fuel pump power problems

[welly_59]

my car starts on cranking but then stops after a second or so. at first i though it was due to air leaks in the intake piping but after a bit of investigation i've found its not.

when cranking, the fuel pump gets 12v but when i stop turning the key the power supply to the pump stops and the engine dies. if i wire up a permanent live straight to the pump then the car will run and not die.

any ideas on what i should be checking?

i assume its an electrical problem unless the pump power supply will stop if i've got an air leak?

[Paul Woods]

welly sounds like the COR is still not wired up properly or its damaged from the last time it wasnt wired up correctly.....but i wouldnt expect this to be the case.Check all five wires to the cor again...

1)W/B earth
2)G/R to ecu pin A14 (rev2) B17(rev1)
3)B/Y to N1 efi relay output wire pin 7 at n1
4)R to B/W starter energiser wire
5)Blue to blue at n1 fuel pump wire

If all 5 are connected up properly it can only be one of two things...

1)the COR is faulty
2)theres no 12v coming from the EFI relay and its faulty or a blown fuse.

If at the end of the day you cant work out why the power is failing to the pump (should be one of the reasons above) then just join your blue fuel pump wire straight onto the unused injector relay output at the N1,this will give power to the pump constantly with ignition on.

[welly_59]

will check again in the morning but im pretty sure its right!

obviously power is coming in to cor as pump is coming on, but the relay isnt staying open when cranking signal stops. that sound right?

fuse is ok as i checked that yesterday. with the efi fuse out the pump doesnt turn on at all so dont think its that.

i did accidently connect up a white wire from the 4pin plug in boot instead of the b/w but that is sorted now. would that have caused the relay to break?

[Paul Woods]

possibly welly....not sure,but the prob has got to be at the COR,its all working but as you say the COR isnt staying switched open when you let go of the key,try another COR in there.

[mart1975]

what was the outcome welly?

[welly_59]

the outcome was that the wiring guide was wrong! Have you sorted your car out now? maybe you should take a look at ur cor wiring as well. how long ago did you download the wiring guide? as paul updated it once i found out it was wrong.

[mart1975]

did it damage your cor as i did the same as you regarding the 4 pin block? or was it just the ecu? no ive checked mine mate, seems fine though i wont know until next week.

[welly_59]

the cor was fine mate didnt damage it at all. whats happening with urs? is the piping between turbo and intake complete? is afm attached and plugged?

check you have 12v going to fuel pump on cranking and make sure it stays there and doesnt stop

[Paul Woods]

welly its not that the wiring guide was incorrect,the description and wiring colours where perfect,i just made a typing error on one picture of the COR,apologies for that but i do believe theres a big feck off disclaimer at the top saying you really need to research the wiring yourself and not 100% trust the guide.....thats all it is,a guide...dont get me wrong it should be accurate but mk1's have different wiring colours at the N1 across revisions,as do mk2T's and even the COR's have different colours,i cant be held responsible for all wiring changes.

Yes i made a mistake on the guide,it was a as simple as swapping a 2 with a 3 on the pins,the colours were still correct and had the necessary study been put in (i did 6 months of diagram study before touching a single wire on my swap) it would have been obvious which wire goes where on the COR,its 5 wires...really easy....ones an earth,one feeds the fuel pump,one is a power in,one is a switched live from the starter and the last is an ecu holding circuit wire...my mistake didnt do any harm as all it did was keep the starter engaged instead of the fuel pump.

Once again chaps,please research the wiring diagrams yourselves and use the guide alongside that when you are stuck...if in any doubt about the wiring just ask me,i know the looms from both cars inside out.

It wont happen again,as i'll proof read future guides 100 times before posting :thumbsup:

[welly_59]

:driving: its all fine anyway paul just wanted to make sure that he didnt make the same mistake as me

[Paul Woods]

(he actually did! joined the starter wire to the WB instead of the BW at the four pin plug) even though it clearly says BW on the guide....i must ammend that so that its 100% clear not to use just any wire thats got white and black on it....see we learn as we go and all that shite :)

[mart1975]

ive ordered my samco hoses which are going to take a week to make, then ill try again.