oversized pistons and pinging turbo
 

I just got my car back after it being in hiatus for over three years, its a story in and of itself. Without going into that, I have an '88 300zx turbo that I had the engine rebuilt on. I had to get oversized pistons because i scarred the walls up when I was a little younger and dumber ( I had the boost up too high on an old engine). I still have that manual boost controller on there and I believe its set to about 6-7 psi. As far as I know I shouldn't be getting pinging from pre-det at this boost lvl unless its running a little lean. Do any of you have some suggestions, even if it is to call me a moron and tell me to turn it down. The guys who re-built the motor never tuned it quite right so I don't know if I should retard the timing or look for vacuum leaks or what. Any suggestions would be greatly appreciated. Thanks

also I do have high flow intake and exhaust on it.

You're a moron... for the fact that you didn't build the motor yourself and that you didn't drop the timing a few degree's to see if it's still pinging.

Welcome to ZDriver! :006: (Hoov forgot to mention that... :D)

So the title of your thread is "pinging turbo"... I assume you mean "turbo motor" not the "turbocharger" ?
How do you know the motor is pinging?
Have you checked the ecu codes?
What octane fuel are you running?
What is the timing set to?
Are you running NGK spark plugs?
Any aftermarket ignition?

resources
 

Hoov, I didn't have the resources to rebuild my own motor. I am running ngk plugs with 93 octane fuel, timing was set at last check to the stock, the people I had do the rebuild were completely inept, as I can be, but at least I don't say i am a professional. Just trying to learn. I don't pretend I am a mechanic, I know enough to do maintenance. I apologize that my specialty is computers instead of cars, but I love my Z and I need some help. As for aftermarket ignition that is a no, and I have not checked the ECU. I know it is pinging because I have ears, and it really lights up in third gear aroud 4000 rpms. As for pinging turbo of course I meant turbo motor, I was just trying to be brief in my description. I really would appreciate any of your help. Thanks, Hans

also
 

Thanks for the welcome NismoPick

I would start by pulling the ecu codes, and checking all the spark plug tips (reading the tips will tell you what's going on).

colder plugs
 

Are you suggesting that I look at the plugs color and maybe try colder ones? If so, and I know this is dumb, but what gap would you suggest I start at away from the stock range?

I'm suggesting to read the plugs, not get cooler plugs. You gap them to the stock specs since you are running stock boost.

How to read plugs:

Attachment 19544

thanks
 

I really appreciate that chart, however, I am not exactly running stock boost. So after I read my plugs tomorrow, would you be willing to help me diagnose the problem? Thanks

http://www.az-zbum.com/information.basic.shtml

84-87 Z31 Turbo: VG30ET, CR 7.8:1, T3, 6.7psi, 200hp @ 5200, 227ft-lbs @ 3600
88-89 Z31 Turbo: VG30ET, CR 8.3:1, T25, 4.5psi, 205hp @ 5200, 227ft-lbs @ 3600

6-7psi boost is pretty much stock.

What are you using for a boost gauge?