Decel cutoff valve wiring hookup
Navistrpwr at aol.com
Navistrpwr at aol.com
Fri Mar 21 17:26:40 EST 2003
A few weeks ago, I finished installing a 5-speed tranny in my fwd '86 5kT.
The car runs wonderfully strong now, especially with the addition of the 1.8
bar WG spring and ECU. I only have one more part to install that's giving me
some problems - the decel fuel cutoff valve. I'm running the car with the
valve installed, but I can't seem to get the wiring figured out. I found a
connector in the engine bay that comes out of the same harness as the CIS
frequency valve duty cycle connector. I assumed that this connector is used
for the decel cutoff valve on the manual trans cars. One of the pins on the
connector has 12 volts present, as shown by both a multimeter and by
connecting a test light to this pin and ground. The other pin connects to
pin 4 on the ECU. I verified this by doing a continuity test and got a
resistance value of .2 ohm. Interestingly enough, my multimeter displays 12v
when I connect it between this pin and ground, but the test light will not
light up when connected in this same manner. However, when I do connect a
the test light, I notice a very slight change in engine rpm. I think this
has something to do with the ECU setting the frequency valve duty cycle to
40%.
When I connect a test light across the pins on the connector, raise the
engine rpm above 1200, and quickly shut the throttle, I do not get a voltage
reading of 12v. Hence, the decel valve isn't getting a signal. The throttle
switch is working correctly, as I just replaced it last year and repaired the
wiring. I don't know what the problem is. Does anyone know if the manual
transmission ECU is any different from the one installed in the automatic
vehicles? I can't think of what else the culprit would be. Do I need to
install an extra relay somewhere, or connect another wire to a pin on the
ECU? I notice that one of the wires coming of the ECU was cut at the
factory, but I don't know what it's for. This is in addition to the pin 6
connector which I cut myself during the tranny install, which is for the
brake circuit / fuel pump cutout on the automatic vehicles.
Thanks in advance,
Ray McCarthy
navistrpwr at aol.com
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