timing and ping

[pathfinder]

When my 1990 pathfinder engine gets hot here in AZ, (unusual, huh) and the a/c is on, the pinging starts. I adjusted the timing (retarded) and it seems to have subsided. Is this OK for the motor? I know the power will go down, but it happens going uphill as well. It's annoying and I feel this will damage a rebuilt motor just installed last year. Is it OK to keep the ping and keep the HP? When the piston heads shake due to early spark/combustion, is that the pinging I hear?

[BigMACKenzie]

just taking a shot in the dark here, but if your car makes noise when you start the AC, I would check the a/c compressor and other components first before I start retarding the timing. It sounds to me though that you might have a better time finding a good mechanic that you can trust and getting some help. either that or take some audio clips and post them up here so we can listen. we need as much info as you can gather to take help you. just remember, the car is like a human body, if someone is having trouble breathing, dont check the feet, look to the lungs! Think about it, a mechanic would not be able to help you at all with this little nugget of info, how can we? not trying to bust your chops, just giving out a little tough loveski. thats right, Russian style. but we do lovez you.

PS: excuse the slightly disjointed sentence structure, I hope you get what I am trying to say.

[pathfinder]

thanks for reply.The knock was from the engine being hot and under load. The a/c checks fine.

How would one ensure the ECM is OK for a newly installed motor, or should the be a worry with a new motor - old computer?. There are no flash indications, in any mode, on the unit itself.

What would I ask a mechanic to look for as far as the knocking goes: compression test? timing? fuel injectors? fuel pump check? fuel filter? plugs?