ericp501 Posted August 9, 2016 Share Posted August 9, 2016 I picked up a 76' 280z thats a major project. I got the wire harness back in and have made some real progress, I'm getting spark and if I spray a little gas into each cylinder and put the plugs back in, the car runs well for a few seconds before stalling out. I don't think the fuel pump is working so I attached a cheap little pump I had lying around, it only pushes about 2psi tho, could that stop the injectors from opening? Or is it more than likely that I'm not getting a pulse from the injectors? I read something about the pulse not working if you don't have the tachometer hooked up? Any help would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 9, 2016 Share Posted August 9, 2016 Proper fuel pressure is very important. 2 psi is not right. Quote Link to comment Share on other sites More sharing options...
ericp501 Posted August 9, 2016 Author Share Posted August 9, 2016 I figured as much, but will that just completely prevent the motor from turning at all? Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 9, 2016 Share Posted August 9, 2016 You already showed that the motor does "turn" and also "fires" if you add gas. It's turning. You haven't said or shown that you know the injectors aren't opening. If they did open what do you think the difference in quantity of fuel will be between 2 psi and 36 psi? Your title is on track - "not getting fuel". The most likely cause is low fuel pressure. The test procedures for the injectors and the fuel pump and much more are in the Service Manual. Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted August 9, 2016 Share Posted August 9, 2016 Yeah you need an EFI pump. 2 psi would not let it run much if at all. And as New zed said you should check the fuel injectors are opening. Pop the fuel rail off and see if they fire after you put in a new pump. Quote Link to comment Share on other sites More sharing options...
ericp501 Posted August 9, 2016 Author Share Posted August 9, 2016 I ordered a new pump, filter and relay. I ran direct power to the fuel pump and it would run, but was very weak, putting out hardly anything. So I'm going to replace all those parts as its clearly gunked in there and wasn't getting power directly. I'm also going to pull the tank to clean it and blow out all the lines. Hopefully that will get the fuel running up to the rail properly. Now on another forum I found this: "Also, the tachometer and its resistor have to be in place for the ECU to work correctly, If your tachometer is not connected or if the resistor has fallen out, the ECU will not fire the injectors." I do not currently have the stock tachometer for the car, I have an aftermarket one sitting on a shelf, but I'm guessing I should hit the junkyard to see if I can get my hands on a tach? Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 9, 2016 Share Posted August 9, 2016 That might have been me who commented about the tachometer. I've seen it twice with stock ignition systems but my 76 car, currently, with a GM HEI ignition module doesn't do it now. So it's unclear. It might be a problem but it's not guaranteed. There's a simple test you can do to see if the injectors are being triggered. Connect a wire to the coil's negative post. Leave the other end dangling free. Turn the key On. Quickly tap the wire to a ground point. A spark will be created at whichever spark plug is in line with the rotor. Every third tap should fire all six injectors. The tapping is mimicking the ignition module and the ECU sees the sparks and responds on every third tap/spark, a full revolution of the engine. If you get injector firing don't worry about the tach. If you don't you'll have to figure out why. You might be trying to do too many things at one time. With the EFI system you can check each component individually, and as assemblies. Read the Engine Fuel chapter to understand how the fuel pump gets its power, and when. Quote Link to comment Share on other sites More sharing options...
ericp501 Posted August 9, 2016 Author Share Posted August 9, 2016 The car was a bit of a barn find that sat so fuel pump, filter and cleaning gas tank is never a bad idea. I'm gonna swing by autozone and snag their noid light set to see if I can confirm I'm not getting a pulse. As of right now I'm pretty sure I have 2 things going against me. 1) I'm not getting a pulse. 2) My fuel system is all gunked and I'm getting no fuel pressure to the injectors anyway. If I'm not getting a pulse with any luck a quick relay swap and that'll be fixed, then once all my new fuel components arrive the motor will run. Now I just need to figure out why the clutch feels like a wet noodle, and replace all the brakes and steering components for safety reasons. I'm pretty good about coming back to forums with updates and answers so that the next time someone is searching on google with a similar issue they can find out not only what the problem was, but what was done to fix it. Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 9, 2016 Share Posted August 9, 2016 I'm pretty good about coming back to forums with updates and answers so that the next time someone is searching on google with a similar issue they can find out not only what the problem was, but what was done to fix it. That's considerate. But there are probably 50+ threads on this forum alone with your almost exact problem description (except for the 2 psi number). One more won't hurt though. Not sure how a relay swap fixes "no pulse". Unless there's no power to the injectors. That can be checked with a meter. Good luck. The clutch problem probably has 100+ threads. You're surrounded by ghosts. Quote Link to comment Share on other sites More sharing options...
ericp501 Posted August 10, 2016 Author Share Posted August 10, 2016 Yea, but if people didn't ask questions this wouldn't be much of a forum would it? I've searched quite a bit, lots of threads about these types of issues, little talk about fixes, and what people come across. Seems like every forum is about how to figure out that you're not getting power or a pulse, not much about what is causing the issue or how to fix it. Quote Link to comment Share on other sites More sharing options...
ericp501 Posted August 13, 2016 Author Share Posted August 13, 2016 So I pulled pretty much everything from fuel tank to engine. The fuel pump was completely clogged with a rusty mud. I flushed the lines using chemtool and an air compressor. Everything should be going in tomorrow and I'll hopefully get the injectors figured out Sunday as I'm 95% sure they're not pulsing.. I'm thinking about putting a small inline filter between the gas tank and the fuel pump just till I'm sure that rusty mud stuff isn't going to gunk up my new pump. Quote Link to comment Share on other sites More sharing options...
ericp501 Posted August 13, 2016 Author Share Posted August 13, 2016 Picked up a noid light set and as I suspected I'm getting no light. Now I don't have any fuel in the tank, is there a switch or something where the injectors wont pulse if the tank is empty? So where do I start from here? Pictures are super helpful! Quote Link to comment Share on other sites More sharing options...
luseboy Posted August 13, 2016 Share Posted August 13, 2016 If you've gone this far you should drop the tank and clean it out as best you can. If the fuel pump is clogged then there's likely a fair amount of crap in the tank. When I dropped the tank on my Z there was about a 1/2" thick layer of rust and crap on the bottom. I chose to replace the tank with a fuel cell but in hindsight it would have been better in some ways to keep the stock tank. Maybe you already did this and I missed it but just in case. Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 13, 2016 Share Posted August 13, 2016 Have you checked Pin 1 for voltage with the key On? Quote Link to comment Share on other sites More sharing options...
ericp501 Posted August 13, 2016 Author Share Posted August 13, 2016 Just check Pin 1 and I have no voltage. Just started doing research as to what to do now.. any input would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 13, 2016 Share Posted August 13, 2016 Follow the circuit. If Pin 1 doesn't have voltage it's either not connected to the coil negative terminal or the coil isn't getting power. Or the coil is bad. I believe the wire at the coil is blue. Quote Link to comment Share on other sites More sharing options...
ericp501 Posted August 13, 2016 Author Share Posted August 13, 2016 Ok, I found my blue wire.. the car is a project car and was a bit ripped apart. The blue wire is not actually connected to anything. It has its clips, but the other wire is broken off.. I see a little white wire about 8" up off the ECU maybe it goes to that? Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 13, 2016 Share Posted August 13, 2016 "L" means blue in Nissan diagram world. 76 still used a ballast resistor, with a start circuit and a run circuit. Your area of interest starts at lower left. http://www.atlanticz.ca/zclub/techtips/wiringdiagrams/76_280z_wiring.pdf Quote Link to comment Share on other sites More sharing options...
ericp501 Posted August 13, 2016 Author Share Posted August 13, 2016 followed and got power to pin 1 by connecting the blue wire to the white wire. I'm pumping fuel, I have spark, and the little noid light is lighting up showing a pulse... but she still wont run. So now I'm really at a loss! I got it to run a few seconds by putting a little fuel directly into each cylinder. Only thing I can figure is the injectors are completely clogged. Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 13, 2016 Share Posted August 13, 2016 Where are your fuel pressure measurements? Between the filter and the rail. Quote Link to comment Share on other sites More sharing options...
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