On Mon, Nov 16, 2009 at 5:57 PM, pdooley <psdooley@verizon.net> wrote: > CIS is pretty robust. Works great up until you get junk past the filter and > into the system. > The control pressure regulator clogs, injectors start spraying weird > patterns, and God help you if the fuel distributor fouls. > Then you have things like the accumulator that leak fuel underneath the > vehicle and those #@$%& copper crush washers everywhere, pretty much > one-time use only. > However the CIS fuel pumps hold up well; I had a 22 yr old Scirocco with the > original. > > If you ever look closely at a CIS system you can really appreciate the > precision machine work and quality of materials. The airflow housing is a > beautiful thing with glassy smooth pivot bearings, machined aluminum funnel > and anodized counter weight. The fuel distributor flow orifices are laser > cut and the plunger is such a precise fit that pressurized fuel doesn't leak > out even with no rubber seals or o-rings. > > CIS is kinda like the last steam powered locomotives- brilliant masterpieces > of mechanical ingenuity, though hopelessly complex and cumbersome. > > Some would argue modern EFI is hopelessly complex, but not from a mechanical > point of view. And with OBD, a simple scan will find most problems and let > you know about it in plain English. > Diagnosing CIS problems OTOH takes a little skill. > >
See know you've got me tempted to pick up a used fuel distributor and airflow housing just so I can oggle them! Great info Pat. I always assumed that CIS was simpler. Electrically yes, but I can appreciate what you mean about it being mechanically complex. I guess it depends on POV and what one has for experience servicing a given system. i.e. I've never laid hands on any CIS component, let alone the stock Digijet or Digifant on the WBX, but even with my limited knowledge of the Motronic EFI I'm running on my Westy, I'm confident that I can deal with. And I must say that OBD is handy. Neil.
-- Neil Nicholson '81 VanaJetta 2.0 "Jaco" http://tubaneil.googlepages.com/ http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines |
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