engine missing

i'll try to give all info without writing a book.. my 92 civic lx sat
for a yr and a half (second time to snap crank) got a donor motor from
a 95 civic. (d15b7) simple remove and replace, installation went
smoothly. just had to refigure map sensor wiring. (92 map is on the
firewall, 95 is in the throttle body) everythings good, but it misses
(or at least thats what it feels like), randomly. sometimes it runs
smooth, sometimes rough.. it seems after a distance it smooths out and
once i stop at a light, it'll start missing again. (yet sometimes i
can still feel it on the highway, usually underload, uphill) once i'm
going again it misses till about 2500 rpm then like a switch kicks on
it runs smooth.
plugs look good (used but normal wear), wires 8k-16k ohms depending on
length(book says 25k max) and dont light up in the dark, checked the
timing and its good, the distributor came off my motor and it didnt do
this before.
i still got my old motor, want to pull any thing off before i return
for core then they charge me to get a part off.
thanks for any help in advance

 

wrote in :

I don't think I would depend on the "don't light up in the dark" test for
spark plug wires.It could also be a bad coil(in the dist.cap?)
A 95 motor would have considerable mileage on it,so it's possible the wires
insulation is going,or the "used" spark plugs are due for replacement.

BTW,did you change the ECU when you put in the newer motor?
if they are different part numbers,they probably have different programming
maps.

 

most definitely - first place to look. plug replacement is a top
priority also.

 

distributor cap has the coil in it; can give funny results also if it
gets cracked or other defect. i know you said you have the one off the
old engine, but if the one from the 95 is around, might be worth a
swap.

 

ok here's what i've noticed recently, starting up cold it runs fine,
once i get the engine warmed up it'll start chugging at idle. ie.
stopped at a light etc.. but it never dies, rpm bouncing down to
3-400. what sensors could have this effect once warmed up?

 

Various engine control sensors are exposed to the cooling
system and malfunction with insufficient coolant. A common
culprit for your symptoms is a low coolant level. First
thing to check are the coolant level in the reservoir and,
with the engine cold, radiator. Top off both with coolant.
Observe. If problems continue, then do an air purge of the
cooling system. Be aware that the engine may have to run
30-60 minutes for the radiator fan to come on twice, as
required by the air purge instructions.

The coolant to use depends on what's now in the car.

Please always state your Honda's year and exact model in
posts. Some problems are unique to certain years and models.

 

wrote in :

whne cold,the ECU uses a preprogrammed map to run the engine.
MAP,throttle position,and air intake temp sensors are used to give a
generic starting point in the map for the ambient conditions.
O2 sensor data is ignored.(open-loop operation)


Once the O2 sensor warms up,in a couple of minutes,then the ECU can begin
controlling the fuel input to get proper fuel/air ratio.(closed-loop
operation)
Once the coolant gets up to temp,then the ECU can fine-tune even further.

 

mileage would help,too. also if any parts have been replaced already,or any
repairs done recently.(motor-related repairs....)

 

come on, read the first post!!!
my 92 has 150-160k miles the motor is supposed to have 120k
im currently running the 95 engine, but have swapped back in the 92
throttle body, map, tps, distributor, wires, plugs, o2 (in bottom of
exh manif)
my dad broke the plastic upper radiator connection and it has been
leaking slightly... im glad you mentioned that, i know what i'm fixing
next!!

 

> wrote

Oops, beg pardon jpurl. I read the subsequent post and it
sounded like a new one [blah blah lousy excuses]