Having replaced a fuel pump (external) I found that the car wouldnt idle
after it warmed up. I asked numerous questions to this board and got an
idea as to how the system worked.
The problem is fixed. I baypassed the air bypass solenoid with a heater hose
with a 90 deg valve inserted in the middle so I could adjust the air flow by hand.
After getting the valve set to where the car would idle when warm I let it sit and
removed the inlet hose from the solenoid. I then started the car (cold) and with
a mirror and flashlight I watched the solenoid as the car ran. When it was cold
there didnt seem to be any movement at all so I assume the coolent temp switch doesnt cause the ECU to talk to the solenoid ( ASSUME is the key word). However,
as the car warmed up I could see movement in the solenoid but it was very slow to
respond (had some crud in it).
At this point I knew 3 things.. the solenoid was alive (kinda) the ECU was alive and the throttle body idle switch was being triggered and worked.
I pulled the solenoid and soaked it in gas. Just the bottom part not the electrical portion. After soaking I cleaned it out with a rag nd then hosed WD-40 through it to flush the crud. Then I applied some silicon spray as WD-40 really is not a lube... more of a cleaner as it has petro in it along with the light oil base.
I reinstalled the valve and ran it around the block to work the valve. Now it sits
and idles.. searches a bit but I am pretty sure the in tank fuel pump assembly needs TLC. The bung nut for the assembly was cleaned and then I soaked it overnight in WD-40... took several minutes of light tapping on a screwdriver to
get it to move but sprayed more WD in there and worked at it. It is now ready to
come out. A project for later today . Fun fun!
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vw bus site - http://www.geocities.com/vw_bus_74/index.html