MK2 Jetta: Digifant II ECU no power at pin 1
Hello,
I have a 92 Jetta (1.8 Gas 8v Digifant 2) that has died on me. Brief
history...this used to be an automatic but 2 years ago I switched it over to
a 5 spd manual.
Symptoms...will turn over and gets spark but no power to the fuel pump nor
injectors. I have tested everything...the fuel pump is good (bridged
terminals at both the fuel pump relay and at the digifant 2 ECU connector,
and even replaced the FP relay. I tested every connection at the Digifant
ECU and Ignition Control unit and they are all OK. I tested the hall sender
in the distributor, the coil, all switched voltages are present at the digi
ecu connector and ignition control unit and all pins have continuity etc.
Except, testing pins 1 and 13 of the ECU while actuating the starter does
not give me any voltage. There is continuity between pin 13 and the
starter\Ground, and I traced pin 1 back to the fuse panel where it enters a
relay stamped with 92 (part number 191 927 181). This relay is only found in
the automatics and serves as a safety to prevent the car from starting
unless it is in neutral\park etc...
I had a battle with this relay about a year ago when my Jetta died then. I
can't remeber all the details but I don't think it would turn over then and
I traced it back to this relay. I thought I was pretty clever and bypassed
it and fed the switched 12V from the ignition switch (50) directly to the
relays output going to the starter, but I spiced it in so the relay would
still get power to the "other" connections that may be switched at the same
time (if the relay was working).
So...that worked like a charm for over a year. Now the car is dead. After
doing some more snooping I found this page:
http://www.the152.com/modules.php?name=Forums&file=viewtopic&t=1920
Seems to be exactly what I did....yeah for me. However...apparently this
relay is also tied to the Digifant II ECU and hence my pin 1 of the ECU
connector tracing back to this relay (I think it also controls part of the
Digifant control unit (#3) relay or also called the power supply relay(?). I
am quite certain the power supply relay is good if I get voltage to pin 14
at the ECU connector (switched)
So, dare I test fate again....would I be safe to tap this wire from the ECU
pin 1 (cut at relay stamped 92) and tap it directly to the switched 50
coming from the ignition switch and feeding the starter? I have a Haynes
repair guide book at I found a diagram that shows the circuit with both the
manual trans and the auto and it is wired this way for the manual. I am
affraid to send a full current 12V to the ECU as the relay may have a few
attenuating components like resistors etc...but at the same time I don't
want to buy a new relay....relay vs ecu....any ideas???
Any guides on cutting this damn relay out altogether for those who have done
a tranny swap?
Jerry Lynds
date: Tue, 12 May 2009 04:13:24 GMT
author: Jerry
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