Problem with 98 Honda Accord

My grandmother who does not have alot of money is having problems with
the car acting as if it wants to stall after you start it. I think the
check engine light is on too.

Here are the codes that came when checked:
0170 - Fuel Trim Malf.
0171 - System too lean bank 1, Sensor 1
0133 - 02 sensor bank 1, sensor 1
0300 - Random/Multiple Cylinder Misfire
0301 - Cylinder 1 Misfire
0302 - Cylinder 2 Misfire
0303 - Cylinder 3 Misfire
0304 - Cylinder 4 Misfire
0420 - Catalyst System below threshold

Any advice on where to start? I dont have a manual for this car. Like
I said it is my grandmothers and she does not have alot of money and I
am trying to help her out.

 

id probably test the O2 sensors, see if theyre working. how many miles
on it? has it ever had a tuneup? new plugs?

on my 98 civic, a bad O2 sensor made the car idle low, run rough, and
stall when decellerating. i never got any of the other codes, tho.

 

last time i saw all these codes at the same time was when we got a
car in that had a 1/2 tank of deisel in it!
Chip

 

What is the procedure for testing the o2 sensor? I have a multimeter
and have done it before but never worked on a Honda before.

 

on the accord? dunno.

on my 98 civic, the bottom 2 of the 4 prongs on the plug are for the O2
sensor heater circuit. both are black wires, IIRC. there should be some
resistance going thru the O2 hearter circuit. if the ohmmeter reads *0*,
its broken.

to make sure, i compared the reading to the sensor on the bottom. it
read .15 ohms, or something like that.

 

SoCalMike wrote:

Perhaps so, but the most common failure mode for the heater is that it
goes open circuit (= infinite resistance), not that it becomes a short
circuit (= 0 ohms). The service manual for my '94 Civic indicates that
the heating element of a good O2 sensor measures about 10 - 40 ohms for
that car.

 

Have a poke around here http://www.autotech-elearning.com/forum/index.php
to see if there's anything. If it's a ULEV engine, there's an additional
AF (Air Fuel) sensor on the exhaust manifold down-pipe on top of the two O2
sensors.

Did all this happen quickly, rather than develop over a period of time?
Any service performed just before hand? It all sounds kinda drastic and a
catastrophic failure is unlikely - more like, as Chip says, a badly
contaminated fuel fill, a bad or unconnected wire harness or even an ECU
failure.

On contaminated fuel, it does happen: years ago, when I worked in the fuels
lab of the Tech Sales Dept. of a major petroleum company, we had a gas
station which topped up their gasoline tank with a load of kerosene -
wrecked the engine of a brand new Volvo... lifted the cylinder head off the
block. Have a sniff at the fuel filler - kero or diesel should be easily
recognizable.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

The car is still having problems. I had the codes erased and they came
back. The misfires and running lean puzzle me. Also what is the fuel
trim code that keeps coming up? What is a fuel trim anyway?

The check engine light is only on when the car has been sitting for a
real long time and is cold. When You give it gas from a stop it lugs
and acts like it will die. It runs ok cruising. When warm the
driveabiluity problem almost disappears.

I put new plugs in it and checked the resistance in the wires. They
seemed ok.

A bad o2 sensor would not cause all these misfires and lean conditions
would they. Isn't the o2 sensor in open loop mode anyway when the
engine is cold?

This is a grandparents car and she does not have alot of money. I am
trying to help her out.

Are there any checks I can do with a multimeter on the sensor?

By the way, one thing I noticed that may be of no significance is I
noticed the little "flapper" valve in the fuel filler neck opening is
missing. (The valve that you stick the gas station nozzel to).

 

Is this Accord a 4-cylinder or a V6? I read somewhere that V6-powered
Accords of this generation ('98-'02) had issues with the EGR system.

 

This is a 4 cylinder. Any advice on where to start?

 

I'm an amateur and am curious about your car's problems. I googled about "fuel
trim": It refers to minor adjustments that the car's computer makes to the fuel
injector duration. So a phrase like "trimming high" suggests the computer has
increased the FI injector duration (more fuel, so richer combustion) to achieve
a combustion ratio smaller than the "usual" stoichiometric ratio of 14.7 lbs of
air to 1 lb of fuel.
http://www.findarticles.com/p/articles/mi_m0BQA/is_7_80/ai_77195162 See both
pages of this link.

See also http://www.ttguy.com/maf-vag-com.html

I'm sure seeing a lot of references to the MAF (= mass air flow) sensor (either
malfunctioning or having an air leak in its vicinity) with regard to fuel trim
codes and problems. In particular, fuel trim malfunction with a too lean
condition points to problems in or around the MAF sensor.

But other possibilities are referenced, too...

Yes. The O2 sensor signal is ignored (= open loop operation) until the car is
warmed up.

So if you're thinking the O2 sensor is not the problem, I am inclined to agree.

FWIW:
Unfortunately if you're going to do this yourself, it sounds like you're going
to have to dig in and spend a little money. You might want to weigh the cost of
all your experimenting against taking the car to an independent shop which might
be able to nail the problem more quickly and possibly at lower expense.

Of course, the advantages of experimenting are you learn a lot. Maybe it's worth
buying parts and tools to fix this problem, as it will help you troubleshoot
future problems.

Updates are welcome, for the archives.

Good luck.

 

Where is the MAF on this car and is there a procdure to trouble shoot
it with a multimeter?

I am on the fence about the 02 sensor. On a Honda Accord board on the
net someone posted they had a similar problem to mine and there's
turned out to be an 02 sensor. (But they only had a code for an 02
sensor)

If it was the MAF wouldn't it have shot a code for it?

 

Don,

1.
I'm pretty sure your 98 Accord uses an MAP (= manifold absolute pressure) sensor
in place of a mass air flow (MAF) sensor. Both attempt to measure the air flow
into the engine. See http://www.hotrodhandbooks.com.au/EMS_2.htm for the
difference.

To see a drawing of the 1998 Accord's MAP sensor, go to
http://www.hondaautomotiveparts.com/auto/jsp/mws/catdisplay.jsp, put in your
car's info, then select "Throttle Body." Look down the list for the MAP sensor.
For a 1998 Accord 4-door LX, it's item 11, costing about $60 if one takes into
account shipping and handling.

2.
For troubleshooting right now, you'd be best off calling your public library and
seeing if they have a Chilton's for your 1998 Accord. Many libraries carry the
Chilton's series.

3.
Online there is the following troubleshooting procedure for the MAP sensor for
1995-1997 Civics:
http://www.honda.co.uk/owner/CivicManual/pdf/11-40.pdf

4.
My understanding is whether the specific trouble code appears for a
malfunctioning sensor depends on the type of malfunction. If a sensor is
malfunctioning, sometimes the only clue will be some parameter further down the
road from the sensor, e.g. in the car's exhaust, to tell the car owner what's
wrong.

If there are no codes for the MAP sensor, then the Civic link above says to
check for poor connection or loose wires between the MAP sensor and computer.

5.
Here's a couple of sites I found that talk in general about malfunctioning MAF
sensors causing a lean condition and giving the fuel trim trouble code:

http://www.motorcars-ltd.com/ubb/Forum22/HTML/000122.html

http://www.myvwlemon.com/ubb/Forum1/HTML/001114.html

I caution you: This is just one shot in the relative darkness.

6.
Maybe the problem is the oxygen sensor. I'm not seeing how, given your car's
problem only occurs while warming up and so presumably in open loop, but I could
be missing something.

Should you want to try a new oxygen sensor, I recommend
https://www.automedicsupply.com/ for OEM ones at perhaps the best price
anywhere. I bought a new O2 sensor for my 1991 Civic from these folks a few
weeks ago and was pleased with their service, as well. (Your car has two O2
sensors: One upstream of the cat. converter (= Bank 1, Sensor 1). One
downstream.)

7.
At a minimum, of course it seems likely it's something in the emissions control
system. I wouldn't rule out a problem in the EGR system, either. Again, even
though there's no specific code for the EGR system, I'd check all electrical
connections to it.

Online, you can try the 1995-1997 Civic manual's Fuel Emissions section for a
lot of good ideas on troubleshooting specific components.
http://www.honda.co.uk/owner/CivicManual/index.html (click on "Fuel Emissions").
Be alert to differences between this car and your 1998 Accord. There is no
guarantee that they are identical when it comes to fuel emissions, though my
(limited) experience indicates there's a lot of overlap. They both have MAP
sensors and EGR systems, of course, for example...

I would stay focused on all the inputs to the computer when the car is in open
loop (= warming up). That link above lists all the sensors for the 1995 Civic.
Maybe consider which of them are giving an "important signal" to the computer
when the car is warming up?

Maybe it's fair to say the O2 sensor signal tends to dominate after the car is
warmed up so that these other inputs can't mess up the engine's operation after
it's warmed up.

8.
Have you eliminated the "bad gas" possibility that two posters mentioned?

9.
Also, as they asked, did this just suddenly start happening out of nowhere? Or
had the car just been filled up or had other work done on it? Just want to
double check...

10.
Again, I'm an amateur armed with Google, a lot of reading on emissions controls
lately, and my own 1991 Civic. Speaking of Google, I did check the archives for
this newsgroup and alt.autos.honda and found darn little on the fuel trim and
lean codes; definitely nothing that offered any help. I did see a number of
folks who had had to replace the MAP sensor. Outside of the Honda newsgroups,
there is more chatter on getting these codes simultaneously.

Sorry this can't be nailed quickly, like so many auto problems. Hang in there
and take careful notes of any new information you care to share.

 

I ran fuel injector cleaner in it and filled up with good high octane gas.

The problem gets better when it is warmed up but does not completely go away.