Down On Power And Bad Mpg Since Head Swap. 1.9Tdi 115Hp

[Torq]

Hi Guys,

following on from my catastrophic timing belt tensioner issue.  I replaced the head, cleaned out the ERG valve and did the turbo seals.  Now I'm down on power and the run that would normally give me 48MPG is now returning 28mpg! Even the slightest incline causes mpg to drop and in 1st gear I've seen it as low as 7mpg!  The figures are correct going by a fill to empty/mileage calculation. I ran diagnostics today and there were no engine faults so it must be a mechanical issue. 

 

It's possible the cam timing is slightly off and I didn't reset the injector rockers.  It is boosting as I can feel the intercooler outlet pipe expand when you give it some revs. I ran without an air filter and that has no affect so it's not an air restriction.  All vacuum pipes are connected and I'm at a loss.

 

Any suggestions would be greatly appreciated!

 

Thanks.

Torq

[insanitybeard]

I take it you swapped your old unit injectors into the new head? I believe the sealing o-rings fitted to the unit injectors that seal the low pressure fuel supply and return can harden with age and especially if you've removed and refitted the injectors into a different head could be leaking fuel.

 

Other than that like you say the injector rocker adjustments could also be affecting it. Is engine performance ok?

[Torq]

Yep I swapped the injectors over and the loom to go with them.  

 

I logged onto a VAG forum (pretended I had a Sharan as the vw forum was far more active than the Seat one!)  ran a few tests using Vag caom and posted the results there.  A site sponsor (who does remaps) read the data I supplied and thought my accelerator pedal potentiometer though going to 100% wasn't demanding enough fuel.   I got a replacement from my local breakers fitted it and now she's fueling much better and seems to have the performance back. 

 

I did the rocker adjustment today and I think she's back to the way she was now performance wise.  But I don't know about the MPG  I have a feeling that there's still something up there and it might be the cam timing though I set it correctly or else the cam sensor is slightly out of position or even the trigger ring on the camshaft pulley may be slightly off.

 

Vag com does show an imbalance with the injectors and it looks like no2 could be over fueling.  My neighbour has exactly the same Alhambra as mine, a sport stylance, and once he's back from holidays  I'm going to run a few diagnostics on his car and compare to mine.

 

 

I'm nearly there!