I'm trying to help a friend diagnose a problem with his 1991 Dodge Stealth Twin Turbo. ( it is bone stock )

Car runs smooth when the gauge reads vacuum, but as soon as the needle gets to 0 or goes +boost, the car just falls on its face. It does this in any gear at any rpm...

My gut tells me that it's a bad sensor, or a vacuum/boost leak. I've never owned a turbo car, so i figured I'd ask here.

Any suggestions of things we should check?

Thanks

 

im gonna go with a big boost leak, I know my car I got on it once and I forgot to tighten my throttle body coupler and it popped of and the car fell dead.

Jay

 

Thanks for the suggestion. I think we'll try to track down any boost leaks first. With twin turbos and air to air intercoolers, there's a lot of pipe and couplers to check...

 

do those cars have maf's? that was why mine shut down bc the engine was sucking in air and the maf was reading it.

Jay

 

Are you seeing any boost on the gauge or dont u have one hooked up? If not get a cheap one from autozone and hook it into a vac line somewhere so you can measure it. Im gonna guess like the rest of these guys that you have a boost leak somewhere and its dumping when under boost and overfueling.

 

Without a boost gauge or A/F, it will be tough to diagnose.

 

Boost leaks or maybe a bad FPR if its falling on its face from the transition from vac to boost

check out www.3si.org

 

The car does have a vac/boost gauge and it does indicate positive boost. Just as soon as the boost gauge reaches 0 and goes positive, it just runs like a dog and falls on it's face. It doesn't stall out though.

Unfortunately we don't have a A/F gauge...

Before posting here I did some searching on 3si.org and socal3s.com... Thanks for the advice all!

 

Sounds like you need to get it on a scanner of some sorts and see what the computer is seeing when you get on it.