My 93 Pontiac 3.8 lt. Supercharged Bonneville has developed a bog on acceleration. Sometimes when I accelerate from a stop or at speed the boost goes up but the engine bogs or hesitates until I let off the gas. This happens at random, 3, 4, 5 times a day. Some days not at all the car runs fine otherwise except it has NO POWER. I have changed the plugs, plug wires, fuel filter, air filter and added a can of Berrymans to the gas. The computer has no stored codes and no check engine lights are on. I have also noticed the nose of the supercharger seeping a little oil, and the bearings seem to rattle a little more than the used too. I have changed the supercharger oil. How do I get the power back? Is the supercharger shot or is it something else?

If your supercharger rattles mostly at idle, and you're still getting at least 8 or 9 psi of boost, I'd consider changing the supercharger coupler. That will give you the chance to re-seal the nosedrive too. I just did this last Satruday. I posted pics in mechanical and maintenance. Topic is M62 Supercharger rebuild with pics.

I agree with Jr. Those are the 2 things I'd look at for the bogging. It'* POSSIBLE but less likely that you have a blown head gasket, too.

I Checked the fuel pressure and it was 42-43 psi with the key on and 38-39 psi with the motor at idle, and when I turned motor off it dropped only 1-2 psi more.I think the fuel pump and regulator are ok.
What is an easy way to check for a faulty cat converter?
My wife refuses to drive it until it has MORE POWER!
Thanks Keith

If you have the ability to check the fuel pressure, you're a wrench-head. How about a compression check too?

For the cat, Jack up the passenger side of the car, and get under there so you can kick it. Listen for a rattle. If you hear debris, change it. If not, it still might be clogged. This is an interesting one. I'd also like you to check all the vacuum lines around the SC. Any one of those can cause the same symptom. I broke a couple last Saturday and replaced them with smaller ones. It held my boost down by a psi until I just now changed them back to the right diameter. If one is broken or disconnected, it can do funny things with bypass/boost.

I just played around with my vacuum lines. While I was replacing a couple. I can duplicate his problem by leaving a couple different ones undone. Like Jr said, if it isn't the cat, I'd be poking around for a vacuum leak, or worst case a compresson loss.

Great minds run in the same track. Of course, if we're wrong, we'll have to raise a flag.

I checked all the vacuum hoses around the supercharger and found them all to be hooked up ,but I replaced two to the vapor canister,one to the trans. vacuum modulator and one to the manifold pressure regulator.None appeared to be leaking but showed signs of old age.I started the engine and listened for vacuum leaks but I could not hear any.I reved the engine and the bypass actuator looked like it worked.I will jack the car up today and check the cat converter if the SNOW is not to deep.Oklahoma 70 deg one day and snow the next!
Thanks
PS I replaced the PCV valve a while back, could that be faulty?? I seem to remember a friend putting the wrong one in his car (don't remember what Kind) but it made the car run like crap.I'll check that too.

Once again, I've reviewed the whole thread,
Getting it all straight in my head.

It'* not happening all the time, forget the compression test,
Time to begin trying all the rest.

I'd get a real scantool on the car,
before you go too far.

Your SC also does need some help,
before you drive to get some kelp.



Sorry. That'* all I could think of that rhymed. Compression is out, since this doesn't happen all the time. The cat could still be possible, and the PCV, too, but that'* a remote chance. It'* time to get a real scantool on this thing and check it out. Do you have one available?

I drove the car pretty hard to town to get a new pcv valve.It ran ok, no bog or hesatation.It just didn't have the set you back in the seat */C feel to it.The boost guage did go up to max mark on the guage (about 9) just short of 10.The counter man at Autozone said they had no scan tool to pull up codes and suggested most of the things I had already tried (been there done that).I changed the pcv and that did no good.
I guess my next stop will be an auto $hop to get the codes pulled with a real scan tool an not a paper clip.
I just hate taking my car somewhere and paying them for something I already know or have tried!!

I will keep you posted as to the findings
Thanks Keith

You may consider buying a scantool if you plan on keeping the car. Mine was only $140.

Tell me more.What kind,brand,model,likes,dislikes,what it will do or wont.where did you get yours?
Sounds good.I would rather add a new tool to add to my collection than help the dealer pay for his!
Does COULD NOT DUPLACATE PROBLEM sound familiar?

Keith