Engine - Updated Compression Check

9218chevy02

Number: 89-250-6

Section: 6

Date: October 1989

Corporate Bulletin No.: 936004


Subject:
COMPRESSION CHECK


Model and Year:
1989 M CAR


TO: ALL CHEVROLET DEALERS

This bulletin cancels and supersedes the "COMPRESSION CHECK" procedure found on page 6-13 in the 1989 GEO Service Manual.

COMPRESSION CHECK


Check the compression on all three cylinders as follows:

1. Warm up engine.

2. Stop engine after warm up.


3. Remove all spark plugs and disconnect distributor wire harness at connector.








4. Remove 15A fuse for main relay (Figure 4).

5. Install compression gage into spark plug hole.

6. Disengage the clutch (to lighten starting load on engine), and depress the accelerator pedal completely to make the throttle full-open.

7. Crank the engine with the battery fully charged, and read the highest pressure on the compression gage.

8. Carry out steps 5 through 7 on each cylinder to obtain three readings.