wheelman Posted August 10, 2005 Share Posted August 10, 2005 The LT1 I installed is from a Caprice cop car and I'm having some issues with the alternator, it's a Delco CS144 140 or 200amp unit. I'm not sure if it's whats called a single wire but I don't think so. It is currently wired up with the main output going through the amp-meter into the rest of the Datsun harness and the F line on the SFLP plug is connected to switched +12volts through a 10amp fuse. When I start the car it puts out 13 volts and does not charge the battery, at least not enough to keep it from slowly being drained by the starter. If I hook the S line up to the positive terminal of the battery and start the car it will put out between 14.8 and 15 volts and does charge the battery. If I pull the SFLP plug it doesn't put out anything and the amp-meter remains centered. When the alternator is working the amp-meter is generally pegged at +60amps whether the S line is hooked up or not. Questions: Should I leave the S line hooked up? Will it over charge the battery this way? Should I unhook the F line? What should be done with the L line, if anything? Should the amp-meter be showing a +60 draw/flow? Thanks Wheelman Quote Link to comment Share on other sites More sharing options...
Guest 305240 Posted August 15, 2005 Share Posted August 15, 2005 First of all, I'd trade in that amp meter for a volt meter. No way would I want that many amps running thru some old wiring in my dash. If it's showing 60 amps while charging, remember, you got one big mother of an alt there. It was made to put out some power to run all the electrical stuff in the police cars. You can hook up any hot wire to your volt meter. If it charges with the SFLP, leave it. However, I'm not an expert on this, but I think 14.8 to 15 is a little on the high side. I would think 13.8 to 14.2 is normal. But again, you have that monster alt going. Quote Link to comment Share on other sites More sharing options...
wheelman Posted August 15, 2005 Author Share Posted August 15, 2005 305240, Thanks for the reply. I've wired it up a little different and the amp gauge reads normal now. I had all the current going into the Datsun harness and then back to the underhood fuse box I took from the donor car. Yesterday I changed it so that there is now a direct connection from the alt to the underhood box and the positive terminal on the battery as well as the main feed line for the original harness. The current now takes the "path of least resistance" and goes to drive the engine curcuits directly from either the battery or the alt and not through the Datsun harness. I also used a 100ohm 1/2watt resister to simulate the charge light in the L curcuit, disconnected the F circuit and attached the S circuit. I now get a steady 14.5 volts at the battery terminals. Don't know if this will charge the battery or not as I haven't taken it out since the change. Wheelman Quote Link to comment Share on other sites More sharing options...
Guest 305240 Posted August 17, 2005 Share Posted August 17, 2005 Now that sounds like a plan. If you are getting 14.5 at the battery, you can bet it's charging. Good job. Care to draw up a wiring diagram? It may help others with some of their charging problems. Quote Link to comment Share on other sites More sharing options...
Bartman Posted August 29, 2005 Share Posted August 29, 2005 Of course wheelman, I have a similar problem:icon52: . I purchased an insulated terminal block from MAD Enterprises http://www.madelectrical.com/catalog/cn-1.shtml and I'm using it to connect all my electrical accessories i.e. - my Painless auxiliary fuse block and my Taurus fan. I think I have all my current running through my Datsun harness the same way you did, which doesn't sound like a good situation. If I understand this all correctly, I should run a new wire from my terminal block straight to the battery. Is this correct? If so, what gauge wire should I use? BTW - The fan seems to be working great now that I'm getting my current from the terminal block and using two relays wired in parallel (still using a switch for now). Quote Link to comment Share on other sites More sharing options...
80LS1T Posted August 29, 2005 Share Posted August 29, 2005 On my LT1 I am only running a single wire from the connector. You should run ignition voltage to the F terminal and run the large wire off of the ALT to the battery(mine goes to the starter and then to the battery). I know I read it somewhere that if you hook up the alternator wrong(run power to the wrong terminal) it will do weird things and premiturly(sp?) burn up. I'll try to find the webpage.... Guy Quote Link to comment Share on other sites More sharing options...
wheelman Posted August 30, 2005 Author Share Posted August 30, 2005 80LT1, I've seen several articles about these alternators each saying something different. I had the F and S circuits hooked up and the large output lead just as you have and when I measured the voltage at the battery it was always at 15volts or more. I was concerned about over charging the battery so decided to hook it up the way I described above. The input voltage to the battery dropped to 14.5 and has remained stable. Some of the voltage drop may have come from the re-wiring of the fan(s) to draw directly from the battery/alternator rather than through the Datsun harness. Technically the fan wasn't pulling directly from the harness as the underhood fuse box is connected to the battery but all charging current was going through the Datsun harness which had a problem keeping up with the drain from the fan. Now with the alternator connected to the fusebox and the Datsun harness everything seems to be working fine. I changed several things at once so saying this or that solved the problem is impossible. I think the alternator would work correctly either with the F or the L line connected appropriately but it definitely wants the S line otherwise I only get 13 volts out of it. Wheelman Quote Link to comment Share on other sites More sharing options...
fastzcars Posted August 30, 2005 Share Posted August 30, 2005 maybe this will help you guys. Quote Link to comment Share on other sites More sharing options...
wheelman Posted August 30, 2005 Author Share Posted August 30, 2005 Fastzcar, I've seen both of those in my searches for information and mine is hooked up exactly like the GM Parts warehouse diagram shows. Wheelman Quote Link to comment Share on other sites More sharing options...
Bartman Posted September 1, 2005 Share Posted September 1, 2005 I ran a 10 gauge wire from my insulated terminal block to my battery as wheelman talked about in his post. It does appear that the current is taking the "path of least resistance" and the alternator charges the battery directly via this new wire instead of going through the Datsun harness. I think the only issue is that it appears that the amp gauge doesn't really serve much of a purpose since all the current isn't going through it anymore. I guess that's a small price to pay for the added safety of not running so much current through the old wiring harness. Quote Link to comment Share on other sites More sharing options...
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