Throttle Plate - PFI: Adjustments

Fig. 60 Primary Throttle Linkage Rod:

Fig. 61 Adjustable Throttle Linkage Rod:

1. Basic throttle setting
a. Adjust push rod for #5/#6 throttle valves to 97.5 ± 0.4mm (3.838 ± 0.016in).
b. Adjust push rod for #1/#2, and #3/#4 throttle valves to approx. 100mm (3.937in).
c. Mount a dial indicator to a fixed mounting point (like a valve cover stud) with the necessary adapters, so that the gauge pushes against the throttle linkage actuating lever, at the back of the engine.
d. Shorten the push rod for #1/#2 cylinders until the gauge needle begins to move, then the same for the #3/#4 cylinder rod. (All three throttle levers should have equal load on the idle stop).

Fig. 62 Full Throttle Measurement:

2. Full load stop.
a. Remove airbox to gain unobstructed access to the throttle plates.
b. Open throttle valves until the plates are parallel to the direction of air flow.
c. Adjust the full throttle stop until it makes contact with the operating lever.
d. Adjust the distance from the top of the throttle plate to the upper edge of the throttle bore to 21.7 ± 1mm (0.854 ± 0.039 in) with the throttle stop screw.
Note; Do not change the adjustment of the push rods for this adjustment.
e. If the specified distance is not possible on all throttle valves, replace necessary components.

3. Synchronization
a. Set idle speed with idle speed screw, located in the throttle housing for cylinders 3 and 4, under the cold start valve.
b. Remove vacuum port caps from each intake tube, and connect a set of matched vacuum gauges or mercury tubes.
c. With the engine running at idle, each cylinder should differ by no more than 5 mbar.
d. If synchronization is necessary, remove the anti-tamper cap from the appropriate adjustment screw(s) (beside each vacuum port), and adjust with a 7mm socket.
e. Install new anti-tamper caps, check idle speed, and reset CO if necessary.