From 914 page: WARNING! FUEL INJECTOR CLEANING!

[Toby Erkson <Toby_Erkson@ccm2.hf.intel.com>]

---------------------------- Forwarded with Changes ---------------------------
From: Owner-timjones@giza.estinc.com at SMTPGATE
Date: 2/10/97 1:11AM
*To: timjones@giza.estinc.com at SMTPGATE
Subject: WARNING!  FUEL INJECTOR CLEANING!
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This is sorta long but I was wondering if anyone who regularly works with 
FI has any comments on what to use to properly clean the injectors.
     Toby Erkson
     air_cooled_nut@pobox.com
     '72 VW Squareback 1.6L modified to 2.0L
     '75 Porsche 914 stock 1.8L
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Subject: WARNING!  FUEL INJECTOR CLEANING!
Author:  Owner-timjones@giza.estinc.com at SMTPGATE
Date:    2/10/97 1:11 AM


HyperNews notification.  Reply via:
  http://www.estinc.com/HyperNews/get/forums/trouble/133.html

Greetings to readers of Tim's 914 Fan Web Page:

  I would wish that others might profit from my screw-up.  I am
not absolutely certain of the failure mechanism, but I have now
had my third fuel injector failure in the span of a week, and it
looks as though I will be replacing all four.
  As near as I can tell, this is because of a cleaning technique
that I employed some time ago. The technique was as follows:

  I operated the injectors on the bench using a bench power
supply, and while operated (valve electrically held open with
application of D.C.), I sprayed Gumout carburettor cleaner
through the injectors.  They were observed to operate normally
at this time, including normal on-off valve action, and good
spray cones resulting as the carburettor cleaner was sprayed
through them.  No attempt was made to flush the injectors with
anything after this procedure, and they were put away wet.
  Some months later, upon trying to fire up the car, I had two
injectors fail, which were replaced with two new ones.
Between shipping delays and work, the next opportunity to
change the injectors and try again was approximately a week
following the first time.  Upon starting the car, it was
discovered that one of the previously working injectors had
also failed, in like manner as the first two.
  The failure mode is that there is no characteristic "rattle"
when power is applied, and the injector valve mechanism is
stuck.  The stick point may be either entirely closed (no fuel
flow) or partially closed (considerable leakage, but not full flow).
  The conjectured failure mechanism is chemical damage to
internal plastic parts (possibly valve seat?) by the carburettor
cleaner.
  This has turned into a $280. "oops", allowing for an average
market price of $70. per injector.
  I have since consulted with a friend who owns an airplane,
and he tells me that the ONLY thing that is permitted for use
as a cleaning solvent on aircraft fuel injectors is 90+%
isopropyl alcohol.

  Therefore, my conclusion must be:  DON'T clean your fuel
injectors using ANY of the popular carburettor cleaners that
come in spray cans!
 USE NO EXTREME SOLVENTS WHATSOEVER!!  The aircraft
injectors mentioned above are mechanical types, not
electronic as used in the 914, therefore I am not even sure that
alcohol is safe for our use.  The only thing that we know for
 sure that is safe to introduce into the injector is fuel; therefore,
I would recommend that ONLY CLEAN FUEL be used as an
injector cleaning solvent.

                                Good Luck,
                                ...