HELP!!! Fuel pump issue
#41
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Thread Starter
Also to say I get the same voltage at both ends of the trigger wire. And I replaced it with a new direct jumper. cable to test it and no difference.
Are there any other sensors that would have a bearing on pump running?
cheeRS
Are there any other sensors that would have a bearing on pump running?
cheeRS
#42
Super Moderator
iTrader: (5)
if you have done as I have suggested and grounded pin 28 whilst ecu is plugged in and ignition on your fault lies in the basic simple relay wiring
bridging pins 30 and 87 is all the relays do
have you studied the workshop wiring diagram and fully understood it
the std fuel pump relay is activated by the injector ecu relay
bridging pins 30 and 87 is all the relays do
have you studied the workshop wiring diagram and fully understood it
the std fuel pump relay is activated by the injector ecu relay
#43
Super Moderator
iTrader: (5)
if you have done as I have suggested and grounded pin 28 whilst ecu is plugged in and ignition on your fault lies in the basic simple relay wiring
bridging pins 30 and 87 is all the relays do
have you studied the workshop wiring diagram and fully understood it
the std fuel pump relay is activated by the injector ecu relay
bridging pins 30 and 87 is all the relays do
have you studied the workshop wiring diagram and fully understood it
the std fuel pump relay is activated by the injector ecu relay
in that ford use rhd and range rovers use lhd relays
check you have the correctly configured relays for your looms
#44
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Thread Starter
Tony. At the risk of sounding stupid, by standard relay you mean the yellow one right? If so, yes I have grounded to a good earth and no difference. And the same relay gets 2 x 12v feeds when ignition is on, as said above so injector relay must be working too right?
cheeRS
cheeRS
#45
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Thread Starter
I think In know what you mean by lhd and rhd relays ie different pin numbers for inputs and outputs? The yellow relay is genuine Ford, and so is the spare I tried. The relay in boot on braided loom was changed for same type too. It has worked fine for over a year and nothing changed overnight between it working and not.
cheeRS
cheeRS
#46
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iTrader: (5)
yes the yellow ones but they must say ford on them
range rovers also use yellow ones but they have different pin configuration but they don't say ford on them lol
I really don't understand why you are struggling pin 30 has battery voltage, pin 87 is battery voltage when the relays are energised
they are nothing more than a remote High current simple switch in this application
if you bridge pins 30 and 87 the load device should work in this instance the fuel pump
range rovers also use yellow ones but they have different pin configuration but they don't say ford on them lol
I really don't understand why you are struggling pin 30 has battery voltage, pin 87 is battery voltage when the relays are energised
they are nothing more than a remote High current simple switch in this application
if you bridge pins 30 and 87 the load device should work in this instance the fuel pump
Last edited by Turbosystems; 15-08-2012 at 10:18 PM.
#47
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Isaac. Which relay are you talking about? The braided loom runs battery to a new relay in boot, and then to pump. It takes the trigger from the black with red wire which is from the output of the yellow relay under dash.
The yellow relay has 12v continuous, 12v ignition, earth to ECU (0v and continuity checked), and the black with red trigger to the boot which has 0v with ignition off and 0.5v with ignition on.
Not at car now to see pin numbers.
cheeRS
The yellow relay has 12v continuous, 12v ignition, earth to ECU (0v and continuity checked), and the black with red trigger to the boot which has 0v with ignition off and 0.5v with ignition on.
Not at car now to see pin numbers.
cheeRS
If the original yellow Ford relay only has 0.5v going into it on pin30 (of the relay) then the new braided sub-loom is never going to work.
If I were you I would measure the supply voltage to the yellow Ford relay, if it is low, i.e the 0.5v you have mentioned then there is your problem.
The fix is simple, just run a new feed to it directly from the battery via a fuse. As you're using a new sub-loom, the original Ford wiring is only used to energise the sub-loom's relay's coil ... as such you won't even need to use particularly high amperage wire.
#48
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Thread Starter
I have just been outside to have a look. Definitely yellow Ford relays.
Pin 87 is trigger wire with 0.5v.
Pin 85 is blue and green with 0v back to ECU.
I forget which is which but the other 2 are battery live and ignition/switched live both of which show 12v when ignition on.
cheeRS
Pin 87 is trigger wire with 0.5v.
Pin 85 is blue and green with 0v back to ECU.
I forget which is which but the other 2 are battery live and ignition/switched live both of which show 12v when ignition on.
cheeRS
#50
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I don't know Tony. I didn't leave it earthed long enough to check with the multimeter as didn't want to risk burning anything out. Just long enough to see if pump primed.
cheeRS
cheeRS
#52
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That is the important bit. If the input voltage on pin 30 of the original relay is 12v then the fault has to either by with the relay, the socket the relay fits into or the "trigger wire" to the new braided loom relay.
If you measure they voltage exiting the original ford relay (i.e immediately after the relay) and it is 0.5v then the fault must be with the relay, if not then the fault must be with black/red "trigger " wire.
If all else fails, you could always rewire it so you do away with the original Ford fuel pump relay and just use the relay on the braided loom. You'll need to mess about a little to do so though.
#54
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iTrader: (5)
yes the yellow ones but they must say ford on them
range rovers also use yellow ones but they have different pin configuration but they don't say ford on them lol
I really don't understand why you are struggling pin 30 has battery voltage, pin 87 is battery voltage when the relays are energised
they are nothing more than a remote High current simple switch in this application
if you bridge pins 30 and 87 the load device should work in this instance the fuel pump
range rovers also use yellow ones but they have different pin configuration but they don't say ford on them lol
I really don't understand why you are struggling pin 30 has battery voltage, pin 87 is battery voltage when the relays are energised
they are nothing more than a remote High current simple switch in this application
if you bridge pins 30 and 87 the load device should work in this instance the fuel pump
#55
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Thread Starter
Isaac. I have tried another new Ford relay and the same results. I have measured from the back of the socket and the relay pins (by half clipping in the relay it left enough gap to get multimeter probes in.)
I have also run a new direct jump wire to boot relay with no difference.
cheeRS
I have also run a new direct jump wire to boot relay with no difference.
cheeRS
#56
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Pin 30: 12v (input)
Pin 87: 12v (output) (Black/Red wire)
Pin 85: Switched earth trigger wire from ECU (blue/green)
Pin 86: 12v
The above is with the ignition switched on.
If I were you, i'd connect a multimeter one probe to pin 28 of the ECU and the other to a +VE connection. Switch the ignition on and make sure you're getting 12v through the circuit. It should't make any difference to the input/ouput voltage on pins 30 and 87 on the relay though.
As I say, if all fails extend the switched earth trigger wire to the new braided fuel pump relay and connect it to pin 85, then connect pin 86 of the braided fuel pump loom relay to a switched ignition +VE feed. This will do away with the Ford relay and wiring altogether.
#57
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Thread Starter
What I thought then Tony, should be 12v. I actually think I did test this when my bro came round to help, and it was the 0.5v, but I will check to be absolutely sure. Whatever it is though, it does not prime the pump.
cheeRS
cheeRS
#59
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Thread Starter
Isaac. Would that not bypass the crank sensor trigger? ie it should only prime pump after cps feeds back to ECU it is correct? Or is pin 28 switched this way? And is it safe to do this? After all, something is not working and I have changed nothing between parking it in the garage and going out to start it next night.
cheeRS
cheeRS
#61
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This is all how I thought and understood it worked. I'm sure I have checked this already but I will do so again.
Definitely 2 x 12v going into the relay, definitely continuity to ECU and to pump relay, changed ECU and changed relay.
The circuit just isn't any more complicated than that so it should work!
cheeRS
Definitely 2 x 12v going into the relay, definitely continuity to ECU and to pump relay, changed ECU and changed relay.
The circuit just isn't any more complicated than that so it should work!
cheeRS
#62
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#66
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Thread Starter
Ok. So with a wire running from the ECU earth wire to battery negative, I get battery voltage out of the yellow relay.
But still no fuel pump.
cheeRS
But still no fuel pump.
cheeRS
#67
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Thread Starter
And from the relay in the boot on the new loom, I am getting permanent battery voltage on 3 pins, regardless of ignition on or off. Clearly this is not right as it should be ignition switched. Nothing from the pump though.
Reading voltage from the pump connectors I am getting 7.5v. Which is extremely strange as I have 12v from the relay going down the wire to the connectors.
cheeRS
Reading voltage from the pump connectors I am getting 7.5v. Which is extremely strange as I have 12v from the relay going down the wire to the connectors.
cheeRS
#69
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Thread Starter
The black with red trace wire does now give 12v permanently (because I've earthed it to battery to test. So as above I now get 12v in to the rear relay on both pins. I get 12v out on the relay pin going to pump live. However only 7.5v at pump connector. So yes the next thing is to replace that wire and test again.
The pump negative/earth goes back to the relay in the boot and shares an earth with the relay earth pin on the back panel. This earth is good as I have taken it off and cleaned it etc. So not back to battery. Has run fine like this for a year.
cheeRS
The pump negative/earth goes back to the relay in the boot and shares an earth with the relay earth pin on the back panel. This earth is good as I have taken it off and cleaned it etc. So not back to battery. Has run fine like this for a year.
cheeRS
#70
PassionFord Post Troll
iTrader: (3)
So pin 86 fuel relay wont get 12v from pin 28 ecu earth switch without the extra earth to battery you added in? What voltage do you get at the battery ?
I wouldn't know but makes you wonder if the circuit that switches the relay via ecu can be affected by the pump wiring /circuit somehow ? Being as its just switching a relay to power another and you have 12v+ i wouldnt think it would. Maybe you have bad earth somewhere nearby.
I wouldn't know but makes you wonder if the circuit that switches the relay via ecu can be affected by the pump wiring /circuit somehow ? Being as its just switching a relay to power another and you have 12v+ i wouldnt think it would. Maybe you have bad earth somewhere nearby.
#71
PassionFord Post Whore!!
iTrader: (1)
If you ground your new relay, i.e. in boot, this should run the pump, this bears no resemblance to the ECU at all, the relay also requires a power source.
If not then I would then move to check the power is actually reaching the pump itself and the ground is good, it could be the pump is at fault.
Martin
If not then I would then move to check the power is actually reaching the pump itself and the ground is good, it could be the pump is at fault.
Martin
#72
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Thread Starter
Well tmrw afternoon I'm hoping to have chance to have a look at this again. First thing will be to run a wire from rear relay to pump as it would appear last week that I am now only getting 7.5v at pump, losing 4.5v from the relay. But this whole thing still screws my head up.
I have only got this far by directly earthing the return to ECU pin 28 wire from the front relay. So what does that mean? i.e. What can be causing this? And how do I fix it? With the earth as it is, it is not ignition switched so I cannot leave it as such can I?
I will have limited time tmrw so would like a clear plan of what I need to do, but this whole thing is cooking my brain.
cheeRS
I have only got this far by directly earthing the return to ECU pin 28 wire from the front relay. So what does that mean? i.e. What can be causing this? And how do I fix it? With the earth as it is, it is not ignition switched so I cannot leave it as such can I?
I will have limited time tmrw so would like a clear plan of what I need to do, but this whole thing is cooking my brain.
cheeRS
#73
PassionFord Post Troll
iTrader: (3)
Maybe you have 2 different faults. As Marty says maybe the pump itself is shot?
If when earthing ECU pin 28 to negative of battery is the only way to get your 12v+ coming out of the yellow O.E pump relay (triggering new relay) then there must be a fault up that end somewhere surely? Have you checked the multiplug above the ECU,s ? A dodgy wire in here maybe the cause.
If the live to ecu is disrupted its not going to earth itself i would of thought.
Not a prof answer mate i know but just interested .
Mike
If when earthing ECU pin 28 to negative of battery is the only way to get your 12v+ coming out of the yellow O.E pump relay (triggering new relay) then there must be a fault up that end somewhere surely? Have you checked the multiplug above the ECU,s ? A dodgy wire in here maybe the cause.
If the live to ecu is disrupted its not going to earth itself i would of thought.
Not a prof answer mate i know but just interested .
Mike
#75
I'm Finding My Feet Here Now
Just read all this - sounds a nightmare. Just my 2 cents worth, going back to school circuitry. If you have 12v on one side of relay, and with relay switched, than it must end up on other pin. But voltage is 'potential difference' - IF there was a spurious voltage existing where it should not be (like feedback) then the difference between the two voltages would give an odd voltage showing on multimeter.
#77
PassionFord Post Whore!!
It depends on what stage of tune you are running your 2WD Saff. If its standard a replacement fuel pump should be fairly easy to buy, if its running big HP then you will need to upgrade to a Bosch 044 pump or similar.
#78
could you by any chance help me find one. its standdardd and almost at 150km.Already bought new coil as that prob is out of the picture.took old fuelpump out today an is rusted pretty bad. please let me know if you find a new pump. thx
#79
PassionFord Post Whore!!
I have just looked and you can get a standard one from various places Graham Goode, Burton and other places. Are you in Holland? Should be easy for you to buy one and get it sent to you. Have a look and see what you want .
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