2.5tdi starting problem

**michael306** · 10-11-2017,10:13 PM

Looking for some help with my a4 2.5tdi. Am having problems starting it, turns over ok but doesn’t fire at all. If you try it a few times it will fire up and runs perfect once started. Will do it when the engines hot or cold.
Have checked for air bubbles in the clear pipe but it’s ok. Getting rpm signal Also checked the glow plugs all working fine too.
I suspect there’s a problem with the control unit on the high pressure pump. But anything else worth looking at first?
Thanks Michael.

**michael306** · 11-11-2017,07:26 PM

Had vag com on it today and got this fault code 00546. Any help would be appreciated.
Thanks Michael

**Vagnuts** · 11-11-2017,07:39 PM

that code is Immobilizer Control Module (J362)

**abyrne153** · 13-11-2017,12:48 PM

Does the key symbol flash on the dash when this happens? Also does the engine try to start and die almost immediately? If it does then it indicates an immobiliser problem and it could be the key. If you have a spare you could try that as the module in the key could be the issue. Mine certainly did that occasionally and if you left it for maybe 10 seconds or so and tried again it would often start first time. If its just hard to start generally it could be the pump timing which is out. The 2.5 engines need to have the pump timing set accurately as if it is out it can cause starting issues.

**Vagnuts** · 13-11-2017,03:09 PM

or the fuel lines might need replacing-we got an a6 2.5tdi V6 hard to start turning turning turnin over then bam away it went-turns out the fuel lines were we bit worn so alowing fuel to run back to tank and with no intank pump, it only lifted fuel when cranking-so crank crank crank then start -just a thought !!

**michael306** · 14-11-2017,01:35 PM

No, key light doesn’t flash when it’s not starting. Sometimes it will cough trying to start but generally just turns over. Normally let it turn over for around 5 seconds then try again. Always starts normally on 4th or 5th time. Was just doing it when cold but now if left for 20 30mins won’t start. Will check the return pipes

**Vagnuts** · 14-11-2017,01:39 PM

it do's sound like fuel returning back to tank, and from what you say--its just got worse !!!

**Vagnuts** · 14-11-2017,01:42 PM

just another thought-- blow-pressure the feed pipe back into tank-if any wee pin hole it will show, cause normaly its sucking so if it just a wee pin hole may not be dripping, return pipe is pressured back to tank-so you would see if that was the prob, but sounds like feed pipe to me !!!