Re: Miss under pressure....

[Shannen Durphey <shannen@grolen.com>]

I chased vacuum for a while.
Vacuum lines source from the tb and plenum.  All were connected, but
removing and plugging them one at a time did not help.  Vacuum leaks
to outside air were checked by (a) using carb cleaner and acetone
based brake cleaner sprayed on suspect areas, and (b) disconnecting
the power brake line and applying air to the manifold while pouring a
soapy water solution on suspect areas.  Vacuum leaks into the lifter
galley were checked by removing pcv and breather tubes and ducting
propane into the pcv hole.  I really tried to find a problem, as I was
sure that lack of fuel or excess air was the answer.
Shannen

JTesta1966@aol.com wrote:
> 
> In a message dated 6/28/00 9:35:38 AM Eastern Daylight Time,
> sabatine@epix.net writes:
> 
> << The car had a pretty severe miss at idle, seemed like a lean skip.  No
>  >ign. scope available.  Replaced plugs, ohm checked wires, bench tested
>  >coil, changed cap + rotor.  Replaced coil for testing.  Injector
>  >balance test showed no problems, fuel pressure was at the low end of
>  >specs but matched several other cars on the lot.  Richening engine
>  >seemed to help, but not cure.  Problem was apparent at all temps but
>  >worse with heat, maf connected or no, open or closed loop.  The miss
>  >was bad enough that the ecm would sometimes increase idle speed at a
>  >stoplight, making the driver work to keep the vehicle stopped.  The
>  >problem went away as loads and rpm i >>
> 
> Is it possible you missed the vacuum line that goes to the cliamate control?
> Or a vacuum line that comes off ONE runner in the intake tract somwhere?
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Jim Testa                                                         TType86 on
> #BuickGN