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VW Golf MK4 PD TDI 115 YR 2000 - Loss of power and limp mode.  
VW Golf MK4 PD TDI 115 YR 2000 - Loss of power and limp mode. - HILL1990

Hello,

I have been having this problem with my car since i bought it in February and feel like i have read every forum concerning the problem and tried nearly everything necessary, so i will now try to describe it as best as possible and hope someone may have a clue as to the cause.

When driving the car, its revs through the range well in 1st and 2nd, however in 3rd gear and higher above 3,000 revs the car seems to enter a prolonged flat spot, losing power but not always sending it into limp mode, when i reduce speed and use less revs the car does not flat spot and will continue to accelerate agin until just above 3,000. In addition and likely the same problem, the car often and easily enters into limp mode when pulling up a hill or just accelerating from low revs in 3rd gear and above. Once restarted the car returns to 'normal mode'.

Since reading many forums of members with similar problems i have been lead to believe something could be causing the turbo to 'overboost'. I have even listened to the turbo when reving the engine and i can hear a 'whirring' noise from very early in the revs and once stopped reving the whirring noise takes a slight while longer to stop. I do not know whether this is normal for the turbo or not so some reference to this would be great.

As i hope there is nothing wrong with the turbo i have done a few other things:

Firstly i replaced the VNT actuator, believing that the membrane inside the actuator could be weak. I also checked to see if the vanes moved freely inside the turbo by flicking the actuator lever up and down which does so easily.

Next i took off the inlet manifold and EGR valve to check to see if there was an excess of carbon build up. Although there was some, it was nothing significant, and once i cleaned it there was barely a smear.

Shortly after i replaced all of the vacuum pipes to rule out any vacuum leaks. I then also swopped the two N75 valves over to make sure it was not this.

All of this has made no difference to the problem and the car still behaves the same.

If there is anyone who could advise me of what i could try next or in their opinion is the likely cause i would be very grateful, and will continue posting so that others may find this useful.

Thanks in advance,

Jordan

Tags: technical issues gearboxes limp mode diesels

VW Golf MK4 PD TDI 115 YR 2000 - Loss of power and limp mode. - unthrottled

You've approached the problem as logically as anyone could. Does your car have OBD2? It must have some diagnostic capability at that age. I think it would be worth paying to get the codes read. Diagnosis by substitution can get expensive! There's not much in the exhaust that could cause problems apart from an oxidation catalyst or the muffler. On the intake side there are no swirl flaps. Intercooler/hose leaks are more prevalent at lower engine speeds.

VW Golf MK4 PD TDI 115 YR 2000 - Loss of power and limp mode. - HILL1990

Hi, thanks for the replies. Im very sorry, but i also forgot to state that i changed the MAF sensor also, so that rules that one out.

Concerning the OBD2, yes it can be put through a diagnostics test of which i was going to do myself as i have the cable. However as i tried to do this i realised i would need to buy the official software from ross-tech which is over 100 dollars online, and going to a garage doesnt seem to be much cheaper. I have also heard of diagnostics test often being inconclusive. So although it might be something i end up doing, i would rather see if anyone has some useful knowledge first.

Thanks

VW Golf MK4 PD TDI 115 YR 2000 - Loss of power and limp mode. - dieselnut

Ross-tech used to have a Shareware version of their software with limited capability that you could download for free, think it was 409.01.

It would display & reset fault codes but not much else. This may have been superceeded by a version of VCDS. Check out their site.

VW Golf MK4 PD TDI 115 YR 2000 - Loss of power and limp mode. - Tim the Grey

I bet you have a grubby MAF sensor.

Mine will, on odd occasion, just lose all POW. It will go, but it won't rev, and I struggle to see 70MPH.

Disconnect the MAF connector, spray with WD or equivalent, and connect it back up. If this doesn't cure it, replace the MAF. They aren't expensive these days, well under £25 from a motor factor.

It's a 5 minute job with a X head screwdriver, and it TRANSFORMED mine. It now has 220K miles on, and still feels like it wants to everywhere at 100+!

And my turbo happily whistles away around towns and villages... It's what they do.

Edited by Tim the Grey on 21/06/2011 at 16:23

VW Golf MK4 PD TDI 115 YR 2000 - Loss of power and limp mode. - Railroad.

What you describe does sound like the common sticky vane turbo problem. Check the VW/Audi/Skoda/Seat forums to see if anyone near you has VCDS. I do, and I'm in Hampshire if that's any good to you. VCDS can check expected boost pressure against actual boost pressure. It can also do the same for expected MAF against actual MAF. This can be shown in graph form, and saved and played back. This should give you a very good idea of what the problem is.

VW Golf MK4 PD TDI 115 YR 2000 - Loss of power and limp mode. - HILL1990

Hello, sorry it has taken so long to get back to you but work has taken up a lot of my time recently.

I eventually bought the license for the VCDS lite and was able to check the specified boost pressure and actual boost pressure as you say. However from what i have read on other sites my readings do not seem abnormal. Although in all honesty i am no expert by a long shot. How can i post the results on here? As i would very much like your opinions.

Thanks

VW Golf MK4 PD TDI 115 YR 2000 - Loss of power and limp mode. - HILL1990

Hello again, i have opened a flickr account so i can post the log.

www.flickr.com/photos/65500030@N02/5964121132/in/p...m

i started in 4th gear on a flat stretch of raod at about 3000rpm and as you can see the actual map (yellow) is much lower than the specified map (green). I then slowed down before a hill to 2000rpm and floored it in 4th gear as seen by the surge, at which point the car went into limp mode and seen by where it reaches a plateau.

I almost forget but the error code that VCDS shows is P1550:

17958/P1550/005456 From Ross-Tech Wiki Jump to: navigation, search

Contents [hide]

17958/P1550/005456 - Boost Pressure Controle Valve (N75): Control Deviation Possible Symptoms
  • Irregular behaviour
  • Reduced power output
  • Limp mode
Possible Causes
  • Hoses/Pipes incorrect connected, disconnected, blocked or leaking
  • Charger Pressure Control defective
    • Solenoid Valve for Boost Pressure Control (N75) defective
  • Turbocharger defective
Possible Solutions
  • Check Hoses/Pipes to/between Components
  • Check Charge Pressure Control
    • Check Solenoid Valve for Boost Pressure Control (N75)
  • Check turbocharger

I have even bought a new N75 valve just to make doubly sure it is not that, of which made no difference. I am now heading towards the idea of the MAP sensor?!?!?

Does anyone have any ideas as to what could be the cause?

Thanks once again.

Edited by HILL1990 on 22/07/2011 at 14:37

VW Golf MK4 PD TDI 115 YR 2000 - Loss of power and limp mode. - dieselnut

Check out this site :- sites.google.com/site/1810martin/home

A wealth of info that should help you.

VW Golf MK4 PD TDI 115 YR 2000 - Loss of power and limp mode. - drivewell

I've seen these symptoms from a faulty fuel pressure sensor, often on a Delphi pump. OK, I know you're on a PD engine, but I'm wondering if there's something similar. Can behave for all the world like a dodgy EGR valve (which you've checked) but is actually the fuel pressure sensor.

VW Golf MK4 PD TDI 115 YR 2000 - Loss of power and limp mode. - japnut04
Did you ever get this figured out ? I'm having the same problem myself ,real pain.
VW Golf MK4 PD TDI 115 YR 2000 - Loss of power and limp mode. - rockster
Did you ever get this figured out ? I'm having the same problem myself ,real pain.

Hi, we have had a similar problem, did you get yours sorted?

We have changed maf, boost sensor, intercooler but still the same flat spot at 3000 wont go over 40 or so! Blew the back off new ic so had 'fault diagnosed' again and it seems that a boost solenoid was/maybe faulty (aparently there are 2) I think this has done the trick but am now looking for another ic has anyone got an idea of what are the most suitable and cost effective?

Cheers

VW Golf MK4 PD TDI 115 YR 2000 - Loss of power and limp mode. - ptaka69

Jordan,

Have you found the problem with your golf? Let me know cause I had the same problem and can let you know what I had to do.

Alan

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