[urq] Warm up regulator mod question

Phil Payne quattro at isham-research.com
Mon Dec 1 11:05:50 EST 2003

> Engine is running lean, therefore stumbling and not enough vacuum to raise
airflow plate which is flapping around.  He has lots of experience with old
VW rabbits, etc. and said that they used to mod the warmup regulator a
bit.  Apparently there's a press fit plug in the regulator that rides
against a bimetallic spring that sets the static cold pressure.  The
heating element in the warm up regulator changes the state of this spring
and pressures increase/flows decrease.  They used to press the plug further
into the regulator to reduce cold pressure and improve cold running.

> He claims it's something that the vw repair people realized and bosch sort
of knew about.  Instead, bosch wants to sell you a new warm up regulator.

If the warm-up regulator is defective, it will cause incorrect fuel pressures and these can
cause all sorts of problems.

However - the proper approach is not to guess but to measure - in ths case the fuel pressures.
Quite easy to do.

Otherwise you run the risk of buying a warm-up regulator that you don't need, finding it
doesn't solve the problem, and then finding yourself standing in this guy's shop with another
pocket full of hard-earned dollars.

  Phil Payne
  +44 7785 302 803

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