[Corsa B 1993-2000] fuel pump

[evolutionuk]

i have a corsa sxi 1.2 1999 it will not start there is no power to the fuel pump but i do have power to the fuel gauge. anyone no wot it can be

[CorsaEdi]

How do you know there is no power to the fuel pump? When you turn ignition in can you hear it prime?

[Taurus]

There are a number of possibilities:

A fuse - check no.26 20Amp

The fuel pump relay - usually on the side of the glovebox area - you need to remove the glovebox to get at it. It is one of the purple ones. (See below how it is triggered)

A wiring fault

The crankshaft sensor is broken. The system is that when you turn the key to no.2 position the fuel pump runs a short priming charge then cuts out. When you turn the key to the start position and then engine cranks over the crankshaft sensor tells the ECU that the engine is turning and it switches the fuel pump relay on again.

Useful diagnostic tools would be a multimeter to check for current, and Opcom which runs on a laptop which can trigger the fuel pump relay independently. That allows you to check if the relay and pump are working without needing the crankshaft sensor operating.

If you say where you are someone local with Opcom may offer to check for you.

Start with the fuse, and then check if you get a short priming run when turning the ignition on. You may be able to hear it run, or you can check at the fuel rail - there is a valve which if you press the middle pin will spray out fuel if there is pressure. So turn the key to ignition on, do not crank the engine, check for fuel pressure in the rail. If none then it's not running the priming run.

Let us know what you find - (and if you can confirm if yours is auto or manual.)

[evolutionuk]

all fuses r ok ive changed the relays but fuel pump does not prime on the 2, ive checked the fuel pump plug to see if there is power the 2 thin wires have power but the thicker 2 dont have power. i have change the ecu to plus we have hooked the car the a delphi diagnostic machine there it says 18. engline lamp & circit error. there is no fuel pressure in the rail brfore crank or after and the car is a manual.

[Taurus]

Check that the engine management light is operating (ie it comes on when you turn the key to no.2 position) and make sure it isn't flashing when you turn the key to crank the engine.

You say you've changed the ECU. Did you install the corresponding transponder and key chip with it? Otherwise you will have an immobiliser problem which will cut off the fuel supply.

Also worth checking, has the car been fitted with any form of aftermarket alarm system?

[evolutionuk]

no there is no engine management light on or flashing, but is there a way the check if the light is working.
i got a full ecu kit which included the ecu,transponder,and 2 key chips.
there is no alarm system installed

[Taurus]

Probably the EML bulb has blown - or been removed? Best thing is to replace it.

It would be helpful to know why the ECU was replaced, if this was running ok before you changed the ECU, or when the problem started - ie straight after changing the ECU?

By the way, the fuel pump relay works by the activating circuit being earthed through the ECU, so check the ECU earth is healthy.

You're probably going to need to check the wiring that supplies the fuel pump relay and also the circuit from the ECU that activates the relay. If you've got a wiring diagram try bridging the relay terminals running through the relay to the pump and see what happens.

[evolutionuk]

i have this problem before i changed the ecu was looking it up and alot of people say that it might be the ecu so i changed it to see if it fixed it but did not lol.
do u no where the earth is for the ecu ?? plus i dont have a wiring diagram was looking for one.

[evolutionuk]

plus i just found out that when it was connected to the delphi machine he could only connect to the immobalizer everything else would not connect dont no if this helps


update
just checked the EML and it has been removed so got to get one

[Taurus]

Let us know what happens when you've replaced the EML.

I think that on the basis of the previous ECU being known to work I'd put it back, and then take a look into the circuits I mentioned above to check what's going on.

[evolutionuk]

ive replaced the EML and it is on all the time not flashing, i put a wire from the purple relay with the wires to the fuel gauge and i think the other 2 wires are fuel pump (the other wires dont have power to them) so 1 end on the fuel gauge to the end of the big black connecter under the relays which has the wire running to the fuel pump turn the key to no.2 and the fuel pump prime till i take the wire off.

[Taurus]

First thing is to get the fault code(s) read. They can be sometimes reluctant to read properly on generic readers so I'd see if there's someone near you with Opcom who can check for you.

I can't really figure out what you've done re. wiring from what you've posted. On the fuel pump relay pin 30 (red wire) is the live feed, pin 87 (red/blue wire) is the live feed to the fuel pump (ie bridge those and power ought to flow to the pump). The activating pins from the ECU are pins 86 (red/blue wire) and 85 (brown/red). The activating circuit activates by earthing out via the ECU so that's something you need to check for. (It's sometimes worth putting an additional earth on the ECU just in case. Since you've tried two ECUs I don't think that will make any difference - but check that earth is being made.)

I'd get hold of a Haynes, look at the wiring diagram for the fuel pump relay, and use your multimeter to check each wire and what current is present when the ignition is on and when the engine is cranking.

[evolutionuk]

kk thank for ur help i will see about getting a opcom reader my self as it might be handy in the future and a haynes manual to i will post my finding.

[Dave]

Hi, please avoid using text talk in your posts in future. It is against forum rules. Thankyou.

Dave.

[evolutionuk]

Hi, please avoid using text talk in your posts in future. It is against forum rules. Thankyou.

Dave.

sorry for this i did not no i was doing it some time it is because i cant spell well, but i will try and stop it in future posts.