Ibiza 2.0 GTi 16v down on power - help please

[morgangrinder]

Hi Everyone,

I have a frustrating problem with my 1998 GTi 16v which is definitely down on power and I'm after suggestions to help me diagnose the problem.

It has the ABF engine which should be good for the best part of 150bhp even with 90k on the clock and it's definitely not as quick as the Mk3 Golf I used to have with the same engine, 150,000 miles and quite a few extra kilos.

There are no particular problems with the way the engine runs; it's just not as quick as it should be throughout the rev range. There's a bit of a kick at 4,000 rpm, as a 16v should have, but no flat spots and it winds up to the red line without much fuss.

I've checked the cam timing and it's spot on. I haven't gone to the trouble of taking the cam cover off and checking the cam-to-cam timing but I have no reason to suspect it's out - the car was a one owner from new when I bought it in April and it came with wads of history but none of it pointed to the cams having been out.

I've changed the plugs, distributor cap, air filter, fuel filter and the middle and back boxes in the exhaust system but what else can I try?

It's had a dose of injector cleaner, I've checked all the vacuum hoses, the throttle travel and all the hoses on the induction system.

I'm left thinking it could be a compression problem, a sensor issue (knock sensor retarding the ignition all the time), a gummed up or collapsed cat or an ECU problem.

Anyone out there had a similar problem or have any suggestions for me?

Thanks in advance,


Stuart

 

[orangemuffin]

i had a power problem with my first valver and it turned out to be only running on half throttle so had the throttle body off an it was given a good clean with carb cleaner and then had a new gasket and it was fine.

If you have a can of carb cleaner get someone to rev and while the butterfly is open send some bursts of carb cleaner down there and it should chuck out some smoke.

If it was the cat then not sure if it would be sending bits of black string out the back ??

Have you tried resetting the ECU ?

and welcome..

 

[Fl@pper]

rolling road it otherwise you are guessing the numbers on from the feel of a different car

especially as the golf is supposed to be 10k lighter as well

cat wise could be an issue but bum dyno's are useful but no substitute for number ones

 

[griff82]

how do you reset the ecu?

 

[orangemuffin]

disconect the battery for 30 minutes mate..

 

[HoopDub]

check throttle body, as stated above, also check your air filter, make sure it actually allows air through. many people forget to clean out induction kits, or even standard filters.

 

[morgangrinder]

Hi Everyone,

A quick update, following the tips from here and on Club GTi:

First suspect was the PCV valve or the vacuum hose leading to it.

New PCV valve and crank case breather hose on order. Vacuum hose temporarily plugged and, bingo, half a second of my 30-60mph time!

According to Dynolicious on the iPhone that's another 8bhp.

I've gone vacuum hose crazy now and I'm changing every bit I can find. This is leading me to discover bits of the car that I didn't even know existed!

Cheers,


Stuart