98 BuickGS Supercharger woes

[JanesGS]

Hi all, I am having trouble with my wifes 98GS. To start the problem around 4k the engine acts like it is rev limiting?? I have replaced the plugs and fuel filter and inspected the serp belt which is fine. The boost never reached over 1lb of boost inside. I also checked out the coil pack and they are fine. The boost actuator seems to be moving when the engine accelerates. I have no idea what else it could be, any help would be appreciated. There is no check engine light comming on either.

Thanks,
St eve

 

[steveX]

I have replaced the plugs and St eve

Sometime, once you remove the spark plugs/wire, by tugging on the wires when removing will cause internal breakage to the core , which can cause misfire under load and high rpm. If you never had this problem before replacing the plugs. i will have to say to replace the wire with AC-DELCO wires.

 

[JanesGS]

Supercharger Woes

The problem actually started before I replaced the plugs. Maybe the wires are bad? I am lead to think otherwise because of the boost being almost nonexistant. I am thinking maybe the intake gasket has given way?? Any additional help would be appreciated. I dont think I want to take on myself trying to replace the intake and removing the supercharger fuel rail and all of the other numerous components on the top end. I wish it was as easy as my 71 GS 455 :biggrin: . I am open to any other suggestions and will most likely go ahead and replace the wires just in case.

 

[steveX]

How does the car idle in park? I can see the engine not making any boost because the cylinders are not firing in order. You should scan can see of you get a DTC300 code. are you reving the car while driving? if the car idle perfect in park, i will rule out the intake gasket as the cause.

 

[JanesGS]

Steve,
Thanks again for your responses. My wife is picking up some new plug wires as we speak (type). The car idles ok not perfect, most likely due to 110k miles, but in park its ok. I was reving the car in park and right at 4k and it sounds like it is rev limiting and or missing at 4k. I am trying to exhaust all of the possibilities before I take it to a garage. I do not have a scanner to read the codes, but wouldnt the check engine light come on if something was amiss? I'll let you know if new wires sort it out, if not maybe the fuel pump is going out?

 

[eastwoodad]

You probably already know this and it may not have to do with the problems you're experiencing, but these cars do have a rev limiter when the car is in park, right at 4k. So you could hold your foot to the floor in park and it will rev limit right at 4K. This doesn't sound like its the problem because you are experiencing lack of boost and a miss while the car is in gear, but hopefully this won't cause you to mis-diagnose the problem.

 

[JanesGS]

Okay,
I feel like a dope and maybe I should pay more attention to my wifes car. Yes I figured out 4k is factory rev limit in park. So heres where im at. The car seems like at normal driving the car even going up a slight inclines starts to miss and run jerky like, however if I put my foot into the gas it seems to go away. I have changed the fuel filter,map sensor,maf sensor,plug wires, plugs, and one coil. I changed the coil today be cause it flashed a code #4 miss. Just in case I also cleaned K & N air filter. Thanks for previous feedback, i'm gettin ready to take it to a shop, I am running out of possibilities. I appreciate any additional feedback.