96 850T black smoke and power loss

seacrow · Post by **seacrow** » 24 Sep 2009, 06:19

Glad I found this forum! This problem is weird - tons of black smoke and engine lag, but it's intermittent. Some days no problem. If I drive up a hill, problem is worse. Also, turbo isn't engaging. Is this a dirty sensor issue? Thanks for any tips.

Craigd2599 · Post by **Craigd2599** » 24 Sep 2009, 06:41

Is the engine "hunting"? Cycling up and down at idle? Try cleaning your MAF sensor and make sure to clean the connector first.

FCPEURO · Post by **FCPEURO** » 24 Sep 2009, 10:32

I would take a look at your fuel pressure regulator. I had an old Chevy that did this and it was the FPR.

Post by **E Showell** » 16 Oct 2009, 07:50

Had a similar problem with wife's 96 850 normally aspirated. Took quite a while to diagnose. Local independent was getting codes for bad O2 sensor. Replaced sensor and no change. Dealer diagnosed in 10 min. and fixed. It was a problem that required removing the manifold to access parts. I can't remember the exact nature of the fix and we have since sold the car, but I will try over the weekend to get access to maintenance history from new owner and will post repair if I do. No guarantee your problem is the same, but it couldn't hurt to check. Good luck, Evan

Post by **E Showell** » 16 Oct 2009, 08:01

I called the dealer that did the work. The car was throwing fuel trim codes. They replaced the vacuum hose under the manifold, replaced the vacuum valve and cleaned the throttle body and it was good to go after that. You might want to have these items checked. Good luck and let us know if that was the problem.

Post by **E Showell** » 16 Oct 2009, 08:45

Forgot to add, car was getting absolutely horrible gas mileage -- somewhere around 15 mpg -- while this whole thing played out.

Post by **jblackburn** » 16 Oct 2009, 13:16

Is the engine "hunting"? Cycling up and down at idle? Try cleaning your MAF sensor and make sure to clean the connector first.

+1.