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.





5. Compare the valve to the reference chart.

If inspection reveals an advanced stage of deposit, i.e. 1 thru 7, the valves may be cleaned with the carbon blaster. (Go to Step D).

If the inspection shows little or no intake valve deposit, i.e. Stage 8 or 9, the carbon blasting procedure is not effective. Refer to Step C.


C. USE OF SUPPLEMENTARY KIT 3531106

1985-1987 B230F four (4) cylinder engines only that experience poor driveability immediately after cold start in warm ambient temperature, (i.e. approximately 20°C - 68°F), may be corrected with supplementary kit 3531106 described in SB 23-204 (P20) and SB 23-708 (p70).


Use of this kit will be effective only if problems are experienced with minimal deposits on the intake valves, i.e. No. 8 or 9 on the reference chart.


D. INTAKE VALVE CLEANING








Correct operation of the Carbon Blaster is outlined in the manual provided by the manufacturer of the tool. These instructions are supplemented by the pages which describe use of the Volvo Adaptor Kits.

NOTE:
Cleaning of the intake valves is considered an owner maintenance responsibility, and is not covered under warranty.

Recommended times for this intake valve cleaning procedure are:


OPERATION NUMBER DESCRIPTION TIME ALLOWANCE

251206 Intake valve cleaning
4 cyl. engines 1.5 hr.

6-cyl. engines 2.0 hr.