When i turn the key on the throttle body fills up
GMC Q&AAsk Your Question
1990 GMC S15 Question: My truck is a 1987 4cyl and when i turn the key on the throttle body fills up.
Answer #1pushrod January 19, 2014, 15:45Master
Leaking injector o-ring seals. Most likely! Unplug injector wire connector to see if it still does it. Post the test results for more info.
Answer #2cardocIII from Gillespie's Auto Service, January 19, 2014, 17:47Master
A defective ignition module was a common cause for this. They would falsely send a very fast pulse on the ref wire to the PCM even without the engine cranking.