INFO: 87 chevy K5 5.7l Tbi
Today I tested the est wire voltage drop tested the wire to the computer in the on position not running and tried wile running but after it started there was a loud boom that my ears are still ringing from and found the muffler had exploded. it runs really really good with the wire unplugged. but will not run hardly at all with the wire plugged in. the dash is out to locate grounding points and to trace wires, nothing looks bad. no grounding issues I ran a jumper from the connection of the est bypass to the computer and it runs good but when I undo the jumper. It stalls and acts like it is
180 degrees off. Can any one help I have alldata available. i have uploaded the wiring diagrams that i have for it with the connector links because i can not find them online anywhere. please sticky this thread for wiring diagrams.
TPS VD test closed was .5v 3/4 open 4.5v full open 4.3v
mapsensor within spec.
coolent temp with in spec
knock sensor not tested
Any help would be quickly put to the test and results poste quickly.

 

did you set the timing to zero with that wire unplugged. the computer is supposed to set the timing itself. i had issues with my 90 similar to yours just not as bad. i replaced the computer and all is well. mine was dropping out timing randomly and felt like the trans was jerking around.

 

timing was set with the est wire unplugged. and started up and runs great but the CE light is on and it needs to pass inspection for NC.

 

Did a voltage drop from the ground side on the computer and the wiire in the harness is bad somewhere so I cut it and put a new wire in. Runs great now