hilleytime Posted November 27, 2014 Share Posted November 27, 2014 I have a 78' 280z bone stock with the exception of a pod filter put on by previous owner. About a month ago I was sitting at a stop light when the car started sputtering and died. Didn't start again till the tow driver came with a jump box and I dove it on the flat need no problem. Being a broke college kid it sat in my parents garage till I could save up some cash to start working. Now with a fuly charged battery the car starts for roughly a seccond, revs up to about 1500 then emideatley falls on its face and dies. Tapping the gas to keep it alive dosent help it still just dies. It has a new alternator, plugs, wires good compression it's got good spark, injector connections look good. Cylinder 1 and 2 have minor injector seepage. If anyone has any ideas I appreciate the help very much. Quote Link to comment Share on other sites More sharing options...
NewZed Posted November 27, 2014 Share Posted November 27, 2014 (edited) 1978 has a fuel pump relay that requires either voltage from the alternator or a closed circuit at the oil pump pressure switch, to keep the fuel pump powered. The relay is overrode during starting. That is one of many possible sources for your current symptom. Just an example. You need to start with the basics of fuel and spark and see which one is missing. There are many ways to do that, like listening to the fuel pump, attaching a voltmeter to the fuel pump leads, watching a spare plug for spark, watching the tachometer while it runs and dies (the tach counts sparks from the coil), attaching a fuel pressure gauge, supplying supplemental power to the fuel pump, etc. Pick a few and break the problem down until you're looking at the part that needs fixing. The Factory Service Manual chapters, Engine Fuel, and Engine Electrical, have many procedures and diagrams that will help. http://www.nicoclub.com/FSM/280z/ Edited November 27, 2014 by NewZed Quote Link to comment Share on other sites More sharing options...
Leon Posted November 27, 2014 Share Posted November 27, 2014 If you can keep the car alive with starter fluid, you have a fuel problem. If not, it's spark or mechanical. Quote Link to comment Share on other sites More sharing options...
NewZed Posted November 27, 2014 Share Posted November 27, 2014 That's a good one too, and very easy. I did have an ignition module go bad once though, that produced a spark only strong enough to start on starter fluid. Odd but true. Tools at hand usually determine which path people take. Quote Link to comment Share on other sites More sharing options...
hilleytime Posted November 27, 2014 Author Share Posted November 27, 2014 I jumped the oil pressure switch same problem and while I was doing some starter fluid tests I noticed with the key in the on and engine off position the car clicks and humms... Clicks and humms and so on. It does this the entire time the key is in this position. I'm going to check the connection to the ignition switch and the switch it's self. Could a bad ignition relay cause this condition? Quote Link to comment Share on other sites More sharing options...
hilleytime Posted November 27, 2014 Author Share Posted November 27, 2014 I jumped the oil pressure switch same problem and while I was doing some starter fluid tests I noticed with the key in the on and engine off position the car clicks and humms... Clicks and humms and so on. It does this the entire time the key is in this position. I'm going to check the connection to the ignition switch and the switch it's self. Could a bad ignition relay cause this condition? Quote Link to comment Share on other sites More sharing options...
hilleytime Posted November 27, 2014 Author Share Posted November 27, 2014 I jumped the oil pressure switch same problem and while I was doing some starter fluid tests I noticed with the key in the on and engine off position the car clicks and humms... Clicks and humms and so on. It does this the entire time the key is in this position. I'm going to check the connection to the ignition switch and the switch it's self. Could a bad ignition relay cause this condition? Quote Link to comment Share on other sites More sharing options...
hilleytime Posted November 27, 2014 Author Share Posted November 27, 2014 I jumped the oil pressure switch same problem and while I was doing some starter fluid tests I noticed with the key in the on and engine off position the car clicks and humms... Clicks and humms and so on. It does this the entire time the key is in this position. I'm going to check the connection to the ignition switch and the switch it's self. Could a bad ignition relay cause this condition? Quote Link to comment Share on other sites More sharing options...
hilleytime Posted November 27, 2014 Author Share Posted November 27, 2014 I jumped the oil pressure switch same problem and while I was doing some starter fluid tests I noticed with the key in the on and engine off position the car clicks and humms... Clicks and humms and so on. It does this the entire time the key is in this position. I'm going to check the connection to the ignition switch and the switch it's self. Could a bad ignition relay cause this condition? Quote Link to comment Share on other sites More sharing options...
hilleytime Posted November 27, 2014 Author Share Posted November 27, 2014 Sorry about that Quote Link to comment Share on other sites More sharing options...
NewZed Posted November 27, 2014 Share Posted November 27, 2014 I jumped the oil pressure switch same problem and while I was doing some starter fluid tests I noticed with the key in the on and engine off position the car clicks and humms... Clicks and humms and so on. It does this the entire time the key is in this position. I'm going to check the connection to the ignition switch and the switch it's self. Could a bad ignition relay cause this condition? Most important - did the engine start and stay running? Put everything back together and just use starting fluid. You're kind of mixing variables, and jumping to hopeful conclusions. Your description is a little fuzzy also - the whole car clicks and hums? In the on and the off postilion? Can't understand. Could be that the click is a relay and the hum is the fuel pump. That would be normal. Also, you might have actually jumped the pressure sensor side of the switch connection. Pretty sure that the way to bypass the oil pressure switch is to just disconnect it. It's open when the engine is running, I believe. It's a flaw in the design. The diagram is hard to understand since Nissan says "On" instead of "closed", but I've seen others describe disconnecting the switch to make the pump run when the key is On. Just pull the connection and turn the key to On. I could be wrong. I have a 76. Quote Link to comment Share on other sites More sharing options...
hilleytime Posted November 27, 2014 Author Share Posted November 27, 2014 Ok yes sorry I am jumping around a Bit here. So by key on engine off position I guess I mean accessory mode where you can turn the lights radio and other junk on but the engine is not running. So when I unplugged the oil pressure leads and left them open I can here the fuel pump humm but the car does not stay running. It will still start for a quick seccond. Quote Link to comment Share on other sites More sharing options...
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