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Discussion Starter #1
Hi guys having a nightmare trying to find the issue behind starting my car after the car has been sat overnight 8 hours plus.

Car cranks hard between 4 to 10 secs before finally starting but once started will start perfect the rest of the day. No smoke when it finally starts and drives 100 percent
Also no fault codes either

So far I’ve changed the fuel filter -pressure regulating valve on the fuel rail- the leak of pipes inc pressure retention valve

Car is in having injectors tested atm.

Any thoughts????
 

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Have you checked the glow plugs?


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Discussion Starter #3
Mechanic said if it was the glow plugs or indeed starter motor being lazy that the car would blow out a lot of smoke when eventually started???
 

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You can have several glow plugs dead and no indication on DIS. You will need to scan the car to find out.
I had three dead glow plugs and no symptoms whatsoever!

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Discussion Starter #6
It has been scanned and no codes at all. Did you have the same symptoms as me 4-10 sec crank etc?

Thanks for your help
 

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I'd change the fuel filter too, inexpensive and easy, just to make sure there is a nice fresh flow of fuel.

Regards
 

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You need to ensire that you have fitted the correct fuel filter cos these cars are VERY sensitive to having the correct bits fitted. Did the problem start after the filter change?? You really need a friendly INDI specialist who knows these cars and has the right specialist stuff like VCDS for instance. A scan will surely help.
 

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Discussion Starter #10
Hi there issue was there before the new fuel filter was fitted. The car is currently in with A Audi specialist who is currently testing injectors 4 of 6 have been tested just waiting on other 2. Any other ideas? It’s just like fuel is losing pressure somewhere and needs time to build up again first start
 

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Question: when you unlock your car in the morning, do you hear a faint whining noise for a few seconds? You should do, as this is the fuel pump priming the car ready start. If it’s not doing this, then maybe it’s not happening like it should?


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Discussion Starter #12
Yes I hear it, and press the ignition on and wait a couple of secs before actually starting the car. Is the hpfp n290 valve possibly faulty losing prime as I’ve replaced other valves and pipes???
 

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Sorry bud, beyond my knowledge now. Maybe time for a good Audi specialist?


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To me it sounds like loss of diesel prime.

Try this;

- Make sure you have 50% + diesel in the tank
- Park the car on a slope over night with the back of the car higher than the front. The goal is to have the diesel tank higher than the engine.

If it starts normal you need to add or change out your check valves / non-return valves.

I had a VW 2.0TDI. I added two check valves where the metal lines changed to rubber in the engine bay problem solved.

Later I also changed out the starter motor when it did not start as nice (smooth) as it once did....not part of a long crank problem. The new starter solved the poor start problem also.

The check valves I used....no the exact but this is the sort of thing.
https://www.ebay.com.au/itm/8mm-5-16-Aluminium-One-Way-Non-Return-Fuel-Line-Check-Valve-Petrol-Diesel-Water-/251790891252
 

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Discussion Starter #17
Hi I will try that when I get the car back! Cheers although I’ve already replaced the pressure valve in the fuel rail and the leak back pipes and pressure retention valve.
 

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Any other suggestions guys?
Manual or Auto? - could be a faulty micro switch on brake pedal if it's an auto (safety feature which enables starter once depressed), or possibly on clutch pedal on a manual?
Also worth checking the Fuel pump module under rear seat?
Hopefully it's not the fuel pump on the way out, as they can fail and even 'swarf' up the entire system (worst case scenario).
 

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I'm surprised nobody has suggested old battery. I had very similar behaviour when mine was on the way out... these cars don't seem to do the classic weak turnover sound when low, they sound like they're cranking fine and strong, it just takes a while.
 
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