engine dieing at idle BPV ISV Fuel pump? '91 200 20v

SuffolkD at aol.com SuffolkD at aol.com
Wed Jul 21 10:30:18 EDT 2004

While the BPV may also contribute to it, I've found (in my case) that the ISV 
Idle Stabilization Valve is the reason. Its easy to figure out.  Towards the 
firewall end of the motor at the top of the intake tract is the ISV.  
Disconnect the connector and see if it continues to stall.
Symptoms are stalling after first starting the engine:  having to use the 
throttle to maintain idle.  It will only throw a code when it really 
malfunctions:  Increase the throttle and sluggish acceleration follows.

You can take it out and test it (the solenoid inside) with a 9 Volt battery.
Most people clean it with throttle body cleaner or carb cleaner.

I suspect the buzzing fuel pump is a separate issue, however if its 
contributing to the stalling, your due to be stranded by the side of the road very soon 
as the fuel pumps worn out.  I've seen them buzz from 3 months to 3 
Keep the tank full of fuel.

Some mentioned adding "mystery oil" (from the FLAPS stores) to the tank.  No 
BTDT and I'm a bit skeptic.
HTH - Scott by BOSTON

From: "Dave Defferding" <>

> Symptoms are classic for a failed TBV (turbo bypass valve) to me.   Check
> Scott M's site regarding replacement.  Not too expensive and quite easy to
> do.
> Regarding likely fuel pump noise-- when in California in warm conditions
> (~90 or better), our pump buzzed as well.  I believe it's their gas mix down
> there, as symptoms disappear up in the Oregon/Washington area.  I've heard
> some have tried adding a small amount of auto trans fluid to the tank to
> help lube the pump.
> good luck.
> Dave D
> '91 200Q
> ----- Original Message ----- 
> From: "Jeremiah Curry" <>
> > Howdy all,
> >
> > Lately my '91 200 20v has been dying while I am coasting up to a red light
> > with the clutch depressed.  I don't notice till I go to start up again or
> > look at the tack.  If I notice while I am still driving I can release the
> > clutch and the engine starts fine, if I am stopped the starter starts the
> > engine no problem.  I noticed this afternoon that there is a unusual
> buzzing
> > sound coming from somewhere by my rear wheel wells, is this the fuel pump?
> > and can that cause these symptoms?  Don't know if this matters, but it is
> > ~95 degrees and humid.  Other than that it runs great.
> >
> > thanks in advance,
> >

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