So the battery is mounted where the spare tire used to be. The neg wire is bolted right to the front metal next to the headlight (front trunk wall). The engine has two large ground wires from the engine to the spaceframe metal, one on a rear fender well and one on the trunk wall. I have heard some people say the neg cable needs to run all the way back to the engine. Does it? Thoughts?
[This message has been edited by 2.5 (edited 10-25-2016).]
It sounds like you only have one point of contact from the negative battery terminal to the chassis. IMO, you should add a second. That second ground might as well run back to the engine compartment. I'd even go one step further, and have the second ground cable attach to the firewall, on the same mounting stud as the cable coming from the engine.
Actually I did exactly that, because having only one ground cable (attached to the chassis up front) eventually resulted in a hard-start condition. That connection developed a little bit of corrosion on it (which is inevitable), and increased the resistance of the circuit just enough to make the starter drag a little bit. My options were to clean and re-grease that connection every few months, or add another ground cable. I decided to run a 4-gauge wire from the battery back to the decklid hinge (the engine ground strap also attaches there), and that cured the problem. The chassis ground up front is still there, also. So the electrical load is split between the two.
[This message has been edited by Blacktree (edited 10-25-2016).]
The negative does not need to run all the way back to the engine. As long as you have a good ground from the motor to the frame and the battery negative to the frame it will be fine. That is how my Camaro is and it would not be any different with the Fiero.
I have heard some people say the neg cable needs to run all the way back to the engine. Does it? Thoughts?
I'm of the camp that feels the more grounds, the better.
I used two "positive" battery cables (taken from a couple of GM cars with their batteries under the back seat) for the front-mounted battery in my Formula. Obviously one of these cables was used as a negative cable... that ran to the rear of the car. What I like about these cables is that each end has a secondary cable several feet long. My negative cable in the front is connected to the battery (doh!) and to the front frame, and at the other end the negative cable is connected to a tranny mounting bolt and also to the rear frame of the car.
[This message has been edited by Patrick (edited 10-25-2016).]
It sounds like you only have one point of contact from the negative battery terminal to the chassis. IMO, you should add a second. That second ground might as well run back to the engine compartment. I'd even go one step further, and have the second ground cable attach to the firewall, on the same mounting stud as the cable coming from the engine.
If I did. How would you start that second cable on the battery end? Would you replace the thick neg cable I currently have with one that has a fat cable to run to the back and a thin cable that grounds up front? I haven't ever seen a double fat cable that can hook to a battery.
I'm of the camp that feels the more grounds, the better.
I used two "positive" battery cables (taken from a couple of GM cars with their batteries under the back seat) for the front-mounted battery in my Formula. Obviously one of these cables was used as a negative cable... that ran to the rear of the car. What I like about these cables is that each end has a secondary cable several feet long. My negative cable in the front is connected to the battery (doh!) and to the front frame, and at the other end the negative cable is connected to a tranny mounting bolt and also to the rear frame of the car.
The secondary cable, would be what I refer to in my post just previous , should it be as thick as the primary cable?
The secondary cable, would be what I refer to in my post just previous , should it be as thick as the primary cable?
If the "primary" negative cable goes all the way back to the engine... no. The "secondary" cable would just be handling the grounds for relatively minor electrical draws.
However it is you wish to run the negative cable(s), there needs to be sufficient capability to handle the grounding back to the battery for the starter. You can't be adding to the resistance by reducing the total thickness of the cable(s) used for that purpose. By running the main ground cable back to the engine itself, there's not going to be any chance of a problem.
[This message has been edited by Patrick (edited 10-25-2016).]
In an ideal world, a nice heavy ground connection to the spaceframe coupled with a nice heavy ground connection from the engine to the spaceframe would be sufficient. In reality, ground connections tend to build up oxide layers between the connections. Oxide is an insulator, so the resistance starts to climb at the connections causing all kinds of problems. Multiple ground connections is good. Periodically inspecting, cleaning and tightening grounds is better.
I will have to look this car over well. I acquired it earlier this year, its not stock and has a smallblock chevy swap. For all I know the only ground the starter is getting is through its mounting bolts thru the block then to the spaceframe.
I found this useful list of ideas on a Jeep forum ( so be aware hes talking about a 70s Jeep) :
-
"First off...
Take a look at the corrosion on your alternator case, look for paint, rust, ect. on the metal brackets...
All that corrosion/oxidation is NON CONDUCTIVE (for our intents and purposes) and it's a real restriction for your alternator, starter and everything else on the vehicle to 'Ground' through all that
Secondly, If your starter gets a 6 Ga. or 4 Ga. Positive 'Feed' wire, Why doesn't it have a direct, 6 Ga. or 4 Ga. 'Ground' wire?
(The reason is the factory was CHEAP! It saved money NOT to put those dedicated 'Grounds' on the major electrical component groups)
With Direct Current (DC) flow, you need the same size 'Feed' as you do 'Ground', and just as direct a path for the electrical device to work properly.
This is just simple electrical FACT... The better the 'Ground Path' (Negative Connection) the better that electrical device is going to work, no matter what it is...
MAJOR, HIGH DRAIN DEVICES NEED DIRECT, DEDICATED GROUNDS.
SO!, Running the 'Ground' wire to the engine head might help with 'Grounding' the temprature sensor and the Secondary (High Voltage) part of the ignition, It's REALLY HARD on the Starter, which is your highest electrical draw on the vehicle if you don't have a winch...
It makes MUCH MORE SENSE to have the 'Primary' or 'Large' ground wire connected to a starter bolt so the starter gets a good 'Ground', Then worry about the smaller stuff with 'Dedicated' grounds from there (or from the battery Negative terminal. ----------------------
THIRD,
Your alternator produces every single usable electron of current for your vehicle. WHY TORTURE IT!
Anything the battery stores, then puts back out is resupplied from the alternator, and the alternator creates every electron the vehicle uses in it's normal operation.
Why not dedicate a 'Ground' wire to the case with a NON-CORRODING contact so that alternator doesn't have to work twice as hard trying to overcome all the restrictions/resistance of the case corrosion, rust, loose bolts, paint, or what ever?
If a 10 Ga. wire is connected to the 'Positive' on the alternator, Then connect a 10 Ga. to the case so the 'Negative' can have a direct path back to the battery! -----------------------
Fourth,
STEEL is a HORRIBLE conductor of electricity for our purposes. Torturing the 'Ground' to the Head Lights, Dash, Ignition, Tail Lights/Fuel Sender doesn't make sense either.
A simple 10 Ga. 'Ground' wire hooked up to the 'Ground' terminal on the head lights/side lights/turns signals in the front will clear up a BUNCH of problems with those lights.
A simple 10 Ga. 'Ground' wire hooked up to the Dash, then going up to the wiper motor will solve a BUNCH of gauge problems, dash light problems, and wiper problems...
A simple 10 Ga. 'Ground' run to the back of the vehicle connecting to your tail, brake, plate light, side markers and fuel tank will take the guess work out of those circuits.
YES, it costs you a couple of rolls of 10 Ga. 'Black' wire, and YES you will have to run those wires through the harness with the other wiring, but it stops so many problems you won't believe it!
There are also SPECIFIC grounds you need to be aware of, Like a DEDICATED GROUND to the engine head then over to the ignition module. The engine head ground helps out the temp sending unit, the SECONDARY ignition (Spark Energy at the plugs) " -
Thoughts?
[This message has been edited by 2.5 (edited 10-26-2016).]
Can't argue that steel is a horrible conductor, as compared to copper.
I use 2∅ welding cable on positive and ground, both to the starter. Soldered copper lugs on both ends. Remember, with DC, the more strands in the cable you have (surface area) the higher the ampacity of the cable. This is important in sudden, heavy load applications such as when starting a car.
Originally posted by Patrick: I'm of the camp that feels the more grounds, the better.
Is a myth. Added grounds can cause "Ground Loop" problems. See google for this term. All it takes for headaches is 1 loose connection or iffy corroded wire to make a lot of noise etc. (Many times people who do audio work for stage etc have seen, often hear, this.)
Is better to emulate the GM setup and fix any missing/iffy grounds then just throw in more wires. If needed replace cables/wires with heavier ones but don't add new ones without a very good reason.
Battery Main cables are best when goes to engine and starter. You have less points of problems when you trying to find what's wrong. If you keep battery to car and engine to car then must make sure you go to heavy frame parts not sheet metal. All connections need metal to metal contact and silicon grease.
Why? If you have Any grounding problems, Coolant is very Conductive and will try to be a ground path and quickly cause big problems by "eating" hoses etc inside. Even Brand new hoses can fail fast and blow out when this happens, often w/ little or no warning. Starter current can be 120+A normally and a lot more when have any voltage drop from the battery and wreak havoc on the coolant system. (See my Cave, Electric Motors) And yes, Alt is grounded thru case, hardware and engine block can energize coolant too when engine is not properly grounded to car and/or battery.
------------------ 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)
Is better to emulate the GM setup and fix any missing/iffy grounds then just throw in more wires. If needed replace cables/wires with heavier ones but don't add new ones without a very good reason.
Did the GM setup neg cable go to the starter or the engine block? I think on 4 cylinder Fieros it is on the head. I suppose if it is on the bolt that holds the starter to the engine block...best of both worlds?
I don't remember seeing a negative cable run to the engine on the GM rear battery cars like auroura or riveria. I think they used the body. When I moved mine to the front I just used a long positive from one of those donors, and a battery to front spaceframe negative that had two ends grounded up front. The Engine is grounded in 3 locations with large wires, to the rear frame and cradle, along with a braided strap from frame to cradle. I have not had any issues from it, but I can't deny that a Neg. to the engine would be "best" for a reliable all season daily driver situation.
[This message has been edited by gen2muchwork (edited 10-26-2016).]
Did the GM setup neg cable go to the starter or the engine block? I think on 4 cylinder Fieros it is on the head. I suppose if it is on the bolt that holds the starter to the engine block...best of both worlds?
Ground is on front head, inboard of passenger hingebox on the V-6.
I'm of the camp that feels the more grounds, the better.
quote
Originally posted by theogre:
Is a myth. Added grounds can cause "Ground Loop" problems. See google for this term. All it takes for headaches is 1 loose connection or iffy corroded wire to make a lot of noise etc. (Many times people who do audio work for stage etc have seen, often hear, this.)
Well, make sure there are no iffy connections then.
My original comment was being somewhat factious. My main point was that it's probably not a good idea to be taking chances with a single ground from engine to frame which may not be capable of handling the needs for a starter motor (such as can occur when the negative cable from a front mounted battery only attaches to the front frame). IMO, running the negative cable from the battery all the way back to the engine/starter eliminates this potential problem.
[This message has been edited by Patrick (edited 10-26-2016).]
For my front battery setups, I weld a stainless steel bolt to the front frame rail to make a corrosion free ground lug. Then run the heavy ground from the battery to this lug, then another heavy gauge wire from the lug to the back to the engine block. All my cables have the lugs soldered vs. crimped, then covered with heat shrink.
Originally posted by 2.5: Did the GM setup neg cable go to the starter or the engine block? I think on 4 cylinder Fieros it is on the head. I suppose if it is on the bolt that holds the starter to the engine block...best of both worlds?
Both engines have short neg cable to head from the factory. Head(s) and block grounds the alt starter and other minor items.
You don't want or need to use a long Neg cable then OE when have factory setup. Front battery neg cable still ground to block or head, even bell housing bolts w/ stud heads, but not starter bolt. GM Starter bolts have a long history of get loose or even falling out and bad things can happen w/ major grounds have problems.
The negative does not need to run all the way back to the engine. As long as you have a good ground from the motor to the frame and the battery negative to the frame it will be fine. That is how my Camaro is and it would not be any different with the Fiero.
True, but you are trusting, spot welds to carry the power,, it will work,, but I have always run the - back to the engine.. I've never had an issue with cranking,, and others have had to get off the line or track on a hook..
If done correctly, you don't need a long neg cable. You need good connections from the battery to the chassis and chassis to engine. I would run multiple cables on the engine/chassis end and periodically check the battery to chassis connection... remove it and clean it every once and a while.
Up to you, but the chassis is one be ground cable, it is the connections that go bad.
(edit... this is how some new cars are setup)
[This message has been edited by jaskispyder (edited 10-27-2016).]
True, but you are trusting, spot welds to carry the power,,
You are also trusting them to hold your car together!
I've always welded a stud to the front cross member and earthed to that from Battery. Up back, weld a stud to strut tower and take engine cable to that. For the +ve, I take it back to the starter and then from there, to the power distribution, that way starter has a straight connection to the battery. Never had any problems.
The real answer though is that there are lots of ways to do this and in reality, one way is probably no better than another for the most part. I do mine my way, others do it their way.
------------------ Anything I might say is probably worth what you paid for it, so treat it accordingly!
For my front battery setups, I weld a stainless steel bolt to the front frame rail to make a corrosion free ground lug. Then run the heavy ground from the battery to this lug, then another heavy gauge wire from the lug to the back to the engine block. All my cables have the lugs soldered vs. crimped, then covered with heat shrink.
So don't need two fat neg cables off the battery post, but the way you did it is more of a bridge to join it together without having to use the spaceframe as the path so much.
[This message has been edited by 2.5 (edited 10-27-2016).]
If I did. How would you start that second cable on the battery end? Would you replace the thick neg cable I currently have with one that has a fat cable to run to the back and a thin cable that grounds up front? I haven't ever seen a double fat cable that can hook to a battery.
I guess you could say I cheated. My Fiero has a master cutoff switch next to the battery. The switch has threaded studs for the cable connections. So stacking battery cables is easy. The two ground cables connect to one side, and a single 0-gauge cable runs from the other side to the negative battery terminal.
When I bought my 3800 it had issues starting and would crank forever before it finally would fire. I found out that it was a grounding issue so, I ran a short negative cable from the battery down to where the horn bracket bolts to the frame since that's nice thick metal. And then I made sure that the motor was grounded to the cradle, haven't had any issues since.
True, but you are trusting, spot welds to carry the power,, it will work,, but I have always run the - back to the engine.. I've never had an issue with cranking,, and others have had to get off the line or track on a hook..
The PO of my car did it the same as you. I have had the car 3 years and 30,000 miles. No problems so far.
Is a myth.
