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Pesky misfire codes
Posted: February 19th, 2024, 1:23 pm
by Katoomrider
Well - a 6 month project only took 3 years. Finally done with my Clegg stage 1 stroker, added .30 over pistons, and 24 LB injectors and a stage 1 cam kit. Runs well, but can't get past inspection due to DTC's. Finally punted the old computer and got a wranglerfix (nice unit!) but still have various codes. Latest is multi cyl misfire. So here's my scary question - I know the HPTuners unit will dive into that unit - but I'm scared of it ( I miss carbs
). If I spec the engine build up and post readings are there guru's here that can keep me from blowing it up and get me to pass emissions in Georgia?
Re: Pesky misfire codes
Posted: February 20th, 2024, 4:35 am
by 75SV!
I'm going through this with a '00 XJ with a mini stroker. I had misfires before the engine rebuild. So, I'd look at plugs and if your distributor is OK. Also, wiring. I am going to try a different ECM myself.
Re: Pesky misfire codes
Posted: February 20th, 2024, 6:19 am
by Katoomrider
Good luck! The Wranglerfix is a nice unit
Pesky misfire codes when warm??
Posted: February 27th, 2024, 1:18 pm
by Katoomrider
2006 Rubicon....Pesky P0300 codes. on a mild build....driving me crazy! New WranglerFix PCM Clegg stage 1 build. Head decked and 3 way grind. balanced internals, new MSD coil rail, 24LB injectors, replaced OPDA (not really needed), cam/crank synced. Replaced injector connectors. Cant get the damn thing plated because I can't go more that 30 miles without throwing a P0300. Seems to be cyl 3 and 4.
Approx 30 Minutes total runtime 28 miles, best guess is 22 miles then 2nd restart and throws code P0300. Scanner says these misfires:
Cyl 1= 1
Cyl 2= 0
Cyl 3= 63
Cyl 4= 20
Cyl 5= 1
Cyl 6= 0
I'm stumped.
Re: Pesky misfire codes
Posted: March 2nd, 2024, 1:47 am
by CaptainBanana
Almost certainly due to the Opda being too advanced or retarded, they can compensate a handful of degrees on the NGC3 but if almost outside of range which is only about 10 degrees from the base timing they will throw that code. Also know that if you bought a Wrangler fix ngc 3 PCM which is 05/06 wrangler style you cannot tune them with HP tuners or anything else.
Loosen the opda adjust bolt with engine running advance a little by hand, clear codes and try again. If you have gone in the wrong direction you will throw a code almost immediately, if you've gone in the right direction you shouldn't throw a code at all.