Up a creek without a paddle

[obryan]

I just built a 4.6L stroker in a 2001 jeep TJ , 10.2:1 compression. I have just finished the break in (cam and rings and stuff) and it was running great yesterday. Yesterday I got an injector open circuit error on #5 injector. Cleared the code ran perfect today got another code for cylinder one misfire and another injector fault code. I just had all my injectors cleaned And they passed with flying colors. What have some of u guys ran into fir problems.

[unlimitedrubicon]

Are you running stock injectors? Do you know what your air/fuel ratio is runnng at? Make sure your harness plugs at the firewall and injectors are clean and fully seated. Also, check that the harness did not get damaged during the swap.

[obryan]

So dumbest thing ever.....it turns out that my exhaust manifold was a tiny bit loose and was allowing fresh air to hit the O2 sensors behind the cats...When that happened I had error codes popping out for everything. I tightened it up and it runs like a dream. im getting just shy of 20mpg doing the speed limit. that running 33's and a 373 rear end. so im pretty happy about that. and yes i am running stock injectors. I have another question, does anyone know how people are bypassing the dowstream cats when you install a header. i know they have the holes for the upper cats, but not the lower ones...is there a way to bypass them or are guys drilling holes and installing them lower???

[unlimitedrubicon]

That is great it was a simple fix and nice mileage. Just make sure you are not running too lean by either reading the fuel trims via the OBDII port or better yet using a wideband O2 sensor. Normally running a header does not make any difference with the downstream cats or O2 sensors as those are on the downpipe. Did you only replace the header, or did you make other exhaust changes as well?