to answer the question: yes, i used the search function before posting this. no, there weren't any posts identical to this.

now that that's out of the way, here's the back story on the car:

88 civic with the 1.5 SOHC motor and 4-speed manual tranny. 100% stock. 265,000 miles. getting this car from a buddy of mine. he got it from a guy as compensation for mechanical diagnosis of the car.the guy was driving down the highway and broke his timing belt. my buddy figured that out, and did a leak-down test on the motor, which it failed on 3 of the 4 cylinders. the machine used for the test was old and often faulty, but all of this was disclosed to the owner. he opted to turn over ownership of the car as payment for work performed rather than invest in fixing the vehicle. this car sat at my buddy's house for roughly 9 months before anything was done with it. i ended up needing a second vehicle, so we decided to try and fix the car.

we pulled the head to find that the valves were in perfect shape, other than just dirty from the 260K miles. cylinder walls in good shape, no evidence of wear or damage. so we put it all back together and fired it off today. here's the issue:

when initially fired (on gas at least 9 months old) it cranked on the first shot. idledabout where you'd expect it to, but loped ever so slightly every so often and was a bit rough. these conditions were not severe enough to cause concern. gas going bad probably.

once warmed up however, the idle went steadily from (no tach, so guessing here) 800 + or - to probably around 3000-3500. at first, this creep up in idle speed was slow (over the course of 30 secs to 1 min, seemed to change with engine temp). we shut the car down and started investigating, looking for anything obvious... throttle jammed open, cracked, missing or disconnected hoses, etc. nothing was out of order. so, we're up to speed.

my question is: what could cause this problem, so i can start going down the list of possibilities.

probably need to mention that my buddy is a mechanic by trade, and i am one by hobby. this is the first Honda either of us has tinkered with, but definetly not the first car. so the dummy stuff isn't likely to be the cause, though i am willing to chase any lead y'all will give. it's bound to be a sensor of sorts, just not sure which one to look at and how to test to see if it's bad.

other info: the car has the dual-point injection (not sure if different styles were available for this car). also of note, the idle, once it picks up, does not lope at all. the other threads i found idle issues on all had loping idles as symptoms.

and finally: the radiator is cracked, so i didn't worry too much about balancing out the coolant/h2o mix. if the car can run sucessfully,the radiator will bechanged. i did notice a bleed-off valve near the thermostat, but we didn't use that, since we were leaving the radiator cap off and not allowing the radiator to build pressure. i don't know if hondas are that particular about the coolant systems and temp sensors, but the system was allowed to burp, so there shouldn't be any air in the system (i noticed several "air in the cooling system" suggestions as fixes for loping idles).

any help would be appreciated.

 

forgot to mention: the check engine light does come on once the idle starts climbing. so... after a while if we started the car cold, or right away if it was already up to temp. not sure how to chase an engine code on a Honda... with other cars i'm familiar with, the light blinks a certain sequence to tell you what code it is...

thanks again