problem is your alternator, especially if the car died while you were driving(due to no power I assume). Further, on that point, you said you did the 3G upgrade so I would check alternator wiring make sure its putting out like it should. Your car wouldn't have died while driving if the alternator was working no matter how bad your vampire is if you actually have one.
It wss tested at AutoZone 3 was good
Sounds like a starter or solenoid issue and/or maybe old cables(positive and negative) causing your starting problems.I'd start by replacing the positive cable to starter and negative cable to block.The terminals on the cables can deteriorate internally and not be noticeable to the eye.They can pass an ohm meter test at low current but not be able to carry the high current necessary to the starter motor.Cables are fairly inexpensive and the age of them is up there ,so I'd try that first.Also the starter motor could be starting to go out.If you have access to a battery load tester,test it early in the morning(when it starts) and then test it when it wont start and compare readings.This will tell you if its a charging circuit/battery problem or a cable/solenoid/starter issue.Good Luck
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