Not again!G

[jamwatn]

I see what you mean.

This is my problem, everything is spot on including the maf graph. I wonder what else could affect low down power??

[jamwatn]

Has anyone got any suggestions please? I've got the evening to tweak!

[vrsRob]

I also have a turbo noise but I am now thinking (have been for a while) that it may be a boost leak somewhere...

 

I intend (over the next month or so) to get a FMIC and EGR delete, I feel that if there is a boost leak, FMIC and new pipes will (hopefully) help!

 

Rob

[jamwatn]

Well it's weird..My noise has stopped totally. It's just lack of low down pull/lag/hesitation that's the problem.

Just don't understand how it could have happened pretty much overnight?

[jamwatn]

I've cleaned the maf with contact spray(which probably didn't do wonders) and even had the battery off for a while to reset the ecu and it's just the same! My only other thought is either injector issue or something holding the car back?

That, or something fuel based that's dirty that shouldn't be. I feel like this has all been since running my fuel tank too low after my long trip to Wales to see how far I could get for the money.

Or perhaps my long trip at one speed has knackered my turbo or caused a sticky vnt or actuator. But then I'd see overboost?

[theezenutz]

I've cleaned the maf with contact spray(which probably didn't do wonders) and even had the battery off for a while to reset the ecu and it's just the same! My only other thought is either injector issue or something holding the car back?

That, or something fuel based that's dirty that shouldn't be. I feel like this has all been since running my fuel tank too low after my long trip to Wales to see how far I could get for the money.

Or perhaps my long trip at one speed has knackered my turbo or caused a sticky vnt or actuator. But then I'd see overboost?

Give a service. Run some injector cleaner though, change the fuel filter and the air filter see if that makes a difference.

 

Has she been re-mapped?

[jamwatn]

I'll do a service, just waiting on the oil.

I plan to map shortly. Real annoying!

[jamwatn]

I've given it a service and I'm afraid it's just the same! I would love the fantastic throttle response again. Just balancing my foot on the accelerator gave a progressive and smooth acceleration and all seems lost now!

Interestingly it seems mildly more sprightly when cold in the morning so I suspect a miniscule vnt response issue.

What is next!?

[jamwatn]

Today I pushed it fairly hard and it's still not perfect.

In third and fourth gear once it's hit boost there seems to be a bit of lag till it hits it's full power. It feels gutless and then the power comes in and it feels fine.

I'm wondering if I'm getting clutch drag?

[SEVrs]

May be a silly question but are your brakes binding front or rear?  Few people bother checking brakes between services and if they're rubbing, heat build up over a few miles will reduce performance and mpg significantly. If boost pressure is ok, that points towards  no problems with the turbo so check out other possibles including a sticking EGR.  This will reduce power, especially if it's not closing on applied throttle.  It may or may not show up on VCDS.  If I thought turbo was fine, boost is fine, there's no boost leaks then all it can be is something in the intake or fuelling system, and my money would be on EGR and intake, all other things being equal. Also check air filter for muck.  All simple checks that tick off one thing after another. You have to be systematic as speculation wont trace faults. Usually it's something very simple related to intake, turbo, fuelling or even a dodgy sensor.  VCDS should throw up any sensor of fuelling faults, the rest can be checked manually if you have an hour or two to spare.  Even stripping the EGR out isn't a big job.

[jamwatn]

I've just replaced my rear brakes so I'll have to check that. It doesn't lose speed quickly or anything though.

I've just blanked out the EGR totally so I'll give it a week and see.

I gave it a drive afterwards and well the low down power seemed to be back but thats probably because I mr muscled the heck out of it as I was doing the EGR anyway.

My concern is still the weird top end power issue as I am starting to think it could be clutch. Only because it feels like the same sort of feeling as if you were to do a naff gear change and slip the clutch; you get that weird wait for the power to build.

But if you slowly build the power up it seems to be ok.

I'm slightly concerned as my Golf mk4 started to drive the same just before the clutch went.

[sepulchrave]

Clutch either slips or it doesn't, to test stick it in top gear ASAP then floor it and see if it revs up faster than it accelerates.

[jamwatn]

Well in that case it's probably not the clutch then as I've done this.

I will test for boost leaks in the next few weeks as a precaution. I remember my old Fabia having no obvious leak noises but as soon as I loaded the system with air, it hissed out of the bottom joint like a balloon!

[jamwatn]

Right people, I'm running out of ideas. I seem to have tried everything.

Can it possibly be psychological?! Surely not!!!

The pedal seems more and more spongy by the week.

[vrs180]

Have you checked the camshaft timing with VCDS ?

Adjusting the cam/crank timing slightly has a significant effect on power delivery and throttle response.

[jamwatn]

I remember checking it when I first got the car but power delivery was fine then so I'll check that again this evening I think.

[jamwatn]

Timing appears to be at -1.1 at present. Could this cause any significant loss in power, or do I need to have a go at adjusting the camshaft? From memory this is easy but a PITA.

[jamwatn]

Right, I think I've discovered something.

Before when my car was running better, my duty cycle for the n75 appears to have been higher.

See graphs:

 

Previously: Dcycle MAP climbs to 64% at approx 2400rpm and peaks to 72% at approx 4000rpm.

 

 

Now: D-Cycle Map climbs to only 57% at approx the same sort of point and only reaches 64% maximum at any revs

 

 

What does this mean? I've done a tonne of Mr Muscles and haven't touched the screw on the VNT actuator. This could explain the lack of power. Perhaps its caused by the timing?

[vrs180]

-1.1 torsion value means the crankshaft is retarded in relation to the camshaft so yes it does effect performance and therefore fuel consumption.

I find the blt engines run best at 0.0 to 0.6.

It's easy to correct your -1.1 just loosen the 3 camshaft sprocket bolts and using an 18mm socket turn the camshaft anti clockwise slightly (therefore advancing the crankshaft), re tighten the bolts to 20Nm + 45 degrees.

HTH Bill

[mogwye]

And it's always best to do an ECU reset after altering.

 

DB

[neiln]

Are you using branded fuel or supermarket or Indy fuel?  Could you have some of suspect quality?  Try a couple of tankfuls of shell vpower,  the detergents in it may help.

[jamwatn]

Thanks for your suggestions. I'll be advancing timing this evening.

Fuel is pretty much always the same place so wouldn't indicate power loss. I've ran bottles of cleaner through with no results.

Here's hoping it's just the timing.

[mogwye]

Thanks for your suggestions. I'll be advancing timing this evening.

Fuel is pretty much always the same place so wouldn't indicate power loss. I've ran bottles of cleaner through with no results.

Here's hoping it's just the timing.

 

You have to be very patient to get it spot on, It only needs moving the thickness of a credit card, if that.

 

I ensure one of the camshaft markers is viewable, I stick a piece of masking tape on the black plastic backplate of the belt cover and mark with a sharp pencil, this allows you to see exactly how much you have moved the timing.

 

Once you have it set correct at 00.00, do an ECU reset and see the difference.

 

DB

Edited 21 May, 2015 by mogwye

[jamwatn]

Done. Timing is now advanced at 0.6. Ecu has been reset.

I drove it and unfortunately, it's identical! I'll upload the logs shortly however I think the duty cycle is far too low still.

What's next?!

I can still confirm vnt movement is smooth.

[mogwye]

I too have been experiencing a lack of power and MPG after a cylinder head refurbishment and I have checked out many settings, then I read about this http://www.audi-sport.net/xf/threads/how-to-guide-pd-tdi-injector-adjustment-clearance-lash.183040/ and I wrote a report of my findings.

 

I purchased a diesel compression testing kit, the results as follows.

 

All tests with a Cold engine.

 

Cyl 1 - 445

Cyl 2 - 445

Cyl 3 - 460

 

I made a jig to attach my DTI gauge to check each Injector tappet adjuster at it's lowest point, then undoing the nut and screwing in the adjuster until a firm stop, then backing it off 180' and torque'd the nut up, I then compared my settings to the original settings.

 

Cyl 1 - was backed off at 270'

Cyl 2 - was backed off at 210'

Cyl 3 - was backed off at 190'

 

This obviously looks where the fault lies and also suggests as though no protractor was used in it's original setting.

 

I then retested the compression

 

Cyl 1 - 450

Cyl 2 - 445

Cyl 3 - 450

 

I ran the engine with the torsion setting still retarded at -0.05, it started without hesitation with no shudder and ran a lot smoother and it felt more like it was running on 3 cylinders again.

 

I then reset the torsion value to 00.00 (00.00 is the official setting), then reset the ECU, where it still ran smooth but I felt it could be advanced a trifle more.

 

I then reset the torsion value to 00.06, went through the ECU reset procedure where it still ran smooth, I then left it set as is for a few days to see what the MPG figures looked like.

 

10 days later - The MPG was now back to it's original readings and certainly goes a lot better but not quite as good.

 

This weekend I will set it back to 00.00 and reset the ECU.

 

Hope this may help.

 

DB