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KHaydock

Engine crank no start

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Hello everyone, new to the club. I'm working on a 1978 280z and this thing has been sitting for years. So to start out I drained the fuel tank and put new fuel in, changed engine oil/ filter, installed new spark plugs & wires. All while I was waiting for a new ignition switch to show up. So once I got the ignition switch installed I started to crank it over trying to get a start. It wouldn't start so I took off the air measuring device and tried some starting fluid. It backfired on me. I verified I had spark at my plugs. I ended up going under the car and checking the voltage at the fuel pump while cranking and I had 0 volts going to the pump itself. Can someone help me out with wiring diagram and or description of up stream components to check from the fuel pump?  (relays/fuses) and the location on the vehicle. Thank you all for the help and the add.

Edited by KHaydock

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Welcome to the forum.  Good information from good people here (not me though). :D

A good start and free pretty much, is to clean all your ground points.  Specifically the EFI grounds.

eficonnections.jpg

http://atlanticz.ca/zclub/techtips/electricalconnections/index.html

Then a clear filter between the tank and the fuel pump.

http://atlanticz.ca/zclub/techtips/fuel/g3filter/index.htm

Read through this too.

http://atlanticz.ca/zclub/techtips/efisystem/280zfuelinjectionbook.pdf

Edited by siteunseen

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Just read something I forgot about.

From the Good Captain " pull the starter solenoid wire off and turn the key to START to get the fuel pump to run without engaging the starter."

And from the Good RCB280Z, " I usually power the pump thru the afm, the cover is held in place with zip ties. It always pressurizes the system right away so I know flow is good.

There's a switch in the AFM under the black plastic cover.

Related image

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Welcome to classic Z forum.

" I ended up going under the car and checking the voltage at the fuel pump while cranking and I had 0 volts going to the pump itself."

Since you already identify the problem that you don't get any voltage, there might be shorting wire for the fuel pump somewhere. The wire to the fuel pump runs passenger side between seat and door. flip the carpet to check the wire. 

Screen Shot 2018-01-18 at 9.02.39 AM.png

And as basic information, check FSM. http://www.xenonzcar.com/s30/fsm.html 

BE Body Electrical.pdf is the one you need to check.

You can find relay at passenger side kick panel.

Screen Shot 2018-01-18 at 9.03.43 AM.png

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On the 78, the Fuel Pump Relay relies on the Fuel Pump Control Relay for power to the coil. It does not rely on the AFM. The connection to the flap on the AFM are labeled as "USELESS" in the factory diagram.

The Fuel Pump Control Relay relies on two signals combined to energize the the Fuel Pump Relay. The ignition must be on, and there must be oil pressure. The fuel pump does not come on with the starter. You will not see any voltage at the fuel pump when trying to start the car. If you want to see if you have voltage at the fuel pump, you have to jumper the two Green/Blue wires at the Fuel Pump relay. (The Green/Blue wire next to the White/Black wire on the connector for the Fuel Pump Relay should have 12VDC to ground all of the time since it is connected to the fusible link.)

I am pretty sure the FSM in the resources section on this site has the wiring diagram. Just click on the Resources tab.

This is a better alternative for a wiring diagram: 

 

Edited by SteveJ
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4 hours ago, KHaydock said:

Hello everyone, new to the club. I'm working on a 1978 280z and this thing has been sitting for years. So to start out I drained the fuel tank and put new fuel in, changed engine oil/ filter, installed new spark plugs & wires. All while I was waiting for a new ignition switch to show up. So once I got the ignition switch installed I started to crank it over trying to get a start. It wouldn't start so I took off the air measuring device and tried some starting fluid. It backfired on me. I verified I had spark at my plugs. I ended up going under the car and checking the voltage at the fuel pump while cranking and I had 0 volts going to the pump itself. Can someone help me out with wiring diagram and or description of up stream components to check from the fuel pump?  (relays/fuses) and the location on the vehicle. Thank you all for the help and the add.

Download this file and go to pages EF-16 and EF-37.  Then read all of the other pages too.  You should have seen power while at Start, cranking.  Make sure you have the plug wires on correctly.  Counterclockwise rotation.  People (me) have got it backwards.

http://www.classiczcars.com/files/file/24-1978-280z-factory-service-manual/

Here's a wiring diagram - http://www.classiczcars.com/files/category/1-wiring-diagrams/

 

 

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