1992 Accord idle problem

I just bought a 1992 Accord with 84k for my teenagers to beat up on. Of
course it seemed to run fine when I test drove it, but now it vibrates
roughly when idling in gear and surges when in park and the radiator
fan comes on. I've learned a lot by reading the info from this group,
and would welcome any insight into my problem and reasoning so far.

The car idles at 1000-1100 rpm when warm according to the dash tach. I
know the motor mounts "go soft" around 750 rpm, which is spec, so I
think the vibration is due to the fast idle.

I removed the top from the fast idle valve, and noted air rushing
through the valve even when the car is warmed up, which tells me the
valves not operating as it should. When I push down on the valve the
idle picked up. I cleaned the valve, but air still rushs through when
the cars warm.

Thinking that the electronic air control valve wasn't operating the FIV
properly, I cleaned the EACV, which did have a dirty screen but it
didn't help the rough idle. In fact, I didn't notice the the surging
while in park with the radiator fan running until after I cleaned the
EACV, although it could have existed prior. When I unplugged the motor
on the EACV the idle didn't drop as I've read it should. I did get a
check engine message and the car starting missing after a while. I
cleared the computer, restarted the car and it runs as before, with the
rough idle and surging in park.

Now I suspect the EACV might be shot, and am considering replacing it,
but I've read it's $300 or so. Is there anything else I should check or
some way to tell for sure if it's indeed the EACV before I start
plugging expensive parts into the car?

Thanks in advance for any advice.

Todd

 

I wonder if it idles rough because the fan comes on or does it run
rough and the fan just happens to come on because it is warming up.

This is just a thought, but does it start to idle rough when you turn
another load on, like the lights, rear defog, etc? If so, it could be
the Electric Load Detector (ELD) as that is supposed to adjust for the
load.

Remco

 

Until the pros show up, consider the following:

The 92 Accord has a free online manual. It has a specific
troubleshooting procedure for the EACV, to either identify
it as malfunctioning or eliminate it as a cause of the
problem. See
http://media.honda.co.uk/car/owner/media/manuals/AccordManua
l/400/6-194.pdf . Backtrack from this address to get to more
troubleshooting procedures that might help. Try both the
idle sections and the emissions control sections. Though the
troubleshooting chart (backtracking from the site above) for
the "Idle Control System" sure does tend to point to the EAC
valve.

I would start by doing a proper air purge of the cooling
system. The EAC valve (among other engine control
components) is cooled by anti-freeze in the cooling system.
If there's air in the system, the EACV line is one place
where it will tend to accumulate. This was a problem on my
91 Civic's EACV a year ago. My car idled high at stops,
shortly after replacing the thermostat. I hadn't properly
purged the system of air after the thermostat job. A proper
air purge fixed my idle problem.

During the air purge procedure, note that it may take more
than 30 minutes for the radiator fan to come on twice.

At first I thought that this likely won't fix your car's
problem, because of the coincidence of the radiator fan
coming on, etc. But then it occurred to me that of course
when the radiator fan comes on, it changes conditions
(temperature etc.) in the cooling system. So maybe all your
car needs is this air purge. Either way, one should start
from as normal a "baseline" as possible when
troubleshooting. "Normal" of course means the cooling system
is filled and purged properly.

I believe the EAC valve runs around $175 at the OEM online
Honda parts sites, assuming I have picked out the correct
valve for your car at www.slhonda.com , which is not
entirely clear (or I've found the wrong valve). for your
Accord, I think it's under "throttle body" and is labeled
"valve assy." The EAC valve is this much for my 91 Civic.

I would also be reading up on the EGR valve. My recollection
is if it's dirty, it too will cause idle problems. Go to
www.groups.google and search this newsgroup for EGR valve
cleaning and discussion. (My Civic does not have an EGR
valve, so I'm going from memory--past reading here--on this
one.)

 

Thanks for the reply. The car idles rough when in drive and stopped.
The car surges between 1000-1500 rpm when the car's in park and the
radiator fan's on. I'm going to try running the A/C to see if it's the
extra load that causes the surging or the change in coolant temp.

 

Thanks a lot for all the great info and advice. You sound like on of
the pros to me. I'd like to get my coolant purged and changed anyway,
so I'll go ahead and do that first. I did change the EGR valve, and the
new one seems to be working, but it's aftermarket and could be suspect.
I may go ahead and get one from the dealer since they're inexpensive.
Great news about the EACV, $175 sure beats $300.

 

I've noticed your last couple of state something like this (referring
to the pros showing up). At the risk of sounding like a smartass, we
have pros on this forum? Why the preamble?

Remco

 

To me, "pros" include any Honda enthusiast or technician
with significant amateur or for-pay experience. So we have
plenty. ISTM you're one.

I on the other hand don't like posts by anyone that mislead
the original poster or others into thinking that the person
posting has significant experience with an area. Folks with
'stuttering' and/or hard-to-start car problems lately, for
example: Now that could several things that I've
explored/troubleshot personally with my car, but it could
also be, say, automatic transmission problems, with which I
have no experience. Some guy posted here recently with a TDC
crank sensor code--I thought sure he was looking at a new
distributor housing. Nope. Starter. How that led to the TDC
crank sensor code leaves me scratching my head.

Lately I'm posting right away 'cause I'm online, watching
the stock market and pretentiously (but in fact actually)
researching personal investments, anyway, and I figure the
poor fellow/gal posting here with Honda problems would like
/some relevant/ guidance, even if it's only where to find
online manuals. Plus I like learning about things mechanical
and electrical; that really floats my boat.

But a little humility is a good thing. Hopefully my preamble
means nothing more than this.

 

Thanks for the clarification. A little while back someone pretentiously
and sarcastically posted that he enjoyed the bumbling answers he heard
on this group, implying he was the pro. Was wondering where you were
coming from (you sound like a pro to me too).

I hear ya and am learning a lot from everyone in this great group. I
particularly like it when someone posts some weird problem and we
collectively come up with a very workable solution, saving someone
significant time and money - not bad for a bunch of amateurs, right?
We don't need no stinking pros here!

Remco

 

Agreed. Until the guy puts up, he should shaddup, AFAIC. If
he wants to post here and give away his expertise for free,
as a community service, go for it. Until then, he's all talk
and no substance.

lol

I think that the learning curve at public fora such as this
is very different from that of a technician who has been
working in a Honda shop for several years. If
one--anyone--reads here enough, s/he will accumulate I
believe many more reports of non-start conditions (to name
one category) and the correction that ultimately worked. A
statistical cluster certainly does occur around certain
causes of non-start conditions, for any make and year of
car. Does Honda even keep count, sending notices out to
dealers? I'm sure it does for major stuff. But not a lot of
the minor stuff that is still nonetheless a huge headache
for customers.

A technician who spends much of the day doing everything
from changing oil to timing belts (not to mention other time
consuming repairs such as putting on a new CV boot or, god
forbid, say, helping research warranties) simply can't
accumulate this sense of statistical proportion for no-start
conditions. So lacking this experience, the bona fide
technicians, especially those with just a few years
experience, can't diagnose as effectively in many instances
as a group such as this, where this is an anecdotal mental
count kept, of sorts, of typical problems with Hondas, by
year and model.

Generally speaking. I'm sure there are exceptions.

Evidence of this is how clueless Honda and other shops seem
to be (based on reports here) about, say, the main relay and
igniter. Again, with exceptions.

And shucks no, next time my alternator warning light comes
on, I don't want to have to pay $300 for a new alternator at
the dealer when I can pay $30 tops for a new brush assembly
and fix it myself.