Jump to content
SAU Community

Relays

Cubes

By Cubes,
in General Automotive Discussion

 Share

Recommended Posts

Cubes Grand Master

Cubes

Posted
Posted (edited)

Hi ppls,

A little while ago I ran a direct volt feed to my fuel pump.

I used a Jaycar 60amp relay.

My usual routine is to turn the key to the on positon, wait for the fuel pump to raise fuel pressure then auto turn off, I then start the car.

Occasionally the fuel pump stays on and keeps priming and priming and priming. :O

The only way to stop it is to pull the earth from the relay.

Is it possible the relay is some how getting stuck?

I run the std fuel pump volt feed through the relay then straight to the chassis as its earth.

Could this be the problem? Kind of like connecting a negative and positive without anything inbetween using some power?!? big sparks and not good. :O

I'm not that electrically minded so I really am not sure where to start looking?!?

Edited by Cubes
Link to comment
https://www.sau.com.au/forums/topic/95019-relays/
Share on other sites
MANWHOR3 Proficient

MANWHOR3

Posted
Posted

Cubes, if you have a look inside a relay, it's a very simple device. It's unlikely that it will get stuck open. Relays do not need much power at all to trigger. Your ecu might still be supplying a small amount of power after priming is finished.

My advice would be to change the relay anyway, in the rare case that it is faulty. They're cheap anyway.

Link to comment
https://www.sau.com.au/forums/topic/95019-relays/#findComment-1717982
Share on other sites
Cubes Grand Master

Cubes

Posted
  • Author
Posted (edited)

Space Ghost...

Great idea.. I'll give that a shot.. lol So simple.. :O

Next time it does it, I'll jump out with my trusty multimeter and measure the volts running from the ecu.

If it is small amounts as the MANWHORE has suggested then its resistor time.

If not, new relay. :O

Edited by Cubes
Link to comment
https://www.sau.com.au/forums/topic/95019-relays/#findComment-1718019
Share on other sites
Cubes Grand Master

Cubes

Posted
  • Author
Posted (edited)

90% of the time the relay works as its should.

Only occasionally it locks on, unsure if thats still possible with a fused relay?

I also observed the relay tends to leak voltage.. The constant feed from the battery see's 0.02v, even with the trigger feeds disconnected.

Edited by Cubes
Link to comment
https://www.sau.com.au/forums/topic/95019-relays/#findComment-1718057
Share on other sites
Abo Bob Grand Master

Abo Bob

Posted
Posted

I've seen them stick on and I've seem them fuse together but the latter is permanent.

It might just be the ECU though. Mine does a similar thing and it is wired in the stock manner. I didn't notice that it stayed on sometimes until I put a GTR fuel pump in because I couldn't hear it before but now I can.

When I say similar... without the engine on it only primes for about 2-3 seconds but it's when it's started that it can go on and on or not depending on it's mood.

Link to comment
https://www.sau.com.au/forums/topic/95019-relays/#findComment-1719740
Share on other sites
paulr33 Grand Master

paulr33

Posted
Posted

i too have since similar results since putting a bnr33 pump in my gtst + powerfc. normally when it first starts the pump runs flat out even at idle, sometimes the only way to make it stop is to tap the accel pedal and the revs jump a tiny bit then back down again and the pump goes off

Link to comment
https://www.sau.com.au/forums/topic/95019-relays/#findComment-1720586
Share on other sites
Cubes Grand Master

Cubes

Posted
  • Author
Posted (edited)

Interestering...

Since I fitted the AP PowerFC the fuel pump constantly runs on high, prior it would run on low at idle then once you touch the accelerator it would run on high.

All though prior to the wiring mod I never had it get stuck on while priming.. Only since after the wiring mod.

Which makes me suspect the relay, or a small amount of voltage still passing that is activating the relay.

The wiring mod was definitely worth wile.. Its much louder as it sounds like its spinning so much harder, it also no longer vibrates the floor pan causing it to be noisy in the car. Now you can only hear the buzz/surge/bubble or what ever type sound it is from the outside once the fuel gets really warm on a hot day with little airflow movement.

Edited by Cubes
Link to comment
https://www.sau.com.au/forums/topic/95019-relays/#findComment-1720608
Share on other sites
RB30-POWER Mentor

RB30-POWER

Posted
Posted

It should be setup something like this.

85 (-12V GND from ECU fuel pump terminal)

86 (+12V IGN switched)

87 (+12V to the fuel pump terminal)

30 (+12V supply from battery with fuse/fusable link)

So what will happen is, when the ecu switches the pump on (nissan usually ground relay for pump) it switches the low current coil in the relay, allowing high current from battery from pin 30 on the relay through to terminal pin 87 into the pump.

when the ecu turns the pump off (opens pin 85) the relay will open and stop pumping fuel.

Link to comment
https://www.sau.com.au/forums/topic/95019-relays/#findComment-1721951
Share on other sites
SKYBEE Collaborator

SKYBEE

Posted
Posted

you need to get a diode protected relay or install a diode in the earth wire on the relay that will stop the relay from engaging they require milli amps to engage thats the beauty of a relay little current to trigger put a relay on it and woohoo your fixed unless your relay is shgged in the contacts catchya !

Link to comment
https://www.sau.com.au/forums/topic/95019-relays/#findComment-1724906
Share on other sites
Cubes Grand Master

Cubes

Posted
  • Author
Posted
I hope you sort out your electrical gremlins ASAP.

The idea of the pump time out is in case of accident, you don't want fuel pumping everywhere even though the engine may have stopped.

If you've had an engine fire fed on 50psi fuel, you'd have the fear believe me.

Regards.

Indeed, the thought is scary. :P

Link to comment
https://www.sau.com.au/forums/topic/95019-relays/#findComment-1725137
Share on other sites
BHDave Grand Master

BHDave

Posted
Posted (edited)

60amp is a big relay for a fuel pump. The 044's only pull about 15-20amps max.I'm running a 40amp on mine as i had one lying around.

I've noticed that the bigger amp fuses (EDIT Should have said relay here but i had fuses on the brain) have a diode built in (typically 30amp up) as mentioned by SKYBEE.

Something else worth considering is the way the relay is mounted. A 60amp relay has a (relatively) heavy set of contacts. If it isn't mounted upright they can stick easily due to gravity.

I've seen this problem with the factory relays located next to the ecu in the footwell as they were mounted upside down. Turned them 90 degrees and the problem went away.

Edited by BHDave
Link to comment
https://www.sau.com.au/forums/topic/95019-relays/#findComment-1726273
Share on other sites
SKYBEE Collaborator

SKYBEE

Posted
Posted

relays are sprung so any way they go doesnt matter when not in use tehy wont fall down unless spring has sprung its last spring :D cheaper relays cheaper springs cant beat the bosch 150 relay so many uses so versitile even has a lug so you can screw it down

thast my experianc

Link to comment
https://www.sau.com.au/forums/topic/95019-relays/#findComment-1736214
Share on other sites
  • 4 months later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • MBS206
      Duncan's V37.......race car?

      By MBS206 · Posted

      Even more fun, leave all the ADAS stuff plugged in, but in different locations, hopefully avoid any codes!   And honestly, all these new cars with their weird electronics. Pull all the electronics out Duncan, and just shove an aftermarket ECU and if needed a trans controller in, along with a PDM. Make it run basic but race car styled!
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      To follow up a question from earlier too since I had the front bar off again (fking!) This is what is between the bumper and the drivers side wheel And this is the navigator side, only one thing but its a biggy! So basically....no putting coolers in the wheel arches without a lot of moving other stuff. Assuming I move to properly race prepping this car I'll take that job on and see how the computers respond to removing a whole bunch of ADAS modules
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      So I prepped the car for another track day on Wednesday (will be interesting to see coolant temps post flushing out and the larger reservoir, with a forecast of 3-14 being 20o cooler than last time I took it out). Couple of things to mention; since I am just driving the car and not taking a support vehicle, I took the rear seats out and just loaded the back up Team Trackday style. Look at all that space! To cover off removing the rear seat....it is weird (note the hybrid is probably different because it wouldn't have folding rear seats) Basically, you remove the lower seat base, very similar to a r series but it is a clip that pulls forward to release the base rather than it being bolted down. Easy Then, you need to remove the side section of the rear seat on each side. There is a 14mm head nut at the bottom of the side piece, the it slides upwards off a hook at the top to release; you also need to unhook the seatbelt from the loop at the top. Then the centre piece is weird. You need to release/fold the seats forward with the tab in the boot on each side From there, there are 2,x12mm headed bolts holding the rear of each seat to the folding bracket, under the trim between the rear seat and the boot (4x christmas tree clips there, they suck). The seat is out but you can see where the bolts attach to the bracket
    • RP1421
      S15 Spec R

      By RP1421 · Posted

      As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • joshuaho96
      R32 GTS (RB20DE) Injectors Replacement

      By joshuaho96 · Posted

      I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
×
×
  • Create New...