New supercharger

[turbo]

The dealer replaced it in a '98 Park Ave. Now there's an air type of leak. It's hard to hear at idle. You don't even have to mat it. If you just get into it a little, it has a gurlgling type of sound. You can hear it easily at any rpm from 2200 up, when you get into the throttle. It feels a little down on power.

The car now idles at least 100-150 rpm higher.

Is there a gasket between the SC and the intake? Does it seem like the guy left it out, damaged the gasket, didn't use some sort of sealer on it, not torque it properly?

Is there anything else in the assembly that would cause this new problem, since they worked on it?

What can I tell them to look for?

 

[disco stu]

Take a can of carb cleaner (make sure it is flammable), and spray around suspect areas (manifold, vacuum lines, etc) and see if it affects idle. This is the best way to find a leak, besides a smoke machine.

 

[JasonGS]

Originally posted by turbo
Is there a gasket between the SC and the intake? Does it seem like the guy left it out, damaged the gasket, didn't use some sort of sealer on it, not torque it properly?

That sounds like the cause of the problem. Yes, there is a gasket between the SC and intake. My guess is the old gasket was not properly scraped off before reinstalling the SC. You could also check the torque on the SC bolts... they s/b 22 lb-ft.

 

[turbo]

Thanks guys!

Here's what I did. Found the factory manual. Checked the torque on the SC nuts, they were in spec.

The top nut on the throttle body that attaches to the sc has a casting line that goes to the rear of the car. But at about nut level on the throttle body toward the front of the car there looks like a crack and not a casting line. It is only on the tb surface that faces the front. It doesn't go around to the nut.

I'm guessing that until you get into a little boost the leak isn't detectable. I did the soap, nothing. Tried carb cleaner, not really certain. Only a bit left in the can. I think it would have to be under pressure, unless the crack is a biggie, to detect it at idle.

Here's what I'd like to know before taking it back to the dealer IS THAT ON ALL THROTTLE BODIES OR IS IT A CRACK?

 

[Lee_Burough]

Do you have a scan tool?

A vacuum leak will show up as a high BLM value at idle....Don't ask me how I learned that

HTH

leeb

 

[turbo]

Originally posted by lburou Do you have a scan tool?

A vacuum leak will show up as a high BLM value at idle....Don't ask me how I learned that

HTH

leeb

Yep, but it's in the turbo car. I'll just take it in tomorrow. They'll have to fix it, since it wasn't doing that when we took it in.

I've never let anyone mess with the turbo car and since I don't drive the supercharged one much, I decided to close my eyes to whatever problems it may develop.

I just wish I could find out if that is a casting mark or a crack, so I could talk to them with a bit of knowledge. I might have to go to another dealer's parts dept. and check a throttle body to see if they come with or without whatever that mark is.

Sometimes, if you don't know, they'll tell you that's the way they come from the factory.

 

[kshef]

i'm not sure exactly where you are talking about...but i looked my 99 over and couldn't find a crack
i do see some casting marks