Need Help with Fuel Relays

[HQLex]

Hi, I am putting a crown V8 in a HQ Monaro. I have followed the wiring diagrams for the 4 relay (duel speed fuel pump) setup but Im having trouble getting the fuel speed relays to operate. The main EFI (master) relay energises when the ignition is turned on but neither of the fuel pump relays energise to start up the fuel pump. The engine check light is not on. Does anyone have any ideas or areas I can check, thanks.

I have also tried (after the 4 relay setup)
3 relay setup (single speed fuel pump)
and rewiring the originial relay box and found the same problem.

I noticed in the 4 relay (duel speed fuel pump) diagram that the Fuel Pump Speed Control Output and the Starter Output Fuel Power Relay both trigger the Hi Speed Relay for the fuel pump. At startup what voltages does the ECU put on the STA, FPR and FC pins for getting the fuel pump going. Just wondering because if the STA is high and the FPR is low, using both to trigger the Hi speed fuel relay will cause a short from high to low at those two pins, lots of current and depending on the devices used in the ECU damaged components.

I hope this is has not happened to my ECU.

 

[Zuffen]

The ECU uses the hi speed relay to start the engine as it has to ensure there is sufficient fuel flow for the rich mixture.

If you're not getting any fuel flow check to see if you're getting power to the relays. By this I mean do you have 12volts on the relays at all times the ignition is on? This is supplied direct from the EFI opening relay.

Additionally you need to check that you have 12volts on the low speed relay trip terminal at all times.

The hi speed relay trip terminal should only recieve 12volts when you turn the key to engage the starter.

I suggest you check and confirm if you have the foregoing.

You could also check the fuel pump is actually connected to the wire you have coming from the speed resister. You may get a surprise and find it isn't as you thought.

Report back and we'll see where we go from there.

I suspect you don't have power at the relays from teh EFI opening relay.

 

[HQLex]

I have 12V from the Circuit Opening Relay but dont have any outputs from the ECU on any of the Fuel pins of the ECU:
FPR pin (fuel pump speed control output)
FC pin (Fuel Pump Power Relay)
and STA pin (Starter output to Fuel Pump Power relay)
All the above pins are floating around 200mV.

I have Battery 12V on Batt+
Ignition 12V on Ign+
and +12V from the relay to both +B and +B1
and all ground have been checked.

The fuel pump is wired correct as I tripped the individual relay with a jumper lead to 12V and got Hi and low speed.

ECU still wont give outputs to energise the relays itself, are there any other check I can do?

Thanks Mark

 

[hiluxmad]

this is spooky im having the exact same prob is there a trigger some where that would stop them from turning on? low oil water? im guessing here? any sugestions?

 

[Zuffen]

HQLex,

Go back and check you have 12volts at the plugs that go into the ECU. Also check you don't have corroded terminals in either the ECU or approriate plugs.

As you have 200mv it means there is voltage (of some sort) going into the ECU. It just looks like it is a little light on.

This may sound dumb but make sure you haven't confused any ECT plugs with the ECU plugs as they fit each other. It doesn't do the ECU and harm so don't stress if you find that has happened.

Hiluxmad,

There isn't any safety cut-off for low water/oil etc.

My solution would be to double check you have power in the ECU. I'd open it p and check you have power after the ECU/connector pins. This would exclude corrosion, bad joints etc from the likely culprits. Essentially I would start at the battery and work my way into the ECU ensuring I have power going to the right wires and pins.

Did the engine run before you pulled it out of the half cut? If it did you know you've done something wrong and the ECU isn't to blame. 99.9% of the time it's us humans that fail to get it right. I speak from experience.

 

[hiluxmad]

ive got power to ecu where and how it should be im begining to think it maybe earth quality. aas in qld started it but its been a while since then. i just know its somthing simple. ill work it out it just may take awhile.

 

[sideshow]

get rid of the hi/low speed circuit all togother
just an extra relay to stuff up

just run the blue wire in the top right corner of the plug on the circuit opening relay straight to the fuel pump

this way all u really need is the ecu triggering the circuit opening relay to run power straight to the pump

i do every car this way i hate havin the pump run low speed

and also make sure the black/white wire on the circuit openin relay has 12 volts only when cranking otherwise the pumps will run all the time too

check to see on the fc terminal of the ecu
make sure u have the correct fc terminal as there is f/c and there is fc for the crown with an auto

use the fc green/red wire check to see if this has an earth when ignition is on and engine not runnin

if it does then u have a problem

remove the fc wire from the circuit openin relay and see if pump still runs

if it does then u have a problem elsewhere

if there is alwasy an earth on the fc wire when ignition is on and engine not runnin then u might have a prob with the ecu

sounds like u miss understood diagrams

sta is an input not output
ecu doesnt control it

fpr is a neg trigger at 4000

fc is a neg trigger when enigne is runnin

sta should have nothing to do with the dual speed circuit

it should only go to the circuit openin relay

if u still cant work it out i can come up for a fee but im in the usa soon till end of december

it will prob only take me 20 mins to sort it out

 

[hiluxmad]

not sure about hq lex but mine isnt triggering anything from ecu im just starting at fuel and working my way through starter cranks fine so not a bad earth to block more than enough earths to lom and ecu all power as it should be but nothing according to an autoleccy i know there should be a signal TO the ecu that tells it that the starter is cranking any idea what this is on crown?

 

[HQLex]

Hi guys

Zuffen,
I have checked the following
Got the right connectors plugged into the ECU.
Opened the ECU and tested the voltages at the board and all input voltages 12V Batt and 12V Ign is spot on, and 12V from Main EFI relay is good to.

I was told when I bought the engine box and loom that it ran fine but didnt see it running as it was out of the car.

Sideshow,
I have looked for the Blue wire on the Circuit Opening relay but have none that are blue. Only colours are
Green/White
Black/Red
Black/White
White/Black
Green/Red

I have checked the Crown wiring diagrams and the black/white wire on the Circuit Opening relay goes to the sta on the ECU. For that wire to have 12V on it the sta pin at the ECU would have to go to 12V making it an output. If the ECU doesnt control it how does it get 12V onto it? Getting very confused.

Still wont energise the fuel pump relays, outputs on FC, FPR and STA still around 200mV.

Anyone out there able to plug in my ECU and give it a test, would like to be sure that the ECU has no problems.

Hiluxmad how are you going with your problems?

 

[sideshow]

if u come down to sydnwey i can tesat yr ecu but im goin to usa in 3 weeks

im tellin u to do the basics

thro away the fpr
just use the circiut openin relay

all u need is fc from the ecu its a neg trig green/red
sta from starter motor to that relay black/white
white /black is an earth
black red is ignition positive to that relay from efi relay
green and white is the power to the fuel pump

i never run the fpr circuit as it is another thing to go wrong

i have the factory diagrams and those colours i told u match

if u make things to complicated it makes it harder to fix and that is yr problem now

if u still have probs getting 12v power to the green/white fuel pump wire

then bridge the green/red wire to earth (the fc from the ecu)

if this still doesnt put 12v to the green/white then check u have 12v comin in to the black/red

i do these with my eyes shut

if u want to do it another way sorry i cant help

if u bring yr car to sydney i can fix yr prob in 10 minutes
i do this setup on the floor on alot of looms

 

[hiluxmad]

side show,
im obviously having the same problem as HQlex what do you mean by neg trigger? should these wires be the relay earth? if so how did every one elses wiring work and ours dont?
STA is input? from where?
any help would be greatly appriciated.we are both stumped

 

[hiluxmad]

also if i courier you my ecu can you test it and send it back? for a fee of course.

 

[sideshow]

earth trigger means ecu or whatever puts an earth to the wire

so that means the other side of the relay should have 12 v
this is the coil section of the relay not the switch
if u dont understand what i mean then get it fixed by a pro

start signal comes from the ignition key when u crank u should get 12v

its sooooooooooooooooooo simple

some people are smarter than others so i guess thats y some work and some dont

sorry for being a smart ass but the more i work with idiots on the phone all bloody day asking for info and in the end i get nothing done the more arrogant i get

these days im so busy i am forgettin bout the small jobs or dont get time for them
which is sad but i guess im goin looking for the big buck jobs these days

 

[hiluxmad]

thanks for the info sideshow it has been very helpful. your entitled to be a smart ass somtimes i get the samething aswell i know it pisses me off. id happily pay a pro at this point but the car is an hours drive from anywhere and it happens to be the only vehicle i can tow with so trailer is out too. bummer.

 

[sideshow]

its very basic once u get rid of the crap

what i do is have an efi relay that gets turned on by the ecu by m-rel wire once the ecu gets ign

the efi relay turns power to +b and also to the black/red wire on the circuit openin relay

the white/black wire on circuit relay goes to body earth

the b;ack/white needs a start soleniod signal so this means 12v only when cranking so just bridge of the starter wire on the ign switch its black/white on a hilux

the green/red is the fc wire from the ecu when the ecu wants to turn the fuel pump on this wire gets an earth so this means 0 volts
when pump isnt runnin and ign is on eu will measure 12v on the fc wire

the green/white is the fuel pump power wire
run this to the pos side of the fuel pump


basically the cicuit openin relay is a 2 trigger relay

one trigger is the starter which when u get 12v it switches power to the pump wire

the other trigger is the fc which when engine has started the ecu earths this wire out
to triger the circuit opening relay to powe the pump while engine is running


one main reason i remove the hi low voltage for the fuel pump is most toyota ecus trigger the hi voltage at 3500 or 4000

now if u were to modify yr enigne and u needed full 12 volts much earlier than 4000 rpm it can only slightly cause small probs

the 2 stage voltage is only for fuel pump life and maybe slightly leaner mixtures

i know the fuel reg is what controls amount of fuel but if yr pump flows more fuel it can adjust the amount of fuel into the engine only minutely


another reason is one less problem to go wrong

 

[Zuffen]

I've been away for a few days on holidays and missed all the fun.

If anyone want's to send me their ECU I'll plug it into my car and give it a run.

I'll sit down later with the wiring diagram and see what help I can give.

Sideshow has given a lot of free advice that is quite valuable to him. This is his livelyhood so each time he gives advice he losses some of his competitive edge.

 

[hiluxmad]

again thank you sideshow this has been helpful to me and others im sure the way you explain it makes sense. now i just need the time off work to get to the car and try it out.

 

[sideshow]

cool sorry if i sound rude sometimes
just get soo many wallys on the phone
and alot of people want things for nothing

but i do over 150 conversion wirings a year and i try to keep it as basic as possible

people think its easy but most of u by the hassles u have know its not

wiring the engine is 30% of the job

the rest is getting tacho
speedo
gauges
lights etc to work

the new engines these days only have afew wires for the dash
some just use one data wire so to get things to work of that is very hard and expensive

and most cars made after 1998 or around that era have security

so in 5 yrs these engines from that era will be popular and will be more of a pain to do

i have to stay ahead of the technology

 

[HQLex]

Thanks Sideshow for test my ECU. Have wired in the STA and NSW. Engine cranks over fine, ECU is pulsing the fuel injectors (so getting fuel now) but have no spark at the spark plugs.

The igniters have constant 12V from the ignition, and I have strap a large battery cable to them via the negative on the battery (so they are earthed). The ECU doesnt seem to by sending the negative trigger via the IGT1, IGT2 pins for the ignitors, any ideas if there is an input that effects these?

 

[sideshow]

check for power at the coils

also on pins igf 1 and 2 need to be connected properly

i think igt is signal to ignitor and igf is the return

if the ecu does not get a signal to the igf wire then it wont spark