2.5tdi ael loss of power

Posted: Sun Jul 27, 2014 6:06 am

hi
old girl was going good until last weak ,when it lost power call it 50% power is lost
i fitted chips from spik few months back and it was flaying, no problems at all,pulling in all gears perfect
now its lost that poke in the back, and going up hill over barton bridge in manchester in 4th it will go max 3k rpm, then just hit a brick wall
no boost leaks, no excess smoke,starts,idles same as before
fited new fuel filter, still same
but i am having few air bubbles traveling up clear fuel line from fillter housing to pump, not sure if that is feed or return ?
as it is a smaller diametar pipe? black rubber one is larger!

will try and rig small boost gauge to see what is boost doing
will need to check all small pipe works ,and n75 valve
but there is few valvle at fire wall on bulk head
and one at the back of air fillter!

can someone help with valves identification please?
and how to check n75 please
any other ideas to look at
car has no cat any more so no chance of blockage
egr is blanked
newish air filter and oil/filter done in last 1.5k

its still driving ok but very reduced power

thank you

Newbie Joined: Oct 15, 2010 Posts: 13

IS IT BLACK SMOKING ?
IF SO CHECK THE TURBO PIPE THE LONG BIG RUBBER ONE FROM THE INTER COOLER TO INLET

Posted: Sun Jul 27, 2014 8:37 pm

Get any fault codes out of the ECU?

That's the next thing I'd check after a visual under the bonnet.

Posted: Mon Jul 28, 2014 6:18 am

intercooler pipes are perfect
i made them using bent s/steel at work and new rubber ends
no leaks there
for geting codes,i dont know anyone with 2x2 vag com
i got access to bosch diagnostic mashine,and snap on one but no good
will play with car on days off, then see if its anything simple
this morning driving up same bridge/hill hit 3k rpm ,brick wall revs droped down to 2.8k

Posted: Sun Aug 03, 2014 2:44 pm

Fuel filter / supply is a good place to look. I had the "brick wall" issue with mine when I dabbled with biodiesel due to blocked filter.

What is the condition of the fuel lines under the car (i know mine are VERY corroded) - pin holed and pulling air in?

Otherwise, check boost hoses especially just before the joint onto the inlet plenum and also the smaller pipe that links the manifold to the pressure sensor mounted on the bulkhead behind the injector pump. Had this split on mine which made it very slow though I don't remember a 3k barrier that time.

Nick

Does it pull ok up to 3k? or flat there too?

Posted: Sun Aug 03, 2014 3:50 pm

Pulls okish in first 3 gears.boost is spot on climes to 16th psi with out a problem. I am getting air in pump infeed pipe,thats reving it standstill,so under load will pull more air.will need to look at fueling aide.it takes longer to start now too.
Thank you

Posted: Sun Aug 03, 2014 6:54 pm

Check water drain on base of fuel filter is tight. Long-shot......

Nick

Posted: Thu Aug 14, 2014 7:26 pm

just to update, its a fueling issue
new fuel fillter fitted today ,still same?

then just to check i fitted my facet fuel pump 120 ltr per hours 7 psi , just before fillter,, bit better but not as it should be

then ran facet pump in to a milk bottle, just to see,, fuel getting trough but not a great deal of it??
same pump lifts dubble amount of fuel on my shogun td
then i took sender unit out of tank, nothing blocked etc , got my hand down in to tank, no crap in there?

now what i am thinking its ether fuel line collapsing inside from tanks out feed to fuel fillter ,or badly restricted ?
i am off on holiday tomorow so it will need to wait until i get back

i blown with compress air feed line to and from tank.all ok?

to eliminate any othere problem i will run a car out of 5lts tub to fuel fillter
and see how it drives ,if it drives ok then i know its down to fuel supply ,if it runs same then fuel pump could be at wrong, etc

will swap fillter housing to good old stile , infeed, out feed no termo valve etc,, done it before on my galaxy tdi and never had a issue with air bubble or any other problems

any more ideas to try boys??
i took the pipe from manifold to map sensor, vaccume tested it its ok, pressure tested it and all fine

Posted: Thu Aug 14, 2014 9:38 pm

Sounds like you are getting somewhere. Test with alternate fuel supply should prove it as you say. After that I can only think that there is a strainer at tank outlet which is clogged or there is something caught in the line. Blowing back the other way may shift it - though whatever it is (and it might be quite small) will still be in the tank.

Nick