Engine - Erratic Idle or Poor Response
83volvo01Subject: Product
MODIFIED CONTROL CARS
PRESSURE REGULATOR
1981-83 CI SYSTEM
Group
B21F, B21F MPG,
B21FT 23
Date: No.
June ,1983 115
THIS SERVICE BULLETIN IS APPLICABLE TO THE U.S. AND CANADIAN MARKETS.
If erratic idle or poor engine response is experienced after cold start at ambient temperatures below 60~F, and all engine settings are correct, the complaint can be rectified by installation of a modified control pressure regulator.
Bosch P/N Volvo P/N
Early version ......079 1276878-4
New version ......123 1336475-7
The new control pressure regulator has two resistors in shunt and will give the following resistance:
Below +53~F : 33.3 - 36.7 ohms
Above +63~F : 11.7 - 12.9 ohms
This results in a longer "choke" time in cold weather compared with the earlier CPR.
NOTE! On the earlier CPR the wires can be connected to either terminal. However, on the new CPR, the wires must be connected as shown, otherwise No. 7 fuse will blow.
The new CPR was fitted on B21FT 1983 model year as follows:
499800 ( M46) Engine # 4314 - 499801 (AW71) Engine # 3406 -