:help2:
Like the title says, there has been a sudden and drastic change in the van. Yesterday, there was a coolant leak so we took it to a Chevy dealer and they found that the water pump was leaking and put in a new one. They then took it on an 8 mile test drive.
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When I got the van back, it was suddenly way different! There is WAY less power and lots of black smoke. Before, the only smoke would come on start up, just one puff right in the beginning. Now, there is a very significant loss of power and under heavy throttle, there is a lot of black smoke coming out. I was planning to take a long trip in it so if there’s a problem, I need to know. It’s such a huge difference, it seems like it has to be a serious problem, unfortunately.

Anyone have any ideas? I'm guess it has to be an air problem? Maybe a problem with the turbo? An intake air leak? Exhaust gas leak?

It has 65,000 miles, recently changed oil, fuel and air filters. The only modification ever is the stock muffler is removed. I replaced the lift pump about 1000 miles ago also.

I feel kinda ashamed. :o: This is only my second thread and the other was about a problem too. Sorry to be freeloading so much.

Edit: I just remembered, the motor is also a lot lowder than before. About the same at idle but a lot louder under any acceleration.

Sounds to me like the mechanics forgot to connect the vaccuum lines between the vacuum pump, solenoid, and wastegate actuator for the turbo.

But I don't know if you'd find those parts in the tupical places that I know of, since it's a van. Follow the plastic line coming from the vaccuum pump. Should lead you to the solenoid. Then follow the other line coming out of the solenoid going to the wastegate actuator. Is everything connected?

Sounds like a problem with the wastegate control system. Could be either the vacuum pump, vacuum solenoid, vacuum actuator or the actual wastegate flapper. On a more sour note, it could be a blown turbo, but i doubt it.

You need to remove the doghouse and look at the turbo wastegate control. At idle, the wastegate should be firmly shut. If not, remove the hose and check for vacuum. If none, follow the orange hose back to the vacuum solenoid, and check for vacuum from the vacuum pump. If the pump is not putting out vacuum, you can A: replace the pump, or, B: install a spring wastegate control such as the turbo-master or hand fab one yourself.

-Daniel

Hopefully just a case of slippery fingers under the hood, and not "I'll get him back in here" deals. Wastegate controller 'noid is on the right side (passenger side) under the dog house. Chances are, that's not where your problem is. It's up around that water pump area they were working in. The vacuum pump is up there in that "I can see it, but just can't reach it location." Either a connection that was forgotten, or broke off, for the vacuum system.

You are not a free-loader. We all around here love to help others out with their stuff. It's a much fun for us to help, as it's a relief for others to get answers. Enjoy.

I feel kinda ashamed. :o: This is only my second thread and the other was about a problem too. Sorry to be freeloading so much.

Edit: I just remembered, the motor is also a lot lowder than before. About the same at idle but a lot louder under any acceleration.What's the idle speed?
The vacuum lines are a plusable senerio for smoke and low power but the coolant temp sensor (on the water crossover) getting unplugged will make it smoke like a train too.

Are you kidding? Freeloading? I'm happy there's someone out there seeking a path to mechanical nirvana.

Chances are...It's up around that water pump area they were working in. The vacuum pump is up there in that "I can see it, but just can't reach it location." Either a connection that was forgotten, or broke off, for the vacuum system.I'm with Knkreb on this one, the vacuum hoses are easy to knock off or break, especially the large one that connects directy to the vac pump. Also, on vans unlike the pickups, the Vac line tees into your blower motor and is used to operate your vents. A break on this line will cause the same problems.
Using that to your advantage, try to cycle your blower in the cab from defrost to panel to floor. If it works, then your vacuum pump works and the supply line to the WG controller is also in place and the lines are good and you have a problem with the WG controller, the actuator or the turbo. If it doesn't then your problem is one of those aforementioned things.

A problem that suddenly occurs after some maintenance activity, can usually in some fashion be ties to the previous activity, cramped quarters, end of the day, long day and it's easy to overlook the simple. I also suspect someting in the vacuum arena either at the pump ar one of the lines, a small crack in the nylon tube could very well be source of the problem. If you don't see the obvious; as a test and test only driving normally not hotdogging it wire the WG shut , and see if the power comes back, if not then problem probably is elsewhere. As for freeloading, don't worry this is fun for us 6.5 addicts, no cure once hooked, your turn to contribute will come.

What's the idle speed?
The vacuum lines are a plusable senerio for smoke and low power but the coolant temp sensor (on the water crossover) getting unplugged will make it smoke like a train too.
Sorry, there's no tachometer so I have no idea about the idle speed. The only thing I know is that it sounds about the same at idle as it did before.

I'll take off that "dog house" in the cab and look at the vaccuum connections and the wastegate. I'll also try adjusting the HVAC controls too.

Wow, you guys are great! :thankyou2 Instead of a sick feeling in my stomach I have some hope!:bounce: I can't wait to go out and check all these things.

You might not have to fiddle with that crazy:banghead: doghouse. Look from the front side of the engine where the vacuum pump is at. Best bet, you're gonna find the problem there.

Take the Pass seat out first so you can take the doghouse all the way out.

Hey TDG, I don't have a passenger seat, I gotz a bus. So for me its:
:banghead:

This poor chap has got:
:banghead::cussing::duh:

Stick with the front idea if you can.

I'm not worthy, I'm not worthy!:hail:

The problem is fixed, gone, done! Yeah!!!

I looked under the hood but couldn't find anything significant, so I took the passenger seat out and took the dog house off. I then took off a heat shield and got a good look at the turbo and motor. Like many suggested, I started at the wastegate. Though I didn't know it at the time, the wastgate was all the way open. The controling arm on the wastgate went to this vaccuum diaphram thing, again like many said, and a hose going to a junction area where a few wires were connected and... there was a little white hose sitting there, not connected to anything! :jawdrop:A half second later, I found a black rubber part at this junction with a hole in the end!

I grabbed some 90* pliers and, in a euphoric state, connected the white hose. I started it up with the dog house still off and the wastgate immediately snapped shut, like some said it should do! I put everything back together and drove down to get some fuel. Immediately knew it was fixed.:D No smoke and the power is back.

A big, big thanks to everyone who helped me fix this.:thankyou2

This is the second time this forum has saved me. (The first time it was a broken lift pump.)