Power loss

[Eugheugh]

Got the AA out when we noticed a sudden loss of power in my 2002 Passat TDI Sport. No fault code was found and the chap said the turbo was functioning okay then mentioned something about anecdotal evidence to suggest that the oil pump could be at fault . So. my question is-does this sound like something to do with a blocked EGR ?. I don't want to replace the AMM as so many people on the forums say that it is a temporary fix and the problem occured suddenly rather than over a period of time. Incidentally, the water temp gauge is intermittent-I can be driving along and it will suddently go down to nowt and other times will not move off zero for a 20 mile trip. That said, it works most of the time, but I was wondering if the lack of power could be linked to an intermittent temp sensor telling the ECU to disalow turbo boost?. To recap-the car cruises down the motorway at 70 but I keep having to change down a gear of two when I encounter gradients. A friend of a friend says it could be one of the two N75 valves but as i said before - there is no fault code showing. Any ideas would be greatfully received?

[Carps]

Despite not want to replace you AMM (MAF) it does sound rather like that is the problem. Especially if there are no fault codes being thrown. approx £55 from VW dealer, and less than 5 minutes to fit...
How many miles has the car done, and has the MAF ever been replaced ?
Do you have access to VAG-COM to do some logging whilst driving - with this you'd be able to see if it was the MAF...

[Eugheugh]

Hi Carps. I didn't actually have a VAG COM done-just the AA mans diagnostics. A friend of a friend who works for a VW main dealer says that it is definitely not the AMM on the evidence I gave him so I took it back and got a refund and was then told that it could be one of two possible N75 valves. At this stage I glazed over and have been waiting for this mate to do a VAG COM for me or point me in the right direction with a few more checks. In answer to your final question The car has done 172,000 miles and has done the last 22,000 miles (since I've owned it) at a very sedate manner.

[Carps]

Best thing to do is get it hooked up to the computer, in that case. Get some live logging done of the various components and then check against spec in Elsa.

Good luck !

[Eugheugh]

Heh Carps. Thanks very much . I'll let you know how things pan out. Incidentally, the power is normal first thing in the morning for about 500 yards and then the power loss is constant.

[Eshrules]

hi and welcome to the forum

please see the below thread, its got another link in it to a past thread and a current discussion with another member who has similar issues to yourself, may prove to be of some help to you

https://www.vwaudiforum.co.uk/forum/s...ead.php?t=6019

in case you cant find it, the 2nd linky is :

https://www.vwaudiforum.co.uk/forum/s...ght=maf+sensor

they are both quite long reads, but they have a lot of usefull info in them

[calum]

Hello,you could try this first before you splash out on a new maf,

http://www.passatworld.com/forums/sh...d.php?t=124928

If the maf is dirty it will restore the car to normal operation,however if it is past it's serviceable life you may have a small improvement that won't last ,either way you will know what's wrong .Hope this helps Calum

[Eugheugh]

Thanks calum and eshrules for the advise. I was thinking about cleaning the AMM myself and the pictures have given me the confidence to give it a go this w/end. Anyhow, the general consensus of opinion is that it is the N75 valve that needs looking at as the problem happened suddenly but a mate is going to look at it on Monday if the AMM cleaning yealds no improvement. I'll let you know the outcome.

[Eugheugh]

Thanks once again to Big Col on this forum for his expert advise-I have lived with this fault for 5 weeks until now. The problem developed into a hard brake pedal that only manifested itself with the clutch depressed or with the steering hard on-lock. Big Col opined that the brake servo was being deprived of air and to inspect the hoses going to the tandem vacuum pump at the rear of the cylinder head cover. After finding a very badly chafed fuel hose (right down to the canvass/nylon), I turned my attention to the vacuum hose at the left side of the tandam pump and while there were no splits, the spigot that the hose fits into was a loose and no dout leaky fit in the body of the tandem pump. I found some old bicycle inner tube and wrapped it around the base of the offending spigot to effect a more or less gas-tight seal until I can source a new tandem pump. Plugging the leak has probably enabled the system to give the turbo the 'green light' as the car is more or less back to its old self. Once again cheers everyone, I hope this helps anyone in a similar predicament.