Poor performance PD150

[S10EAT]

I have a strange problem with my pd150, up until a few weeks ago it was running as sweet as a nut but recently has suffered a power loss.

The problem can be best described as the engine feels as though it is restricted/ holding back like the engine is constantly engine braking.

It's effected the entire rev range, so far I've replaced air filter, fuel filter, n75 valve, maf.

I've checked boost pipes and I've got no leaks as far as I can tell, turbo has been cleaned recently and actuator is moving freely, boost normally comes in at 2100 but the power seems to come in very slowly now, couldn't tell you where the full boost point is.

I had a long journey up north recently and it really struggled to maintain speed, I had to keep adjusting the throttle with blips of the pedal, top end is really awful as well it really struggles to break the 100 mph barrier (private road).

Any ideas, i have read various posts on these kind of symptoms but none have been very useful, could it possibly be the fuel temp sensor? But surely it would flag a MIL light?

Its really making the car not enjoyable to drive at all and is doing my head in!

Cheers,

S10EAT

 

[MJ]

Lift pump in the tank?

 

[S10EAT]

Could be, but I have just checked my injector balance and it looks worse now than it has in a few months, especially injector 4, this was +1.67 about 2 months ago when I checked last.



In your opinion, looking at the values of the injectors would you say that 2, 3 and 4 needed replacing?

Thanks,

S10EAT

 

[MJ]

Those injector balance readings are within spec but your MAF reading is way out! Have you logged it in 3rd gear up to WOT?

 

[S10EAT]

Yes, I logged MAF and Boost.

Please see below:





Thanks,

S10EAT

 

[S10EAT]

On a seperate issue, have the SFS Turbo Inlet Pipes been known to collapse under vacuum? Because I just replaced the OE one with SFS and I'm sure I've lost power just from that.

 

[MJ]

Actual still seems very high compared to specified.

Maybe there is a fueling issue as the MAF is obviously reading but the fuel system might not be able to meet the demand to match the intake air mass.

If its logged no fault codes it usually points to a non monitored or mechanical component.

 

[MJ]

On a seperate issue, have the SFS Turbo Inlet Pipes been known to collapse under vacuum? Because I just replaced the OE one with SFS and I'm sure I've lost power just from that.

I'm not a fan of the SFS stuff.

 

[S10EAT]

Well after having the turbo outlet pipe from SFS that rubs on the driveshaft and now the supposedly upgraded TIP from them, I can safely say I will not be purchasing anything from them in the future.

So you think injector 4 is ok with a +2.07 value? my mpg on average at the moment is anywhere between 35-43mpg which is shocking.

No fault codes have been logged, my gut feel was the fuel system, and when I saw that injector 4 was overfuelling more than it was a few months ago I suspected this could be upsetting the balance.

How often do lift pumps go faulty?

Any other information I can provide to work out what could be going wrong?

Thanks for your help so far MJ, much appreciated.

 

[Seal_LCR]

Worth doing a smoke test?

 

[Seatmann]

The lift pump should come on briefly when you open the drivers door, you should hear it.

How's the cam? Have you checked it for wear?

http://www.myturbodiesel.com/1000q/multi/camshaft-inspection-replace-vw-tdi.htm

 

[vroomtshh]

Worth doing a smoke test?

This. I'd suggest the MAF reading is away out either due to a boost leak, or it being a bad MAF.
Did you buy genuine?

 

[S10EAT]

I have replaced the re-manufactured MAF from Bosch with the original MAF (which coincidently didn't have a problem in the first place.) I don't think it is the MAF at fault as it's been no different since it was changed a few days ago.

Here's a question, if a ecu map data is capable of small adjustments on its own, is it possible for it to become corrupt/create incorrect measurements?

I'm going to put the standard map on tonight anyway for fault diagnosis and if I have time put the standard TIP back on as I definitely see no gain with having the SFS pipe on, could this have screwed the reading?

Cam photos below taken about a month ago:









Seatmann, I had a look at the guide for cam wear but couldn't really tell whether there was wear or not.

What would the smoke test prove other than I have a fuelling issue?

What do your cars fuel temp read when car has warmed up to full temp? Mine reads as 68.4c? Is that high or low?

Thanks guys, I'm willing to try things so any other suggestions would be great.

 

[MJ]

I dare say he means a leak detection smoke test.

If anything the high MAF readings are indicating that the ecu is seeing a lean AFR meaning its under fuelling. Fuel temp should be a few degrees lower than coolant temp (90degrees C approx).

Also the injector quantities are an indication of compression.

High injection quantities indicate low compression as the ecu is injecting more fuel to compensate and encourage ignition.

Low injector quantities indicate high compression.

Tolerance is between +2.99 & - 2.99

2.99 continuously would indicate a bent rod, valve gasket or ring fault.

 

[S10EAT]

A few months back I asked my mechanic to test cylinder 4 for compression and he said it was so high it blew his tester to bits lol, so based on what you have just said cylinder 4 would have been the culprit if any were presenting low compression?

Leak detection as in for a cracked head or block, or are we talking about the boost pipework?

What would suggest I check then? Should I get Cylinder 4 re-tested?

Any easy way to check the fuel pump output? Power seems to come in eventually but only way way up the rev range like 3500 onwards but tops out at 80-85 at a push I can get to 100 but really struggles with top end, which would indicate as you said an under fuelling scenario.

 

[MJ]

Boost leak check was what I was on about.

Fuel pressures need to be checked using pressure gauges, there's one for the lift pump and another for the high pressure pump. You'd need comparable reading from another vehicle to test it properly.

 

[S10EAT]

Ok, well I could purchase a boost leak tester I suppose and as for the fuel pump, I would probably need to find a local fuel injection specialist that knows these engines well and knows what to expect from the outputs.

Based on what I've described so far what would you put your bets on it being? Do you think it could be the tandem pump or in-tank pump that could be at fault, if it suffers with WOT and mid to top end but is fairly happy pottering around town?

 

[S10EAT]

I did some more logs tonight with the OE TIP in place and I also replaced the vacuum hose that goes from the n75 to the actuator.







Also the injector balance on injector 4 seems to have gone down when I finished my drive it like I stole it run!

What do you think of the logs now?

 

[S10EAT]

Sorry forgot to mention it seems to be running smoother now, power still isn't quite there but that could be the fact that the vanes are now clear and it's not over boosting (I run a mr muscle treatment through it at the weekend).

 

[S10EAT]

Well forget my last post, it's still running shite.

I put the standard map on and I remember what that used to pull like, but it feels like I've lost 20-30bhp.

Takes forever to accelerate even with my foot to the floor.

Fuel Temp at idle after a run and been sitting for a few minutes is 74.7 degrees c, I read somewhere that this is quite high? Can anyone advise? Could it be a clogged in-tank lift pump?

I'm running out of ideas on this one, can anyone assist?