ECU code 71 need advice
 

posting for my brother he has a 98 integra (b18b2) the check engine light keeps coming on and its engine code "71 random misfire cylinder 1"

we have changed the plugs,cap,rotor and wires. the plugs looked good but its still coming up.

im thinking a burnt valve but before we dig that deep do you guys have any suggestions on anything else to change or check before i take the head off.

its been years but i can always count on the H-T community thanks alot!

Re: ECU code 71 need advice
 

Check that injector might be faulty. Also check the timing belt might have skipped a tooth.

Re: ECU code 71 need advice
 

Do a compression test. If you suspect a fuel injector problem, move it to another position and re-test. If the mis-fire code moves, then your problem is fuel injector related.

If the compression is good, ignition system is good and the fuel injector works in another hole, then the problem is the ECU. Replace it with a known good ECU and re-test.

Re: ECU code 71 need advice
 

Sounds stupid, but I have seen this way too many times to not mention: did you make sure the wires were put back in the correct order?

Re: ECU code 71 need advice
 

yes the wires are on correct. they were changed because of the engine code.

i injectors didnt cross my mind. i will switch #1 and #2 around and get back to you guys. thanks alot

Re: ECU code 71 need advice
 

I literally had the exact same problem as you, same motor, same code, everything.

Turns out my primary O2 sensor was garbage, replaced it and my code went away.

I'm not implying that this is your magical solution, but it wouldn't hurt to check the quality and reliability of your O2 sensor.

Re: ECU code 71 need advice
 

Also have you checked compression? Valve lash?