740 L4-2.3L SOHC VIN 88 B230F (1985)
Idle Speed: All Technical Service Bulletins
Engine - Poor Driveability When Cold
Section:
Group: 00
No. 101
Date: August 1989
RE: Intake Valve Deposits 700
This Service Bulletin Applies To U.S. And Canadian Dealers
Reference: SB 23-129; 3/88; Fuel Injector Maintenance Shop Equip. Bulletin No.11; 6/89 SB 23-204; 4/89; B230F Cold Start '85-'87 Automatic
Excess carbon deposits on the intake valves may produce poor driveability immediately after cold start-up or during initial engine warm up.
Recent studies have shown that a major source for these deposits is the gasoline itself. As gasoline is blended to perform well under a variety of
conditions, it can also be blended with resped to deposit control. Therefore, the customer should be advised to use a gasoline with a proven deposit
control additive designed specifically to keep the entire intake system clean, including the intake ports, intake valves and the fuel injectors.
At this time, Volvo is not aware of any deposit control additives that are effective in the complete removal of all intake valve deposits. Therefore, it may
be necessary to remove these deposits by mechanical means, as described below.
In cases where poor driveablity exists despite the use of proper fuels, the following repair guidelines aresuggest
A. BASIC ENGINE ADJUSTMENT
These items must be checked before proceeding to any of the other operations:
1.
Check ignition timing, and if necessary, adjust to specification.
2.
Check basic idle/throttle plate setting, adjust and/or clean as necessary.
3.
Adjust CO content to specified amount.
4.
Check for air leaks (Air bellow hose).
If engine performance has not been restored by performing the basic engine checks, proceed with step B.
B. CARBON DEPOSIT INSPECTION
1.
Remove the negative battery cable.
2.
Remove the fuel rail and injectors.
3.
Rotate the engine so that the intake valve to be inspected is closed.
4.
With a small flexible flashlight inspect the back of the intake valve.