(112k on Bonneville) Approx. 15k ago I got the supercharger rebuilt. I did all the work myself except I had texas tbirds press out and replace the bearings. The Bonneville ran fine afterwards. A couple of weeks ago a problem appeared that I cannot track down. The car begins to "shudder" or "chugg" when I approach half boost. If I accelerate slowly this symptom appears at greater boost level. I cannot source a problem.

Another problem is the coupler appears to be failing again (the rattle when running which goes away under acceleration and play with the belt off). This seems to be an extremely short lifespan for this coupler. The oil level in the SC is fine. Does anyone know of a reason as to why this would happen?

Any help would be greatly appreciated. Thank you. Quest :(

In experience with my car, I've had a similar shudder caused by two things.

1: Dying fuel pump. It would lose pressure under high demand when it got warm.
2: Dying tranny (TCC solenoid) and did it cold and warm.

Could also be a miss. Have your fuel pressure tested with the vac line off the FPR when the car is nice and hot to try and rule out #1.

I think #2 would give a code. Have it scanned or do the paper clip trick found in techinfo. The TCC code might not turn on the SES light, I can't remember.



The coupler could fail early, I suppose. I don't know what specifically would cause early failure, other than a weak coupler.

With the belt on, can you grab the belt and move it so any pulleys rotate some? If so, it could be the harmonic balancer dying. Look for cracks in the rubber on the crank pulley.

Thank you for the reply. I forgot to mention there are no codes posting and I did replace the fuel filter. The symptoms did not change. I will get the fuel pressure tested, but what is the FPR ?

Fuel pressure regulator. It is on the fuel rail, tucked behind the throttle body. You can pull the vac line off it straight up. And if there is any fuel in the line that means you need a new FPR.

There are some codes the PCM will store that won't turn on the SES light.

Indeed. Code 39 - Torque Converter Clutch Problem - will not turn on SES light. I should know this as my trans is now on it'* deathbed and displays this constantly, even after trying to clear it.

willwren seems to know a lot about these things, maybe you should PM him?

Have you checked your catalytic converter? Sounds like that may be the issue mine sure felt really werid when it was going and took alittle bit to track down.

Ed