A6 c6 2.4 bdw engine 2007 car wont start urgent pls

[Adel75]

Dear Mates ,

I would like to thank first Admin and mates on the forums for the valuable help given before:

CAR WAS HAVING MISFIRE ISSUE

I sorted out the misfire issue by placing a 6 new spark plug and got another disaster issue : Car drive for 2 days perfect and then wont start :

1-/ Analysis : Fuel pump not working , measuring fuel pump electricity on the socket ( 4.3V !!!) , measuring on the 20 A passenger side door open , 4.3 V !!! , going to the engine side in front of the driver open the relay box and fuses : relay 614 in the middle testing working , problem is when I remove the replay : all the 4 pins on the socket all have voltage : the 2 main have 12 V battery and the other 2 have 4.3 V !!! in continuous when I put key in 2nd position before starting .....

trying to feed pump directly with 12 v , result = nothing pump burned , some thing happen and burned the pump but how could no fuse gone !!!

diag done : no error


Please help , I am going crazy


regards

Adel

[Crasher]

So the fuel pump will not run even if you put power to the connection on the top of the sender unit with 12v and an earth? Please do this with the sender still in the tank and the fuel pipes connected so no raw petrol is in the area.

[Adel75]

So the fuel pump will not run even if you put power to the connection on the top of the sender unit with 12v and an earth? Please do this with the sender still in the tank and the fuel pipes connected so no raw petrol is in the area.

Thank u Mate for ur reply .

this fuel pump is burned , finish done like u said also in the fuel tank no sound , no fuel nothing goes out , my real problem is even if i will buy a new fuel pump it will not work ; reason is : there is only 4.3 V on the socket , not 12 V ! I have verify fuse and 614 pump relay every thing is ok

diag done : engine 0 fault Immobilizer 0 fault

regards

Adel

[Crasher]

Have you had any water in the car?

[Adel75]

Have you had any water in the car?


Never and even when I have inspected the engine ECU and its box also the fuse and fuel pump relay in front of the driver side : no water or wrong connection....

the car was running smoothly 2 days ago just when I took the car to measure the fuel pump pressure so the guy took out the electric socket and the fuel inlet tube and then he couldn't measure because he doesn't have the right tube link , he put every thing in the right place I drove the car back home for 6km everything was ok , only 1 thing : the fuel gauge was not working then it works back alone , then suddenly the engine shut down ....no petrol ...during the 6 km nothing special car run smooth engine idle perfect no cuts nothing

[ototest]

How you diagnosed ? With odis ? Do you see petrol pressure on rail ?


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[Adel75]

How you diagnosed ? With odis ? Do you see petrol pressure on rail ?


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Thank u for the replay

diag done : no error , done with VCDS and Launch , no error , no fuel in the rail.

[Delta_V]

I would disconnect the fuel pump socket and measure the resistance of the wires. Primarily between the ground wire on the socket and a good body ground, or battery negative. This will tell you if you have a bad ground wire. Then measure the resistance of the positive wire in the socket against the relevant pin in the fuse box; with the fuse removed. This will tell you if the wire between the fuel pump socket and fuse box is bad. Next measure the resistance of the other side of the fuse pin in the fuse box (with the fuse removed) against battery positive. This will tell you if the positive wire between the battery and fuse box is bad. Also measure the resistance of the fuse, the fuse might have increased in resistance causing a voltage drop. Ideally all readings should be as close to 0 as possible. The socket to the fuel pump should be disconnected throughout all of the above resistance testing.

[Adel75]

I would disconnect the fuel pump socket and measure the resistance of the wires. Primarily between the ground wire on the socket and a good body ground, or battery negative. This will tell you if you have a bad ground wire. Then measure the resistance of the positive wire in the socket against the relevant pin in the fuse box; with the fuse removed. This will tell you if the wire between the fuel pump socket and fuse box is bad. Next measure the resistance of the other side of the fuse pin in the fuse box (with the fuse removed) against battery positive. This will tell you if the positive wire between the battery and fuse box is bad. Also measure the resistance of the fuse, the fuse might have increased in resistance causing a voltage drop. Ideally all readings should be as close to 0 as possible. The socket to the fuel pump should be disconnected throughout all of the above resistance testing.

Thank u mate for the reply

ur tests sound good I will do them and let u know , for the fuse , I changed the fuse with a new one nothing happen , still what s strange for me is :4.3 V on the socket !!! and even it s on the fuse : between the fuse pins fuse removed and batt negative and the same on the relay 614 fuel pump relay .

regards

Adel

[Delta_V]

Just make sure you select resistance mode on your multimeter denoted by the ohm symbol Ω when doing the above tests. This will help you find the offending wire. Measuring voltage is a good first step but it only tells you that something is wrong, not what exactly is wrong like the resistance test will show. Based on your description and voltage measurement I'm certain that either your ground wire or positive wire has high resistance due to corrosion or physical damage. Most commonly the ground wire is the culprit.

[Adel75]

Just make sure you select resistance mode on your multimeter denoted by the ohm symbol Ω when doing the above tests. This will help you find the offending wire. Measuring voltage is a good first step but it only tells you that something is wrong, not what exactly is wrong like the resistance test will show. Based on your description and voltage measurement I'm certain that either your ground wire or positive wire has high resistance due to corrosion or physical damage. Most commonly the ground wire is the culprit.

Thanks , very clear , tell me just one thing if u could help , do u have wiring diagram for fuel pump and it s feeding !?

regards

Adel

[Delta_V]

I do not have any wiring diagrams sorry.

[ototest]

Hello friend.
i suggestion change relay again, sometimes meausrement not enough. Maybe relay contacts can not work under current.
Send me VIN , i will try for find your wiring diagram.


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[Adel75]

Hello Mate ,

Thank u for the support u provide .


my car VIN : WAUAE74FX8N000211 , very interested with diagram .

for the relay the ECU relay is same reference and it s close to it (614) , I tested both of them outside and they are working , then I switched both , nothing happen , done diag again after trying to restart the car , o error .


regards

Adel





Hello friend.
i suggestion change relay again, sometimes meausrement not enough. Maybe relay contacts can not work under current.
Send me VIN , i will try for find your wiring diagram.


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[ototest]

338923389333894

[Adel75]

Thank u MATE

PLS as I am fun of AUDI , can u tell me what s the source of this diagram , Thx

338923389333894

[ototest]

Thank u MATE

PLS as I am fun of AUDI , can u tell me what s the source of this diagram , Thx

i have friend i asked him.
He can help for online coding and remote software update. if need PM me.


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[Adel75]

Thanks everyone my problem solved by installing a new fuel pump




Just make sure you select resistance mode on your multimeter denoted by the ohm symbol Ω when doing the above tests. This will help you find the offending wire. Measuring voltage is a good first step but it only tells you that something is wrong, not what exactly is wrong like the resistance test will show. Based on your description and voltage measurement I'm certain that either your ground wire or positive wire has high resistance due to corrosion or physical damage. Most commonly the ground wire is the culprit.