Hi All:

Some wierd problem I have been experincing for two weeks now.

Only when I turn on the A/C I get this knocking and pinging sound from the engine compartment. Once I turn on the A/C it will do it. The A/C doesn't have to be on. Just turned on once during a drive. Up hill, down hill flat ground it just does it.

I can drive it no problem if I don't turn on the A/C. Once I turn it on, it knocks and pings. I stop on the side of the road, shut off the engine and startup with out the A/C, back to normal. Turn on the A/C, problem starts again. Pull on the side, shut down, startup again, no problem.

Has anyone heard of this problem? Is there a knock sensor on this model? It has a 2.6 inline 6.

Timing is still at factory specs, I have retarded the timing only to have very poor performance and still the same problem. I have since changed it back. I have also tried using different gas hoping I got bad gas. I have also tried octane booster by Synergyn. No luck so far.

Any ideas would be greatly appreciated.

Thank you in advance.

Aloha,
Eric

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1987 260E Charcoal Grey 157,000 Miles
1987 260E Forest Green 120,000 Miles