Technical fuel pump fuse blowing randomly - help!!

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Technical fuel pump fuse blowing randomly - help!!

arc

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Not sure why the car has started doing this. It keeps blowing the 20A fuse in the engine bay. Yellow fuse holder near the ECU. It is the fuel pump fuse.

Everytime it blows, i get out and fit a new one and it fires up again.

There seems to be no pattern to it. Doesnt happen on bumps, doesnt happen when cornering fast, or sharp. It hasnt done it when cold yet though.

I suspected my ICE grounding near the fuel pump might be the problem - so i moved that to one of the seat mounts and it made no difference.

It does it with ICE on or off anyway.

I recently swapped out the rear gearbox mount, is it possible ive trapped a cable somewhere doing that? Ive tried wobbling the running engine - but that doesnt cause it to blow.

It was suggested i check the reverse light switch wiring. I did, it was damaged. I unplugged it. It blew the fuse later that day. I repaired the wire with some tape and plugged it back. It's blown the fuse again since. Somewhere in that lot it blew the reversing light bulb.

No wiring fault with the reverse light now though.

I'm running out of ideas. Where does the wire for the fuel pump run from and too - help!
 

T14086

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Not got diagram to hand but can you give details engine/year A.S.A.P as might have some info to hand.

What I can see it also supplies lambda,injectors,coil aswell.

Do you know what other circuits are on that fuse? Have you tried disconnecting the reverse switch altogether?
 
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Whats it fuelling like? It may not be in your case, but the facet pump used in our kitcar would keep popping fuses just before it went pop.
 
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arc

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T14086 said:
Not got diagram to hand but can you give details engine/year A.S.A.P as might have some info to hand.

What I can see it also supplies lambda,injectors,coil aswell.

Do you know what other circuits are on that fuse? Have you tried disconnecting the reverse switch altogether?

I've not looked at the wiring diagrams yet - so not sure what else it kills.

I've tried disconnecting the reverse switch all totally and it still blew.

It's a 1995 Cinq sporting.



rallycinq said:
I think the wiring runs down the nearside sill.

Cheers

D

ahh.. i've had the NS sill off to run some RCA cables. wonder if ive disturbed the wiring and caught it in a clip or something.

Luke1985 said:
Whats it fuelling like? It may not be in your case, but the facet pump used in our kitcar would keep popping fuses just before it went pop.

fuelling seems fine, but i do have a spare pump to try in there!
 
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arc

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Got haynes in front of me. It has wiring diagrams.

Power comes from the battery straight to the 20A fuse. Then it goes via a Brown/Black wire to the fuel pump relay. From there it goes via a orange/black then into a green/black wire to the fuel pump.

The relay has two outputs when it is on. The other output is connected via a light blue wire to various bits. Both coil packs. The lambda sensor. Fuel injector and the canister purge solenoid.

This is gonna take a while to trace and check!! :(

have checked for damage to wire in the NS sill. its fine.
 
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T14086

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Diagram I have shows engine control relay(except sporting:bang: )feeding pump,coils,injector,EVAP & lambda sensor,have a quick visual look around these components/wiring.
Other diagram I have is for 92 0.9 Cinq showing relay with 2 outputs as you describe feeding the same components mentioned above.
 
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arc

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i've just been out and had a look around that general area.

Haynes diagram does not match up. The purge can solenoid has different coloured wiring to what haynes says.

I suspect the diagram in haynes is for the 899.

Next to the ECU there is a relay, which i assume is the engine control relay. It has more connections than the fuel pump relay appears to have in the wiring diagram.

I have just quickly checked for any damaged cabling - didnt see any. I did have a HT lead coming over the top of the LT connections to the coil, so i moved that on the off chance that was anything to do with it.
 

T14086

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According to info I have here engine control relay has 12 wires is this right/matches your car?(does say not sporting though?)
 

T14086

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Giz few minutes to write this lot out!

1)br/sw to ign amp
2)not connected
3) + 11) br to battery supply
4)ge/bl to injector
5)gn/sw to fuel pump
6)gn/sw to lambda & evap
7)sw/vi to ecu
8) + 15) br to battery supply
9)not connected
10)bl/rt to ign amp
12)orange(changes colour later) toalarm control module & ecu
13)nbl/gn to coils

Relay module appears to sit to the right of the ecu,purge valve sits infront of coils & slightly to right.
 
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arc

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module i was looking at does sit in the same place, and the purge valve is in roughly that area - stuck to the side of the charcoal cansiter.

out of that lot, which are directly connected to the 20A fuse next to the ECU. Is the relay just a simple a relay, and switches all that lot on - or is there more going on inside it?

Cheers for all this btw :)
 

T14086

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Appears to go into module at terminals 8 & 15 (check first by pulling fuse & seeing supply dissapears with test light/meter etc) also it seems to be a battery live is this correct?
It feeds(switches)4,5,6 & 13 from the relay outputs.
 
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arc

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it's pissing it down at the moment, and i dont have a garage - i will check as soon as i can, but it does sound like you have the correct diagram for it there!
 

T14086

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Trying to print it off for you now....damn printer:bang:

I'll scan it & email(p.m. your email)but i'll try & post it up here first.

It's in my gallery.can you read it ok?

K46 is relay
M12 fuel pump
Y3 injector
T1 coils
Y104 purge solenoid
B72 lambda

cinqwireing.JPG


you can see the fuse feed 8 & 15 then when switched supplies 4,5,6 & 13
 
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arc

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thats brilliant, cheers mate. the haynes diagram doesnt really look anything like that!!
 
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