Injection Pump - Residual Quantity Adjusting
9231vw01
Group: 23
Number: 92-01
Date: March 31, 1992
Subject:
Injection pump with idle speed boost - Residual quantity adjusting
Model(s):
Jetta with engine codes ME & 1V From 1986 MY
The following will appear in the next update of the repair manual microfiche W42-001-131-F3.
Idle speed and idle speed boost, checking/adjusting
Injection pump with idle speed boost
1 - Idle speed adjustment screw
2 - Maximum speed adjustment screw
3 - Stop screw for minimum idling speed
4 - Stop screw for maximum idle speed (idle speed boost)
5 - Previous idle adjustment screw covered with a tamper proof cap (should no longer be adjusted)
Idle speed, adjusting
Note
The idle adjusting procedure has been changed. The old idle screw is covered with a tamper proof cap and can no longer be turned.
^ turn idle speed set screw 1 to adjust idle speed RPM's
^ checking value: 850 + 30 RPM
^ turning to right increases engine speed
^ turning to left reduces engine speed
If the idle speed cannot be adjusted to less than 900 RPM via adjusting screw 1 because the stop on the limiter screw touches it:
^ loosen bolt 3 (for low speed idle) and retighten
^ adjust idle speed at set screw 1 by turning linkage
^ 850 RPM
^ turn set screw up to stop for low idle and tighten
Idle speed boost, adjusting
Note
By placing the coldstart cable in the 1st detent, engine speed must increase by approx. 60 RPM. When the cable has been completely withdrawn, engine speed must increase to 1050 +/- 50 RPM.
The basic pump adjustment assures that normal idle speed can be adjusted within specifications, and when the coldstart cable is fully withdrawn; specified RPMs will result. If the idle speed cannot be adjusted as described, or if the increased idle speed cannot be obtained; perform the following basic adjustment.
If, after completely withdrawing the coldstart cable, engine speed is NOT within the specified value of 1050 +/- 50 RPM:
^ disconnect cold start cable to allow access to stop screw 4
^ loosen stop screw 4 and adjust engine speed to 1050 RPM by turning
^ re-tighten screw 4
Residual volume, adjusting
On injection pumps having an idle speed boost, idle speed adjustment screw 5 is covered with a cap and should not be adjusted; the adjustment is performed at the factory instead.
If the screw is adjusted the following may occur:
^ screw turned in = residual volume too great
In this case engine speed is too high and idle adjustment is not possible.
^ screw turned out (free play on adjustment lever) = residual volume will be too small
This condition can be recognized by long cranking time, delayed acceleration from low RPM's or jerking in all gears.
If any if these complaints apply; perform the following basic adjustment using screw 5 (residual volume adjustment).
Residual volume too small:
^ remove tamper proof cap
^ loosen adjustment screw 5
^ turn in screw until engine speed increases
^ as soon as engine speed increases; turn screw back 1/2 turn
^ tighten screw 5 and cover with a new tamper proof cap
Residual volume too large:
^ remove tamper proof cap
^ loosen adjustment screw 5
^ turn out screw 5 until engine speed stops decreasing
^ turn in screw until engine speed increases
^ as soon as idle speed increases; turn screw back 1/2 turn
^ tighten screw 5 and cover with a new tamper proof cap