JSM Posted June 21, 2011 Share Posted June 21, 2011 (edited) For the life of me I have such a hard time reading this portion of the wiring diagram. I'm trying to understand what the "Y" yellow wire does on the 63M plug. Reading this, it appears to me that (B,S) in the start block of the ignition switch grid only has power going to the "Y" wire when you start the car? Then no power through it. Is this correct? Tracing the "Y" wire around it looks to feed: Starter, Antenna timer, and most importantly the ECU. Curious if anyone knows why the ECU would only want power once at start up? Edited June 21, 2011 by JSM Quote Link to comment Share on other sites More sharing options...
bthomp Posted June 21, 2011 Share Posted June 21, 2011 after a long talk with my brother about redoing the wiring in my car, we spent some time about the ign of the car and its relation to the ecu. what we came up with is that the ecu does not want to be on sending signals to objects like the injectors until the car is on, so that your key and be on the on position without flooding the engine with fuel. once the key has been flipped to start, then the ecu can send a signal to the injectors and bring on the fuel. Might be completely wrong about this, or just be irreverent to the question at hand, but just seemed like the one i just got talking to my brother about 10 min ago, lol. Quote Link to comment Share on other sites More sharing options...
JSM Posted June 21, 2011 Author Share Posted June 21, 2011 That does make sense. A sort of saftey to ensure the ECU is suppossed to be sending fuel. So do you agree that the "Y" wire is only on when you turn the key to engage the starter? Quote Link to comment Share on other sites More sharing options...
JSM Posted June 21, 2011 Author Share Posted June 21, 2011 The diagram above is from an 86 300zx Turbo. What is interesting is it's input on + voltage. It has 5 sources going into it. 2 from the EFI Relay, 2 from the Ignition relay (Fuel Pump and Coil) and 1 from the Starter switch. Quote Link to comment Share on other sites More sharing options...
NewZed Posted June 21, 2011 Share Posted June 21, 2011 (edited) The 280Zs have an ECU controlled fuel enrichment when starting, described in the FSM. I assume that it adds injector open duration. Maybe the 300ZXs have the same feature. Edited June 21, 2011 by NewZed Quote Link to comment Share on other sites More sharing options...
bthomp Posted June 21, 2011 Share Posted June 21, 2011 (edited) well after retyping this about 7 times, im going back and forth about it. Most of me says the y wire is only active for a moment, then the other part of me is saying that its on once the car is running, due to the fact that power would have to be either cut from the antenna to start its timer, or sent to it again to set off some what of a click to the timer(first power click rises it, second moves it to lower) im not really the best person to ask that question unless im staring at my colored wire diagram for a while tracing everything. Someone else is probably more fit to fully answer this question for you than me. Seems to me that the answer is in the ign switch part of the diagram, i just cant remember what means what with the dots ... Sorry JSM its almost 12 here so my brain has been trying to shut down for a while now XP Edited June 21, 2011 by bthomp Quote Link to comment Share on other sites More sharing options...
JSM Posted June 21, 2011 Author Share Posted June 21, 2011 I think it has to be for a moment only if it is going to the starter. Quote Link to comment Share on other sites More sharing options...
JSM Posted June 21, 2011 Author Share Posted June 21, 2011 In the Ignition Block Grid, what does the B stand for, Both? Meaning it's on when both started and running? B = ? A = Accessories IG = Ignition S = Start Quote Link to comment Share on other sites More sharing options...
Leon Posted June 21, 2011 Share Posted June 21, 2011 Looking at the wiring diagram, I would say "B" stands for battery. It's the power feed from the battery to the ignition switch. Quote Link to comment Share on other sites More sharing options...
Leon Posted June 21, 2011 Share Posted June 21, 2011 To answer your original question, the yellow wire is energized only during starting. I'm not too familiar with the particular FI system, but as NewZed alludes to, it may have something to do with cold start enrichments. Quote Link to comment Share on other sites More sharing options...
JSM Posted June 22, 2011 Author Share Posted June 22, 2011 Thanks. I confirmed w/ Jim Wolf technology on the Fuel Enrichment. Doh, battery that makes sense. No I just have to figure out the (-) grounding fuel pump through the relay. 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.