I drive about 45,000 miles/year in my 95 Accord EX, 4-cyl VTEC with auto and have countless hours on cruise control to watch and wonder about my car. It seems like the gas mileage is low, especially compared to the 94 w/5-speed I used to drive. At first I chalked that up to the difference between auto and stick and the change in Texas speed limits. But I have noticed that when I'm cruising on flat terrain at 70 mph, the RPM will sit at about 3100. When I start up a hill, the RPM drops down to 2900 (I can feel the shift) until I hit the peak of the hill, when it returns to 3100. Sometimes on the back side of the hill the RPM will drop down to 2900, too. Also if I'm on a 2-lane road and need to pass, I step harder on the accelerator and the RPM drops down again to 2900 before speeding up from the extra fuel. It seems like the transmission sits in 4th gear on flat terrain and shifts into overdrive to pass or climb. My mechanic, who I trust implicitly after 25 years of excellent service, tells me the computer says everything is fine, so he doesn't know where to start. I believe he believes that and cannot help. But still it seems like I have two wires crossed or two vacuum hoses crossed. Does anyone have experience with this or suggestions of where to look?

 

the auto trannys only have 4 gears.. 1st, 2nd, 3rd and overdrive.

And it seems pretty normal to me, your vtec kicks in when it needs to.

 

Thanks for the gear count. I didn't get a book and really haven't delved into this other than basic transportation.

So you're saying the engine should drop to lower RPM when it needs more power? Why does that seem counterintuitive to me?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sony224422 &raquo;</TD></TR><TR><TD CLASS="quote">the auto trannys only have 4 gears.. 1st, 2nd, 3rd and overdrive.

And it seems pretty normal to me, your vtec kicks in when it needs to.</TD></TR></TABLE>

Are you kidding me? That doesn't sound normal for the torque converter to lock up only when going uphill. It's doing the exact opposite of what it should.

DSA, I suspect maybe a TCU issue. Then again, my knowledge on auto trannies is limited.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by philadd &raquo;</TD></TR><TR><TD CLASS="quote">

Are you kidding me? That doesn't sound normal for the torque converter to lock up only when going uphill. It's doing the exact opposite of what it should.

DSA, I suspect maybe a TCU issue. Then again, my knowledge on auto trannies is limited.</TD></TR></TABLE>

the clutch pack will lock up during high speed highway driving, it will provide a small physical contact.

before looking into anything tranny related, i should ask did you keep up with the maintanence?

air filter
fuel filter
pvc
sparkplug
tire pressure
egr condition
map sensor condition
all the drivetrain fluid

etc

 

But from what he's saying, it's not locking up while cruising at highway speeds. It only does it while going uphill and occasionally downhill. To me, it sounds like the Grade Logic is kicking in and doing the opposite of what it should be doing. (I was under the impression that the 5th gen autos had Grade Logic... correct me if I'm wrong.)

 

check your t-stat and make sure that it is working. It sounds like maybe yours is not closing all the way or not allowing the car to reach proper operating temp.

for a 5th gen I4 auto your rpms for 70 should be about 2800 or so. If your torque converter is not locking up in 4th your rpms would be where you say that they are about 3100-3200 at 70.

The reason the torque converter is not locking up may be due to the fact that the ECU will not allow the converter to lock up if the engine has NOT REACHED proper operating temp

Another cause is that the lockup solenoid is bad and needs to be replaced.

 

all the more reason I think it is the t-stat as engine heats up and torqe converter locks. Once the additional load is removed, it will unlock because the engine temp comes back down.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by iam7head &raquo;</TD></TR><TR><TD CLASS="quote">

before looking into anything tranny related, i should ask did you keep up with the maintanence?

air filter
fuel filter
pvc
sparkplug
tire pressure
egr condition
map sensor condition
all the drivetrain fluid

etc

</TD></TR></TABLE>
I bought the car used, so this is an excellent suggestion. This car had THE most unusual things wrong with it at first (how do you break the last inch off a front axle???). The spark plugs, tires, and air filter are the only thing I know are okay from this list. Engine oil is changed monthly, tires are new and rotated and checked monthly. Transmission fluid has been ignored (which all of a sudden seems so obvious that it makes me wonder why I even asked this question, duh!).

Does the motor heat up? Here are my only clues: The gage inside seems to move at the right time and about the right distance (almost half way on the gage), there's always adequate heat in the winter, and when I stop the car, the radiator fan comes on for about 3 minutes. But compared to the subtleties of what the computer is looking at, these are pretty rough tools to judge by. While I'm having all the rest checked, I think a thermostat test or replacement would be in order.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by iam7head &raquo;</TD></TR><TR><TD CLASS="quote">

before looking into anything tranny related, i should ask did you keep up with the maintanence?

air filter
fuel filter
pvc
sparkplug
tire pressure
egr condition
map sensor condition
all the drivetrain fluid

etc

</TD></TR></TABLE>
I bought the car used, so this is an excellent suggestion. This car had THE most unusual things wrong with it at first (how do you break the last inch off a front axle???). The spark plugs, tires, and air filter are the only thing I know are okay from this list. Engine oil is changed monthly, tires are new and rotated and checked monthly. Transmission fluid has been ignored (which all of a sudden seems so obvious that it makes me wonder why I even asked this question, duh!).

Does the motor heat up? Here are my only clues: The gage inside seems to move at the right time and about the right distance (almost half way on the gage), there's always adequate heat in the winter, and when I stop the car, the radiator fan comes on for about 3 minutes. But compared to the subtleties of what the computer is looking at, these are pretty rough tools to judge by. While I'm having all the rest checked, I think a thermostat test or replacement would be in order.