Re: 5KS Acceleration Problem (?)

[Pcarselle <pcarselle@worldnet.att.net>]

Henderson Nuuhiwa wrote:
> 
> My '86 5KS is currently stumbling on acceleration when cold.  It starts fine
> (no problem with cold start valve) and idles perfectly (so much for ISS),
> however when the accelerator is depressed RAPIDLY the engine (when cold - not
> at normal operating temp) will stumble badly, and in some cases die.  Also, the
> response from the engine is delayed (depress pedal, nothing for about 3-5
> seconds, then stumbling, and also popping sound from the intake side) and this
> all occurs while under no load (in park).  On a VERY GRADUAL acceleration I can
> get the RPMs up to 4000+ without experiencing these symptoms.
> 
> After the engine reaches normal operating temps, the symptom disappears,
> (acceleration response is fine on a rapid - floor the pedal, and gradual basis)
> ......
> 
> Where should I start looking????
> 
> TIA
> 
> Henderson Nuuhiwa
> http://www.angelfire.com/NuCommIntl/index.html
> 
> '85 BMW 735i (her car)
> '86 5KS (my car)
> '88 5KS (for sale)

Henderson:

Sounds like a "very lean" condition when angine is cold. Insufficient 
fuel to match the air admitted to intake.
Check fuel supply items and pressures.
Check for vaccum leaks ( air volume excessive when cold entering imtake 
without proportional gas ) when cold
Check for operation of temperature senders to ECU.
Clean connector  from ECU to pressure regulator located at fuel 
distributor.
Good luck !
Pablo