fuel pump wiring

Subafury · Post by **Subafury** » Wed Dec 19, 2007 8:50 pm

just a quick one- can fuel pump run straight off power or does it need relay/special wiring to stop it once finished priming etc.

anyways mine is hooked up like this atm but engine still wont ignite n start up. only cranks forever.

might have to have someone check it out

thx matty

Gannon · Post by **Gannon** » Wed Dec 19, 2007 9:21 pm

The fuel pump is controlled by the ecu.

When you first switch on the ignition, the fuel pump primes for one second and switches off. It only starts up again once the ecu recognises that the engine is turning. The pump can only run when the engine is turning.

Does your pump prime when you switch on the ignition?

If it does run, its not the pump. The pressure stored in the lines will allow the engine to run for about 5 seconds after the fuel pump stops.

Have you checked your ignition?

Matatak · Post by **Matatak** » Wed Dec 19, 2007 10:48 pm

to answer ur question Matt about putting straight power into it.

i done this at work once with an intank one and connected it straight into a Fuel pressure guage and got up to 40 PSi or wtever measurement it was and stayed there even tho the pump was still going.

so wt im sayin is yes i beleive it can run with striahgt power and not needing cutting off when finished gettin up to pressure kinda thing. (ur FPRegulator shuld work neway)

make sure u got spark obviously.
and remove a fuel pipe (carefully

) near the engine which is after the pump to see if theres any pressure gettin up there. when pumps running.

Subafury · Post by **Subafury** » Wed Dec 19, 2007 11:43 pm

i had a talk with the wiring genius earlier and have a couple more ideas and things to check up on tomorrow.

SuBaRiNo · Post by **SuBaRiNo** » Wed Dec 19, 2007 11:46 pm

I belive the main reason for it being hooked to an ECU is for Safety. Motor stops... so does the pump.

Imagine you have a head on crash and the pump is simply hooked to ignition.... last thing u will do after the crash is turn the key off, you wont be thinking straight, so your car is all there bent out of shape... your running around making sure everyone is ok. In the mean time your nice high pressure pump is squirting fuel all over the joint in your engine bay on the ground... wont take much and BOOM.

So for testing it would be fine... i would be worried about leaving it like that if you can help it.

Dave

Subafury · Post by **Subafury** » Thu Dec 20, 2007 11:06 am

no luck with having the old wires still connected so it goes through the ecu too. battery was giving me the ****s so its on charge for a couple hours now. maybe ive got another fuse or somthing underneath the dash or at ecu controlling the fuel pump. ill check that soon.

discopotato03 · Post by **discopotato03** » Thu Dec 20, 2007 11:50 am

How it actually works is the computer switches the fuel pump relay , pump current doesn't actually run through the computer itself .

If your car is having pump wiring issues you may need to access its fuel pump relay to see if its a relay problem . If its not the relay itself it may be the wiring between the relay and pump or relay and computer .

If for whatever reason the computer is not getting an RPM signal via the ignition system it won't inject fuel either - prevents flooding if ignition systems not working .

Also I'd check the fusible links .

Cheers A .

Subafury · Post by **Subafury** » Thu Dec 20, 2007 2:59 pm

ok got a new idea after speaking to 4muff. he reckons its the ballast resistor, as he had a similar problem before

Subafury · Post by **Subafury** » Thu Dec 20, 2007 3:42 pm

scrap that idea, after a search it seems ea82t dont have ballast resistors

BrennyV · Post by **BrennyV** » Thu Dec 20, 2007 5:03 pm

u have one matt im sure, ive seen it in ur engine bay

Subafury · Post by **Subafury** » Thu Dec 20, 2007 5:57 pm

ive found half the problem. was a dodgy fuel pump relay. so now ive hooked a new one up and double checked that every freakin wire is going where it should. fuel pump still wont come on at acc ir ON like normal. i can get the car to start if i hook power to pump straight off some other ignition power.

seems like my microtech ecu isnt giving power to the relay when its sposed too.

Gannon · Post by **Gannon** » Thu Dec 20, 2007 6:07 pm

Ok so you have aftermarket engine management.

Fuel pump shouldnt come on in ACC. It should prime once when first switched to ON. And only run when the engine is running. Its very unsafe othewise.

Does your ecu have a dedicated fuel pump relay output?

D3V1L · Post by **D3V1L** » Thu Dec 20, 2007 6:10 pm

im heading up to matt;s house shortly to sort **** out

dave

SuBaRiNo · Post by **SuBaRiNo** » Thu Dec 20, 2007 7:08 pm

Call me if you need me.

Dave

Subafury · Post by **Subafury** » Thu Dec 20, 2007 7:15 pm

ok cheers.

Fuel pump shouldnt come on in ACC.

the way the auto eleccy wired up my turbo timer means that it does prime once for a couple secs when its switched to ACC, no difference once turned to ON. he's prolly done it wrong then i think. im out of ideas, better wait till dave comes with some fresh eyes.

Matatak · Post by **Matatak** » Thu Dec 20, 2007 8:12 pm

ur car wont have a Ballast resisitor Matt (reading Brenny V

)

its an electric dizzy and has no need for one.

Subafury · Post by **Subafury** » Thu Dec 20, 2007 9:48 pm

well after checking and probing everything im sorta back where i was before. ecu isnt sending a fuel pump signal when it should. dave and i hooked up a wire straight to fuel pump and had the car running. then later after seemingly doin nothing its back to no spark. wont run. grrrrrrrr real pissed now.
if anyone else wants to come n give it a go be my guest.

SuBaRiNo · Post by **SuBaRiNo** » Thu Dec 20, 2007 10:24 pm

Sounds like a challenge.

Should hopdfully get there tomorrow after work. I don't have your address so i will SMS you for it. I hope it's not far away.

Dave

YouTube · Post by **El_Freddo** » Thu Dec 20, 2007 10:36 pm

Have you checked out your dizzy? If you have a hotwire AFM you have an optical dizzy - if its faulty you need a new one as they're not repairable. If you have a flapper AFM you've got that poelecronic dizy. One of the transistors may be dodgy and need replacing...

Sorry, Kez getting annoyed gotta go...

Bennie

D3V1L · Post by **D3V1L** » Thu Dec 20, 2007 10:54 pm

no afm because its an aftermarket ecu...they dont require them/....im lost...dave have a go :P