[Vwdiesel] Cold start Knob ----( But WHAT does it DO ? )

[H .Hagar]

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When I got the first Rabbit (1980 on special) , it became painfully clear t=
hat it would not start if not plugged in and cold start knob was not pulled=
 out.  Not having an owners manual , and never having driven a Rabbit befor=
e I phoned a Stealership ---Capilano VW in BC Canada. . First I was on "hol=
d" listening to a song and dance routine about the factory trained expert m=
echanic's and bla bla bla..  Finally the service department came on the pho=
ne. Sir what exactly does the cold start knob DO ?.  Answer : It gives the =
engine more fuel for starting. ------  I then asked HOW does it do that ?. =
    --- answer : there is an extra injector.       My eyes were starting to=
 glaze over.       I asked all over the place , never got an answer I liked.
Finally I put on my hillbilly coveralls and set to find out. Dissected an o=
ld pump , now I know exactly what it does or does not do.On 1980 to 1984 Ra=
bbits with Bosch pumps , here is what is does.  It is a very short stub-sha=
ft with a camplate pushing on timing piston. No valves or needles or anythi=
ng else. Pushing on piston advances the timing of injection. So what if you=
 forget to push in after starting and drive from Waterville to Miami non st=
op ???.   Will it damage anything ???.      Not to worry it does not do no =
harm in normal driving. After about 2000 rpm the piston has moved away from=
 cam , and Knob has no effect what so ever.
Here is what VW book  WSA 561.506.23A  say (1984 Rabbit Volkswagen owner's =
Manual.).  (I need permission from VW to tell you this)    Pull out cold st=
art knob at any outside temperature. At temps above  minus 18 C do not depr=
ess accelerator pedal. Below  minus 18 C  depress pedal while cranking and =
release slowly as engine begins to run. About 2 minutes after starting full=
y push in knob.    So what does it all mean ??? ,  it means that you have t=
o experiment and find what works best for any one machine. Remember when I =
suggest something it has to do with OLD volks..Sagged out tired  everything=
.Volks in top shape do not have starting problems.  I have not used cold st=
art lever all summer.        Thanks to finetuning.       Hagar.
PS: Mike Smith  please read the archives , it is all there .As a HAM you ca=
n hook up an indicater bulb hooke directly to glowbuss.And clean all connec=
tions on starter circuit.Test battery.

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