something is very wrong. when i try to start my engine, the starter cranks for about a half second and then quits. and one of the ground wires gets really hot when i do this. so hot in fact it burnt through the rubber coating and through electrical tape!



what the hell is goin on with this thing?

My guess is a bad ground. I would look for a loose ground connection. Others will chime in.

Steve

try hooking your jumper cables to just the negative side of the battery and the engine block and see if the car cranks ok if so you need a new ground cable to the engine block.. if you o't have a good ground to your engine when cranking the starter the ground will come from enywhere is can and in your case it's through a little 16 guage wire wich isn't nearly enough for the amperage that a starter pulls

edit: i would also look that harness over really good because if it is getting that hot it may have burned it's way through some other wires in the harness.. you may have to pull all the tape and sheilding off to look

[This message has been edited by 86 toy (edited 02-15-2011).]

High heat = high resistance. Check the cable from the battery to the block, replace if it's more than a couple years old with a nice 4 gage or bigger cable.

You are supposed to have the battery cable go from the battery to the block. That cable is open, and the secondary cable from the negative terminal to the frame and the cable from the frame to the engine are carrying all the load. Those cables are way too small to carry that much load and are heating up bad.

Replace BOTH battery cables.

Check/fix engine bay grounds...
Bell housing to frame, black think wire
Engine head to frame, braided "wire"
battery to head and frame

See my cave, wire service in general electrical.

And Where is that picture took?

You have alot more problem to fix...

1. Get Service Manual, http://www.fieronews.net/fusion/downloads.php
2. See my cave, wire reading in general electrical. Tell you how to read wiring diagram.

See Ground Distribution diagram, Circuit 150. G202, G504, and S213 and wire for them is primary concern. S212 and G201 needs checking/fix.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

ok ill check the grounds tomorrow.

that picture was takin inside the cab by the fire wall. why do you say i have a lot more problems?

oh, and this is a 3800 sc swap in an 84'

Because the hot ground wire most likely melted into other wires on your harness.

well i realized it wasnt as late as i thought it was, so i went outside with a work light to see if i could find the problem. and guess what! i did. it was a bad ground connection. i feel like an idiot. but i fixed it and the starter works fine now! so...

thanks for the help everybody! super appreciated.

since its dark out now i will wait till tomorrow to check to see if the ground hurt any other wires. god i hope not. i hate electrical!

84? Even Worse. You hate wire? Fix it now or fix it later after car dies on highway...

the ground that you fried...
Major Ground circuit 150. Ground for:

Fuel pump and sender
most all lights, inlc idiot lights and tail lights
lighter
A/C/heater controls, blower, and mode motors
cruse
radio
washer pump
instrument panel
etc

See 84-Fiero-Electrical-Diagrams.pdf


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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

[This message has been edited by theogre (edited 02-15-2011).]

yep. ill see what the damage is tomorrow. ill just replace that ground wire anyway though. everything was working fine. so i dont think too much damage happened. but like i said ill know tomorrow

AND, theres a thread here named "everyone who has a 6 cylinder, read this" .you need a real good ground ,battery to block, 1 from body to frame, 1 from engine to frame. good grounds take care of alot of potential problems.

quote Originally posted by RWDPLZ: High heat = high resistance. Check the cable from the battery to the block, replace if it's more than a couple years old with a nice 4 gage or bigger cable.

^ this ^
due to: poor/dirty connection or
old cable - copper corrodes - turns green & get WAY 'resistive'
likely your (+) cable is bad as well.

Another problem I encountered with the 84's (not sure if every year was like this) is that the fusible links that connect to the starter (+) post were always giving me problems. the wires were getting old and brittle and they get exposed to a lot of heat being so close to the cat. I ended up re-routing them directly to the positive post of the battery, I picked up a new battery post bolt that has a stud and nut (used mostly for adding accessories like amps to side post batteries), connected the new fusible links to that and have had no more electrical issues.

If/when the A fuse link fail on 84 and below GM models... You can fry ECM and other things.
See cave, alternator sense in change & start section.
And see https://www.fiero.nl/forum/Forum2/HTML/113614.html

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)