what are yours attatched to? i got a small black one on the left, (completely disconnected), and a thick uninsulated one on the right, (one side is connected to the engine, the other is disconnecte).

oh yeah i forgot, reardeck lid, 86 v6.

thanks ahead

The 4 main ground ties and positive leads.

#1. (-)Braided block to body ground deck lid hinge. The main braided strap is critical.
#2. (-)Trans to body. The trans to body is a backup.
#3. (-)Battery to body. Battery (-)post to tray.
#4. (-)Battery to engine block. The big batt cable (-)post to bolt on engine hoist hook.

Positive leads (+)

#5. (+)Battery to starter
#6. (+)Battery to main terminal below C500.
#7. (+)Alternator feed to main terminal below C500.

NOTE. The Ogre has mentioned that if #7 is bad, you will get large voltage drops under load just like a bad ground. We all know what bad grounds do to a Fiero's electrical systems!
All my life I have been a real stickler about good grounds and connections. It was theogre who taught me about those grounds and also the positive feeds on the Fiero so credit where the credit is due, all I did was to put it on a list for everyone to see.

[This message has been edited by jetman (edited 10-15-2004).]

so the braided engine to body should attatch to one of the 4 hinge attatching bolts. great! but i also have a small thin black wire completely disconnected that is attatched to the decklid by a small blastic tac. one side has a clip and the other has an eye.

quote Originally posted by dfoxslim: so the braided engine to body should attatch to one of the 4 hinge attatching bolts. great! but i also have a small thin black wire completely disconnected that is attatched to the decklid by a small blastic tac. one side has a clip and the other has an eye.

That wire is to ground the decklid to the body. The eye connects to one of the bolts on the decklid hinge, and the clip mounts to a small sheetmetal land on the underside of the decklid.

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GO BUCKS!!!

quote Originally posted by jetman: NOTE. The Ogre has mentioned that if #7 is bad, you will get large voltage drops under load just like a bad ground. We all know what bad grounds do to a Fiero's electrical systems!

just what exzactly do they do if there is a bad ground?

use your imagination. A lot of us have been chasing electrical gremlins, only to find out it was a bad ground. Do a search on my username to read some of my misadventures.

Dave

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85 SE 2m4 resurrected

quote Originally posted by jetman: The 4 main ground ties and positive leads. #1. (-)Braided block to body ground deck lid hinge. The main braided strap is critical. #2. (-)Trans to body. The trans to body is a backup. #3. (-)Battery to body. Battery (-)post to tray. #4. (-)Battery to engine block. The big batt cable (-)post to bolt on engine hoist hook. Positive leads (+) #5. (+)Battery to starter #6. (+)Battery to main terminal below C500. #7. (+)Alternator feed to main terminal below C500. NOTE. The Ogre has mentioned that if #7 is bad, you will get large voltage drops under load just like a bad ground. We all know what bad grounds do to a Fiero's electrical systems!

where is #2? any pic?

thanks,
tom.s

# 2 is a heavy 12-14awg wire from the front of the transmission, usually a bell housing bolt, to the left side deck hinge area. This ground is often wrapped into the harness.

A small correction to comments about # 7.

Yes, The Alt output cable can be big headaches. But...

Anything connected to the main terminal below C500 can cause problems similar to a bad ground. That junction is the single most important + connection in the whole car. Everything except the starter motor runs thru that for all Fiero but 84. (84 has some connections at the starter.) This junction is easiely over looked and very commonly loose corroded etc.

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The only thing George Orwell got wrong was the year...

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

Thank you for correcting me, I appreciate that.

All my life I have been a real stickler about good grounds and connections. It was theogre who taught me about those grounds and also the positive feeds on the Fiero so credit where the credit is due, all I did was to put it on a list for everyone to see.

I actualy made myself a 10 gauge ground from the trans to the space frame. I connected it from a M-12 x 20 mm -1.75 pitch bolt ( same as the transmission hose support bracket on automatic) to the M-8 bolt on the space frame that holds a small transmission hose bracket. Not exactly a factory stock item but highly effective.

Now on my 4-speed, I took off the ground wire on the left side deck lid hinge bolt and moved it over to the side of the deck hinge. There is a hole for a plastic wire loom which I removed and I was able to use a M-6 x 16mm bolt for a nice secure ground. That minor modification actualy looks cleaner.
EDIT,,,, My above 4-speed ground wire (clarified) is the trans to body ground, not the ground strap on the right hand deck lid hinge.

[This message has been edited by jetman (edited 10-27-2004).]

Ok, I am stupid, but what is C500? Is that a pinout detail or something?

Actually there are two grounds at the trans. I am surprised no one caught this the most important ground at the trans is the chassis ground for the O2 sensor.

Everybody needs to start reading the factory service manuals once in a while.

ok so dont call me stupod but what is the c500 connection and where is it

quote Originally posted by newfierokid: ok so dont call me stupod but what is the c500 connection and where is it

C500-- on my 84s, c500 is located in the center of the front firewall. It is the large connector that interfaces the engine/tranny components with the ECM, dash, ignition switch, fuse panel, rad cooling fan relay, etc. In other words, it's the connector that electrically connects the back of the car with all the rest of the car. It was moved over near the battery on later year models I believe.

C500 is the huge connector next to the battery on 85-88 Fiero. It connects the 500 and 400 harnesses to the 200 harness that runs thru the interior of the car. There are notes about the different harness "zones" in my cave. (Wire service article I think)

Under C500 is the main power junction. (This is also in wire service) That junction ties all the power feed for the whole car. The battery thin + wire, the alternator, and several fuse links for stuff inside the rest of the car. You must disconnect the battery before working on this item. One slip of a tool and you could do major damage by causing power spikes that rip thru the car even if you don't blow fuses or fuse links.

Depending on the version of Fiero you have... there are grounds bolted all over the engine and transmission. I've covered this many times now. A problem in any of them will often affect the whole car. I usually list the major grounds because the exact location of minor ones can vary by both year and engine package. O2 is just one of several. Both HEI and DIS also have engine grounds. Others are less obvious... You'd be amazed how many people, including many so called professionals, miss getting a good ground thru the mounting hardware for the alternator. If you aren't sure of the hardware, use a braided strap between the alt and engine block, making sure both ends bite bare metal.

ok still confued ill just have to go look in the morning

quote Originally posted by Dave Rodabaugh: That wire is to ground the decklid to the body. The eye connects to one of the bolts on the decklid hinge, and the clip mounts to a small sheetmetal land on the underside of the decklid.

Could you elaborate and possibly give a picture? Thanks. Mine looks like it has been disconnected for quite some time now. It would be nice to know where that clip goes.

dfoxslim,

You may of had a replacement ground cable installed. Does the small wire have a butt splice terminal or a ring terminal, or is it cut off?
As many of the others have said, there should be a large wire to the engine block from the negative battery terminal and a small one to the frame from the negative battery terminal.
If the small wire is cut or has a butt splice, it would be wise to reattach it to the frame (Strut tower for 84, deck lid hinge for 85 and up), as relying on the engine straps to carry the load also induces noise into the electrical system. In other words, if you get a whine in your audio system that changes with the engine rpm, you have ground issues! Or a bad alternator!

OOPS! Forgot to mention, the clip for the deck lid ground sometimes corrodes and breaks off... The plate it connects to is to reduce the ignition noise being radiated, which can cause a popping noise in the radio, AM more than FM... Not a big deal, but I have had this happen...

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crash... The Fierowrecker

[This message has been edited by Fierowrecker (edited 10-27-2004).]

i got my car out of my nieghbors yard and this (half assed gm (used to be mr goodwrench teacher) redid the wiring for me but he is old and dont care about what he does but he is cheap i checkd his wiring and its horrible. absolutly horrible the tranny was grounded to the plastic trunk some wires were diffretn colors its a mess

due to the fact that squirrels ate the wiring outta the car. it runs just the grounds are shitty n the rest of the wires are horrible.

im sorry for my mood im exhausted where do i get new wiring harnasses

Year? engine? Auto/stick? makes a differance.-B-

1984 se 2.8l stock automatic

That small black wire on the decklid is to remove electrical interference to the radio.
Don

quote Originally posted by 86fierofun: Could you elaborate and possibly give a picture? Thanks. Mine looks like it has been disconnected for quite some time now. It would be nice to know where that clip goes.

I think this one is the one you're asking about.