This car belongs to the wife and my son also drives it - I do the hard bit and maintain it best I can. Just to let you know I've changed the head gasket, heater matrix, rear suspension dampers, track rod ends and break pads/shoes so I'm not really a novice.

OK. Got a call from my son late at night saying it wouldn't start. I checked it and suspected there was no fuel getting to the engine so I called the lads from the RAC out. I must say I was quite impressed by his determination. He suspected a duff fuel pump and towed it home for us [at 3.00am in the morning].

The local Fiat dealership said 160GBP for a replacement (not fitted). A local diy motoring shop said 136GBP and the local scrap yard wouldn't give a quote without a part number (which I don't have at the moment and the dealers won't tell ).

Before I go to the expense of buying a pump and finding this not to be the fault (which someone else did on this forum). I'd like to be absolutly sure first.

According to the RAC guy he said we had 'power' to the pump plug but my confidence was lacking in this since he started checking fuses after this statement . I've since checked the wiring diagram in the Haynes manual and the colour codes I'd be interested in checking is the +ve line to the pump (brown and white) and the black -ive line. According to the manual this latter line goes to the inertia switch before going to ground via a black and violet wire.

When I get the car off the road and onto my drive [don't ask ] I will be checking with my mutlimeter for the obvious etc. What I'd really like to know is, is the inertia switch the same thing as the fuel cut off switch I've read about on here and if it is, is it under that black rubber button to the left of the passenger seat?

Does anyone have the part number for this fuel pump in case I need to get one from the wreckers?

According to the Haynes manual there is a 20A fuse somewhere for the fuel pump (big innit?). Any idea where this is located?

PS - what is the job of the inertia switch [to turn the fuel pump off in the event of a collision?]

Thanks

In anticipation

Dave

hi there, the inertia switch is the fuel cut off switch yes i'm not too sure where it is on a punto though (i'm a cinq boy lol) But if you get in the car and turn the ignition on, you should be able to hear the pump priming.

As for the cut off switch the fuel pump is earthed through it, so when the NC contact in the switch breaks the pump has no -ve feed. And yes, it is to cut the fuel pump off in the event of a collision.

The fuel relay could also be your problem? It is under the bonnet in the engine bay, and is a rectangular white box (near the ecu, along with the fuse in a cinq anyways) have alook for that and check the plug is in properly and the contacts are clean.

Hope this sheds some light on your situation

Lenny

hi.

the inerita switch is to cut the pump when there is a collision or other large jolt. Hit a big enough pot hole and it can set them off.

when you turn the ignition on, you should hear the pump prime. if you don't - it does not always mean a pump failure. it could be the fuel pump relay, fuse, or the interita switch.

the system is easy to test if you've got the diagrams and a meter in front of you.

do not pay them prices for a new pump. http://www.frogbitz.co.uk if you want a new one - or scrap yard prices.. i paid about £40 for a Punto 85 pump. The pump itself is a common part, so you you'd get away with buying one from another car and then swapping the pump over from the carrier.

Thanks for the speedy reply(s).

Would it be fair to say that if I was getting a +voltage with respect to -ve at the pump contact on turning the ignition on then the problem would not be the relay/fuse? I think I'm right but thought I'd ask.

Also, in my mechanical days to prime a pump was to fill it with the fluid you intended to pump with it. Is this what you mean when saying hear the pump rpiming or were you refering to the pump priming the system? i.e. making sure there was a fuel pressure at the carb inlet?

Dave

the noise you are meant to hear is the pump itself simply filling the sytem with fuel ,once it reaches the injectors/carb it will stop until you start the car when the pump obviosly kicks in again, not very loud more like a faint buzzing -- the cut off switch on a mk 1 punto is by the side of the passenger seat between seat and door you cant miss it

jaybee said:

once it reaches the injectors/carb it will stop until you start the car when the pump obviosly kicks in again

Click to expand...

I'm interested to know what causes the pump to stop once it's primed the system and before the engine is started? Does it stop or is their an unloading valve in the system? If it does stop I'd be interested in what makes it stop as this could have a bearing on my fault finding exercise.


btw, is it a possitive displacement pump or centrifugal type?

Dave

what sort of system have you-spi?-mpi? these are controlled by fuel pressure regulator and the ecu-- pre 1998 have seperate system, post 98 the whole system is integral part of fuel pump,

I know this is not very "health and safety" but if I remember rightly on the top of the fuel pump there are two arrows on the feed pipes why not simply disconnect the pipe feeding the injectors and turn on ignition you will at least have a visual check to see if pump is working
this item is on ebay for around £50--item number 320183139782

the fuel pump/injection relay the white thing people are talking about is controled buy the engine ecu it's on a timer as there is no fuel pressure sensor

if you have live it should stop within a few seconds after turning on the ignition

all you need to do is check the continuity between pump and earth

if you have the hatch under the back seats up you will defiantly be able to hear the pump if it's running

so then it's just a case of replacing the pump

i think 55 60 75 80 90 and gt are al the same pump

but i'm sure someone will correct me on that now

littlepip17 said:

the fuel pump/injection relay the white thing people are talking about is controled buy the engine ecu it's on a timer as there is no fuel pressure sensor

if you have live it should stop within a few seconds after turning on the ignition

all you need to do is check the continuity between pump and earth

if you have the hatch under the back seats up you will defiantly be able to hear the pump if it's running

so then it's just a case of replacing the pump

i think 55 60 75 80 90 and gt are al the same pump

but i'm sure someone will correct me on that now

Click to expand...

OK thanx 4 that.

I have now got the thing on the drive (the car that is) and guess what? the RAC man was not right. I have no power to the pump after turning the ignition on (save 4 a few mA) so I am now focasing my attention to the electrical circuit. It's not the cutoff switch cos I tried a different earth path from the pump (the sender eart actually which I tested before hand) so it's definatley a fault on the +ve feed. Nerxt stop I think is the relay. I've located a white relay under a black plastic cover bolted to the bulkhead just to the right of centre. The contacts look fine. My next plan is to interrogate the Haynes manual and take it from there.

At least it will be cheaoper than a pump

well if the pump is not running first things to check are that the code light on dash illuminates for 0.7 seconds and goes out and that the injection light goes out after about 7 seconds

if these are normal then the code system is functioning correctly

after this the only things to check are fuse relay and wiring to pump

if you clean off the top of this relay there is a wiring diagram numbered with pin numbers

if you look in the plug there are pin numbers next to the pins

it's basically 2 relays in one
one single normally off switch
and a make brake switch
there are also diodes in series with them to look for when manually testing the operation of the 2 switches

but if you can make them both click when powered that's a good sign as coils fail more regularly than the contacts

for example if you power pin 7 and earth pin 14 one should click
and if you power pin 3 and earth pin 10 the other should again click

if the code light does not go out
there are a few reasons for this the code box may not be functioning or the key code aerial may be damaged or the engine ecu may have not accepted the code due to failure

if there is no code light at all
check the permanent live
switched live
and earth to the code box near the internal fuse box on drivers side with 2 plugs to it it's a small black box
use a test meter and make sure the permanent live is the full 12v as below 9v it will not function

switched is orange and has a 7.5amp fuse after the ignition switch in the interior fuse box and goes to pin 8
permanent is red it goes thou the under bonnet 40a ign fuse then a 7.5a in the interior fuse box and to pin 3 on the code box
earth is black pin 4

ps do not use other circuits to earth the fuel pump or any other high power equipment you may seriously damage some wiring as it's not designed to take high current

I was intending to do just that re powering the relay coils but I wanted to check that the inputs were 12v first before 'blowing' anything up.

To do this I was going to put a meter across the socket pins 8/15+ve and earth and also between 12+ve and 7-ve

Will I be ok to power each solenoid then with a 12Vdc supply?

Thanks for your thorough reply and I take your point about using secondary earting on a 20A circuit.

btw, if I don't get a 12v supply on pins 8/15 this would point to the 20A fuse - physically where is this located?

the fuse is mounted on the metal cage infront of the relay under the plastic cover if not this circuit does not have one other than the main 40a ign fuse

don't try and manipulate the relay on the car you will brake things it's controlled at crucial times buy the engine ecu and ignition key and without a full wiring diagram you wont know what should happen when you do it

it controls lots of functions within the ecu not just the fuel pump

your ok to use the cars battery to test it disconnected or could even use a test meter to check continuity across the windings

Thanx for the advice.

I had the relay in my house and using a 12vdc power supply. Got both relays to operate and output switches triggered just fine.

I tested the 20A fuse by checking I was getting 12v at pins 8/15 and that was fine.The thing to check next was continuity between pin 4 and the pump supply (both brown and white wires.

NB There was no contact for pin 4?? but since these are all commoned up within the relay to pins 5,6 and 13 I wasn't too bothered at this point as the system was workingf at some point.

Not a sausage between these two points (pins 5,6 or 13). According to Haynes manual there is a connector between these two points located somewhere in the fuse box.

A bit of luck here ... just about the only brown and white wire visible within the nest proved to be the right one as I got continuity between it and the pump

On testing between this and the relay socket though began to show strange readings??!! -- but I realised my mistake. Because of the distance I was using wires on crock clips and one must have been touching to earth causing these strange readings. Anyway to put it in a nutshell I appear to have a break in a wire between this connector in the fuse box and the relay socket although it may well be somewhere else as pin 4 does not exist. Must be tied up to either ignition coil, canaster solenoid, fuel injector or heated lambda sensor.

If anyone has any better drawings than those supplied by Haynes manual showing the actual connection and would like to share that knowledge with me it would be much appreciated.

Thanks again.

is this usefull


were it says n.d. next to a wire with a dot and the colour codes in andout that's an ultrasonic weld in the harness things to look out for if your trying to find a break these do from time to time

this might be good too
shows the relay but i cant quite find the fuel pump yet

Thanks for that. The second drawing looks the most useful. I found the pump .... it's to the bottom right of that drawing. It looks like the feed is off pin 13 of the relay contrary to the drawing I have

There doesn't look like there is a connector though between it and the connector in the fuse box. I check it physically when I can work on it in daylight - looks like that might be the weekend as it's dark when I get home.

it will go throu something because there is a connector between front and rear harness

i might just be a connector block

that's what part 7 on the diagram signifies

Job done .........

But not what I expected!

Hindered somewhat by inaccurate drawing in Haynes manual really, I decided to trace the wiring myself. I traced the ign. coils wiring to pin 5 on the relay. The lambda plug didn't register?? and neither did the pump? I stripped out the loom to trace pin 13 and 6 and these were joined together and passed through a 15A fuse. It was this fuse which was intermittent - it hadn't blown but was 'loose' and making and breaking!! - job done!

Thanks for your help

well done , theres obviously life in the "not so" old dog yet

well done a true auto electrition

fiat change the harnesses from 94 to 97 to 98 and such like that so it's all different

the on i gave you was 98 so that will be good for your 99 model

it's often a lose corroded fuse or relay block causing problems