Transmission ?
 

Hello,
I am having a problem i have never seen before. First off my vehicle is a 1992 EX Coupe 2.2L FI 4 cylinder automatic transmission, i believe its a KA4AT. Any further info needed please ask i apologize if i left something out. The car does currently have a CEL 41
(oxygen sensor) which i have replaced but the light comes on still during extreme cold start. OK now on to the actual problem, when i am at highway speed say 65 MPH steady on a flat road, the RPM's will drop about 300, then a second or two later rise back up 300 RPM's it does not happen unless i am at highway speed and the rpms does not rise above normal speed/rpm than it would be. did that make sense example would be at 70 MPH im normally at say 3000 rpm, it will drop to 2700 then pop back up to 3000. it has gotten increasingly worst over the last week. Any suggestions on were to start would be appreciated, im not sure if it is transmission related or maybe an ECU issue? thanks in advance

When the RPM drops, do you feel anything in the car? I'm thinking that's the torque converter locking & unlocking. It feels a bit like the tranny shifting gears, only more subtle/softer/weaker.

I'm trying to decide between flaky tachometer signal, vs. the transmission hunting between locked & unlocked torque-converter.

Checked your tranny fluid? Also are you using ONLY honda AT fluid? If not then your tranny won’t like you much.

jim i do feel it in the car, i hear the exhaust sound change, its almost like its downshifting but not changing nearly enough RPM for that. thanks

g22ccd5 i did check its filled, its a little brown, probably can use a change, and ill be sure to use honda AT fluid, i just didnt want to change it right away if the symptoms seemed to not fluid related, IE low or burnt. thanks

So it IS locking & unlocking the torque converter.

That's partly controlled by rpm & road speed, as well as by the downshift cable. That's the cable from the throttle-body down to the trans. That cable should be adjusted so the lever on the trans begins moving IMMEDIATELY when the throttle begins opening.

Partly, it might be just the nature of the beast. Later years (like 1998) Honda started using more computer control for the auto-trans. Part of that is to prevent hunting gears & lockup like that.

thanks again Jim, i found that in the archives here and have checked, the cable does move at the transmission when i manually apply throttle. I let the car warm then i manually applied throttle and watched the cable to transmission move. i believe thats the procedure correct? so that slight rpm change is the torque converter than ? if the cable is ok, what would be the next thing to check ? it happens anywhere above 55 mphs, it has happened as high as 65mph. thanks again for your help.

I'm no auto-trans guru, so I hope someone else chimes in.

The T-C is supposed to UN-lock when you step on the gas. So check whether the cable is too tight. If you loosen the cable nuts just a bit, does it go slack?

For many MANY types of cars, this has been a common annoyance & part of the reason for more sophisticated computer control over the trans. But back in 1992 that stuff was for more exotic expensive cars.

I'd change trans oil (Honda ATF like others say). Drain & fill, don't have it "power-flushed". Depending on how dirty it comes out, repeat the drain/fill a couple times with 10-200 miles inbetween. The torque converter doesn't drain, so you can only drain about 1/3 of the total fluid. As you drive the fluid mixes into the torque converter & dilutes the old stuff out.

i will check to see what happens with the slack, i will otherwise still drain and refill thanks for all your help.

the cable adjustment seemed ok. tonight i am going to begin the 3 part transmission drain. i have bought 9 quarts of honda ATF and will be draining and refilling tonight then again friday and then again sunday if necessary. i also noticed it does not do the lock/unlocking after about 20 minutes of driving, i figured it was due to the fluid heating up and thinning? does that make sense? thanks again

Never owned an automatic in the 1992 era, so I don't know what makes sense. Fill the fluid based on dipstick level, don't just pour in 3 quarts. Maybe overfilling/underfilling can cause some of this??

Honda (unlike most other automatics) wants you to check ATF dipstick with the engine warmed up but TURNED OFF. Are you checking level with the engine idling?

right, im going to drain, then slowly fill to level, according to manual your suppose to fill to level, start, then shift park-D2 and back to park then shutoff, check again and fill if needed. im going to fill like that. when i initially checked i let the car warm, then shut off, then checked. it was brownish black, def overdue. thanks again

Does the D4 or the S light start flashing when you are driving? That would indicate that the transmission computer detected a problem (it is separate from the engine computer)

There are two sets of solenoids on the transmission that you might want to clean with throttle body cleaner. Crud can buildup in there over time and they have a screen that may be blocked up.

In the Online manual thread in the DIY section, I posted a site to a 91 shop manual that would show you the locations of the solenoids, etc.

thanks PA, no they don not flash. i have done 1 change of tranny fluid and although the car does seem to shift smoother the TC is still hunting. I did though notice today for sure that it does not go away after driving for a while, but i did notice that when i hit an incline the rpms drop 300rpms and when i crest the hill and begin to pick up speed they rise 300rpms ?? does that help to diagnose?? i have a haynes manual so i will look for the solenoids you speak of PA thanks. i will also look at the shop manual. I am not fully sure i understand the adjustment of the throttle cable, i was told if i mess up the adjustment that i will def damage the transmission over time. saturday i am going to have a buddy who has adjusted it give me a hand and see if that helps.
again thank you all for the help.

The actual throttle cable (from the gas pedal to the throttle) MUST go a bit slack & MUST NOT be used to adjust idle RPM.

Sounds like you loosened the downshift cable & it goes slack. Then tighten it up just to the point where it doesn't go slack. That sounds to me like you did it right.

It seems to operate backwards, if that makes any sense. When you climb a hill, the TC is supposed to unlock - & RPM will go UP a bit. Then when you go to level or downhill, it locks.

thanks guys. i will give the cable a go, and clean the selanoids too. jim my car does the opposite, the rpms drop when i climb hill. they should go up when climbing the hill as you stated. well either way i am going to try both saturday and i will let you know the results. thanks again for all the help !!!

noticed something today that i havent noticed since ive been working out the TC problem. My car when fully warm now idles at 900-1000k rpm's which unless im crazy is high? i think prior to the TC problem it was at like 7-8 hundred rpm's. could the higher idle be related to the TC problem? i have done the ICV, FITV and throttle cleaning a few months back already just as normal maintenance. any suggestions gents? related or not? thanks again for helping troubleshoot.

700-800 is more like it, but I don't really think that's related.

Find your idle adjust needle valve (recessed in a hole above the throttle bore)
Set your base idle like this:
- vacuum leaks eliminated
- throttle body cleaned & throttle plate actually closes
- engine all warmed up, idling, & ALL loads turned off
- unplug wire from IACV (it'll almost stall so nurse it with throttle)
- adjust to about 550 rpm
- turn off engine, plug IACV back in, let it cool down & reset the ECU

Start the engine without touching the gas pedal. Let it warm up completely without touching the gas pedal.

excellent thank you jim

Same Problem Fixed
 

I had the exact same problem, described exactly like your problem. After going through this thread, I Did some of the things noted here. I took off the lock-up-solenoids, and also the shift-solenoids, they were very clean, but, sprayed them anyway, with carb cleaner. Changed the trans fluid, got all the bubbles out of the radiator, adjusted the trans throttle cable, and put everything back together. And BAM, it works now. I dont know which item(s) solved my problem, but it is solved. I was going to do them one at a time, to see which one was giving me a problem, but I just decided to do all of the things that I did at once, because they may be next on the list to give me problems later on, and it seems like its a good idea to knock them out of the way while I was in the mood.

I went through this on my '92 EX this winter and finally got it to work how I wanted it to. First set throttle cable freeplay to 10-12mm at throttlebody. Verify correct idle with engine at operating temp. Adjust, if needed, per JimBlake post above. With engine at operating temp, hold the arm at the transmission down with your finger/thumb (don't just watch it, you need to hold it). With other hand operate the throttle until the RPM just comes above idle. The arm at the trans should begin to move right at the RPM increase. Adjust trans cable as needed to achieve this. Test drive the car and check operation. If it still kicks in and out often (or sooner/easier than you would like) you can readjust trans cable up to 3mm tighter(shorter). Do this last step in small increments, road testing after each new adjustment. I ended up going 2mm over initial setting and rarely have the converter unlock on the highway, all shifting was improved as well as a nice fuel milage gain. Good luck!

My wife's dad just got her a 92 Accord EX 4 door 4 cyl 4 speed auto and it will not lock up at all. I changed the top solenoids and still no lock up at all. No dash lights on at all except the ABS light and it only comes on once you start driving it and im almost sure its due to the bad CV joints. Day she got the car she blew the horn and the car would not shift out of gear and had no brake lights. Go figure, blow a horn fuse and no brakes lights and no shift out of park! Anyways I would really like any other ideas on why this thing would lock the converter. Trans shifts great and car runs like new but the RPM's are way to high in 4th and it's killing the mileage and if its anything like some GM cars it wont rout fluid to the trans cooler if its not locking up. I have put power to the solenoid with it unpluged from the car and it clicks when you power it so im wondering what powers it from the car? I can't find and fuse and wonder if the trans computer might be bad, anyone know what powers the lock up solenoid? Thanks in advance for any help.

Bad news
 

I tried adjusting the throttle cable and trans cables today and still no lock up. So I went next door with my tail between my legs and ask the guy running the transmission shop next to my shop and he believes it to be a bad converter. Buzz kill! I wish I had not dropped my ALLDATA account or id find out witch solenoid was lock up and witch was first gear and disconnect the one for lock up and run a test wire to that solenoid and fire power to it wile driving at 50 mph and see if it would lock. I just am not sure what one of the top pair is is the first gear switch. Kinda sad i liked that little car for buzzin round town. I just cant see putting 600.00 worth of parts and labor into a 500.00 car. I took it to 70 mph today and it was running around 3200 RPM's.

There's a sticky on here where you can download a pdf of the factory manual. That and some help from the boards will do just as well as an Alldata pass.
Mine wasn't locking up when I bought it off a couple I know, and they had no idea there was anything wrong. The mpg gain and smoother shifting at smaller throttle openings was very noticable to me. Who knows how long it was driven that way, but it's fun giving them crap for the things I've repaired on the car for no more than the cost of some beer and quality time in the garage.

Here's a parts drawing for 1992.
#5 is the shift solenoid.
#7 is the lock-up solenoid.
http://www.hondaautomotiveparts.com/...m401_atm01.png

Dose it say what soil. is for lock up and what one is for first gear? #7 has 2 soil. Thanks for the info. I know on some GM's with out lock up there is no flow to the trans cooler untill the soil comes on.

Dave

No, it doesn't say other than the entire part #7 is called the lock-up solenoid. This drawing is from on-line parts places, so it's not as much information as the actual Helm shop manual.
Look in the DIY section for a sticky thread about on-line manuals.

Thanks

Dave

back in the day......
 

All this lock up stuff relay makes me miss my 10 sec 87 GN
with its 4000 Non lock up stall converter! :D Set the brake and floor it pull the e-brake handle and pray it stays off the guard rail. Then it was grind my teeth until the traps and pray the head gaskets held, then it was pray I could get her slowed down from 130 mph by the 3 exit:eek: That really was a fun car!

Found Problem
 

The converter is bad. I ran wires to the lock up soil. and it gets power when it should lock up. Only thing left it could be is the converter itself or something else internal. Thanks for the help. looks like I got one for the scrap yard. :mad:

Dave

So the solenoid gets power... so what? Does it click? Does it change state (open/closed)?

I changed the soil. with a known good one. Once I installed it I powered it up and it clicked. Then I used my "Power Probe" test light and test leads, ran the wires into the inside of the car and it light up around 40-45 mph in 3rd gear and also in 4th. I held the throttle and just tapped the brake a little and the light went off. Then let off the brake and it came back on.

OK so you did check the solenoid. I was just trying not to take that for granted.

yup. I was hoping it was something that simple. I went and got one from a clean car that was hit hard in the side and bench checked it even though the one on the wife's car checked good. After checking the wiring I adjusted the cables, only thing I did not do is change the trans fluid. It looked and smelled good and with the filter being internal I thought it to be a waste of time and money. Thanks for your input.

Dave

Voodo Dance or Magic wand?
 

Anyone had any luck with magic wands or daces? :D For real though I own a repair shop but was in a head on crash last year and my help stole from me and left while I was out of work in physical therapy. I work on mostly Turbo Buick or cars with the GM S/C 3800 engines. I have 3 S/C Rivs and a 97 GTP. I also have a 99 olds silhouette van, S-10 pick up and my baby Toyota 4X4 V-6 pickup.

I had to drop my ALLDATA Acct, so Im running blind working on this Honda. Has anyone one changed a converter in one of these? any idea of flat rate hrs to R&R.

Look in the DIY section, there's a sticky-thread about on-line manuals. There's pdf files of the Helm shop manuals. That's the official factory book. But some of them are Brit versions with RHD & smaller engines. Some of them are not very well indexed, just a collection of 700 pdf files. But it'll have a REAL GOOD detailed section on dismantling the auto-box.

I don't like automatics, so I don't know too much about them. But it seems Honda is unlike others. Still, there's a chapter in the Helm book about rebuilding it.

Worth a look, Thanks
 

Thanks I will give it a try. I was a tech at a Honda Cycle dealer for 10 years and the few automatic motor cycles they made were a pain in the butt to work on. Only trans work I have ever done on a Honda car has been shifters,clutch's and slave cyl.

I got a p0740 code. Its def is torque converter clutch solenoid circuit. does anyone know anything about this code? I am new to this website btw!! I do have a 2000 honda accord ex coupe 6 cyl

Place to start......
 

I don't know if your trans is anything like mine but first thing I did was unplug the solenoid from the car and apply power to it and listened for it to "click" then I took it off and cleaned it and bench tested it with air. It checked good but I changed it out anyways. You need to make sure you have the same set up as my 92 4 cyl. before you do anything and be sure and unplug it from the car as not to back feed the computer and fry anything. A few post back is info on manuals id start there first. You might have a completely different set up. You might get lucky and have a bad fuse or brake light switch or something simple. Good luck.

Dave

Hey thanks for the info I will check on the manual and make sure. Yeah I don't want to fry anything! Thanks again