I posted a thread about my mk2 gti 8v, I said that it is lacking in power down low. After checking a few things i.e. induction pipes and breathers and vacuums, I found that there is a pipe MISSING! It is situated on the back of the manifold, near the inlet pipe, just behind the throttle body. I had the engine while "cazzooom" Jonny put his finger over it and it was sucking jonny...s finger! but seriously just wondering where a pipe coming off that should lead? Im doubtful if this is the reason for such a large lack of power but it needs to be sorted anyway and hopefully it will lead to the problem being solved. Your help is mucho appreciated!
No, it's more like 18-20 at best. The MFA pipe would be the one going into the bulk head? That one was there
any pics so we can see? if its a digifant- pb engine with standard airbox? there should be two pipes coming from the airbox. i think one is only 3" long and connects back into the airbox and another runs up towards the inlet manifold. NEED PICS!
Unfortunately I can't post pics cus I aint a paid member There are two vacuum pipes off the air box. The one I'm talking about seems to come off the back of the inlet manifold(a different one) don't know where it goes or comes from. Would it be possible for anyone to post some pics of their engine bay so I could see any potential pipes that need to go there? Or does anyone know of what I'm talking about and can tell me where a pipe going there should come from?
The vacuum pipes. What I guess 1mm-2mm? Just the normal vacuum pipes. It would be a great help if someone could post some pics of their engine bay, preferably close ups of the back of the manifold and in general showing where all the vacuum pipes go. Pretty Please!
I've found out don't worry and signed up. Bit dark for photos now unfortunately. Has anyone got any ideas or some experts on vacuum systems?
Get some pictures when its light and im sure somebody can advise what needs to go to where. Quite possible its the cause of the problem. I had a high idle and 20mpg because a sensor had disconnected. Super glued it back on as it kept unclipping itself and now im getting 30mpg and a smooth idle of 900. Small things make big differences.
If its the one on the back of the throttle body on an 8v GTI PB, its supposed to be blanked off. You use a short length of vacuum tubing with a small metal rivit looking thing shoved in the end, just like the blanked off vacuum pipe on the front Edit: Bring it over to my house if you're near Bracknell, I'll fix it. I make Digifant engines my b1tch
Its sucking air because its not blanked, so its throwing off the mixture because unmetered air is getting past the AFM That connection is for extras like aircon and/or automatic gearboxes.
Right thats cool, so just to confim its the pipe situated on the back of the manifold, near the inlet pipe, just behind the throttle body, and I need to block it off? Do you think that will sort my erratic idleing? By any chance would you know what the problem is with the lack of power in the lower revs, anything below 3.5/4k revs there is no power then its fine?
Could explain the idle issues. The other common cause of uneven idle is the idle switch under the throttle body being out of adjustment, or the wirinf to the throttle switches being snapped. The idle switch should click just as the throttle is closed. Before you mess with the switch though, check the throttle snaps shut up against the stop, and that the throttle cable isn't too tight! No power low in the revs is usually caused by the timing being out, make sure all the marks line up, then set the ignition timing to exactly 6 degrees BTDC using a timing light down the gearbox inspection hole. It needs to be set with the oil temp at 80 degrees, with the blue temp sender disconnected whilst the revs are held at 2.4k RPM. I use various credit cards wedged into the throttle stop till its sat where I want it
thats wicked! nice and technical then wedging credit cards in! ok thats cool, i gotta new timing belt as my other looks a little worn so its probaby worth changing? I had a few people say its the timing so do you think that will solve the problem beacuse im really worried it may be something more and I have only bought the car 3 weeks ago!
