no noise from fuel pump

[vala]

i recently been having trouble getting my 172 to start.
i've noticed that when im turning the key the there is no noise coming from the fuel pump. i've lifted up the rear bench again and turned the key and can definately confirm that no noise is being emitted.
if the car has been attempted to start many times would the fuel pump still prime? or would it not bother as there would be already fuel in the system and it would prevent it from flooding?

 

[geesus69]

no it should prime every time on ignition

check the fuel pump connector, check there is voltage there, if not start working your way back to trace the fault

also check the coil pack is getting voltage, one relay sends power to both

 

[benstone]

i had this problem with my old 1.2, but in the end it turned out it was the fuel pump relay was a bit dead. I just swapped a couple around to single out the broken one and whether that was the problem, opened it up (need to snap a few clips) sprayed some wd40 in there and it was working again

 

[vala]

no it should prime every time on ignition

check the fuel pump connector, check there is voltage there, if not start working your way back to trace the fault

also check the coil pack is getting voltage, one relay sends power to both

pulled the connector off the fuel pump and got 4 connections, you wouldn't happen to know what colours represent live and earth?
where's the connector on the coilpack? or do you mean just the voltage at the relay?

 

[geesus69]

yeh you can check it at the relay or at the coilpack, there is a 3 wire connector attached to the coilpack, will be under the engine cover if you have one fitted?

im not sure on the mk2 fuel pump connector, but 2 of those wires will prob be thicker than the others

someone will confirm it but there is prob these colours:

black - earth
red - constant live
yellow - ignition live
white - feed from the relay

what you want to check is that there is 12v (or thereabouts) at the ignition live wire and the wire coming from the relay (prob white) on ignition. also on ignition try and hear if the relay is clicking

 

[vala]

i'll have a gander for 2 thicker wires and see what i get.

i've seen the 3 wire connector under the coilpack. i'll have a look at that and try to make which is live and earth...unless you happen to know?

i take it the relay is one of the smaller relays in the engine fuse box?

 

[geesus69]

cant remember which wire it is on the coil, use a multimeter to find which one it is

yeh there will be a big yellow relay and 2 smaller black ones, as per this

 

[vala]

relay is clicking under the bonnet.
spotted the 2 thicker wires and im not getting 12V at all to the fuel pump.
could i test the connection between by running 2 lengths of wire directly off the battery to the live and earth on the fuel pump?

 

[jordan172]

the fuel pump does not prime every time. i had this problem try it a couple of times

 

[vala]

thanks for the reply.
to test the fuel pump is working could i run 2 cables from the battery to the fuel pump direct and see if it does 'whirr'?

 

[jordan172]

are you getting 12v? try putting a multi meter on the 2 thicker wires (forgot colours now)

and try turning igniton on and off 3 times to see if you get 12v as it does not always prime if the pressure is already at what it should be

 

[vala]

im not getting 12V on the two thicker wires. however the relay is clicking so im assuming this is fine.
so by the sounds of things if somewhere within the wire that the fault lies? would running power and earth off the battery to the fuel pump work?

 

[jordan172]

ah not sure then bud i would try putting a live on it then to see if it primes.

be carefull though as you dont want to get a spark near that fuel

 

[vala]

just had a thought. if i removed the fuel line from the fuel rail this might de-pressurise the fuel in the system.
then if i attempted to start it up the fuel pump 'may' prime meaning a) its working, b) there's no problems with the connection and c) the fault lies elsewhere.

just thinking it may be a way of being able to test the system and its operation.

 

[jordan172]

yeh good idea remove it at the rail in the engine bay, face it out of the bay and try starting to see if its acually getting fuel, should spray fuel all over your drive lol

 

[vala]

i'll get a container and try and catch most of it in there.

 

[jordan172]

yeh put a pepsi bottle or similar over the end to catch it

 

[vala]

well gave it a go and no fuel coming out. gonna try powering up the fuel pump via the battery to eliminate whether the fault is with the fuel pump or the wiring.

 

[geesus69]

did you have any luck with this?

 

[Adey.]

ever sort this problem out?