Can't find turbo boost line location

[dmastroluca]

Looks like the plastic line was melted in the engine compartment, and for the life of me, I can not find where it connects to the engine. I looked all around the turbo with no results. Has anyone replaced/repaired this line?

[dennis45]

Originally Posted by dmastroluca

Looks like the plastic line was melted in the engine compartment, and for the life of me, I can not find where it connects to the engine. I looked all around the turbo with no results. Has anyone replaced/repaired this line?

Look around the Intake Manifold.

[BFlinn181]

Check the website of the gauge brand for installation instructions. Some boost gauges connect to the intake manifold, some to the inner cooler or lines running to or from it. Some use a hollow bolt into the intake manifold. Good luck and find the connector, you're losing boost through the melted connection.

[Mike Canter]

It will be a small brass fitting screwed into the intake manifold and not into the turbo.

[dmastroluca]

Ahh, I was looking on the wrong side. Thanks.

[monacojim]

Dan, the melted line is an indicator that you may have a cracked exhaust manifold. You might want to check it out.

[dmastroluca]

Would that cause lower boost psi readings? On my ScangaugeD, the max boost I am seeing under full load is 22-23 psi.

[dennis45]

Originally Posted by dmastroluca

Would that cause lower boost psi readings? On my ScangaugeD, the max boost I am seeing under full load is 22-23 psi.

A cracked exhaust manifold will cause a drop in boost pressure. Normal manifold pressure should be in the range of 24-25 PSIG. You will be able to hear a pronounced Popping Sound when you first start the engine if it is cracked.
You can also look at the manifold between the #3 & 5 cylinders toward the back. The crack will be blackened and quite visible.

[Mike Canter]

The broken boost gauge plastic line will also cause a loss in boost pressure.

[dennis45]

Originally Posted by Mike Canter

The broken boost gauge plastic line will also cause a loss in boost pressure.

Are we certain the plastic line is for manifold pressure? If it were, would he still see 23 PSI on his scan gauge? Maybe a photo from the OP of the plastic line might help ID the issue better.

Is it possible the plastic line is off the Air Filter Minder?

[BFlinn181]

If you start it and check, you should more easily find the connection, it will be blowing air at a pretty good rate.

[Mike Canter]

Yes I am certain the small plastic line to the intake manifold is for the boost gauge. The air filter reminder reads vacuum on the other side of the throttle body between the air filter and throttle body. My guess would be about a two to three pound loss of boost through that broken line.

You w I'll not get much air out of that broken line at idle. There is hardly any boost out of a turbo at idle. Maybe even a vacuum on that line at idle.

[dmastroluca]

Originally Posted by dennis45

Are we certain the plastic line is for manifold pressure? If it were, would he still see 23 PSI on his scan gauge?

I traced the yellow plastic line to the back of my inop dash boost gauge. I am reading the boost from the ECM using the scangaugeD. That is one of the reasons why I bought it. I wanted to make sure my turbo was working when I purchased the coach....I addition to learning I am getting 8-9 MPG pulling a Caddy across the Mojave desert.

[dennis45]

If you're seeing 8_9 I doubt you have a cracked manifold. Plug the fitting in the manifold and go with the ScanD