low rpm misfire
Posted: Sat Jan 03, 2015 8:00 pm
hi guys, i have a mk2 gtx, running an abf block on kr injection and ce1 loom.
car starts fairly well, though the idles a bit crap, the isv loop doesnt seem to be doing much, the isv doesnt buzz and nothing changes when i unplug the control relay, tried replacing it but no difference. when its warm it idles fine at 1-1.1k rpm
revved from idle it stutters the slightest bit but otherwise revs freely.
pulling away though and it drops to 3 cylinders, runs terribly, sometimes slowing down when i press the accellerator before continuing to accellerate. above 3k rpm its fine, and pulls well to the redline.
the misfire pulling away is worse if there is someone in the car with me, and going uphill. itll run along at a certain speed fine but if i add throttle to go a bit faster it misfires, sounds breifly like an impreza before smoothing out.
i've searched and searched for vacuum leaks, and can't find any, even using smoke blown though the lines.
so far, i've replaced the:
coil
rotor arm
dizzy cap
leads
isv control relay (ebay so unconfirmed if its working good or not)
plugs
tried changing the temp senders but gsf seem incapable of sending the correct ones, despite me getting a description off their sales guy what the picture was on his screen, and i still got the wrong ones, twice...
looking inside the dizzy cap and one terminal doesnt have the same arc markings, could this be the culprit, cheapo dizzy cap?
![Image](http://i1082.photobucket.com/albums/j362/ap046/Mobile%20Uploads/20150103_190309.jpg)
its the no.4 cyl terminal and the spark is weaker on that one, ive tried various plugs and leads on it and made no difference.
any help would be greatly appreciated.
thanks, Aid
car starts fairly well, though the idles a bit crap, the isv loop doesnt seem to be doing much, the isv doesnt buzz and nothing changes when i unplug the control relay, tried replacing it but no difference. when its warm it idles fine at 1-1.1k rpm
revved from idle it stutters the slightest bit but otherwise revs freely.
pulling away though and it drops to 3 cylinders, runs terribly, sometimes slowing down when i press the accellerator before continuing to accellerate. above 3k rpm its fine, and pulls well to the redline.
the misfire pulling away is worse if there is someone in the car with me, and going uphill. itll run along at a certain speed fine but if i add throttle to go a bit faster it misfires, sounds breifly like an impreza before smoothing out.
i've searched and searched for vacuum leaks, and can't find any, even using smoke blown though the lines.
so far, i've replaced the:
coil
rotor arm
dizzy cap
leads
isv control relay (ebay so unconfirmed if its working good or not)
plugs
tried changing the temp senders but gsf seem incapable of sending the correct ones, despite me getting a description off their sales guy what the picture was on his screen, and i still got the wrong ones, twice...
looking inside the dizzy cap and one terminal doesnt have the same arc markings, could this be the culprit, cheapo dizzy cap?
![Image](http://i1082.photobucket.com/albums/j362/ap046/Mobile%20Uploads/20150103_190309.jpg)
its the no.4 cyl terminal and the spark is weaker on that one, ive tried various plugs and leads on it and made no difference.
any help would be greatly appreciated.
thanks, Aid