Can it be the Turbo???

[Buzzp]

A few months ago after much trouble shooting, I finally realized that I had a wiped cam. Sure enough after pulling the old original cam, the number 3 lobe was wiped. The car before that smoked a little and sounded like it had a dead miss. The injectors were changed, coil pack, plugs, wires, maf. A new Comp Cam 205/205 was put in the car with new lifters, water pump changed, timing chain. Started the car up and it fired right up and sounded healthy. did the break in procedure. After about 5 minutes, I noticed the smoke (oil) but not as bad as before the cam job. Still also sounded ok. I then shut it down and started right back up. Went for a ride and it sounded good, ran well, but not great power. The turbo lights would hardly come on even after getting on it pretty good and still a little smoke at stop lights. Obviously I am not getting any boost or very little. Checked the light by blowing compressed air into the sensor that is on the fender wall and the light would come on for low boost and high boost so I know the light is working. But I basically have no great neck snaping power and I am pretty sure now that my problem was two-fold. the cam and the turbo. Can someone confirm thatt his is a sign of a bad turbo?? Also, I checked the hoses to the turbo and the "Y" etc. I checked the connections for intercooler etc. But basically it is running like a V6 and runs smooth but no boost. Also I purchased this car with these problems and do not know the history, but I am getting the impression that the previous owner wiped a cam and new about it and basically swaped ot a good turbo before selling?

[Keller]

Originally Posted by Buzzp

Can someone confirm thatt his (sic) is a sign of a bad turbo??

There are some basic things to check, of course: Signs of oil leakage on either side within the turbo, signs of wheel contact internally, and/or excessive movement fore/aft up/down in/out or side-to-side.

If you have a boost gauge on the car you could see if it was generating full boost. It may not be.

You still may have a leaking combustion chamber, or it may be leaking into an adjacent cylinder.

[Buzzp]

I had done a compression test and it was ok, about 150 in each. The smoke is not much and it is also not all the time. If there was leakage across cylinders, I think i would see smoke at startup?? and continuous. It seems that it smokes at higher rpms, above 2500. that is what leads me to believe it is bad turbo . I am going to hook up a boost gauge tomorrow and drive it around, but I know I will not see above 4 psi. I did forget to mention that I do have a small exhaust leak at the cross over before it goes up to the turbo but I have not had a chance to fix it. Is it possible that a very small exhaust leak would yield such low boost? I know that the exhaust pressure drives the wheel and I know I really need to fix the leak but seeing the smoke made me think it is more the turbo.

[Keller]

Even a small leak can have a big impact. You might be surprised just how big an impact. I've driven a 11.0 car that had such a leak, and it suddenly felt like someone had dropped anchor...from an ocean liner. Getting the crossover sealed back up got the performance back up where it belonged.

When you have an exhaust leak in the headers, the turbo does not get spooled as aggressively. Not as much boost is produced. Not as much boost means not as much air is being pulled in. But the same amount of fuel as ever is injected. You have a motor with little or no boost running VERY fat, choking on fuel and not making power.

I would give the crossover a look before panicking with anything else.

[Buzzp]

Thanks Scott, I will get it all sealed up first and take it from there.

[Buzzp]

I checked the turbo and there is very little oil on either side (normal). The blades spun freely and there was hardly any play with no damage. I would think that I would get even some boost. My friend and I found it odd that it was continuosly hunting around and the idle would raise and lower as it warmed up. it was definitely running rich when it smoked. We decided to try an experiment since we did not feel like there was much coming out of the exhaust for the higher rev that it was under (about 800-1000 rpm). we both placed our hands over each tailpipe and blocked it up to see if it would make a difference. There was not even enough pressure to blow our hands off, it was not hot enough to even burn our hands, and even holding it there for about 10-15 seconds, we could not even get the car to stall although it was stumbling. This leads me to believe that in addition to a small leak, this car probably also has a blockage and most likely it is the catalytic converter. I looked underneath at it and it did not look great (outside rust) and looked to be original. if not original, it is probably well over 10-15 years old. I plan on fixing the leak at the crossover and taking the cat off. I should see a difference.