that94hatch

Alright ive got a problem with my civic ive tried a whole mess of things and cant figure it out. Its a 94 civic dx with a d15b7 5 speed. The problem is that when im in a higher gear under load i get a rapid missfire/sputter. The motor came out of a junkyard car, i used the block, with my old head, most of the sensors and everything are from the old engine which never had this problem. The only thing in the top end from the new motor is the intake with sensors. The throttle body is also from the old motor. it runs good when cold, but once it gets warm the problem occurs. The timing is good both mechanical and dizzy. If im light on the throttle and let it rev up without much load in a lower gear it doesnt do it. I did new plugs the other day and it seems like its running lean, the plugs are a whitish greyish color with a hint of brown. So given everything im kinda thinking o2 sensor. Does the first bank o2 modulate air fuel ratio on these cars or something else? When i swapped the head out i had the manifold disconnected and hanging, i pulled the coolant plug in the block not thinking and dumped a bunch of coolant right down the exhaust. I want to say its the o2 sensor or maybe the cat but im not sure. Thanks ahead of time guys. I have a video of the problem ill try to post as well.

that94hatch

theres the video of the problem

MisereNoire

did some light searching, found similar problems and some ideas...first off
1: If you think the O2 is your culprit, unplug them and if the stutter goes away, they are likely your problem.
2: test your distributor components per your FSM (esp. coil, igniter,rotor, check the wires leading to the sensors for damage, and check for oil seeping into the dist. body and also for shaft play)
3: your fuel filter may be old and clogged, its a cheap item to replace, you may wish to do this anyway
4: check your wires for damage/degradation per the methods outlined in the FSM (you should change your wires with your plugs anyway)
5: if the above is thoroughly checked and does not give a hint to the problem, borrow a known good ecu and see if it makes a difference.
6: As for coolant down the exhaust...I would have pulled the whole damn pipe/muffler assy and drained it out before I even thought about attempting to run the car...perhaps you fouled your cat (which may or may not be causing your problem, but check the above first).


Note: To anyone else, more ideas with more efficient methods than mine are appreciated...i just perused the searches, and gave advice that should be common sense. Add/amend by all means.

that94hatch

thank you very much. i pulled the o2 sensor while it was idling and it seemed to not make a difference in the way the throttle was while connected. thats the only thing bringing doubt to my mind. ill pull the plug again tomorrow and drive it to work like that and see how it feels. im not sure what fsm means to be honest haha. but i swapped the distributor from the motor that came in the car and it was fine then so its a known good distributor. the plug wires were new when i bought the car, though they have been battered around quite a bit. the ecu is also original to the car so im doubtful on that too and dont really have access to another one as im the only person in my area who owns a stock eg. haha ill look into the fuel filter but im doubtful on that because the problem isnt prominent when cold only when hot. like i said ill try unplugging the o2s tomorrow and see what happens on the way to work. ill check all my sensor connections over again although i already have a couple of times. the engine harness is also from the junkyard motor and iirc there may be a wire cut and spliced on the passenger side. well see after some more diagnostics, ill post again tomorrow with my findings. any further knowledge and ideas would be greatly appreciated. running out of ideas here.

MisereNoire

K, make sure ALL O2 sensors are disconnected, just disconnecting one wont help if the one you dont disconnect is bad. From there you can decide which is bad if things get better. FSM is short for Factory Service Manual. You can download one from Hondahookup.com - Honda / Acura Aftermarket Parts, Accessories, Forums, Photo Galleries, Racing, and more! .with the fuel filter, hot/cold wouldnt be the problem, flow rate would...and clogs will reduce the flow rate for whats needed at higher rpms.

gobeavers08

Try cleaning your points in the distributor cap with sandpaper see if it helps...I had the same problem, did what I mentioned and put new plugs in no more missfire... new it was definitely time for a tune up lol

that94hatch

today i adjusted my valve lash from the cam and rocker assembly switch cause they were pretty loose, while i was doing it i pulled off the cap to verify the cams position and noticed my rotor is totally shot, super worn down and there was a black spot almost like it was burnt, my caps studs are also very worn and corroded, i cleaned up both a little bit and it helped some so ill get a new cap and rotor and plug wire set and hopefully that will do it. im trying to get it running right to sell it, i wouldnt feel right selling a car with issues. ill get back once i do the tune up. fingers crossed this works, ive got way to much money and labor wrapped up in this pig. haha

MisereNoire

I DO believe you are right, I was pretty much recapping what was said in a thread diagnosing an EK..still...all can be 1. :wink:

But yeah, tune up for sure.

that94hatch

o2 sensor being unplugged didnt really make a difference. gonna grab a cap and rotor friday when i get paid, ill probably do wires as well while im at it. gonna pull the plugs tomorrow and see if its still running lean, hopefully fixing the timing helped. noob question what does OP mean? ive seen it alot in my research through the forums and im baffled. haha

that94hatch

ah quick google search told me original poster. i now understand lol

that94hatch

alright i did a new cap and rotor and it made zero difference. messed with the timing today and retarding the mechanical timing one tooth (its never been perfect, always looks a tooth off one way or the other on the timing cover, yes i know what im doing, no it will not line up.) and messing with the distributor fixed the problem, im gonna do the ignition timing properly tomorrow and see how it drives. im not all that concerned cause im picking up a swap for it this weekend but id still like to figure it out.

badcarma

the head needs rebuild... I know it seems improbable but its what I would do. you already went through your timing and egr stuff sensors. valve lash.. worn head by all means correct me if im wrong
best regards dave

that94hatch

The head is fine. I swapped this head from my old motor because the head from the "new" motor had burnt valves. The cam is from the "new" motor which is good, rocker assembly is all good. Everything on the head and block is fine. I found out that my mechanical timing is right didnt realize that the tdc marks were the ones that align with the top of the head, i was using the plastic pointer on the timing cover as my tdc reference and thought it was off. So i messed with the distributor and got it to pretty much go away. Still does it if im lugging really hars but i think its just a lack of power at this point. Thanks for all the help guys, at this point its driveable until i have the money for a swap.

that94hatch

The car runs perfectly fine except under load. The problem was there before i switched the cam, only reason i did is because i ran it low on oil not being used to how much it burns and wiped out a cam lobe. Its definitely a timing or ignition problem. Seeing as messing with the timing almost fixed it its most likely the culprit.

that94hatch

new problem, massive amounts of oil in the spark plug hole in cyl 1, i know theres seals when you unbolt the rocker assembly but i opted to not replace them, anyone know what theyre called at the parts store? definitely need them bad. on another note i fiddled around with my car this weekend and well its definitely not timing, mechanical and dizzy are on point now. im thinking cat converter at this point. that or i read somewhere that the plugs for the map and tps are interchangable not sure of how true it is, but if so its possible they couldve been mixed up in the motor replacement. so my list for tomorrow is as follows...
-switch plugs and see what happens
-02 sensor cause i know it definitely needs one regardless of it fixing this problem
-if all else fails im gonna shotgun a test pipe and fuel pump in because theyre the only two things at this point that have gone unchecked. i uncovered a thread either here or on another forum of a guy having the exact same problem and it ended up being the fuel pump.

that94hatch

got the o-rings shipped to my local parts store, picking them up tomorrow and putting them in friday before work (i work night shift) along with new plug wires and plugs. i cleaned up the throttle body from my original motor and im gonna slap that on and see if maybe the tps or something is bad. also pulled all the sensors off the intake manifold from the new motor and im gonna put them in one at a time and see if any of them help, also cleaned up the iac from my old motor and im going to use that one. if none of that works im going to hollow out my cat, and put in a new o2 sensor. if neither of them work then ill try a fuel pump. after that hell i dont even know. hopefully i can figure it out for sure so that if anyone else comes up with this problem they dont have to go through all this ****.