92 Accord EX Tach Jumping Help & Tach Question

Thanks for looking,
Like I said 92 Accord (auto) about 155,000 I bought it around 150,000,
and have no problems yet. Only when I get to about 55 or 60 MPH does
the tach bob up and down speratically about 100- as much as 300 RPMS,
but not when I get past about 70 or 75. Some days it does it and some
days it doesn't. Obviosly when ever I get someone in the car to show
them it never does. What could this be? Also for all you Accord
owners out there. I have the 2.2 engine what is the avg. RPMS when
going 60 flat?

Thanks
-Adam

 

Have you confirmed that this is travel speed related, and not engine speed
related? For example, if you shift in to 2, and get the rpms to about the
same place (as they are at 55mph in 4th gear), can you ever get this
behavior? If you don't have a tach, you'll have to do it by ear.

Does the speedometer ever jump around? Is your Check Engine light lit?

-Arthur

 

Thanks for the response. I will try that and get back to you all.
Speedo doesn't jump around at all so I am thinking it is some type of
belt slipping of some sorts. The Check engine light someimes comes on
but when I turn off the car and then back on it does not come on. It
is spuratic it is more off then it is on. I am showing an ABS light
though but I don't think the two are related
P.S. Please respond to the post or email me at

 

Adam,

Please read out the check engine light codes
( procedure here: http://home.earthlink.net/~michaelpkeefe/ )

Even when the light is off, the ECU will remember the codes, so you don't
have to wait for it to come on again.

At this point, I'm guessing that your igniter is dying (the igniter is a
solid state switch with some logic around it that switches current to the
ignition coil. It lives inside the distributor housing on your car.) The
DTC that you read out should help.

-Arthur

 

As for rpms at 60mph, these are from the 91 Accord Helm book for the non-EX
trim version, and should apply to you:

Stock tires P185/70 14" put you at (if I did this right) 185mm*0.70(aspect
ratio)/25.4(mm/in)*pi=24.2" diameter, or 76" circumference.
At 60 this is 833.5 (tire) rpm.

Final drive ratio is 4.285:1, and 4th gear is 0.674:1, your torque
converter is locked, so that puts your engine rpms at 2407.

-Arthur

 

AWESOME.

Thank you for your help. Today I figured out that this problem only
occurs when I am in 4 gear going about 60-65 mph. I will try and get
the codes tommorow.

THANKS!
Adam

 

Hi Arthur,

Off topic, but I'm just skimming threads, gleaning info which I might
think later useful. I just purchased a '93 Accord LX 5 Spd with 136
KMi and so am particularly interested in your experiences with your
'93 Acc: please consider leaving all information relating to your old
car up on your site, thanks!

I wanted to ask if you'd experienced any rust around the rear
wheelwells and a few other questions, but I should start a new thread
to do so, please look out for it..

CJ

 

Whoo hooo! No, that's not my site. I got a new kid, and a freakin demanding
job. Even if I had the time, I'm not up on web coding. Mine's a 91 also, by
the way, but they're all the same (90-93) pretty much.

I'd write articles for someone who had the time to integrate them into a
site, but that's a bit much to ask. I like Grant's new site...still posting
for professionals-only though.

OK, I'll watch for your new thread. I got a rust issue too, maybe I'll
side-thread it.

Arthur

 

Excellent. I am finally getting somewhere. I got the code and now am
in a stuck position. The code I got was 12 and I am positive of that
I checked it about 10 times. This could relate to the problem I have
been having with my ABS light. When ever I turn the car on it is off
but once I start to move the ABS light turns on. I have no idea if
these 2 are the same. I checked on that websites chart and it didn't
have a 12 (Just my luck) I will do some more searching and get back to
you guys.

THANKS
Adam

 

Eh' crap. I just check the "back up radio" fuse (7.5) and it was
blown so I replaced it with a 15. Is this going to be a problem?

Thanks
Adam

 

Folks always recommend not doing it. I don't do that because you risk
overheating wiring if the fuse is too heavy and you have the right kind of
fault.

However, an interesting question is why it blew. If you don't know why the
fuse was blown, you should be very careful putting a higher current one. I
would probably put in a *LOWER CURRENT* one for now (no less than 5A
though) until you find the fault cause. If you know why it blew, then
they're easy enough to get, so I also would recommend that you put in a
7.5A fuse when you can.

The backup fuse powers the ECU and the TCU so they can remember the
modified/optimized fuel map and shift schedule. Without it, your car will
always be learning how to trim the fuel injection timing to keep the engine
burning clean (and in doing so it will not burn as efficiently/cleanly as
it could)

-Arthur

 

ABS Light: you should read out the trouble codes for that system as well.
My car doesn't have ABS so I'm talking from the manual here.
Remove fuse ALB-B2 for 3s. Wait till the light comes on again, and leave
the engine running. The control unit is along the right side of the trunk.
I suppose you have to remove the trunk liner from the right side to access
it. It's a squarish box, mounted at an angle. Once you have access, there's
a maintenance plug in the unit (the plug closest to the trunk lid), and
behind that is an LED that will blink out codes.

=====

12 = Exhaust Gas Recirculation System trouble. I don't think this is
related to your tach jumping around. At each exhaust port on the exhaust
manifold, there's a port to an exhaust rail. At the end of the rail,
there's a variable, vacuum controlled valve (EGR valve). When the valve is
open, exhaust gas passes through and passes back around to the intake
manifold, where it is admitted to the intake mixture entering the engine.

The vacuum to control the EGR valve is controlled by an electro-mechanical
control solenoid valve. In addition, the vacuum that is on the "supply
side" of that solenoid is regulated by the CVC valve (constant vacuum
control, I'm guessing). The CVC doesn't have other inputs so I think it's
just a regulator.

The EGR valve assembly also has a lift sensor that feeds back how much the
valve is open to the ECU. The EGR light will come on if the ECU commands
the valve to open, but the lift sensor feedback doesn't match.

A common problem with our I4 Accords is that the EGR ports from the exhaust
manifold become clogged with soot. If all four get clogged, the engine runs
fine but the system will throw the EGR code (I don't know how it knows
there's no flow, but it does). If some of them are clogged, then the engine
stumbles in some conditions, but the system won't throw a code.

In controlling the EGR valve, the ECU uses signals from the MAP sensor, the
TDC/Crank angle sensor (distributor/igniter stuff), the throttle angle
sensor, and the TW (temp) sensor.

#1: warm car up till Check Engine light comes on (try to run at 1700-2500
which is when EGR system is most active). Locate EGR valve (it's in back of
the valve cover, in back of the distributor but in front of the throttle
body). It's a small round housing with a metal bracket held on by a wire
clips on either side:
(http://www.cncar.net/jdwx/honda/accord~1/a06/IMAGE/b4601.GIF)
First thing to check is that if you remove the small vacuum hose from the
valve, that there is vacuum present in the hose.

Post back with results.

- Arthur
P.S. Don't worry, your car isn't hopeless. Do you have access to a junk
yard for parts though? If you end up swapping control boxes, they are
prohibitively expensive to buy new.

 

By the way Adam, if you're a car guy, and you like your Accord, and you
want to keep it and want to work on it some yourself, I would buy the
Service Manual. It is definitely worth it. You might find one on EBAY, but
if not they're still available new. You want the silver one published by
Helm Inc. I would not recommend screwing around with Chiltons or Haynes.

-Arthur

 

I do have a service manual right now and I am a "kinda" car guy, I
know my stuff, but the manual I have right now is BS I belive it is
indeed a Haynes. It has NOTHING about TCM codes or anything.
The reason the back up fuse could have blown is becasue the guy
before me but in a new reciever and it looked TOTALLY butched when I
got it. So he might have shorted somethign out.
I did look around a little bit more and found 2 sites that had a
code "12". It's bad EGR (Exhaust Gas Reserc.) So I am the process of
seeing if it is a leak or if the sensor is bad on it. Do you think
this could be my problem?

Thanks,
Adam

 

Please see my other post to this thread (5/29/04 8:52AM) for EGR system
details.

Get yourself the Helm book. It's the bible. I don't endorse EBAY, but
here's the book you want: http://tinyurl.com/yrqq3 Seller wants $45 which
is IMHO a fair price. I don't know what he means by "reprint", it looks
authentic...