Fleetwood V8-368 6.0L VIN 9 FI (1982)
1.
Fast Idle, Ratcheting, Code 30: A low TPS voltage may cause a fast idle by allowing the throttle angle to reach the low TPS limit too soon,
preventing the ISC from retracting any more.
A low TPS voltage may also cause ratcheting when the engine is not running. Because the ISC must extend to the desired TPS value, a low
TPS voltage may cause the ECM to extend the ISC until it ratchets without ever reaching this desired TPS value.
B.
ISC Related
1.
Fast Idle, Code 30: ISC adjusted out too far. The ISC is unable to retract far enough to obtain the commanded RPM.
2.
Ratcheting, Code 30: ISC adjusted in too far. The ISC is unable to extend far enough to obtain the commanded TPS reading when the engine
is not running.
C.
Minimum Air Related
1.
ISC Inoperative, Possible Code 27: Minimum air screw is adjusted out too far. This prevents the throttle lever from contacting and closing the
ISC throttle switch. Under these conditions, the ECM does not use ISC for idle control. The ISC will not extend unless engine reaches the
"save stall" condition. Use of the DFI throttle switch test and status light will verify proper throttle switch operation.
2.
Minimum Air Adjusted Too Low: No affect on operation of the vehicle but could cause incorrect TPS setting when adjustments are made.
IV. ISC-TPS ADJUSTMENT PROCEDURES
The symptoms above are the only symptoms that indicate misadjustment of the ISC or TPS. If ISC or TPS misadjustment is suspected, verify the
following conditions exist before checking or adjusting the ISC or TPS:
A.
Verify that no codes are displayed. Unless the trouble tree for the code calls for checking the ISC or TPS adjustment, repair any codes before
adjusting the ISC or TPS.
B.
Repair any vacuum leaks before checking minimum air. Leaks such as those caused by a loose intake manifold will affect idle speed. Refer to
Serviceman Bulletin #83-88 (May, 1983), Group 6A, for additional information on HT4100 intake manifold leaks.
C.
Make sure that all switch tests pass.
D.
Turn air conditioning off - Disengage the A/C clutch as follows:
1.
When not in diagnostics, turn the Electronic Climate Control to "off".
2.
When in diagnostics on 1982-1983 models, depress the "outside temp" button to turn off the "outside temperature" indicator (A/C
compressor clutch status light).
3.
When in diagnostics on 1980-1981 models, the A/C clutch is off.
E.
Check engine timing and verify it is correct before adjusting ISC-TPS.
If any of these conditions above are not met, an incorrect minimum air reading and consequently an incorrect TPS adjustment may result. On 1982-1983
models, a quick check of TPS readings can be made. Refer to 1982 Service Manual 6C8-8 and 1983 Service Manual 6D3-12. By retracting the ISC and
using the DFI parameters, the minimum air rate, TPS and ISC settings can be quickly verified on most cars without the need for tools or meters.
The tamper resistant welds must be removed to adjust the TPS. The procedures for TPS adjustment differ for each model year, and it is essential that the
correct procedure is used. These procedures are summarized as follows:
1980
-
File tamper resistant spot welds and adjust per 1980 Service Information
Manual 6C-166.
1981
-
Remove throttle body, use 5/16" drill bit to remove tamper resistant spot
welds and adjust per Serviceman Bulletin 81-5A.
1982
-
Remove throttle body, use 5/16" drill bit to remove tamper resistant spot
welds and adjust per 1982 Service Information Manual 6C8-8.
1983
-
Loosen adjusting screws and adjust per 1983 Service Information Manual
6D3-12. (There are no welds.)
