HELP! 1.6l to 1.8T conversion wiring issues....

[Stan]

thanks GAV and Jmac, you guys have been very helpful - beers for you when i get this going!

[Stan]

pump back to relay seems ok, battery to relay seems ok, all voltages are good. Relay is good, fuel pump good.
that leaves comms between relay and ecu or a dud earth or something....

[grtuned]

just to get an idea did you only replace the harness outside the car or did you replace anything inside???

[grtuned]

check the 15 amp fuse S228 and terminal 1 on pump connector if you got power there relay is working with ignition on.
you should also check fuses S243 10 amp and S234 10 amp these run of the same line which flow to the N80 and the N75 funny thing is
this also flows to another fuse S232 10 amp which flow to the injectors. Hope this can help this is from a golf 1999 agu audi may be
different i will check difference tomorrow.

[Stan]

thanks grtuned, i appreciate your help.

replaced the two main bundles from the ecu. the rest is original. it's all pretty similar mate, thankyou.

suffice to say I've been spending a lot of time reading diagrams and chasing wires

[Stan]

ok, closer now:

squirt fuel into the intake manifold and car runs until the ecu cuts it off

hotwire the fuel pump and it doesnt....

[Shadow_Rusty]

Is something shorting out the injectors??
Possibly a loose earth / power connectors?

Also, does the fuel pump 'prime' when you open the drivers door after unlocking the car?

May also need to check the fuel pressure sensor as if it thinks there is full pressure, it may not turn on the fuel pump... Shouldn't stop the injectors though...

[Stan]

Yes pump primes.
My suspicion is an earth issue as well , either off the loom or bad ecu earth. Thanks for the suggestions

[Shadow_Rusty]

If the fuel pump primes, and then doesn't run again, the car thinks it has full fuel pressure...
I don't think it's the fuel pump circuit you should be looking at, but rather the ignition/injector circuit...

If you plug a multimeter into the injector sockets, can you see a pulse when you crank the engine?

[Stan]

I tend to agree
Yes, I get 5 volts with ign on and flickering wirh cranking

[Jmac]

Fuel pump relay wiring different in the A3 to the 1.8T, different ECUs . 1.6 is SIMOS and Motronic for the AGU. Some major players on the relay go to different spots between A3 and Golf. Pm sent with wiring suggestion, ill only complicate matters if i post it here.
Jmac

[Stan]

All received Jmac - cant wait to get home and try this out!!!

thanks Stan

[Stan]

SUCCESS !!! Got the car to run after changing a wire in the plenum chamber from the brown plug to the orange one, which involves the fuel pump relay! (purple/white)


Thanks guys, especially Gav who spent a lot of time on the phone with me and Jmac who discovered the actual wire (after a fair bit of time checking out circuit diagrams - he is the wiring guru, will have to get this guy to chip it later).

Also to Steve who offered me the chance to try his computer and check out his cars if need be.

What a great forum

[Shadow_Rusty]

Congrats mate... Glad it's all sorted...