2.5 TDi fuel pump issues after replacement

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Hello!

I'm looking for some help before I have another heart attack!!

Car is a 2002 A4 2.5 V6 TDi AKE

It's had a new fuel pump (diesel bob), a new needle lift sensor/no 3 injector (Bosch) and a coolant temp sensor.

Timed up and was running ok but a little smokey (white), sat for an hour idling fine, came back in the morning and it wouldn't start. Advanced the timing and she started, reset the timing to just below the green line on the vagcom graph. Left to cool down overnight and now it won't start. Cranks, fires then runs for a few seconds and cuts out. It's done this a few times now. Rechecked the timing and advanced and retarded it, same thing. Keep getting a brake warning light on the dash which seems a little odd. Car has been stood for quite while. Added new fuel and a return valve on the filter as i broke the original one!! Bed the system and still no joy, no fault codes in vagcom.

I'm really at my wits end now, its almost as if the ecu doesn't like a signal from something and its cutting the fuel off??

Please help!!
 
If it starts then cuts off - check any fault codes thrown by the immobilizer.
Its happened to me a few times in the past "engine start blocked by immobilizer"
 
If it started and ran ok then it must be assumed you matched the immobiliser to the pump with the PIN code. Your coolant sensor might be sending a dodgy signal hence you might be getting an incorrect reading on your timing checker. Make sure also that the timing is being set in basic mode or you will also get the pump adjusting the timing and giving you incorrect results. These engines run best when the timing is set as advanced as possible without throwing codes. You could advance the timing manually take for a run and make sure that you don't get any engine management lights or fault codes. Repeat until you get a fault code and then back the timing off a tiny amount. It isn't a very scientific way of setting the timing but I have done it before and the result has been fine. I'll probably get my ears slapped for doing it this way but if the computer is broken ?
 
mine is set advanced also and it runs as sweet as a nut. Adamss24 set it slightly advanced when he did all the belts etc. I cant offer any more help other than to reassure you that running them advanced isnt a problem. I did a mpg calc lately aswell and its doing 41mpg combined
 
The brake warning when cranking can be a sign of a dying battery. I think the engine had to crank at a certain speed for the injectors to squirt.
 
Cheers for all the comments! It almost feels like an immobiliser fault, but no codes relating to it, even in the instruments section. It's strange that it seems to play up when left overnight. Is it a cold start or a fault due to something in the immob resetting? The battery isn't the best but I've had jump leads on it this aft with the same results. Cranks, smokes, runs and the dies. Runs for maybe 5 seconds
 
Immobiliser normally cuts in after 2-3 secs. I would fit a known good or charged up battery
 
If its the immobiliser you should get a fault code stating that starting is blocked by the immobiliser. Also the immobiliser doesn't usually allow starting at all. You would hear the engine catch and attempt to fire but thats as far as it goes. You said initially that it started after you fitted the new pump. If so then you must have matched the pump to the immobiliser with the correct PIN code. Brake warning lights during startup usually indicates low starting voltage. Are you sure there is no air in the high pressure lines? The absence of codes is a bit baffling if its a mechanical or electrical fault.
 
The immobiliser will start the car for 2-3 seconds then kills the engine, as stated above.
 
Had a very similar problem recently. Not with fuel pump but my wife was driving car one day in heavy rain. She left it parked went to work came out 8 hrs later and it would start. Would crank but not start. Had abs warning and brake warning on dash. Vcds would not let me communicate with the ecu.

Left it overnight and it started 1st time the next day and I was then able to communicate with ecu. Fault code logged that said no signal from ecu. Drove it 10 miles then left it for 2 hrs and it did the same. Once again couldn't communicate with ecu using Vcds.

After bit of googling and advice from forum members was pointed to ecu and relay box in plenum chamber. Opened it up to find my ecu power relay and neighbouring relays to be under 3 inches of water. Wiring and relay were completely corroded. Stripped wiring back and fitted new connections and replace main ecu power relay and had no problems since.

I also drilled a few holes in the bottom of the ecu box to aid drainage and prevent water building up again.

Just when yous say the car had been sat for a while then it may have been getting a fair bit a rain water. Also the fuel pump relay is also in there next to the ecu relay.

Worth a look but it's a right pain to get the ecu cover off. Had to take windows wipers off and remove scuttle panel to get to back torque.

Hope you get it sorted
 
Was that a genuine fuel filter ? had many aftermarket fuel filter loosing prime so i only use genuine, hengst or bosch filters. Also it's easy to pinch the Tee valve seal, make sure it's seated properly... Running slightly advanced timing is beneficial for engine/fuel economy.
 
Gonna chuck a fresh battery on it this morning. Might try recoding the pump again. The batt has gone flat a few times so I wonder if that's causing a problem?
 
Still no joy. Tried a new batt. Checked as much live data as I could, immob seems ok, it's chucking fuel in, can see fuel spurting out if I crack an injector pipe. It's so strange that it'll run for a few seconds then die, almost like the ecu doesn't like something. Still no fault code. Soooooo frustrating
 
Fixed it!!!! It's was the egr valve!?!? Timed it all up again today, same prob. Whilst scratching my **** I pulled the vac line off the egr and now she runs like a dream! I wonder if it's blocked with crap as I cleaned the inlet manifolds up while it was all apart. Main thing is it's done now and can go back to my mate!
 
adamss24 said:
Was that a genuine fuel filter ? had many aftermarket fuel filter loosing prime so i only use genuine, hengst or bosch filters. Also it's easy to pinch the Tee valve seal, make sure it's seated properly... Running slightly advanced timing is beneficial for engine/fuel economy.
Click to expand...
hi chris I'm having problems coding new/ recon pump to immobilser after being done by diesel bob. Where do if find new pump code or do I have to have it retrieved cheers
 
The pin code for the pump can be retrieved from the engine ecu using a Super VAG k+can reader. Then code the new pump edc using vagcom. Instructions are on Ross Tech website.
 
Hi
abyrne153 said:
The pin code for the pump can be retrieved from the engine ecu using a Super VAG k+can reader. Then code the new pump edc using vagcom. Instructions are on Ross Tech website.
Click to expand...
hi thanks. So Ross tech vcds won't retrieve the code? I have latest version
 
audi upgrades
Hi so vcds won't retrieve the code? I have the latest version
 
Also it's a 2001 a6 . Should it not just recognise the new pump anyway. Any help much app
 
Diesel bob most likely fitted a new ecu to the pump and if so then the new ecu comes open for a new code. Vagcom cannot recover the pin code from your car. The super vag k+can device can recover the pin and you can then use it to match your new pump to the car using vagcom. If using a second hand pump that has been previously coded to another car then you must have the correct pin for both cars to match the pump. The reconditioned pump will likely throw up an engine start blocked by immobiliser fault code until you get it matched.
 
Last edited:
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If the engine ecu has the immobiliser removed or turned off do you still have to match the pump ecu?
 
I'm fairly sure it will start if the immobiliser is deleted but will show the key error light on the dash. Only one way to be sure. Try it.
 
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