Hey Fellows,

On my 91 Accord LX, while driving at higher speeds, my Tranny is unable to shift into 4th gear (over drive)... even though it shifts into 1st, 2nd and 3rd fine. I have already changed my VSS (vehicle speed sensor), which was what i thought was causing it, but its not. Could a bad TCU be the cause of my tranny not shifting into 4th.

 

make sure you have plenty of ATF, and that its not burnt smelling and thats its pinkish.. or just get it changed completely.

 

You may have developed an issue with one of two solenoid packs mounted to the transmission case. They are (most likely) responsible for your shifting issue.
I don't think it so much a solenoid failure, but crud which has clogged the serviceable screens located below the solenoids.
Here is an illustration:



And the link for pricing, if it should get that far;

http://www.hondaautomotivepart...USING

Remove the solenoids (#5 and #7), clean the screens (#8 and #6) and reassemble. Let us know how you made out.

P

 

My Tranny fluid levels are fine and it doesn't smell burnt.

Also... from the looks of the diagram, i am unsure if the solenoids are located on the outer part of the Transmission or is it on the inner part? Also if it is on the outter part, am i able reach it from up top or bottom of the vehicle.

 

Oh... i see the solenoids are mounted onto the tranny. It looks like its on the back end of the engine bay. Meaning i'll have to go from bottom up...

 

They face forward, towards the Radiator/shroud.
Note the arrow (points to vehicle front)

P

 

Is your gas mileage crap?
You could have a failing coolant temp sensor. That car has two of them and if the car thinks it's cold so the torque converter won't go into lockup (no overdrive)

 

You make a good point with the gas mileage. So yes, my gas mileage does run like crap. Will look into changing those sensors.

 

does the car go into 4th but the torque converter not lock up? If that is the case, you might have stuck open thermostat. IF your car is not going into 4th you would be turning over 3K at 45mph................

 

I don't think that is the case, because it doesn't go into 4th at all. But thanks for the suggestion.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by YeuEmMaiMai &raquo;</TD></TR><TR><TD CLASS="quote">does the car go into 4th but the torque converter not lock up? If that is the case, you might have stuck open thermostat. IF your car is not going into 4th you would be turning over 3K at 45mph................</TD></TR></TABLE>
That's the other side of my statement, but the most common cause seems to be a crapped out temp sensor in the side of the head right beside the heater hose outlet and below the distributor (one pin connector).
THe reason I mention gas mileage is because the car will dump more fuel if it thinks it's cold. Even if your temp gauge is working ok the other sensor may not be. (one sensor goes to the ECM and the other goes to the gauge)

 

I think you are mistaken MooGo, I know you work on alot of different models. On the 91 from the outlet hose back to the head under the dist there are 3 sensors or switches. The front one is the fan switch. The middle one has one wire and is the sending unit for the temp guage. The third one back is the Engine Coolant Temperature sensor and talks to the ECM. The Honda part # for the ECT is 37870-PK2-015.

 

In either case, wouldn't a defective (out of range) sensor set a code and illuminate the "check engine" indicator. There has been no mention of it.
And just on the face of it, wouldn't the loss of an operable 4th & Lock-up predicate a fuel milage loss (just on it's own?)

P

 

No, when it comes to the ECT the computer will just think the engine never warmed up and will remain in default. It won't throw a code because many times the ECT's develop higher resistance and just simply are out of range.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by P_Adams &raquo;</TD></TR><TR><TD CLASS="quote">
Remove the solenoids (#5 and #7), clean the screens (#8 and #6) and reassemble. Let us know how you made out.
P</TD></TR></TABLE>

I have a question about cleaning the solenoids... what do you use to clean them?
Would brake parts cleaner be too strong or damage the unit?

 

Clean the screens. (The solenoids are a different matter)*

*if you want to use some brake cleaner (the stuff that smells like Dry Cleaning Fluid) you can give them a brief spritz. Like anything electronic, you don't want that stuff getting inside.

You shouldn't find any crap in the solenoids anyway (assuming the screens do their intended jobs).

The screens can be cleaned with Brake cleaner** as well. It drys without a residue.

P

** or Carb Cleaner

 

before replacing parts why don't you chk 4th clutch pressure ???

pressure plug is the furthest rear on rear case ,, remove plug, hook up a gauge , raise the frt wheel off the ground, start car run at 2000 rpm, remove the cable from the throttle lever,,,,,,,,with throttle fully closed should be over 67 psi,, and with throttle 1/4 open should be above 107 psi..
If lower you got issues with 4th clutch pac

 

Oh, I get it now... you said "clean the screens (#8 and #6)" on the diagram.

Thanks

I'm going to try this tonight.

 

I definately don't reccomend using brake clean on shift solenoids. Only compressed air is safe.
And no a bad ECT will not give a DTC, that trouble code did not come along until OBD 2.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MooGoCow3 &raquo;</TD></TR><TR><TD CLASS="quote">
That's the other side of my statement, but the most common cause seems to be a crapped out temp sensor in the side of the head right beside the heater hose outlet and below the distributor (one pin connector).
THe reason I mention gas mileage is because the car will dump more fuel if it thinks it's cold. Even if your temp gauge is working ok the other sensor may not be. (one sensor goes to the ECM and the other goes to the gauge)</TD></TR></TABLE>

Well, I took the solenoids out last night and they looked pretty clean. I didnt spray anything on them, just blew some air thru the screens.

Now that I read your other post i've noticed something else. First off, i've noticed it takes a a long time for the temp gauge to go up. And this morning while driving to work the temp gauge was at its normal location, but after about 30-40 minutes of driving, it dropped completly to cold . It wasn't that cold outside either. Maybe in the 40's...
I've also had bad gas milage.

I know I didn't start this thread and I don't mean to hi-jack it,
but thanks for the help. I figured i'm having the same problem...

 

replcae t-stat

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by YeuEmMaiMai &raquo;</TD></TR><TR><TD CLASS="quote">replcae t-stat</TD></TR></TABLE>Now I know what you meant to say was replace it with a Honda thermostat, right?

 

ahha of course. i only use 100% honda parts

 

I know it's a very old post from y'all
but I own a 97 accord se coupe and i have some issue now
I swap the tranny with a jdm f22b2
and when. I did the fluit a lot of metal peaces came out my 1234 gear work someone tell me
the I need overdrive gear
but at 60 mpg goes to 3k rpms
And when I turn the car off my fan turn on about 4 times and my gas mileage are really bad
I check the codes and only have the code for bad catalytic converter .

 

Why did you swap out your original transmission?

Check a few basics first.
Make sure you have enough ATF in the transmission. Warm up the engine, place the trans in every gear for a few seconds and then place it back into Park, pull out the trans dipstick, wipe it clean reinsert and pull out the dipstick again. It should be within the hash area. If you live in a hilly area fill the fluid up to the upper most portion of the hashed area.
Recheck that your TV cable(cable between throttle and transmission) is properly adjusted. It should have no slack but should have no tension in it. Verify the lever on the trans returns to it at rest position on its own.
Adjust the slack out of the TV cable. The lever should begin to lift when the throttle begins to open.
With the car off.
Disconnect the electrical connectors to the shift solenoids(mounted facing the radiator), and the torque converter lockup solenoids(located on top of the transmission). Using a jumper wire connect each solenoid directly to the positive terminal on the battery. The solenoids should all make an audible click on. Remove power and it should click off. If any of the solenoids do not click on/off replace it with one from your old transmisison and retest.

If you have code P0420, this does not mean the catalyst is faulty, it means that the catalyst has fallen below threshold efficiency.
This occurs if the catalyst cannot compensate for the emissions output of the engine.
This can happen if the engine is out of tune, or there is an exhaust leak before the catalyst that affects the primary HO2S which will affect fuel injector input that can place the engine out of tune.
Clogged EGR passages or too tight valves may also cause slight misfire issues which will also affect emissions output and cause a P0420 code.
Hondas PGM-FI speed density system is a little slow when it comes to self diagnostics. It will often spit out the P0420 code before any other code, which can be misleading as to the actual fault that is occurring.