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Matt, Engineer
Category: Car
Satisfied Customers: 21878
Experience:  Honors degree in Mechanical Engineering, worked 8 years as a Formula 1 engine engineer.
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1979 280zx: spray starter for a few seconds..same thing

Customer Question

i have a 1979 280zx, i have to spray starter fluid to get it to start. it start but i have to rush to get to the throttle to keep it running, it will run for a few seconds than it will die,than i have to do the same thing over again. no matter how much i open the throttle it will die. please i need your, because i need work.
Submitted: 7 years ago.
Category: Car
Expert:  Matt replied 7 years ago.

This could be a lack of fuel pressure from the electrical fuel pump

If the connections to this are corroded or damaged then the pump could stop at any time or could not be running at full speed. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse,
Ideally measure the pressure at the carbs and if this is low ( should be 3-5psi ) check the pump as described and also consider changing the fuel filter as if this partially blocked this too will reduce pressure.
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Customer: replied 7 years ago.
because my electric fuel pump countinue to run even when the car is running. should'nt it turn off after it is primed? or could it be the relay that's not turning it of after it is primed(bad relay). you mentioned carb did you me carberator because mine is fuel injected.
Expert:  Matt replied 7 years ago.



The pump will run all the time the engine is running as it should prime the system when you 1st turn on the ignition and then stop after a few seconds, it'll then run again once the engine is running.


I did think this this year was still on carburation hence my carb comment but as your's is injection the pressure will be higher (30-37psi).


So I'd 1st locate the pump ( should be under the car close to the tank) and see if it runs, if its doesn't 1st investigate its relay in the fusebox and see if theres 12V at the fuse.


If these are both OK (relay clicks on with ignition) then check the pump terminals for corrosion and you run a new wire direct from the battery to see if the pump will actually run - so confirming if the fault is with the pump or the relay


If the pump is running with the engine then its likley that that the ECU isn't opening the fuel injectors, if the injectors are working you can hear them click - its difficult to hear them with background noise so use a long screwdriver like a stethoscope, placing the handle end in your ear and the metal tip against the body of the injector whilst your assistant turns the engine over.

Also check the ECU power and crank speed sensor relays and fuse and mentioned for the fuel pump

Edited by 350Matt on 9/18/2010 at 10:04 AM EST