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Discussion Starter #1
i am relocating the battery to the trunk. i ran a 2 gauge wire from the + up to the starter solenoid. and im grounding the battery to the frame, quad shock bolt, also 2 gauge. i also plan on grounding both heads from the crossover pipe bolts to the frame. and i will ground the block to the frame. all three engine grounds w/ 4 gauge wire. is this enough? do i really need to ground the intake? and any suggestions where to ground the heads and the block, obviously the frame, but any specific bolts? and i read that the computer has to be grounded to the battery. is this true? would it hurt to ground the computer to the frame, like in the same spot as the block ground? should i put a fusible link in the battery ground? if so, what rating?

i really appreciate any advice/help
 

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Cylinder heads are generally not the best place for a high current ground. The only ground path to the block is through the head bolts, which almost always are a good connection, but not always. If the head doesn't have a good low resistance path through bolts (intake is even worse for a ground) current can flow through the valve train, and that isn't ever going to be good.

Most high current grounds are to the block or to a component that if (in some rare case) develops a high resistance any arcing or electrolysis will be harmless to bearings or critical surfaces. The bellhousing would be an excellent choice, and the timing chain cover nearly as good.

Best places to worse places in order for high current grounds:

Bell housing and engine block
Timing chain cover
Heads
Intake

The computer ground is near the computer, and most critical ground leads float back to that point. The LAST thing you want is the engine grounding back through the computer so your choice of multiple grounds is a good idea. You don't want the block floating up from starter current.

There are a few safety issues created when locating a battery in the trunk, one is the chance of fire if the positive lead to the solenoid (or starter relay) gets pinched to ground. I always relocate my starter solenoid to the trunk so the big heavy cable is only active during cranking, and it can go straight to the starter terminal to save lead length and keep the voltage up. I run a lighter number 4 wire up to a terminal where the old starter relay or solenoid was located, and I fuse that wire with a fuse link because it is always hot. But that's just me. I like full voltage when the engine is hot and not having to worry about a cable getting pinched and starting a melt down.

Tom
 

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Discussion Starter #3
ok so the multiple grounds is a good idea. heads to frame, factory ground to frame (factory ground from block or timing chain cover?)
should i ground the bellhousing to the frame as well? or would it just be overkill beacuse of the other 3 grounds up front and the battery ground to the frame in the back?

as for the + from the battery running up to the starter solenoid, im not too worried about pinching because i ran it behind plastic body panels and in padded areas. i would like to put a fusible link somewhere inline though. should i put it in the + or neg? and what rating?

what is the additional 8 gauge (i think) wire coming off the factory neg battery cable and grounding in the engine compartment?
 

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Discussion Starter #5
does the ECC have to ground to the - battery terminal? or can i ground it to the frame?

what size fusible link can i put in line, just to be safe? should it go in the + or - battery cable?
 

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does the ECC have to ground to the - battery terminal? or can i ground it to the frame?

what size fusible link can i put in line, just to be safe? should it go in the + or - battery cable?
The EEC grounds to the vehicle chassis inside the car.

The smaller wire from the battery to the vehicle chassis is the primary electrical system ground. It is a small wire because it does not normally handle much current. The alternator and starter both ground faily directly to the engine block, and they are the high current things.

You should "fuse link" the negative terminal if you trunk mount because it will be the only negative path. You COULD fuse link the plus, but the negative would be easier. I'd use a short #6 wire (like a foot or so long maximum) with a non-flammable sleeve (like Teflon) for the negative to chassis lead. Then if you ever have the positive fault to the chassis the negative lead will get red hot, melt, and open the circuit without the #2 battery lead melting or the battery exploding.

The computer will be fine as is. Don't mess with its ground.

Tom
 

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Discussion Starter #7
ok so that 8gauge cable that comes off the stock neg battery terminal can just be cut off when i remove the stock wire? it grounds to the chassis, right under the starter solenoid. or should i cut the wire right at the terminal and ground the end to the frame? or run it back to the battery and ground it back on the neg terminal?

i got a 100A manual reset breaker i was going to mount under the hood and run in line with the + would this be ok? i fugured that if the + does ground out i dont want it to cause other stuff under the hood to short or blow fuses/fusible links/relays, so id put the breaker in the + cable to kill the power in case of a short
plus the + is the one that runs back up to the engine compartment so if it does short id think that would be the 1st thing that would potentially catch fire
 

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There are two ground points for the ECM. One is the case ground(PIN 20 at the ECM). Which is grounded underneath the ECM, by a 10mm(I think) bolt. The other grounds are PIN 40 and 60 at the ECM. They are usually grounded behind the battery on the inner fender well
 
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