1992 Honda Accord Coup - RPM issue

[laloquera]

Wow! Just got back from Southern Cal yesterday. 92 Honda runs great, got 488 Miles on one tank, yup ran that sucker on fumes. Heck!, car even felt light, gliding down the grape vine. I usually don’t run my car that hard, mom is the original owner and doubt if she ever travel more that 65 mph. Anyway, on my way home, I did push the car hard doing 80 to 85 mph. I notice my RPM slightly jumping, like from 3.5 to 4 and did feel a slight jolt. Anyone have a clarification for me. Imp schedule to drive down for thanxgiving weekend and do not want to have the same issue. Thank you
Laloquera

[laloquera]

Anyone?

[jeffcoslacker]

Sure it wasn't just the TCC locking and unlocking as needed?

Should lock up and drop rpms by 200-300 when cruising comfortably, will unlock and revs go up same amount when you push the gas a little bit...slight bump felt almost like an overdrive shift but not as noticeable...

[laloquera]

I don’t know about the TTC? Like I said, I was cruising 80 to 85 mph. Lets say, I was doing 80 with cruise control on. My foot was off the gas pedal almost the entire trip, I just notice the rpms spiking up and down and did feel the a slight jolt. I’m back to my regular commute and do 60 to 65 mph, no rpm spike or jolt. Should I be concern, or should I just go easy on my next long trip. 1992 240k miles, do the schedule lube changes my self.
Thanx
laloquera

[jeffcoslacker]

I was basing this on the assumption it is an automatic tranny? If not, something is not right.

TCC lockup is more noticeable the faster you run, and it will jump in and out of lockup more often at higher speed (harder on the motor to maintain speed at 85 than 65, so it need to jump out of lockup more often)

I really think this is what you were feeling.

Watch your rpms when you get on the highway and just let it cruise. After it shifts to top gear, after a short distance of driving unloaded on a flat road you'll see the rpms drop about 200-300 rpm and notice a slight change in the engine's sound...that's the TCC going into lock. Touch the gas pedal or brake and it'll unlock and rpms will rise by the same amount.

At 85 mph, that 4 cylinder is working about 25% harder than at 65...so any slight load (rise in the road, headwind, etc) is going to force it out of lockup.

The TCC mechanism mechanically locks the drive and driven sides of the torque convertor turbine together to eliminate slip and improve fuel mileage...but it can only operate like that when cruising at a steady speed, lightly loaded...any additional demand on the motor will force it to unlock...

[laloquera]

jeffcoslacker
Thanx for insight. So, I take its expected to perform in that matter. I will tend to take it easy on my 92baby, I plan to be driving it alont time.
Thanx again
Laloquera

[jeffcoslacker]

The only other thing I can think of is if the tranny is hunting in and out of overdrive excessively...on the older GM cars we called this "overdrive search and lurch" but I don't see it on Hondas ever...

You wouldn't have gotten fuel mileage that good if this was happening...

[jeffcoslacker]

Hey I just wanted to report a bit on this.

I got to drive my '95 a fair distance the other day through rolling hills at 60-80 mph...done this before but just never paid much attention to engine speed.

It did do a lot of TCC lock/unlock cycles, especially with the cruise control on, and you're right the rpm range of the lockup is about 400 rpm up or down, a little more than I'm used to (I normally drive a V6 Chevy with much more torque, lockups are not really noticable and only 200 rpm drop or so...)

But anyway, I'm confident this is what you noticed...the bump is quite noticeable, I actually shifted it down to D3 from D4 just to verify that it was not a gear change...it's definitely not hunting gears, that's a much larger rpm change...