Here's one that'll surely throw you all for a loop. My 96 Accord EX Auto actually drops in RPM by about 150-200 on the tach at part throttle vs. "cruising" throttle. For example, If I'm giving it just enough gas to maintain 60mph the tach sits at about 2200rpm in 4th gear. If I give it just a little more (~2-5%) throttle the rpm will drop to 2000 before rising with acceleration. That sure doesn't seem very mpg-friendly. I double-checked the TPS calibration, it's a steady 9.8% at closed throttle and the only other troubleshooting I've done is clean the transmission main- and counter-shaft sensor tips of metallic debris. Problem still exists. Drain & fill x3 was around a year ago with 1 more done about 3 months ago. Genuine Honda DW-1 was used every time. Any ideas?

 

Post a vid

 

2200rpm @60MPH is correct with lockup with an Accord trans 4th gear(.674) and correct final drive(4.133). But the 200rpm drop is a bit strange. What are the four letters on the barcode sticker on the transmission? It should be on the side of the trans the faces the radiator.

Does your tach ever do anything else strange? Jumping, skipping or slow to react?

 

I still have similar problem but it happens on idle too. Took a graph and advance timing dips before rising. Uncertain why that happens

 

@holmes I will work on getting a vid this weekend.

@Mike It's a BOYA if that's the 4 letter code you're referring to. Tach has no other issues and this problem is reproducible 100% of the time.

Unsure if related, but when I first bought the car 2 years ago it had what I believe to be TCC shudder. I was able to diminish this to where I can no longer feel it with the proper fluid servicing. I suspect it was filled with a universal fluid at some point prior to my acquisition of it as there is a B&G Transmission flush sticker on the upper rad. support. The trans. does slip some during the 1-2 upshift when below normal operating temperature.

 

Yup. And BOYA is correct for your car.

With the hood open and standing facing the engine, look to your left where there is the wire harness and fuse box. In that harness there will be a single wire with a rubbery blue connector on the end of it.


This is an image from a V6 car that is why the tag has 'WHT' rather than 'BLU'.

That is the TACH TEST connector. It will give the signal off the coil/ECU of the rpms. If the gauge is doing something goofy you will see the difference by using an auxillary tachometer hooked up to this signal wire.

Click on the TECH AUTO link in my sig, and then click on the Transmission link in the upper left menu. Browse through and make sure that your shift solenoids click, the screens are clear, and that the throttle cable is adjusted correctly.

If the autoparts store nearby sell SeaFoam, look for the TRANS TUNE by SeaFoam, similar can. Next fluid change, dump in the whole can into your trans and then top off with ATF. Dexron III will be fine. No need to use the uber pricey Honda Fluid.

 

"Next fluid change, dump in the whole can into your trans and then top off with ATF."

So should I leave the Trans-Tune in there or drive a bit and change fluid again? I was going to do this a while back but was unsure if the trans-tune was safe to leave in there or if it should be changed out in 50-100 miles.

Also, If DEXIII is okay, what about Castrol Multi-Import? They sell it at my local walmart MUCH cheaper than Honda fluid.

 

If your car is at idle and you press throttle does it rise instantly or first dips down and then rises

 

@afnan My problem only occurs when the vehicle is in gear and in motion. This is what leads me to think a transmission problem. It's almost as if some clutch is engaging. At idle (in park) the engine revs with no drop or other problems when I press on the accelerator.

 

This may sound stupid but do following test:

1. Connect Fuel Pressure gauge
2. Cruise at 2200 RPM constantly for a minute or so
3. Press the throttle. Or do what ever replicates the symptoms.
4. Make sure you have video camera on gauge so you may not be able to give attention while driving.
5. What happens to fuel pressure reading?