Mechanics

TRANSMISSION FLARE

1998 Honda Civic • 4 cylinder FWD Automatic • 164,000 miles

I have a 1998 Honda Civic DX with automatic transmission. When I purchased the car it had a shifting flare from 2nd to 3rd gear. The flare wouldn't occur until the transmission had warmed up by driving and then would persist. The one exception was that with a soft exceleration it would flare, but a hard acceleration it wouldn't flare.
Later I discovered that after some trips of about 75 miles or longer the transmission wouldn't flare anymore no matter how I drove it until after I shut the car off and turned it back on then it returned to flaring again.
I recently changed the transmission fluid and checked all the transmission solenoids for resistances within Honda specs and all activate when energized manually.
The car within the last week had gotten warm while driving so after letting it cool down I replaced the thermostat and bled the system of air.
Now the car's temperature guage fluctuates from normal to hot opperating conditions occaisionally and when it is fluctuating the shifting flare is non existent and when the temperature guage remains at normal position the shifting flare occurs between 2nd and 3rd. Also the left blinker started acting up (first it blinked like a bulb was burnt, then it worked fine, then blinked very slowly and is back to working properly) at the same time that the coolant temperature did. The check engine light is also not on.
The cooling fan works properly and when shorted so fan operates manually it will not cool the coolant temp as indicated by the temperature guage on the cluster.
I took the car to a transmission shop and after investigating it they guessed that one of the "pressure switches" were bad (assuming they were referring to the solenoids). I didn't have them do any further work to the vehicle after that.
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Ihbigred
June 6, 2011.



I couldn't tell you honestly what would happen or might happen. It might fix the issue in the short run, but it may cause other problems over time as well.

Rivermikerat
May 28, 2012.
Bgorpy, I believe from my research that the linear solenoid is a variable position solenoid controlled by the PCM. My guess is that for some reason there is a bad set of voltages going to it and by me tricking the computer reading a different temperature then that solenoid is being held in a slightly different position. I have looked into building a "Black Box" that would contain the circuitry to bypass the ECT sensor when it got to a specific resistance and then if the car really got "hot" then allow the ECT to take back over, or whenever the car cooled back down the ECT would gain control again. But I have not had time to sit down and go through the circuit theory. One thing I did not like about the potentiometer is that if the car sat and cooled down it had to be removed so the car could start because of fuel/air mixture cold start purposes. Kind of became a nuisance! I wish you lived close so we could try my EX PCM out on your car. Because I continue to stick with it being a PCM issue as I have found it to be the problem on the 98-02 Accord shift problems. I agree with rivermikerat, it could cause issues later on down the line not knowing where that solenoid should be positioned, but that 150 ohms was basically right when I got the shift flaring to stop, so I personally would run it that way until I got a good computer to test out, or every time it came time to shift from 2nd to 3rd just let of the accelerator until it shifted then continue with your acceleration process.

Tiny
Ihbigred
Jun 11, 2012.
I'd seriously be surprised if anyone at a dealership or transmission specialty repair shop would be able to give a 100% accurate answer to the question of what other problems this "work-around" may cause in the long run. As far as electrical theory is concerned, I don't see any issues. It's when you get into the lines of programming code, hydraulics, etc where I get lost.

Rivermikerat
Jun 14, 2012.
Ihbigred, check out this site it might help.
http://www.hondasuv.com/members/showthread.php?t=57575

Tiny
Thiang
Jul 20, 2012.
Wow. This thread is STILL Active after all these months. Amazing.

Rivermikerat
Jul 20, 2012.
Thiang,
I read over the thread you posted and I never checked the TPS for resistances that were out of wack. Not going to rule that out, but why would a car that I worked on with a non-vtec shift flare, but once I changed the PCM to a vtec PCM the flare went away. I'm assuming that was not a TPS issue.

Rivermikerat,
Usually threads stay active that usually have no answers. Looks like it still has yet to be satisfied. Still want to hear from the other people who posted as to what they've done to improve their rides

Tiny
Ihbigred
Jul 20, 2012.
I agree, ihbigred. I just figured that after this long, the issue would have been resolved. I also remember, vaguely, without reading through all of the latter posts, that you acquired another vehicle and somewhat gave up on this issue.

Rivermikerat
Jul 20, 2012.
Yes, I actually sold the problem vehicle. But it was to someone I know so I have access to it if I think of another solution. I may try the TPS out next time I see the car. But, if I come across another one, I'm going to keep chasing it.

Tiny
Ihbigred
Jul 20, 2012.
Ok. I was hoping I was right. I'd hate to think my memory was that bad. Hope you finally figure it out. I'm at a loss now.

Rivermikerat
Jul 20, 2012.
I had the same exact problem with my 98 Civic EX 4-door. If you are a purist you won't like my answer, but here's what fixed it. The TPS went bad, so I replaced it with an aftermarket (Dorman). Since the new TPS had bolts that could be loosened, unlike the factory TPS, there is a small range of adjustment on the new TPS. I rotated it slightly so it appears to the computer that the throttle is open slightly more than it really is. That resolved 99 percent of the flaring. It took me several tries to get the adjustment right, and shifts are often at higher RPMs than before, but overall I am much happier!
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Tiny
Rberq
Sep 10, 2012.
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