87 chev fuel injected timing issue
 

Hi everybody i am having an issue with a 1987 chev truck 305 fuel injected
the wire that you have to unplug for the timing does not have power on it
and when you set the timing on the distributor to 0 degrees and then plug the wire in it doesnt do anything what i did was take a test light hooked to the positive battery terminal and touched the bare wire of the unplugged timing wire while the engine was running and the engine stalled out im not sure what to do any help would br great thank you everyone

Re: 87 chev fuel injected timing issue
 

You did some very bad things to your truck! The set EST connector is controlled by ECM and should only be opened when setting base timing.
The EST circuit triggers the ignition module. The computer does not know what the actual timing is, what it does know is when it gets a reference signal. It uses this reference signal as a base point and advances or retards the spark from that point. So, if on vehicles where the base timing is adjustable, and the base timing is set incorrectly, the spark curve will be off through its entire range by the amount that the base timing is mis-adjusted. An open or short to ground in this circuit will set the code and cause the engine to run on ignition module timing. Connecting one of the two ends of this circuit may have damaged ECM or ICM - you are not suppose to apply any voltages to this connector!
Once base timing is set - usually 0 deg for LO3/LO5 motors, shut off engine, reconnect set EST plug, disconnect battery for 30 seconds to clear code 42 EST.