i have a 92 talon tsi stock. the car has been running very poorly for a while. it gradually became worse until now the car is running extremely rough and has a lot of black smoke. it seems to be flooding. when i try to accelerate is just doesnt have any power and has a bad vibration. it also idles rough and on occasion will almost die. it seems to run better the warmer it gets, however it never runs close to right. the boost gauge is always high sometimes even at idle. i think its getting too much fuel i just cant figure out why. i am not great with cars but there seems to be no mechanic here that is really comfortable working on it. i've changed the o2 sensor and the fuel injectors. i've also been researching about the egr valve, could that be a possability? any suggestions would be appreciated.

Check for boost and/or Vaccum leaks, this sounds like the most likely cause of your woes.

If there is a leak, it allows metered air to escape, but the ECU still thinks it's there, thus supplying fuel for air that doesn't make it to the combustion chamber.

Best way to check is a hommade boost leak checker, or you can take a hefty bag, fold it a few times and take a hose clamp and cover the inlet on the turbo. You can then pressurize the intake via one of the vaccum ports on the intake manifold. Listen for the escaping air.

here is a link on how to do a boost leak test
click me

^^^that's the one I made.

Make one now, you'll use it a hundreds times in you start modifying your car!!

well. it turns out that at least part of my problem is a bad fuel injector. i fixed that today. but there is still something going on with the turbo. i cant find a boost leak, not to say there isnt one. i did find that the wastegate actuator rod was not attatched to the turbo. i reconnected it, but it doesnt seem to be working. could someone explain to a newby what its for and what kind of symptoms it would cause.

is there a vacumn line attached to the wastegate?

To clarify, is there a vacuum line connected to the wastegate actuator? The rod is pushed forward by a diaphragm in the actuator when a certain boost pressure is reached. The rod is connected to the wastegate so when it is pushed forward it opens the wastegate allowing exhaust to bypass the turbine so a consistent boost pressure is reached. A turbo is a positive feedback device. If there were no wastegate to govern it, it would continue to increase your boost pressure until either the turbo or your engine grenaded.

the vacum line is attatched. should i be able to move the actuator rod by hand? should the place where the rod attatches to the turbo be loose and move easily when the rod is not connected?

The rod is not easily moved by hand. The internal wastegate which the rod attaches to should be very easy to move when the rod is not connected.

thanks

well, here i am again. i know i am bringing up an old conversation again, but i still havent fixed this problem. i have found a shop that is comfortable working on it, however they are now stumped too. they have changed several parts and we have tried every suggestion we have heard. we sent the computer off for testing and mitsubishi says its good. the guys at the shop want me to replace the computer even though mitsubishi says its good. does anyone have any experience with the computer going bad and its symptoms? any more ideas are welcome. thanks in advance

were are you located? if your close we could hook it up to my logger and see if there are any errors. have you tried replacing the maf?

i'm in arkansas. what is the maf? i have replaced the mass air sensor if thats a maf. the shop i've been working with checked the codes if that is what you mean by logger. it had several codes in it. all of them referred to sensors. if i remember correctly most of the codes had to do with fuel. i have changed the o2 sensor that was one of the codes. they tested several other sensors that tested good. but i cant remember what they were. thanks

Did you do the boost leak check?!?!?!?! I'd put $100 on that being the problem.

they told me they checked it.

would a boost leak cause the car to be undriveable? it is flooding so bad that you can barely get it in and out of the garage

yes it would. With a big enough leak it won't even idle.