Guest Grenade300 Posted February 7, 2005 Share Posted February 7, 2005 I have a '73 240Z There is a small box that appears to be a relay of some sort on the firewall almost across from the oil filter. It is about 3"x2"x2". What is it? I have been trying to unscrew the wiring in my car from the previous owner. Right now the old owner had a jumper wire running all the way from the windshield wiper circuit to the electric fuel pump in the back! If I am correct then the origional green wire that comes out near the fuel pump from the wiring harness used to be for the positive side of the fuel level sensor and for the positive side of the electric fuel pump. All of my wire tracing led me to the 4 or 5 metal boxes inside the car mounted just below the glove box (appear to be relays as well) under the dash. Those metal boxes appear to connect to the large relay in the engine compartment I mentioned earlier. I am attempting to get the wiring back to normal. Right now the origional green wire for the fuel pump and fuel sensor is not working. It is not connected to ground or to the pos side of the battery when the ignition is on or off. I also found that when the ignition is on if I connect a positive source to the yellow wire going into the large relay in the engine compartment it clicks and changes the some of the surrounding wires from positive to ground and some from 0 volts to 12 volts (four wires total going into that box). Please help me. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted February 7, 2005 Share Posted February 7, 2005 Sounds like the regulator for the alternator. Quote Link to comment Share on other sites More sharing options...
COZY Z COLE Posted February 7, 2005 Share Posted February 7, 2005 These are the wires to the regulator.... Black white- goes to the 20 amp. ign. fuse in the fuse box. Black - goes to the alt. White - goes to a fuseable link to the starter. White black- goes to the alt. Yellow - goes to the alt. LARRY Quote Link to comment Share on other sites More sharing options...
Guest Grenade300 Posted February 7, 2005 Share Posted February 7, 2005 Thanks for the responce Tim and Larry. That was more helpful than you will ever know. Larry, you especially have taken the time to answer many of my posts, thank you. Now, if only I could get you guys to tell me what all those "relays" under the glove box I mentioned are for. Also, if any of you know where the green wire for my fuel pump/fuel sensor origionates (I know it branches off in a few places) or is supposed to get it's 12 V charge that would be awesome. I am think of going to a junk yard and pulling an entire harness from another '73 if I can find one in tact, unless one of you know where I can aquire a new one. I really would like to use the origional datsun harness instead of the "painless", but who knows, may be the "painless" would be my best route. Quote Link to comment Share on other sites More sharing options...
COZY Z COLE Posted February 7, 2005 Share Posted February 7, 2005 Damn... finally found the right wiring dia. in my old Haynes owners workshop manual. The fuel pump is in the upper right and the green wire goes to a 20 amp fuse and then connects to the black/white wire that goes to the 20 amp ign. fuse in the fuse box. That b/w wire comes from the ign. sw. That dedicated 20 amp fuse on the green wire could be the problem. BTW I don't mind doing this because I'm restoring my 72 240Z now and you can never have too much info on these "old babies"...... LARRY Quote Link to comment Share on other sites More sharing options...
Guest Grenade300 Posted February 8, 2005 Share Posted February 8, 2005 Does anybody know where in the car this 20A fuse is (the one closest to the fuel pump)? There are only 3 inline fuses that I have found. All 3 of them are right near the fuse box under the radio. Two are blue in/blue out and one is white in/white out. I did not see any other inline fuses anywhere under the dash or in the wiring harness bundle. Quote Link to comment Share on other sites More sharing options...
CruxGNZ Posted February 8, 2005 Share Posted February 8, 2005 I also have a '73 and going off the wiring diagrams, NONE of the colors match those of the wires connected to the relays that are pointed out in the pictures below. I would love to get rid of as much as possible, but I don't know which ones I still need. Z relays 1 Z relays 2 Z relays 3 !M! Quote Link to comment Share on other sites More sharing options...
CruxGNZ Posted February 8, 2005 Share Posted February 8, 2005 Does anybody know where in the car this 20A fuse is (the one closest to the fuel pump)? The inline fuse for my fuel pump was right where the rest of yours were found, just below the radio next to the fuse box (on the left side, I believe). It was clearly marked as FUEL PUMP with a white sticker and black lettering. I'm pretty sure the fuse was inline with a red wire. !M! Quote Link to comment Share on other sites More sharing options...
COZY Z COLE Posted February 9, 2005 Share Posted February 9, 2005 You got to love this........In the 72 that I'm restoring, I've just pulled the center consle and I'm ready to pull the dash, so I looked at my wiring at the fuse box.... Damn. One in- line fuse with red/blue in and out is just hanging with one end not connected.I'm guessing that's the ACC relay to heat glass sw.One of th in-line fuse blue in and out is connected to a swich at the manual choke at one end and nothing on the other. A wiring harness with 4 connectors ends at the fuse box. One of the connectors has the green and the black/white in but isn't connected to anything. Amazingly the car starts and I had driven it around the area last week!!!! My suggestion is to run a new dedicated wire to the fuel pump and fuse it right. I'm thinking that most of us have wiring that is completely different then any of the many wiring diagrams and pictures I've seen...... LARRY Quote Link to comment Share on other sites More sharing options...
Guest Grenade300 Posted February 9, 2005 Share Posted February 9, 2005 I'm thinking that most of us have wiring that is completely different then any of the many wiring diagrams and pictures I've seen...... LARRY Gonna have to agree with you there Larry, I just want to do this project right. Quote Link to comment Share on other sites More sharing options...
Guest Grenade300 Posted February 12, 2005 Share Posted February 12, 2005 OK, after all the tracing and wire diagrams, I fineally seem to have found the end of the green wire that attaches to my fuel pump. It seems to come to an end at one of the relays under the dash and nowhere else. I am wondering if the relay is operating correctly. When I turn on the ignition, none of the wires attached to the relay change voltage. It is one of the larger relays in the group under the dash on the passengers side. The colors of the wires attached to the relay go through a 4 pin connector to the rest of the wiring harness, however they change colors after they come out of the other side of the 4 pin connector. Can anybody tell me anything about this relay. Here are the colors of the four wires. Relay side---4 pin connector---Wire harness side Blue---------4 pin connector---Green White/Blue---4 pin connector---Green Yellow-------4 pin connector---Yellow Black--------4 pin connector---Black By the way, the four wires coming out of the 4 pin connector on the wiring harness side have what appears to be the part number for the wiring harness attached at this point, this tag says "24034 N3300" on my harness. Perhaps this will aid in telling what connector and relay I am talking about. Please Help Me! (again) Quote Link to comment Share on other sites More sharing options...
COZY Z COLE Posted February 13, 2005 Share Posted February 13, 2005 I'm going to give one last shot at this.... Datsun is famous for using different model year parts so depending on your build date this could be the fuel shut off relay. Coming into the relay; Black is neg., yellow is pos. from alt./volt.reg. Blue and white/blue- one is + for a few seconds at start from the ign. sw. and one is + after 400? rpm from the oil pressure unit. This is to shut the fuel pump off if the engine dies while driving. Look under and at the rear of the pass. seat. There should be a connector with two green in and out. One set goes to the pump and one to that relay. If that's not it I give up..... LARRY Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.