CIS to Digifant 2 conversion

[ydrogs at gmail.com (Gordy Stedman)]

So after finding a lot the the missing pieces this weekend at the junkyard I
decided to do a write up on how Sean & I are going to convert my 2.0l
3A-1.8l JH CIS with knock engine over to Digifant 2 pulsed injection.  One
major note is that we installed a VW knock sensor system previously which
you need to do for this conversion.  I suggest going here
http://www.driversfound.com/scirocco/ and look under "Tech Tips" and go to
"Knock Sensor Install".  All the parts for the knock sensor system can be
found on the vehicle you get all the Digi2 stuff out of.  The knock sensor
system in stand alone like it is on CIS-E systems so if you install Digi2 on
a 16V that step is already done.  Also a note that the Digi2 system uses the
same ignition control module so you will already have that also.  Another
thing is to make sure your exhaust system has a bung for an O2 sensor if you
are not using one currently or you will have to weld one in.

Here is a photo of most of the parts
http://picasaweb.google.com/ydrogs/DIGI2CONVERSION/photo#5136696519914064546.
We got lucky and found that adapter that goes on the intake side of the Mass
Air Flow sensor which will allow for the tossing of the A2 air box and go to
a cone filter air intake.  Our original plan was to adapt everything to the
JH head and the A1 intake system.  We decided to use the A2 Digi2 intake
manifold since the air intake system would be better suited on the
passenger plus there would be more room for the filer and MFA.  This would
also let us use the original vacuum routing for the Idle Stabilizer Valve
and the location of the connections on the wire harness to the MFA and the
Throttle Body would not have to be lengthened.  It would have been possible
to use the scirocco intake manifold so this step is just for our personal
choice

We are still not sure if the JH head will work with this system due to the
air shrouding of the CIS injectors.  The vacuum attachment nipple on the
back of the head needs to be removed so the fuel rail can be bolted down in
that spot.  The Digi2 does not use air shrouding on the injectors so
plugging this hole will be necessary.  We will research this more tomorrow.
I do have a Digi2 head from the engine I got in NM this summer so I might
just swap it out, but then I would have to get head bolts, head gasket and
switch out cams.  Plus I do not know if the head is warped so it might have
to go to the machine shop.

We purchased the electronic injector seats (PN 037 133 555 A) and new o-ring
seals (030 198 031).  The temp sensors, fuel injectors and MFA were checked
for resistance per the Bentley and they were good.  The harness was checked
for continuity, broken wires fixed and new O2 sensor was installed.  We
purchased a cheaper universal one but had to make our own connector with
parts from Radio Shack since we did not have any spare stock connectors.

Got to sleep so I will post more when more happens.

-- 
Gordy
MK1 x 4