IDLE SURGE AND/OR CODE 30 LOSS OF POWER
MODELS AFFECTED: ALL WITH HT4100 ENGINES
The following information will summarize the appropriate service operations for vehicles which experience abnormal distributor drive gear wear. This information supersedes Bulletin T-86-24 which should be destroyed.
Some Cadillacs equpped with the HT4100 power system may experience abnormal or premature distributor gear wear. The symptoms of this condition are idle surge and/or code 30 or loss of power. If these conditions are exhibited, the following service procedures shouyld be followed:
1. Remove ignitior, distributor as described in Section 6D of the appropriate Service Information Manual.
2. Inspect both the drive gear on the camshaft and the driven gear on the distributor shaft for evidence of advanced wear.
3. If either gear is worn, the following three actions must be completed:
A. Replace the distributor driven gear. A redesigned gear, P/N 10499163 has recently been released to supercede 1979546. This new gear is identical to previous designs except that a tin plating operation has been added to improve break-in characteristics and minimize premature tooth wear. It can be easily identified by its "silvery" appearance. GMWDD service stock of distributor assemblies has also been updated with this improved part.
B. Replace the camshaft. P/N 1628822 is used for all engines. Refer to Builetin T-84-90. Be sure to prelube all contact surfaces including the distributor drive and driven gears with the lubricant provided in the cam kit (lubricant available separately as P/N 1052365).
C. Remove the engine oil pan and oil pump and inspect the oil pump gears and housing for wear. Replace oil pump and clean oil pan as required.
For warranty purposes, use labor Operation T6135 with the following appropriate time.
Vehicle Time
1985-1996 FWD Fleetwood and De Ville 9.6 Hours 1982-1995 RWD De Ville and Brougham 8.6 Hours 1982-1985 Eldorado and Seville 10.4 Hours 1986 Eldorado and Seville 10.7 Hours
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
