urgently wanted

candy red

Club Member
Hi have problem with fuel pump relay 280zx the car runs for about 20mins then just dies fuel pump relay gets very hot and cuts the pump any ideas ,what sends signal to relay to shut off
also when ignition switch on the pump dose not start up every time when the pump dose start up and charge the fuel system it keeps running it should stop after the system is charged to the right pressure then start when the engine is fired up , could the problem be elsewhere and not the relay

pump works

This is the relay i am looking for please PM me if you have one


many thanks for any help or advice

Derrick:rofl:
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
I know nothing about 280ZXs but could fuel line/filter blockage be an issue?

Is there a chance to 'hot wire' the relay circuit so that the car run without it and see if it's ok, or would constant running harm something?
 

jonbills

Membership Secretary
Site Administrator
It does sound to me like the relay is sticking Derrick. It should be possible to open it up and repair maybe.
Do you have a photo looking down on the pins? may be same layout as a standard modern relay.

Spare one in one of your spare cars?
 

STEVE BURNS

Club Member
being a complete numperty mechanical wise I remember when I got my first 280 years ago it it would only run for about 20 minutes and then cut out and would take 20 minutes for it to start again only for it to cut out again after a short while
turned out in the end the rollers in the pump had worn and it was not pushing out a regular fuel supply
 

candy red

Club Member
The relay is a double relay in one not sure what signals it to open and close apart from ignition when turned on to start pump ,what signals are sent to turn relay off as that may be where the problem lies

Derrick:confused:
 

Ped

Club Member
Are you positive the fuel pump is OK? Next time it happens give the fuel pump a tap with a lump of wood and see if it helps. My guess would be the pump is on its last legs?
 

AndyMinto

Inactive
Derrick,
What year is it please as there are some great trouble shooting guides about but the pins on the ecu lead differ from year to year and you use a multi meter across the pins to diagnose most aspects of the Fuel Injection system.
 

candy red

Club Member
hi its 1980 I'm going to put a fuel pressure gauge on the fuel line and see what its reading

thanks for all your advice ;)
 

candy red

Club Member
Hi all sorted the problem this afternoon 10 out of ten for Rob it was the fuel filter blocked seems it wood run for a while burn fuel for awhile then suck particles into filter lose pressure burn fuel in fuel rail then gradually die then turn pump relay off ,the particles would then settle to bottom of filter after a while then would start and and continue the cycle all over again:rofl:
put new filter on now running fine :D:):driving:


thanks for all your help and suggestion this is what makes this club and forum so good people willing to help others :cheers:

if anyone does have a relay like the one i was after please Pm me as it would be good to have one as spare

Many thanks Derrick;)
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
Glad it's sorted Derrick.

Fuel filters are there for a reason and on Datsun's that I've had they've done a good job of catching the tank rust particles.
 

candy red

Club Member
false alarm after changing fuel filter car ran for hour n half thought it was sorted went back out to it again tonight started the car and now only just running with lots of black smoke and fuel pressure gauge reading 40 psi but nearly ticking over could it be the fuel regulator ?:confused:

the only positive thought i have is it beats watching coronation street lol
 

jonbills

Membership Secretary
Site Administrator
The fuel pressure is meant to be about 40 PSI isn't it?
black smoke is fuel, so maybe the AFM got disconnected when you were changing the fuel filter?
 

candy red

Club Member
hi john think the pressure should be about 32psi at tick over and spike at 40 when revved hard this is 40 at tick over and over fuelling fuel filter opposite side to arm so not likely to have come disconnected thanks for your input many brains are better than one :thumbs:

Derrick
 

eastman

Well-Known Forum User
If fuel psi is good then the pump seems to be doing its job, if its blowing black smoke i would think that it is getting to much fuel but not enough air??, maybe check fuel solonoid + regulator, make sure you have got good ground on your electrics.
 

AndyMinto

Inactive
Derrick,
There are so many parts of the EFI that could cause this including but not limited to air temp sensor, pressure reulator, cold start sensor, air flow meter etc. The quickest and most accurate way to diagnose is to get a multi meter and follow the trouble shooting guide step by step until you identify the culprit.
 
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