GMC 1989 Light Duty Truck, Repair Manual, Page: 631 / 998

MODEL 220 THROTTLE BODY 6C3-7
3. Attaching screw assem blies, precoated with appro­
priate locking com pound to threads. (Short screws
are next to injectors.)
&
Tighten
• Screw assem blies to 3.0 N m (28.0 lb. in.).
THROTTLE POSITION SENSOR
Install or Connect
1. TPS on throttle body assembly, while lining up TPS
lever with TPS drive lever on throttle body.
2. Two TPS attaching screw assemblies.
&
Tighten
• Screw assem blies to 2.0 N-m (18.0 lb. in.).
3. Electrical connector.
4. Check for TPS output as outlined in Section 4 of the
Light Duty Truck Fuel and Emissions Manual.
IDLE AIR CONTROL VALVE
N O TIC E: S ince th e IA C valve was re m o v e d durin g
service, i t ’s o p e ra tio n s h o u ld b e te s te d e le c tri­
cally w ith th e I A C /IS C M o to r T ester (J -3 7 0 2 7 o r
B T -8 2 5 6 K ). H o w e v e r , i f th e v a lv e p in t l e is
e x te n d e d e le c tric a lly , it m u s t also b e re tra c te d
electrically. B efo re in s ta llin g a IA C valve, m e a ­
sure the d istan ce b e tw e e n th e tip o f the valve
p in tle a n d the m o u n tin g surface. If the d im en sio n
is g re a te r than 2 8 m m (1 .1 0 in ch es), it m u s t be
re d u c e d to p re v e n t d a m a g e to the valve. This
m ay b e d o n e e le c tric a lly u sing an I A C /IS C m o to r
te s te r (J -3 7 0 2 7 o r B T -8 2 5 6 K ) o r m a n u a lly b y
e xertin g firm pressu re, as s h ow n in figu re 11 o r
12, with a s lig h t s id e -to -s id e m o v e m e n t on valve
p in tle to re tra c t it.
Important
No physical adjustm ent of the IAC valve assem bly is
required after installation. The IAC valve pintle is
reset by turning the ignition “ O N ” for ten seconds
and then “ O FF” . The ECM then resets the pintle to
the correct position. Proper idle regulation should
result.
-►4-
Install or Connect (Figures 3 and 4)
1. IAC valve into throttle body as follows:
• Thread-m ounted valve — install with new gas­
ket.
• Flange-mounted valve — install with new lubri­
cated O-ring, using attaching screw assemblies.
Figure 11—Adjusting Valve Pintle — Thread Type
Figure 12— Adjusting Valve Pintle — Flange Type
N O TIC E: N e w IA C valves have b e e n re s e t a t the
factory a n d s h ou ld b e in s ta lle d in th e th ro ttle
b o d y in an “ as is ” co n d itio n , w ith o u t an y a d ju s t­
m en t.
Tighten
Thread-m ounted IAC valve assem bly to 18.0 N-m
(13.0 lb. ft.) with 32mm (1W ') wrench.
Flange-mounted attaching screw assem blies to 3.2
N-m (28.0 lbs. in.)