sohc issues...

[SicSX]

alright, so iv got a new and difrent situation then iv ever seen before. a good friend of mine just picked up a 89 hatch, and when we drove it home it had an intresting missfire. i brushed it off as timeing at the time and told her i would re time it when we got to my house. make a long story short iv now re timed it, checked for good spark, comp tested it, and it still has a missfire. the really weird part is this, on all 4 cylns it runs like ****, but if i pull spark on cyl 4 it runs mint... but with cyl 4 runing the motor shakes bad and cant keep an idle at all.. but runing on 3 cyln's it idles perfect and keeps right at 1100 rpm. with all 4 runing it goes from 200-2000 rpm...

[Fla240sx]

check plug wire connections..... check fuel injector connections

check fuel injector for proper operation

[SicSX]

i was thinking the same as far as injectors so i swaped #4 with #1 and #2 with #3 to see if it then changed cyl. prob is still in cyl 4.. iv also checked wires and did a spark test to every cyl, and switched out plugs..

however there is no o2 sensor in the vehicle.. ( after market header) so im wondering if thats adding to the problem.

[Fla240sx]

yes u need that, that is one of the few things the computer actually uses to adjust fuel

you need these at the minimum hooked up and working

TPSMAFCoolant temp(the plug with 2 wires)O2Crank Sensor

this is mainly what the computer uses to adjust fuel ratio, you defintely need an o2 sensor

[SicSX]

i just dont get why it runs perfect on 3 cyl and doesnt shake at all, but on all 4 cyln it shakes and missfires. is it just runing to lean with no 02? it doesnt change at all when the motor warms up. i let it run for 2 hours today and it was at perfect temp still acting weird.