Drag Racing Tech - Battery Relocation Wiring
06-01-2008, 09:02 PM
Sorry if this is a repost, searched and only found one thread but it didn't tell me much.
I'm relocating my battery to the trunk with the turbo install I'm about finished with. Currently I have no box and cutoff switch, but will once I get the car lined out and track ready in a couple months.
For now I have the battery in the back and grounded. I have a main hot lead that runs up directly to the starter. From there I have a lead that runs from the same hot post on the starter up and over to the stock + aux post on the fusebox under the hood. On that same stock + aux post on the fusebox I have a lead running to the alternator. I have also added one more engine block ground up front (8 gauge I believe - same as the larger stock one).
This is just to get the car going and basic-street tuned to put some miles on before going to the dyno for power numbers/tune. Once I add a battery box in the back and cutoff switch, will I be able to keep everything configured and routed as it is now?... with the only change of removing the alternator lead from the aux + post on the fusebox under the hood and running a new hot lead straight to the alternator from the other + side of the cutoff switch? This should work how I want it to right? Thanks
06-02-2008, 12:23 AM
Yes, you can run everything to one spot. It doesn't matter what goes to what. I ran my alternator wire to the starter and then the wire from the starter to the aux post when I didn't have a cut off switch.
When you do the box and cut off you will run the alternator cable directly to the battery cut off switch so it will not charge or send any power to the battery unless the switch is on.
06-02-2008, 06:27 AM
Sweet, thanks for confirming!
07-11-2008, 10:48 AM
OK...more 'issues' - possibly having to do with wiring the battery this way.
Batterys in the trunk, the Batt + from the actual battery goes to the starter, on the same starter post I have a ring terminal coming off the starter running up to the batt + spot under the hood by the fusebox. On that I have a lead going to the alternator. Thoughts were this was a fix for now, when I get a box and switch out back I'll connect the main lead to it on one side of the switch, and the other side of the switch run a lead up to the alternator connected directly to it and pull the current lead off going to the batt +.
The car has been down for about 7 months for a motor rebuild and turbo install (as well as 60 lb injectors, speed inc rails, all new lines, aeromotive reg, stock feed still, full return tapping into the one at the tank, dropped the tank and added a 2nd walbro pump - so 2 255 pumps wired together, racetronix harness/relay already in the car from previous). Bout done with everything, scheduled for a tune tomorrow.
OK...so on to priming/setting the fuel pressure.
We double checked everything, battery good and charged, turned the key to 'on'. Nothing. Relay clicks - no sign of pressure on the gauge. We don't smell gas, so no leaks. Get under the car with a test light to see if we can diagnose the problem. We found that the relay is getting continuous hot, is grounded well, the accessory post (top on the relay) is connected to the lead going to the pumps, and the trigger lead is connected.
Everything is together and should be working, but when you turn the key the trigger lead doesn't supply any power to turn the pumps on. Everything tested with a test light, all working except the turn on lead.
So we dick around with that for an hour or so, and didn't get anywhere, can't figure it out. So we pull out a chiltons, the diagram shows that the fuel pump trigger goes thru the PCM - PCM connector connector C2 (blue) - pin 37 - dark green/white wire....so with that in mind we were thinking maybe theres an issue on the other side of that trigger lead somewhere else on the car (worked fine before...weird..)
So we get irritated enough with that we decide to see if we can get some oil pressure in this bitch. Disconnect the coil packs, pull the inj 1&2 fuses.
Yeah, nothing. Lights are on in the cluster, everything sounds normal, turn it over and it barely clicks the starter (doesn't kick it over). Get under the car and put the tester on the little trigger lead, turn the key, and it barely lights up the test light.
So..in short...I got trigger issues! Any thoughts? Insufficient ground? Grounds seemed good, but we'll double check them.
We're going to mess with it more tonight, but I'm hoping it's something easy we just didn't notice. One thought I had was maybe something in the PCM connections having to do with the dark green/white wire maybe? I pulled the pcm up and out of the way to run the new main hot lead behind there thru the firewall to run down to the starter.
Called my tuner, he's convinced that I absolutely NEED to run the main batt + from the battery up to a distribution block, from that one lead to the starter, the other to the batt + post on the fuse block. Then run a dedicated lead from the battery up to the alternator. He thinks that will fix all my problems due to insufficient power or charging issues it may be having now.
The guy thats helpin me do my install where my cars at (friend and very knowledgeable shadetree mechanic type) says that shouldnt have anything to do with it and both should be getting sufficient power and is convinced its a ground issue or the green/white wire is having a problem somewhere.
I still don't understand why the trigger wire on the starter isnt doing anything...is it in conjunction with the green/white wire somehow for the fuel pump signal?
Thanks guys...any help/ideas are appreciated.
07-11-2008, 11:05 AM
No, you will have to change one thing: You have to take the wire that runs from the ALT to the fuse box off, and attach it to the battery in back directly before the cutoff. I would highly suggest a fuse on this wire, in the engine bay as close to the ALT as you can. This way, when you hit the switch it kills all power to the car. Without it done this way, you can hit the switch, and the car will stay running. I know 100% becuse I had this same issue with my battery relocation, and this solved it.
07-11-2008, 11:53 AM
Will doing that cure the fuel pump relay turn on lead not coming on though? Or the starter not having enough power to turn over??
I fully intend on doing this and understand you have to run a dedicated alternator wire to the other side of the cutoff switch, but I don't a box/switch in the car yet. This was just 'quick fix' to get the car running and miles put on it before dyno/track
07-11-2008, 02:03 PM
If you run the alt. feed line to the battery directly, all of the power has to come back up thru the push/pull switch. This is the best way to kill all power to the car, and this will insure that there is no power running anything at all.
07-16-2008, 01:21 PM
OK...got a new 4 gauge wire routed up from the batt + in the trunk up directly to the alternator, but the voltage is still low and its not helping to charge the battery at all. I have a main lead (1 gauge I think, freaking big) lead up to the starter + post, then off that a 4 gauge lead that runs over to the aux + spot on the fuse box.
The battery low voltage light comes on and off, stock volt gauge is around 10 volts. All the accessories (headlights, etc) work fine, but I'm getting kickback in the starter when I fire it also. After starting the car several times yesterday the voltage never dropped, but didn't get any higher on the gauge either after driving it around.
Anyone else have low voltage issues with moving the battery to the trunk this way??
07-25-2008, 11:40 AM
The 4 ga wire is not large enough for that length of distance I would believe. At least you got it started. Mine just clicks, possibly have to change the starter I guess.
JL ws-6, you said to run the wire directly from the alternator to the battery? In a couple of diagrams, it shows the wire from the alt going to the kill switch and then on the same post on the switch a smaller wire going to the battery +. Are you saying to change that? If so, I might give it a try too.
07-28-2008, 04:02 PM
07-28-2008, 04:46 PM
I ran a 4 guage wire right from the alt. to the + of the battery directly, and a big 0 guage wire from the battery to the kill switch then the same size up to where the stock wiring met the battery, just used a big ass crimp connector to attach all 3 wires then tinned it with an 80 watt soldering iron, and then shrunk wrapped it.
Ground for the battery is also a 0 guage wire that runs to a big stud that's welded to the plate the cage is attached to, so it's grounding the whole car.
I need to/should put a 200 amp fuse in the wire that runs from the alt to the battery just to be safe, just haven't done it yet. It's on the list.
07-28-2008, 05:04 PM
I think I'm going to redo the grounds in my setup with some bigger stuff (battery and motor) and run a distribution block up front for the hot leads when I install the battery box/kill switch next month. This stupid starter clicking isn't going away, but everything else is fine.
07-28-2008, 11:58 PM
Thanks guys:thumb: I'll take a look at my setup tomorrow. Best of luck to the OP as well.