fuel pump constantly priming

[mathew_colville]

hey ive noticed my fuel pump constantly primes in the on position, every other car ive had normally stops after a few seconds so im presuming that this shouldnt be happening on this car. The car runs fine and everything but would like to fix it if it shouldn't be happening

ive read that it can be the fuel pump relay on other cars but i just want to know if anyone has had an issue like this on a lancer gsr/evo and if so how they fixed it, if they did?

thanks mat

 

[4piknup]

The mitsi don't prime till you crank it.
Sounds like the relay. If you unplug the relay does it stop? Maybe someone has hard wired it on.
Hard wiring may only mean the pump trigger wire has been earthed

 

[BMGTZ]

just a guess....

it might have had a wire run to it from the battery pos via a non standard relay so that it gets 12v all the time. was a trick from the old days when a standard pump was asked to flow a bit more.

 

[mathew_colville]

yeah it looks like the previous owner may have done something to it as there is a red and white wire that is earthed to the metal using a non standard metal clip thing

one of these with the round end-

i noticed when i have the hood up i can hear the fuel run through the rail and back to the tank constantly, should the fpr hold the fuel until it gets to a certain pressure then turn pump off?

if it has been hardwired, is this an issue,will it cause any problems to anything?

thanks mat

 

[khubner1]

could make the pump run hot and heat up the fuel causing it to loose density and thus despite being at correct rail pressure less fuel is there and is more likly to detonate (thanks to hot fuel)

 

[mathew_colville]

so how do i undo the hardwiring? where does the red and white wire that has been earthed go?

 

[BMGTZ]

"if it has been hardwired, is this an issue,will it cause any problems to anything?"

probably not.

 

[EVOCPE]

How can it make the fuel pump run hot??

It's pumps always on when he car is running

Are you running an aftermarket ecu? I know with the haltech it primes on accessories and you can set the duration of the prime too

 

[mathew_colville]

i just presumed it had a stock ecu, ill have to go and have a look

 

[mathew_colville]

ok i had a look it looks like a stock ecu, this is the number on it?

 

[evo-gsr]

Yep standard ecu. The loggable one at that.

 

[evo-gsr]

could make the pump run hot and heat up the fuel causing it to loose density and thus despite being at correct rail pressure less fuel is there and is more likly to detonate (thanks to hot fuel)

found this quite amusing!

 

[4piknup]

Dude, it is very unsafe to run your pump full time. The factory make them turn off and this is for good reason.

If you have a accident and rupture a line, then you will empty your tank in a minute or so. I can think of several reasons this is not a good idea. INFERNO!
You know the fuel line runs directly under your seat, and on the bottom of the chassis rail. It is quite vunerable And a decent hit or just banging over a kerb will stuff a fuel line.

Fix it now. Think of the children

 

[ENGINR]

 

[BMGTZ]

mmm...fried Kid chops!!


the goat kind tho

 

[EVO-00X]

Wire up an aftermarket internal fuel pump as per one of the following diagrams and you will be fine.
Im running a switchable circuit breaker in the boot on mine only so I have a quick kill switch and a means of turning off the fuel and power to the car at the flick of a switch.

 

[EVO-00X]

Mat did it previously stop priming after a few seconds? then only just started to prime constantly?
It could be an ECU issue also.

 

[mathew_colville]

nah im 99% sure it has been like it since i bought it but it only just clicked in my head that it shouldnt be like this, and as jack of all said it really is about the kids, last thing id want is my children to be burnt to death from something that could easily be prevented.

ill remove the hardwire and see if it works because as evo-00x said some people hard wire the fuel pump because there is an issue with the ecu affecting the fuel system

 

[mathew_colville]

ok so this is the red and white wire i am talking about, comes out of the fuel relay (top right wire) this wire had been cut and earthed to metal to cause it to run constantly, i connected the red and white wire back up and now car wont start as fuel pump isnt doing anything



does anyone know where this red and white wire goes or what it does so i can try troubleshoot where the issue is?

 

[4piknup]

Have a look in my profile. Im pretty sure the wiring for fuel pumps is in there. Ie the factory diagrams.

I think the ecu will earth the red/white wire through one of the driver ic. Maybe one of these is damaged inside the ecu.
The drivers are the same as described in my evo1-3 sticky on idle control issues.

If the red/white wire goes to the ecu (I think it does) check its connected and continuous. If so pop the cover on the ecu and look for corrosion under the caps and/or a burnt ic driver.