Some thoughts on a possible boost leak

[f2evotomo]

Hi all,

I took my car apart at the weekend as something somewhere just doesn't seem 100% up to a couple of months ago I was regularly seeing around 40-45 average MPG but now I'm seeing 30-35 if lucky, I can't help but think the power seems a little down as well. I cannot seem to suss the answer completely but I thought I'll carry out a few jobs.

1st job was I pulled the plugs and re-gapped as there seemed to be a lot of distance in the gap against the suggested 0.8

2nd job was clean the intercooler as it was looking a little gunked up

3rd clean throttle body

4th check all main joints on pipes including CAI are all tight

5th check all pipes under manifold etc... for leaks ( all seemed ok visually)

After I carried out these jobs it seems more responsive in some areas when driving but still down on power overall, plus no improvements on MPG after a run to and from work today which is 35 miles E/W, most of which is motorway driving at a steady rate.

Anyway getting back to the title, while carrying out the above jobs I did notice some wear to the intercooler surface so would this contribute enough to cause a boost leak do you think or can anyone suggest whats going on with the drop in performance and MPG

I know the rear brakes can stick on at times and mine has done this but would I be safe to conclude it shouldn't be a factor if the car rolls ok with the handbrake off ??

here are some pics of the work and what I found on the intercooler, I'm interested in your responses.

you can see the markings on the bottom left uprights of the intercooler which have been made by the scoop which channels the airflow to the intercooler

Gary

[Bowders1]

Best bet is get the car hooked up to VAGCOM and see if you have any codes logged. If you have a boost leak this should be logged.

Is your Engine check light on?

Boost leaks can be common on these cars if not maintained

commons areas are:

Loose Turbo pipe. from pancake to upper pipe behind the engine. The seal can go on these.

Loose pipe from intercooler to pancake pipe

Faulty DV

Split "Y" piece hose (top side of engine.gearbox

split S pipe (located under inlet manifold)

Blocked fuel filter

Spark plugs worn or faulty

Coil Packs faulty or lifted from spark plugs due to worn rubber seals

hope this helps

P.S intercooler looks ok to be honest, certainly not damaged enough to give issues

[f2evotomo]

Cheers for your input bowders, I've looked over most of the hoses and they seem all fine. Areas for further checking as you mentioned would now be seal on pancake pipe at the rear of the engine and poss the DV, maybe it's just the cold, I just seem to be burning up the fuel massively lately like £35 every few days yet sometimes that's lasted me the best part of a week :-(

[Bowders1]

Cheers for your input bowders, I've looked over most of the hoses and they seem all fine. Areas for further checking as you mentioned would now be seal on pancake pipe at the rear of the engine and poss the DV, maybe it's just the cold, I just seem to be burning up the fuel massively lately like £35 every few days yet sometimes that's lasted me the best part of a week :-(

only other thought is a faulty MAF

When these go they can still run ok but cause heavy fuel consumption

Unplug the MAF and see if it still runs ok or better. If it runs ok or better MAF is suspect , if it runs worse then probably MAF is ok.

[Almal]

What's the temperature gauge work like? Is it slow to heat up? Coolant temperature sensor could be a possibility and doesn't always log a fault. If it is faulty that can mess about with the fueling a little. Just a thought

[f2evotomo]

The temp gauge moves all fine and reaches temp ok and within a reasonable time

I haven't tried the maf as yet, if I disconnect this will it through up the CEL ?

[f2evotomo]

I take it no one could answer my question on the MAF.

Anyway a little update, a couple of days ago I removed my cold air kit and put the standard airbox back on with a k&n panel filter which I bought when I first got the car, I have seen a small increase back on my average MPG which now reaches back to 40 again but more than anything is the improvement in pure driveability, there is more torque and more mid range throttle response so gonna continue with it like this for now, maybe the metel cold air kit is just to cold a throwing things out for fuelling in this icy weather

[missingmyvrs]

dont forget weather will also cause differences in mpg readings

but the only way to test for boost leaks is smoke test as even if it looks okay it may leak under pressure