Check engine light 3FE

[91cruiserrr]

hello everyone,

I did my valve cover gasket 2 days ago and now i got a check engine light on,

codes
25
26
71

I am not sure what the reason could be I only disconnected some vacuum lines and the air intake pipe.

if anyone can help me, please let me know.

Thanks

 

[jonheld]

hello everyone,

I did my valve cover gasket 2 days ago and now i got a check engine light on,

codes
25
26
71

I am not sure what the reason could be I only disconnected some vacuum lines and the air intake pipe.

if anyone can help me, please let me know.

Thanks

25 and 26 is A/F ratio and is usually O2 sensors, but could be other things.
71 is EGR system.

The top half of the 3FE wants to be air tight.
Check the intake tube for cracks in the bellows section. Any unmetered air will play havoc with the ECU.
Be certain there are no air leaks in the upper half of the motor that you opened up.
Valve cover gromets should have been replaced along with the PCV valve/grommet to prevent air leaks.

Remove the 15 amp EFI fuse from the relay box on the left fender for a few minutes and let the ECU reset.
Replace the fuse. If the codes come back, then troubleshoot according to the FSM.

FWIW, I remove the EFI fuse whenever I do work under the hood.