Still the '90 Civic

Hey there, I am still having the same problem with my civic and can not
figure it out.

When the car is cold, it acts OK for a short while. A little driving
quickly brings the problem back. The car will spit and sputter and have
severe power loss. Sometimes once it is over 3000 rpm it will kick out of
this and regain power. It is especially evident in OD at 35-50 mph.

I have changed all of the fluids in the car including the tranny. I
replaced the therm which was a cold one with a 180 temp. I cleaned the
carb with good carb cleaner and ran a bottle of Lucas cleaner throught the
tank with 92 oct gas. None of this has helped. The old lady had the timing
belt replaced not but 6 months ago along with a new dist cap and rotor.
Mayby htese things were installed incorrectly but I am not sure how to
check the timing belt. The cap and rotor looked good and all the wires
were in the corect location. Could a plugged Catalytic cause this? I am
running out of thing to look at here. The car does not have an EGR and I
unplugged the O2 whch caused the check light to come on and the
performance was very poor untill I plugged it back in. Help! Please.

Zak

 

Sounds like fuel flow problems.
Try replacing the fuel filter. Check the carb float bowl for rust
powder. Try a fuel flow test to make sure the fuel pump is OK and its
intake filter isn't plugged with big rust flakes from the tank. Put
some isopropanol de-icer in the gas tank to eliminate any water
rolling around in there.

 

First of all 180 is the wrong temp for the thermostat.
Plugged at will more then likely show up as a high RPM
problem.
Did this car ever work correctly after the T-belt etc repair?
Does it idle OK?
Can you rev it up under no load with out hesitation?

Two for free tests.
Have you cleared the ECM by pulling the ECM and HAZARD
fuse? Doing some tests last fall I mangaed to confuse my
ECM so it would drive "Good". Hard to discribe, but lousy
acceleration, bucking during in gear coasing. Idle would hunt
AFTER the engine got warm. No ECM error.

Disconnect the O2 sensor. It doesn't have that much effect, but
can cause an ECM to go nuts and not to set an error. Somewhere
Ihave a toyota ECM course theat details what degree of influence
the variuos sensors ahve and O2 is way down there. Important,
but you can run "fine" without one.
Simple to do, with the engine COLD, like in the morning, look
for a single wire going to a spark plug sized object mounted in
the exhuast manifold. Easy to see when viewed from the left,
when standing in front, side under the heat shield. The exhaust
manifold runs very HOT. I work with an idio, er missguided
guy who managed to burn himself real good by working
on his car with the manifold still hot. Let it cool for several
hours if not overhnight! Drive it for a day and see if things get
better or worse.


If the T-Belt was off a tooth I would expect high RPM to be worse
then low RPM.
If the valves were way out of adjustment I would expect it to not idle,
or to run rough at all RPSMs.
Fuel flow is almost always a real high RPM starvtion issue.
I have seen filters that would allow idle and slow speed ,
RPM, driving, but "et" down on it and the engine would stall.
Could be a fuel preasure regulator, but I haven't ever had one
fail and from what I understand it isn't real common. If one
allowed two much preasure, maybe th injectros could leak,
and the excess cause problems but that seems a long reach.
Bad plugs would kill idel and high RPM.
Bad ignitor and/or coil, and/or distributor/wiring would tend to
kill idle and high RPM.

How do the spark plug gaps/cones look?

If you get a spark plug wire "out of place" the engine will either
not run, or run REAL! BAD!!!
Don't ask how I know that one!

IT looks like you re going ot have to get a qualified mechanic to
work on it. Shade tree mechanics, if they really know their Hondas
might be able to do it, but I would really want someone that Icould
trust.
Dealers are often the best, but there are very good independents
around.
as an example here in Lex KY I owuld trust Steve Demartine over all the

Honda/Toyota shops in the state! As the honda owners you know, good
shops get a good reputation.

Pehaps Ihave missed it, but tell us about this Honda Civic.
We know the year but is it a AT/MT, californica, US. or Candian.
What engine number.
How many miles.
What is your climate?
Are you all the original owners and do you KNOW if
all the scheduled maintinance was performed?
When was the last time your fule filter was changed?
spark plugs?
Air Cleaner?
PVC valve? (though I can;t concieve how a failed PCV would cause this
problem).
TeGGer Am I leaving anything out?

Terry

 

ok, i had persistent similar problems. each of the following steps made
incremental differences.

1. check all the vacuum hoses & operation of the tandem valve. does the
tandem valve open ok when you open the throttle? i had big problems
with this on a previous '89. replacing the 1.5" hose between the
diaphragm body & the throttle solenoid [old one was cracked & leaked
air] allowed the tandem valve to open fully much more quickly.

2. change pcv valve. i thought this made a difference, but it was
small. helped oil consumption tho.

3. make doubly sure all plugs/electricals are good. remove plugs &
check insulator cones to be sure all are firing.

4. injector cleaner. helped a lot.

5. replacing the timing belt helped a huge amount. turned out the belt
had not been tensioned correctly so there was a lot of "whip" in it.
when looking at the timing marks with a strobe, the marks were jumping
all over the place. <-- [this is a good candidate being as the belt was
recently changed.]

6. making sure the [spark] timing was set right. as in, *dead on*. helps.

7. and finally, while the above got the old girl pretty much on track,
she was only 96%, not absolutely perfect. an igniter problem lead me to
replace the distributor condenser - a pita job, but the transformation
in the car is quite remarkable. not only has the hesitation completely
gone, but she positively roars off down the road and gas mileage has
improved substantially. evidently the spark had been weak before as a
test showed the condenser was near dead short depriving the sparking
coil of current. this is logical because different compression
conditions require different sparking voltages. weak spark = weak
combustion, if at all.

 

The '90 Civic is fuel-injected, so whatever you cleaned, it sure wasn't
the carburetor. Have you changed the PCV valve?
Also, the O2 sensor can foul but not set an error code; you might try
replacing it, although it's pricey for the Honda sensor.
You can't tell if a distributor cap is good by looking at it, try
changing it out. Were the spark plug wires ever replaced? How do the
plugs themselves look? Your ignition coil can develop cracks and that
can cause problems similar to what you report.
You also don't belong in overdrive at 35 mph, you're lugging the engine.

--Gene

 

Hey Terry, the civic is a 90 with a 1500/AT. I live in VA so the climate
right now is from 40s-80s with fair humidity. Te car has 197k on it and we
do have the service records for the vehicle for the last 5 years. I just
changed the fuel filter, not the one on the tank though, and the air
cleaner. All the plugs are in good shape and we have new wires/dist cap
and rotor. This car does not have an EGR valve. I have cleaned the
throttle body, removed and cleaned the injectors as well. The tandem valve
appears to be operating normal but i have yet to hear of a definitive test
for this from anybody. I'm just working my way down the tips list that
everbody gives. Let me know whats next

Zak

 

it's a vacuum diaphragm. test for leakage by pressing the actuator in
by hand, then placing a wetted finger over the vacuum pipe. if it stays
in, you're fine. if the actuator comes out, the diaphragm is punctured.
ime, the diaphragm's are pretty good - it's the small length of hose
between the diaphragm & the actuator solenoid that cracks & leaks.

 

My money is on the distributor assembly.

 

At idle if you gun the throttle the tandem barely moves, but (with
everything in place) partially blocking the air intake with your hand
and gunning the throttle should make the tandem valve open all the way
(you will also notice the air intake hose sucked in).