Honda Car Forum

I had an old K car that would misfire under a load. I would briefly
test it by one foot on the brake and the other on the gas. The culprit
was a bad or weak coil.

James Goforth wrote:
> I am curious as to whether he has gauged the voltage from the coils at
> the spark plugs.
> If I've read correctly, he can get the misfire to occur at will by
> increasing throttle pressure relative to extant engine RPM--in other
> words, putting enough load on the engine--to the point of the voltage
> being insufficient to ignite charge.
> For what it's worth, it is also within the realm of possibility that
> the engine controller itself it the culprit, hence no MIL (check engine
> light).
> Note that I'm not experienced with Hondas in particular, I'm just
> throwing this out as my 2ç.
> New to this group (looking at a Honda in a car lot)! :0)

"Alan" <twobutnot2@comcast.net> wrote in
news:1142994848.517630.271720@z34g2000cwc.googlegr oups.com:

>
> I had an old K car that would misfire under a load. I would briefly
> test it by one foot on the brake and the other on the gas. The culprit
> was a bad or weak coil.


Considering that Honda/Acura autos are known for failing ignition
coils,this would be a good place to start.


--
Jim Yanik
jyanik
at
kua.net

Elle wrote:

........A bad O2 sensor will not necessarily set off a CEL on a
1994 Honda (pre-OBD2). Since the problem occurs after
warmup, that makes me especially suspicious of the O2
sensor. https://www.automedicsupply.com/ has the best
prices I've seen for OEM O2 sensors: About $69 altogether. I
have used them. Good, prompt service. Maybe not a bad
investment for a car this old.

Elle, I went to this site, & an O2 sensor for my 94 VX is $289.99.
Before I spend this much money, what symptoms would I be
seeing?


......Purge cooling system thoroughly of air. Follow the
manual's instructions. Getting the fan to come on may take
as much as 40 minutes of idling. If various ECM sensors
aren't cooled properly, then this may cause erratic
behavior.

I'm following the manual for a 92 Civic, & reference a 95 PDF
which is identical. I've pulled & cleaned the reservoir, then
replaced. It appears the radiator drain plug turns counter
clockwise. Any hints on how to get it to move without breaking
it?

I started the car, put the heater temp control lever to max heat, then
shut off the engine. No mention of whether or not to have the fan
running while I purge the system. Any ideas? I'll top up the
fluid today, then once I can get the drain plug to move, do a complete
refill.

I've tried bleeding before, but had the cap completely off. Manual says
to put it on to the 1st stop. I was still getting the erratic idle at a
stop
with this approach.

"Mike Doyle" <sigifrith@frontiernet.net> wrote
> Elle wrote:
>
> .......A bad O2 sensor will not necessarily set off a CEL
> on a
> 1994 Honda (pre-OBD2). Since the problem occurs after
> warmup, that makes me especially suspicious of the O2
> sensor. https://www.automedicsupply.com/ has the best
> prices I've seen for OEM O2 sensors: About $69 altogether.
> I
> have used them. Good, prompt service. Maybe not a bad
> investment for a car this old.
>
> Elle, I went to this site, & an O2 sensor for my 94 VX is
> $289.99.

Oops, sorry. The 94 Sensors seem to be far less for any
Civic that is not a VX.

Still, this price beats www.hondaautomotiveparts.com , at
$340 + s/h.

> Before I spend this much money, what symptoms would I be
> seeing?

If after performing a tuneup (new plugs, possibly new
ignition wires, new distributor cap and rotor, new air
filter, new fuel filter, check timing), the stumbling and/or
poor gas mileage continues, I would consider a new O2
sensor.

> .....Purge cooling system thoroughly of air. Follow the
> manual's instructions. Getting the fan to come on may take
> as much as 40 minutes of idling. If various ECM sensors
> aren't cooled properly, then this may cause erratic
> behavior.
>
> I'm following the manual for a 92 Civic, & reference a 95
> PDF
> which is identical. I've pulled & cleaned the reservoir,
> then
> replaced. It appears the radiator drain plug turns
> counter
> clockwise.

Yes it does. The usual rightie-tightie lefty-loosy threads.

> Any hints on how to get it to move without breaking
> it?

IIRC sometimes it's very tight. I have used a pair of pliers
on its end to get a good grip.

Might be a good idea to buy a spare from your dealer in
advance in case it does break. Though I haven't heard of one
breaking.

> I started the car, put the heater temp control lever to
> max heat, then
> shut off the engine. No mention of whether or not to have
> the fan
> running while I purge the system.

Leave the passenger car fan off.

> Any ideas? I'll top up the
> fluid today, then once I can get the drain plug to move,
> do a complete
> refill.
>
> I've tried bleeding before, but had the cap completely
> off. Manual says
> to put it on to the 1st stop.

I would perform (and do perform) the bleed with the cap
completely off. I too noticed a similar discrepancy between
what's in my Chilton's manual and what's in my owner's
manual for this procedure. I see the service manuals at the
site below say to leave the cap completely off for the CRX.
(I think the Concerto manual has a typ-o on this point.)

It makes more sense to me to have the system under the
lowest pressure possible so as to encourage air to escape
it.

> I was still getting the erratic idle at a stop
> with this approach.

Try the Concerto manual at
http://www.honda.co.uk/car/owner/workshop.html, under "Fuel
and Emissions" then under "Idle control system," for other
things to check, especially the Electronic Air Control
Valve. This group gets a few reports of this failing every
year (assuming the air purge above doesn't fix the problem).

Can you clarify: Is the car both stumbling while
accelerating and has an erratic idle?

"Elle" <honda.lioness@nospam.earthlink.net> wrote
> Leave the passenger car fan off.

I meant the "passenger compartment blower" should be left
off.

Elle wrote:
...... Can you clarify: Is the car both stumbling while
accelerating and has an erratic idle?


Acceleration is fine for a VX. It's sitting at a light, or
stop sign with all accessories off. The car doesn't die,
but the idle tends to drop low enough that I think it
will. Turning the fan on to it's lowest setting stops this,
but thats just masking the problem.

I bought it in August. So far, I've replaced the plugs &
wires with OE. Put on an after market fuel filter. Honda
dealer replaced the timing belt & water pump. I've
added an after market cruise control. Not sure if it would
cause any trouble. I've had them on all my other 3 Civics.
Just passed 200K on a trip to Texas. 40+ MPG since I
bought it.

I went ahead & replaced the Antifreeze today. Careful
use of some water pump pliers loosened the drain valve.
I'll keep a close watch on the overflow reservoir this week.
30+ miles each way to work, so hopefully any remaining
air will be purged.

"Mike Doyle" <sigifrith@frontiernet.net> wrote
> Elle wrote:
> ..... Can you clarify: Is the car both stumbling while
> accelerating and has an erratic idle?
>
>
> Acceleration is fine for a VX. It's sitting at a light,
> or
> stop sign with all accessories off. The car doesn't die,
> but the idle tends to drop low enough that I think it
> will. Turning the fan on to it's lowest setting stops
> this,
> but thats just masking the problem.

This doesn't sound like the oxygen sensor.

It is worth checking the ignition coil, especially if this
occurs after the engine is warmed up, like after 20 minutes
of driving. An older ignition coil will be persnickety at
idle, especially at warmup. Ultimately it will fail
completely.

See info on checks you can do on the coil at
http://www.tegger.com/hondafaq/start...s.html#badcoil

> I bought it in August. So far, I've replaced the plugs &
> wires with OE.

I would replace the cap and rotor, too.

Put on an after market fuel filter. Honda
> dealer replaced the timing belt & water pump. I've
> added an after market cruise control. Not sure if it
> would
> cause any trouble. I've had them on all my other 3
> Civics.
> Just passed 200K on a trip to Texas. 40+ MPG since I
> bought it.
>
> I went ahead & replaced the Antifreeze today. Careful
> use of some water pump pliers loosened the drain valve.
> I'll keep a close watch on the overflow reservoir this
> week.
> 30+ miles each way to work, so hopefully any remaining
> air will be purged.

I'm not sure that's the same as getting the car temp up high
enough to get the fan to come on twice, with the rad cap
off.

I changed my 91 Civic's thermostat in March 04 and did not
do a proper purge. I started having idle problems around
July or so. I found the cooling lines to the EACV empty. It
seems to be a high spot. A proper purge fixed the problem.