Rough cold start. Rough when running. 1986 305 FI
08-13-2023, 08:39 AM
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Rough cold start. Rough when running. 1986 305 FI
1986 305 FI Trans Am.
I have replaced the cap, rotor, plugs, wires. Confirmed locations of wires. Replaced fuel pump and sending unit. Replaced fuel filter. Replaced most vacuum lines. Starts hard when cold. Have to turn key on and off 3 cycles then mess with throttle to start. I’m going to check fuel pressure today but figured new pump and sending unit were good to go. I don’t have tester but have access to one. I don’t want to keep throwing parts at it but I am stumped. I did get codes. 33,36,42. Engine light sporadic when running. New battery and alternator as well.
compression is 180psi on all cylinders.
fuel pressure 42 key on. 32-35 at idle. 80 when pinching return line. 42 when unplug vacuum to regulator.
I have replaced the cap, rotor, plugs, wires. Confirmed locations of wires. Replaced fuel pump and sending unit. Replaced fuel filter. Replaced most vacuum lines. Starts hard when cold. Have to turn key on and off 3 cycles then mess with throttle to start. I’m going to check fuel pressure today but figured new pump and sending unit were good to go. I don’t have tester but have access to one. I don’t want to keep throwing parts at it but I am stumped. I did get codes. 33,36,42. Engine light sporadic when running. New battery and alternator as well.
compression is 180psi on all cylinders.
fuel pressure 42 key on. 32-35 at idle. 80 when pinching return line. 42 when unplug vacuum to regulator.
Last edited by Bobncin10; 08-13-2023 at 10:04 AM. Reason: Add compression numbers
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