A little confused all in all... 1.8T problem.

[freebird]

Hi Guys,

I've reviewed the forum and read a million and one threads about possible problems and issues, but thought I'd post this and see if I get anything new spring up, or people just reconfirming what has already been said.

I have a 200(X) 1.8T Sport VW Passat with an engine problem. Its got hiccups. Basically the throttle response is frustratingly random. Some times is sticks so any increase in throttle results in zero increase in power, but then it wakes up and goes "oh is that what I'm supposed to be doing" and sticks me to the back of my seat.

This occurs ar all speed ranges but primarily around the 300 rev range. I have my theories and have listed them below.

1. The DV. Reading peoples comments and previous suggestions this sounds like a typical DV problem and the fact the car has done 107k means it's likely the standard Bosch DV has packed up. Now the 1.8T in these Passat's is a longitudinal engine and the turbo is squeezed in the lefthand front corner. I believe the DV is at the front of this and it doesn't look like there is a lot of space around it. The standard diaphragm valve is quite low profile, unlike the Forge (FMCL007P)and Bailey replacements you can get. Is there enough room to squeeze these in? I know Forge also do a FMACVAG02 purposely for these engines but it's more expensive than the FMCL007P for all 1.8T VAG engines.

2. The MAF sensor. This is the other typical culprit by my understanding. Situated on the other side of the engine bay near the right-hand front (behind the headlight). A faulty sensor such as this would create very similar problems. Used to have a Ford Escort, and an old V6 Sierra, which suffered from problems associated with this sensor becoming faulty or more often than not, just falling off or disconnecting. How cheap and easy are they to replace and where would you get one from in the UK?

3. Air Hoses. Now, one bit of information I neglected to mention was that about 7 months ago some bright sparks decided to have a traffic accident in the road next to where I was parked and a nice '52 Renault Clio though it would be nice to park itself in my drivers side front wing. Now all body work and general mechanic were fixed but this problem may be due to a tear or whole in an air tube coming from or leading to the DV, including the bleed tube that's supposed to connect to the manifold (I believe). Has anyone experienced these symptoms due to this problem before? And if so how was it resolved? Was it necessary to replace all the tubesaround the Turbo or is there one particular tube that's prone to splitting under stress?

Thanks in advance for your help guys.

Just to make you all laugh - VW quoted me over £200 to replace the DV with another standard Bosch unit!!! Bearing in mind I think it will take me about 15 minutes if that, that double the price of me buying the Forge unit! Criminal!!!!... but if you think that's funny - you want to see what the quoted to replace the 2 CV bushes that my mechanic later gave the thumbs up for another 20/30k! Why are Car Dealers such crooks!

[freebird]

Anyone got any ideas... looking for a nudge in the right direction?

Thanks

Matt

[Lex Luthor]

Is it DBW ?

[paddymm]

I had a similar problem with a 95 A4 (trying to overtake or pull away from junctions - nothing happened when I pressed the throttle.) It turned out to be a dirty throttle body butterfly valve which was very stiff and sometimes stuck. My engine also idled very erratically though it may help to have a look at yours. There are many threads on this site regarding cleaning of throttle bodies including one i've seen for a passat.
Hope this works - its a bit of a bummer when you think you are about to pull away from a junction in the gap before an artic lorry only to find you stop in the middle of the road panic, floor it and give yourself whiplash and soiled pants...nice.

[freebird]

Lex Luthor... DBW? Don't know what that means?

paddymm... low revs seem uneffected, hence why I looked at the Turbo as a possibility as it doesn't really kick in until around 3k. Will look at the threads regarding cleaning throttle bodies anyway as a good clean never hurt anything. Cheers!

Anyone else got any possible diagnosis - I'm happy to investigate anything that doesn't cost an extortionate amount of money!

[Sam]

DBW - drive by wire, it being an X plate '00 I think it may well be, but it could be one of the cross-over models.

Hoses split all too often, the main culprit is the "L-shaped hose".

What you're describing sounds a bit like limp-mode but not enough to make me think it is that.

I'd vote you wait to see what Lex has to say, he's quite handy

[tea drinker]

I had a problem like this before when my hose to the N75 valve was chaffed through. This is the small hose that connects to the top of the turbo, near enough the Turbo inlet. It points vertically up, "on the shoulder" of the turbo. It's extrmely difficult to check this as it's very tight. But see what you can see. Also it's possible another hose in the same area is leaking. Make sure your turbo inlet pipe is firmly on and tight.
Mt car is doing the same thing again now, I am waiting on new part from VW, was up there today, they had received the new part, but there was the DV valve in the box! Correct part No. on SEALED box.