Ive searched all over and cant find the answer to this. Found all kinds of info on how to check and how to adjust but not the correct spec. What is the correct timing spec for a 1989 4bd1t non California USA motor?
Thanks
Officially it is 13 degrees before top dead centre for a 1989 4BD1T in USA for EPA and California emissions, but think about trying the Australian spec (Aus was not as tight on NOx emissions back in 1989), which is 15 degrees BTDC.
The following pic shows the 13 degrees BTDC timing advance setting for a 5th month, 1989 4BD1T engine for USA and California.
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