Gollum Posted June 4, 2009 Share Posted June 4, 2009 So I'm 99% finished wiring my car back up after several months of downtime and I've got it turning over again, but gawd the conversion done on this car sucks big huge monkey balls. There's two wires that come up from the fuel pump relay in the back. One I'm 100% positive was hooked up to constant battery + and there's a second wire that I can't seem to figure out where it was hooked up to before. I'm worried I might have cut or pulled the connector off and didn't mind what it was hooked up too (moe134%!F4k!) If you guys need me to I can post up some pictures, but I'm sure once someone reminds me what the fuel pump wiring is "supposed" to be switched by I'll feel like an idiot and go hook it up. I tired searching for the answer, and went through the turbo wiring guide but it wasn't of much help. Part of the problem is that my car is so freakin' hacked up. I really want a new turbo wiring harness to start over from scratch. (or just drop a V8 into it...) Thanks in advance guys. Quote Link to comment Share on other sites More sharing options...
BayAreaZT Posted June 4, 2009 Share Posted June 4, 2009 Do a search for "fuel pump hotwire". You should be able to find how to properly wire the relay. Quote Link to comment Share on other sites More sharing options...
Gollum Posted June 4, 2009 Author Share Posted June 4, 2009 I ended up hooking it up to the ignition key's "ON" position. Car fired right up and seems to drive fine. Before when I went to the on position the fuel pump would prime for 5 seconds then shut off, now it just stays on. Oh well, it works I guess. Quote Link to comment Share on other sites More sharing options...
cgsheen Posted June 5, 2009 Share Posted June 5, 2009 Before when I went to the on position the fuel pump would prime for 5 seconds then shut off, now it just stays on. The "5 seconds and off" is how it works stock and that's controlled by the ECU. The ECU controls the Fuel Pump Relay. The Fuel Pump Relay is a simple "normally open" relay (and a relay is just an electrically operated switch). It gets voltage from the WB (white-black) off the ignition switch to it's "common" or input pin and outputs it to the +12v side of the fuel pump on the "NO" (normally open output) pin of the relay. The "coil" is the part of the relay that turns the switch ON or OFF (oversimplified). One side of the coil is connected to ground and the other is connected to the ECU (Don't know the ECU pin but it's the LR (blue-red) wire on the white "CONNECTOR 3" (the 6-pin connector) of the turbo ECU harness). So, the ECU controls one side of the relay coil and thus whether power goes to the fuel pump or not. With the fuel pump connected to IGN, hit a tree (or another car) and the puel pump may keep pumping gas even if the engine is no longer running. If something broke in the crash, that may be "adding fuel to the fire". With the ECU controlling the fuel pump that's not likely to happen - if the engine stops running, it shuts down the fuel pump... They designed that as a safety feature since the engine isn't driving a mechanical fuel pump anymore. Quote Link to comment Share on other sites More sharing options...
Gollum Posted June 5, 2009 Author Share Posted June 5, 2009 Thanks for the input. I pretty much understood the theory behind all that, I just had no clue what pin on the ECU it was, and I'm still not seeing where it had been spliced in before, so I'm still kinda left in the dark on how it was all hooked up, but that's been the story of my history with this car. Still lots to revamp and correct. I'm just going to leave it on the ignition for now, it'll do. Quote Link to comment Share on other sites More sharing options...
DCZ Posted June 5, 2009 Share Posted June 5, 2009 +1 to what cgsheen said above. All you need to do is find that Blue/Red wire. It is definitely listed on one of the diagrams in the FSM which will show what pin on the ECU connector it is connected to. On my 83 it was on a connector on the passenger side inner fender well, in front of the battery. Find that wire and don't krispy-kritter yourself! Quote Link to comment Share on other sites More sharing options...
Gollum Posted June 5, 2009 Author Share Posted June 5, 2009 Thanks for the help guys. I'll find the wire and see what's what and get it wired correctly. Quote Link to comment Share on other sites More sharing options...
cgsheen Posted June 6, 2009 Share Posted June 6, 2009 IIRC on my 81 ZXT donor the 6-pin connector "3" (as it's labeled in the wiring diagram) was near the battery (and may have been in the fender beside the battery with it's wiring leading down to the fuse box / relay assortment by the passengers feet...) On the Turbo ECU harness, that Blue/Red wire is part of of the wire bundle that goes across the firewall from the main bundle (splits off near the brake booster) over to the battery side. That bundle also carries the wiring for the cylinder head temp sensor and the knock sensor... Quote Link to comment Share on other sites More sharing options...
Gollum Posted June 6, 2009 Author Share Posted June 6, 2009 Sweet, I had a feeling that's where it was. Yea, my harness is a mess... You guys are the best. Quote Link to comment Share on other sites More sharing options...
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