danman Posted February 14, 2005 Share Posted February 14, 2005 I have a 1983ZXT motor. There are two wires hanging loose on my harness near the injectors. Let me see if I can describe them. There is a large harness that runs to the injectors. In addition to the wiring for the injectors there are two additional branches. One branch is hooked to the underside of the distributor. The last branch contains two single wire connectors. Where do these go to? I can see one sensor with loose wire. It is located directly below the connection to the top hose of the radiator. I can not account for where the other wire may go and not sure which of two wires should connect to sensor below radiatior hose. I am running VERY rich. My car will foul the O2 very quickly and go into limp mode. I get many engine codes: MAF, No Ignition reference pulse, Idle switch, Air temp sensor, EGR. I have 300ZX MAF, 300ZX Coil, no vacumm to EGR valve. I am getting frustrated. I don't want to spend hundreds or thousands of dollars chasing my tail. What would you guys reccomend. I figure I could spend about $500-700 buying sensors, lord knows if the wiring is to blame. My friend pointed me to a shop where I can get S14 SR20DET and tranny installed for about $4,000. My clutch is going very shortly and tranny is not that great to begin with. So I could spend another six hundred just on clutch and install. I can replace sensors, but clutch is a bit over my head. Should I stop wasting money on an old hybrid and just save toward a new one like SR20DET or LS1??? I am tired of looking at my car and not driving it much. Quote Link to comment Share on other sites More sharing options...
fl327 Posted February 14, 2005 Share Posted February 14, 2005 4k install is cheap if they dynotune it with the install. If they dont, I would say that you would be paying a little much. Typical install charge over here is about 1.2k thats after taxes. Sounds like you would be better off in the long run with the sr. Sounds like the z31 ecu and maf on an 83 setup? they run good if the wiring is perfect, but most of the times, its not. Or, you could try to put in a new head temp sensor..... Quote Link to comment Share on other sites More sharing options...
danman Posted February 14, 2005 Author Share Posted February 14, 2005 My wiring is a mess. I see several connectors on the starter side disconected. I am not sure if this is because 83 motor into 74 body or if things are disconnected and contributing to my issues. Will try head temp sensor, I think I bought one and never installed it and I have new pigtail to solder in just in case its the connector. I have been fighting this thing for months. I hard soldered in the MAF to eliminate the connector being an issue. I cleaned the O2 sensor in 99% alcohol and changed the spark plugs, they were foulded too. That helped it get out of limp mode, but then it slipped back in. I also get a little racing once in a while about 200-300 RPM in addition to running very rich. I would hate to trash a good motor, it screams when it is running right, but I don't have money to waste. Quote Link to comment Share on other sites More sharing options...
frank280zx Posted February 14, 2005 Share Posted February 14, 2005 maybe you have to dewire the engine.... get a wireing scheme of a 83 zxt and hook it back up, however the Z31MAF could be the issue, or whatever you have wired in there apart from stock ........ I would try to go MS and S ( megasquirt ) Quote Link to comment Share on other sites More sharing options...
GrayZee Posted February 14, 2005 Share Posted February 14, 2005 maybe you have to dewire the engine.... get a wireing scheme of a 83 zxt and hook it back up, however the Z31MAF could be the issue, or whatever you have wired in there apart from stock ....... Yeah I'm starting to think that is good advise to anyone doing a turbo swap. They should use the 280zx ecu and afm FIRST then when they have done that successfully THEN think about doing a z31/maf swap. Especially if the person has a limited knowledge of vehicle electrical systems. There are enough people out there who have problems wiring up the stock system, let alone the upgrade. If I had a few wiring harnesses laying around as "cores" then I'd start selling ready made "plug in and fully labeled" wiring harnesses for the swap. Quote Link to comment Share on other sites More sharing options...
danman Posted February 15, 2005 Author Share Posted February 15, 2005 Unfortunately I bought this hybrid and did not build it myself. I am learning a lot though, which was the point of buying the car. I am thinking of taking it to a Nissan dealer and pay an hour labor for mechanic to point out which wire hooks up to my sensor and explain what the other wires connect to and if they need to be reconnected or if they were deleted on purpose. My setup uses OEM parts, just in a creative confusing mixture. I think the unplugged sensor must be the coolant temp sensor because it lies just below the top hose of radiator. Just not sure which of two loose wires to connect to it. Any of you guys live in the Bay area of Northern California. I live in Walnut Creek, CA. I could sure use some help. Quote Link to comment Share on other sites More sharing options...
260ZRED Posted February 15, 2005 Share Posted February 15, 2005 What color are the wires you don't know? In any case, get a factory service manual, or just the full wireing diagram from it. I have my blown up copy here on my desk, if you tell me what color the wire is, I can pinpoint you in the right direction. also, clean every connector and every ground, it helps alot. The stock L28ET wireing is pretty simple, trust me. Its another thing tho when someone else jacked with it and you dont know what exactly they modded (or screwed up in your case?) Quote Link to comment Share on other sites More sharing options...
danman Posted February 15, 2005 Author Share Posted February 15, 2005 You guys are going to laugh I'm color blind. (Pause for laughter). This being said. The wires in question are running in the same trunk as the fuel injectors, in addition to the fuel injectors there is a branch that terminates in a strange half moon and two pin connector: four wires total which runs to connector under the distributor. The last branch (which runs with fuel injector branch and four wire branch) has two single wire connectors. These two single wire connectors are the problem. One seems to be white the other light brown or light green, both are SOLID COLOR no stripes. Again keep in mind I'm color blind and mix up shades. For sure they are solid though and run together in same casing until end. They hang loose near front of engine. There is sensor with single wire also hanging loose. The sensor is screwed into same housing that top radiator hose connects to, just below the radiator hose. The engine is 1983 ZXT as well the harness should be 1983 ZXT. It should be same stuff everybody is running just with Z31 computer (computer has sticker saying it was sent to Jim Wolf and sticker mentions MAF as well as 420cc injectors), MAF, and coil. I am unable to pinpoint where second wire may go, nor am I able to say which of these two wires connect to mystery sensor. The other loose connection is on the same trunk that feeds the head temp sensor (the two lead sensor connected to passenger side of head. The head temp sensor is hooked up, but there are two other connectors again single wires one is red the other black. There are other wiring issues as well, but these stick out at me. Do they sell new wiring harness's still? What about interior harness's? Any help would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
260ZRED Posted February 15, 2005 Share Posted February 15, 2005 I see a light yellow (looks like whiteish-yellow) and a green on mine. Both of them comeing from the same bundle as the fuel injector wires. There are TWO! sensors there, very close to each other. The second sensor was hard to see, but its there, at least on my engine (82). If you're standing in front of the engine (so driver's side is your "right"), the green wire goes on the sensor on the left. Now about 1 inch to the bottom right of that and about 1-2 inches deep is another sensor, where the whiteish yellow wire clips onto. you can't really see it b/c of all the stuff in the way but its there. The actual wires are female and clip onto the male sensors. The area is right near and below the water neck for radiator. Sorry if I confused you even more. If you post a picture I'm sure lots of people could tell you exactly where everything goes. Quote Link to comment Share on other sites More sharing options...
danman Posted February 15, 2005 Author Share Posted February 15, 2005 Thanks for reply that is big help. Do you know the names of the sensors from left to right. The wires look pretty fried must be real hot sitting on valve cover will have to solder in some new wire. I almost want to say there are three sensors there one on left I described, one in middle that appears to have been plugged on my car and another on the right side that ties to harness on driver side. I have pics, but.... How do I post pictures, I looked and my account does not allow attachments??? Quote Link to comment Share on other sites More sharing options...
240ZinTN Posted February 16, 2005 Share Posted February 16, 2005 I have an 83 turbo harness I have been working on and might have some answers for you. The two wires you have near cyl head temp sensor sound like connections for the knock sensor(black and red wires on my car). The wires and "mystery sensor" in the thermostat housing sound like the thermotime switch for the cold start valve(yellow on mine) and water temp switch for aux cooling fan( white). This is the best I came up with after searching the red Haynes Manual p290 for 83ZXT , bottom left of page. Quote Link to comment Share on other sites More sharing options...
danman Posted February 16, 2005 Author Share Posted February 16, 2005 How important is knock sensor and what happens if it is missing like mine? I remember reading article about new SER Spec V's that there knock sensors are overly sensitive and retard timing too much. Is this why person would have deleted this sensor or did 300Zx computer not have knock sensor? I will take 260ZRed's advice and buy service manual cd because my Chilton book doesn't cut it. Quote Link to comment Share on other sites More sharing options...
260ZRED Posted February 17, 2005 Share Posted February 17, 2005 best money you ever spent (factory manual). I would have gone with a paper copy, I like real books, but I guess its all same. You will laugh at the other repair manuals once you open up the factory one. I didn't connect the knock sensor and it runs fine. I don't think too many L28ET swappers use it, I may be wrong tho? Fact is you don't NEED it to run... Quote Link to comment Share on other sites More sharing options...
danman Posted February 17, 2005 Author Share Posted February 17, 2005 Connected green wire to sensor under radiator hose. Now car is running LEAN. I pulled a spark plug and they went from black and fouled to white. Car runs horrible below 3000 RPM sputters and runs unevenly then seems to pick up again. I get a little smoke out of tailpipe now instead of unburt fuel. Affraid to run now fear detonation. Not sure if I would hear over loud exhaust. I read somewhere that MAF is only working below 3000 RPM. Possible cause? What causes lean running? Pulled codes off Z31 computer, where is test selector supposted to be mine was all the way counterclockwise. I turned it clock wise till two lights went off while ignition turned to on but not running. Also car now doesn't start first turn of key , but always on second try. Used to always start on first try like fuel is not flowing well now. The sensor you can see is the one that was already hooked up. I highlighted the harness it travels in it is the thicker of two you see. I hooked up the green wire to the sensor you can't see just under the radiator hose. Now car went from rich to lean. http://album.hybridz.org/showphoto.php?photo=1468&size=big&sort=1&cat=545 Quote Link to comment Share on other sites More sharing options...
260ZRED Posted February 18, 2005 Share Posted February 18, 2005 Time for megasquirt? Or a stock, [factory manual] install of stock components first? Sorry dude I tried to help but you got some bigger problems with running different ECUs, MAFs, etc. AND not knowing exactly what was done? Quote Link to comment Share on other sites More sharing options...
danman Posted February 19, 2005 Author Share Posted February 19, 2005 Thanks for all the help. I have been trying to avoid it, but it's looking more and more like a rewire of the entire engine is in order. I am going to check MAF wires again and a few other things before going down that drastic road. Where can I find new wire harness, do they have something like the painless kit for Nissan? Quote Link to comment Share on other sites More sharing options...
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