hello everyone.

i have a misfiring/sputtering issue after full warmup for a while now, even before i installed the current engine/setup mentiond below i had it, it wasnt a big deal when runing with crome because i assumed crome was the issue,

sympthoms are:
-when cold until fully warm its runing fine,
-after about 25-30 mins of driving when coming back to idle, the engine misses randomly and bogs at idle rpm every few cycles.
-as i rev it up to 1500 rpm it missfires alot (in random cylinders i think), somtimes pulling the rpm by itself to 1300 rpm,
-at 1500rpm+ it just missfiring bad,
-at driving start the engine bogs abit for a second and regain power, (transition from high vac to lower vac)
-at light cruising it misfires just a tad, it just not powerful enough to be felt.

logs and tune are OK,

things i allready tried by order:
changed engine (75.50 vitaras / 59300 cam)
new wires
new dizzy cap + rotor
new plugs
new coil
new icm
borowed a dizzy from a friend
several p28 ecus
resoldered main relay


-97 civic
-"new" p28 ecu + ectune
-new 780cc precision injectors
-new 4bar hondata map (it did it with the stock map)
-venom intake manifold (disabled iacv, ON fitv, disabled purge valve)
-walbro 255 with a relay, switched by the main relay, grounded to the car body next to the pump,
-3 big fat engine ground wires,
-calibrated tps





any ideas guys?

thanks a bunch

 

Sounds like a wiring issue. Have you checked over your wiring harness or considered replacing it ?

 

hello,
well i checked the dizzy harness yesterday and it seems ok, other then that the rest of the harness was modified by me not too long ago (had this problam before), so i trust it,

also,i just ordered me a aem 30-1040, and i might try a cop setup(twin fire/epm/01+coils). so yeah i might redo the whole engine harness,

 

bump

 

This may sound stupid, but have you done a compression & leak down test ?

 

yup, 150 all across

 

have you tried a new fuel filter??

my EG ran like crap at light load after warm, in my case, a fuel filter fixed it

 

just did a second comp test, it was 160 all across

i change my fuel filters quite often, (no where near the service limit) but thats an idea, ill try to replace it,

 

do you have a 100% oem/stock ignition setup?

 

yup

 

air/fuel ratio when fully warmed up? if you add a bunch of fuel does it go away?

my rc750's have a random pop/miss at idle. can't get them to run very smooth with ectune.....i suppose i can i just need to spend a **** load of time going thru all the settings.

check your battery voltage/compensations also.