I've looked at diagrams and pictures of the downshift throttle cable in pre-2000 Accords and they show a second cable running from the spring-loaded reel on the throttle plate shaft to a lever on the transmission. Am I right in concluding that the 2000 auto trans has a position sensor to electronically tell the transmission where the throttle plate is instead of a cable? If yes, can this sensor be rotated to raise or lower downshift points or are they strictly controlled by the computer using other inputs? I've experienced the shudder described by others while under light load between 30 and 40 mph and, if cleaning the EGR ports doesn't do the trick, I hope to bias the lock-up a little higher as mentioned as a fix for older units. Does anyone know where a free service manual for the 2.3 can be found?

 

The physical cable (from throttle to tranny) dissapeared beginning in 1998. I think the shift control comes from the engine load calculated within the engine ECM. It's not as simple as throttle position.

The engine controller & transmission controller are integrated into one box, called the Powertrain Control Module (PCM) and the shift points come from software/firmware within that PCM.

After cleaning the EGR, you might try resetting the PCM (pull fuse #13 at the right-end of the dashboard). I suspect there's some "learning" within the PCM about your driving habits. I remember hearing something about 'grade-control logic' to prevent it from hunting between gears & lockup/unlock of the torque converter.

 

Thanks, Jim. I will clean the EGR this pm and see if that does the trick. The instructions I've seen for the individual EGR ports doesn't compute - I can see the valve OK but bosses, ports, plugs, whatever I'm looking for is not in the area indicated on older engines. Do I have to strip off the injection rail, etc. to be able to see them?

 

I had a 1998 (same generation) and I think the ports are all different. But I never had to clean them. Possibly you can take off the EGR valve & look into the opening where it was mounted. If it's all cruddy & plugged, you might have to remove the manifold. Not sure, so I hope someone else chimes in.

 

Well, the EGR valve was just a little dusty so I brushed it out and put it back. It looks like the EGR exit dumps into the plenum just downstream of the throttle plate instead of splitting off to each intake runner so I conclude there is no reason to pursue this anymore. I'll get back to trying to understand the sensors, actuators and logic involved in telling the lockup solenoids to activate. By the way, those solenoids are each 16 ohms and click as expected when 12 volts is applied. Also, the screens that filter ATF in the solenoid valves are clean. I now think my next step is to drain and fill the transmission a couple of times. Any suggestions on the cheapest source of Honda brand ATF?

 

I think that the EGR port on the 98-02 four cylinder runs down the side of the intake manifold to the egr valve.

From the picture it is above the #8 label. It runs from the square hole for the egr valve to the upper part of the intake manifold. You may have to remove #10 (get a #11 gasket) and clean out that passage.

 

Yes, you have to remove the upper intake to clean the (1) EGR passageway. Remember where all of the coolant and vacuum lines connect on it! You'll need some steel wire or something to force your way through the passageway. Cleaning the ends and the EGR valve itself will not free it up enough. The #11 is a multilayer metal gasket, I've had success reusing it with no leaks.

Might be beneficial to clean out the IACV while you're at it too (on #10, where the 3 rectangular ports are)

 

It sure helps to see how things go together. Is this illustration from the Helms service manual or from a parts book and where can I find it/them?

 

The Helm manual actually has much better illustrations.

Lots of on-line parts places have the same pictures, so I bet they're from Honda's electronic parts catalog. That's what they give to dealers, instead of the older system of parts drawings on microfiche.
hondaautomotiveparts dot com
hondapartsdeals dot com
few other places like that...?

 

Thanks Jim, the illustrations at those sites are helpful but I still need to get a Helms.