Fellows,

My check engine light has been flashing both at idle and on the road for some time. I thought I fixed the problem. But it's back!

I did compression test on my cylinders twice:

1) With throttle closed: C1 210 C2 205 C3 210 C4 210

2) With wide-open throttle: C1 210 C210 C200 C4 200

I followed instructions in the FSM, the only procedural difference between the two tests is the throttle opening angle, Test 2 is true to the FSM.

Which are the repercussions for the high numbers? Good? Bad? Any insights?

Regards

 

Was the fuel system and spark disabled before you tested? Any evidence of coolant when you pulled the spark plugs? If you did everything correctly, I'd try another gauge and see what you come up with.

Has the engine ever been rebuilt? Head resurfaced? Are the spark plugs oily, carboned up, wet with gas or coolant or look normal?

 

Thanks for the response. I followed instructions in the Factory Service Manual. No trace of coolant on the spark plugs. The engine is stock. The plugs have a little blackness on the ring at the top and a little blackness on the porcelain tip. I will look at the plugs to check the fuel ring and timing straps. By the way, the plugs are relatively new with above 50 miles on them.