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MK1 4.2 R-Tronic
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Discussion Starter · #1 ·
Hello greetings,


I spent my evening today to replace the intank fuel pump and G393 fuel sender unit on 4.2 mk1 R8.

Car previously has stalling issue in higher rpm (6400rpm), logged fuel pump duty cycle and fuel pressure, it shows that actual fuel pressure couldn’t cope up with requested fuel pressure and also with high 1/2 duty cycle at 80% during idling with engine warmed up.



Did the installation pretty straight forward, removed (-) terminal, removed the rear panel, move the relay box and fuse box out of way, replaced the senders on the LH side of tank and the LPFP on the RH side of tank. Double checked the fuel connectors and harnesses and it is installed correctly. However try to crank the car, the starter wont even turn. The relay just clicks and no start, not even cranking.

Scanned with VCDS it shows:
P3049 - Control Circuit for Starter Relay 2 - Open Circuit.

Then i proceeded with priming the fuel pump with VCDS and another fault code pop out:
P3073 - Fuel Pump Circuit - Electrical Malfunction.


The car would start n fire up with no sweat prior installing the pump, any idea where should i start to check on?

Fuel sender is working fine, no more tank malfunction fault on instrument, but the car just wont crank!

any help?

Thank you.
 

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Is there a possibility you didn't plug in one of the relays full for the starter when removing the fuse and relay panel. Also a possibility of maybe touching one of the fuses and and creating an open circuit. I would just go through and check the fuses really quick. There are many different scenarios this could be due to removing the module tray and disconnecting everything.
 

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Discussion Starter · #3 ·
Is there a possibility you didn't plug in one of the relays full for the starter when removing the fuse and relay panel. Also a possibility of maybe touching one of the fuses and and creating an open circuit. I would just go through and check the fuses really quick. There are many different scenarios this could be due to removing the module tray and disconnecting everything.
Hi Matts, thanks for replying !

All the relay & fuses is plugged in, and the fuse circuit is completed as i checked on them. I have ordered two 614 relays and to try if that causes the no start issue.
Starter has been removed and checked, starter is working fine though. :unsure::unsure:
 

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Hello greetings,


I spent my evening today to replace the intank fuel pump and G393 fuel sender unit on 4.2 mk1 R8.

Car previously has stalling issue in higher rpm (6400rpm), logged fuel pump duty cycle and fuel pressure, it shows that actual fuel pressure couldn’t cope up with requested fuel pressure and also with high 1/2 duty cycle at 80% during idling with engine warmed up.



Did the installation pretty straight forward, removed (-) terminal, removed the rear panel, move the relay box and fuse box out of way, replaced the senders on the LH side of tank and the LPFP on the RH side of tank. Double checked the fuel connectors and harnesses and it is installed correctly. However try to crank the car, the starter wont even turn. The relay just clicks and no start, not even cranking.

Scanned with VCDS it shows:
P3049 - Control Circuit for Starter Relay 2 - Open Circuit.

Then i proceeded with priming the fuel pump with VCDS and another fault code pop out:
P3073 - Fuel Pump Circuit - Electrical Malfunction.


The car would start n fire up with no sweat prior installing the pump, any idea where should i start to check on?

Fuel sender is working fine, no more tank malfunction fault on instrument, but the car just wont crank!

any help?

Thank you.
Hello greetings,


I spent my evening today to replace the intank fuel pump and G393 fuel sender unit on 4.2 mk1 R8.

Car previously has stalling issue in higher rpm (6400rpm), logged fuel pump duty cycle and fuel pressure, it shows that actual fuel pressure couldn’t cope up with requested fuel pressure and also with high 1/2 duty cycle at 80% during idling with engine warmed up.



Did the installation pretty straight forward, removed (-) terminal, removed the rear panel, move the relay box and fuse box out of way, replaced the senders on the LH side of tank and the LPFP on the RH side of tank. Double checked the fuel connectors and harnesses and it is installed correctly. However try to crank the car, the starter wont even turn. The relay just clicks and no start, not even cranking.

Scanned with VCDS it shows:
P3049 - Control Circuit for Starter Relay 2 - Open Circuit.

Then i proceeded with priming the fuel pump with VCDS and another fault code pop out:
P3073 - Fuel Pump Circuit - Electrical Malfunction.


The car would start n fire up with no sweat prior installing the pump, any idea where should i start to check on?

Fuel sender is working fine, no more tank malfunction fault on instrument, but the car just wont crank!

any help?

Thank you.
Did you ever figure this out and get it to crank/start? Having the same issue with my mk1 4.2 09’ R8. Replaced the fuel pump completely, made sure all relays and everything are good to go, try to start it up and nothing. Was thinking that you may have have to reset the ECU after replacing the fuel pump? Haven’t found much on that but can’t pinpoint why it won’t even crank and start up. Really frustrating lol
 

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Discussion Starter · #5 ·
Did you ever figure this out and get it to crank/start? Having the same issue with my mk1 4.2 09’ R8. Replaced the fuel pump completely, made sure all relays and everything are good to go, try to start it up and nothing. Was thinking that you may have have to reset the ECU after replacing the fuel pump? Haven’t found much on that but can’t pinpoint why it won’t even crank and start up. Really frustrating lol
In my case, it was a wire from rear relay panel to ECM came loose. Soldered back and it fire up straight away
 
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