This past weekend I installed Autometer boost and air/fuel mixture gauges to try to figure out why my car is so gutless.

At full throttle the boost gauge reads that my car produces 0 psi of boost and gradually decreases to about 4-5 psi of vacuum when close to redline. I was told my turbo is worn and should be replaced. Do turbos just "wear out" like this?

The air/fuel gauge says my car runs between stoich. and rich above 3500 rpm. But under 3500 the gauge switches between very lean and almost rich so quickly that 2/3's of the gauge is lit up at once. The idle is very erratic; when it fluctuates, about 100 rpm drop, the gauge reads very lean. What could cause readings like this? I plan to replace O2 and mass airflow sensors.

I have kept up on maintenance since I got the car in June. Before I bought it, it was owned by an 80 year old man and then sat for a year.

ignore the narrow band o2 gauge. they are only usefull to give you an idea. a narrow band o2 sensor is only accurate at 14.7:1 afr. basicly at idle and part throttle the o2 sensor bounces back and forth rappidly, and that means its right around 14.7:1. at full throttle it will read rich, as its richer than 14.7:1. if you ever see the guage show lean under boost, by the time you see it, the motor is cooked.

as for the boost, it could be a few things. one possibility is that the wastegate isnt staying closed. check to make sure the actuator is pulling the wastegate shut and be sure your boost controll solonoid isnt stuck open.

Like Sharkey sez. the wastegate system might be the problem. A quick check of turbocharger health can be done as follows: pull the vacuum hose from the wastegate actuator. This will allow brief, but "unlimited" boost to the system when you kick it - until the ECU figures it out and shuts off the fuel! Worked every time for me, without screwing up the engine! (This technique was suggested to me by the engineer assigned to the 2.0l project....)
If you smoke the tires, replace your wastegate solenoid - a $25 part from your friendly GM dealership.... That was the problem with both my 1.8L turbo and '89 2.0L turbo 'Birds. With an inoperative wastegate solenoid/driver, all you're gonna get is 2-3psi boost - if you're lucky!
Best of luck!
Moe

I will test my wastegate to see whats wrong with it. Is there anyway of removing the wastegate or sealing it in the closed position to replace it with an external bov? Or is it not worth it?

As for the constant lean reading when my idle fluctuates, I am going to take my car to a mechanic I know with a Snap on diagnostic computer to see if he can help.

Thanks for the help so far.

I tried testing the turbo, but there was no change to how the engine was running when I removed the vacuum from the wastegate. Throughout the test, the air/fuel guage remained constant in the mid range of the "Stoich." section.

I noticed that there was no vacuum from the line for the wastegate, is there a valve, or could the line be plugged or damaged?



I tried drawing my intake manifold. I hope it makes sense, because I don't have my camera anymore.
Does the green arrow point to the vacuum line that goes to the wastegate? If it does, I can't get any air to flow through it.

**The box that the green arrowed line is coming from is the one way valve.