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1998 Honda Civic Transmission Flare

Tiny
IHBIGRED
  • MEMBER
  • 35 POSTS
I ended up not changing the solenoids first. I bought a 5k potentiometer to chase after my hunch with the overheating making it shift right. I measured the resistance of the engine coolant temperature (ECT) sensor to be 260 Ohms at operating temperature. I took the connector that attached to the ECT and attached my potentiometer and made the resistance 150 Ohms. The car shifted wonderfully through all gears and went into overdrive also. I went and purchased a new ECT and replaced the old one. The car continued to flare from 2nd to 3rd and the resistance at operating temperature was 270 Ohms on the new ECT. I'm not sure why a lower resistance alows the car to shift right, but I also considered the thermastat being bad and not letting the car warm up enough, but I just recently replaced that with the head gasket.
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Saturday, November 5th, 2011 AT 6:41 PM
Tiny
MERLIN2021
  • MECHANIC
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Did you ever check with Honda for a PCM update? They may have re wrote the control section for this flare condition.
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Saturday, November 5th, 2011 AT 7:15 PM
Tiny
MERLIN2021
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  • 17,250 POSTS
You can also try this recomendation from Honda:
BEFORE REPLACING ELECTRONIC COMPONENTS, TRY THESE TIPS
TECHNICAL SERVICE BULLETIN
Reference Number(s): HSN 0102-12, Date of Issue: January 2002
Related Ref Number(s): HSN 0102-12
ARTICLE BEGINNING
SERVICE INFORMATION
Many of the electronic components in automobiles have computer chips. Besides ECMs/PCMs,
you'll find them stashed in audio units; speedometers; odometers; clocks; climate control systems;
control units for ABS, TCS, ATTS, and SRS; security systems; keyless remote transmitters; and
multiplex control units. The downsides of all this high-tech stuff are software glitches or bugs, and
vulnerability to voltage spikes. And if that isn't enough, static electricity, lightning, ultraviolet light,
strong magnetic fields, radio waves, and radar can make a software bug even worse. Before you
replace a suspected electronic component, try these tips first. They could spare you unnecessary
replacement.
Disconnect the positive and negative battery cables, and touch them together for a few minutes.
This forces all capacitors in the component to drain, which clears and resets the computer chip.
If a software glitch is the cause, resetting the chip this way is usually as effective as installing a
new component.
Unplug the connectors from the component, wait a few minutes, then reconnect them. If a poor
connection is the villain, disengaging and engaging the terminals in the connector cleans
contact surfaces and usually fixes the problem. While you have the connector unplugged, look
at the pins and terminals for signs of contact. If you have any doubt that things are connecting
properly, remove the female pin and use it like you would a feeler gauge to check the contact.
If terminals are damaged and need to be replaced, see the article HSN 0800-04 - NEW
TERMINAL INSPECTION FEELER TOOL SET, in the August '00 issue of ServiceNews.

HONDA: All
CATEGORY: Honda Service News
APPLIES TO:All
BEFORE REPLACING ELECTRONIC COMPONENTS, TRY THESE TIPS -1998 Hon.
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Saturday, November 5th, 2011 AT 7:29 PM
Tiny
RIVERMIKERAT
  • MECHANIC
  • 6,110 POSTS
I agree with merlin
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Monday, November 7th, 2011 AT 3:56 AM
Tiny
IHBIGRED
  • MEMBER
  • 35 POSTS
I can't say I've honestly touched the positive to negative terminal yet, but many times had the battery out for long periods of time and also pulled the fuse that holds the memory for the car. And no, I have not contacted Honda previously to now, but just put in an inquiry to see if there is.
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Monday, November 7th, 2011 AT 12:36 PM
Tiny
RIVERMIKERAT
  • MECHANIC
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Let us know what you find out.
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Monday, November 7th, 2011 AT 10:17 PM
Tiny
IHBIGRED
  • MEMBER
  • 35 POSTS
I talked to Honda technician and he said there is no reflash for the PCM in the 1996-2000 civics for shifting issues. I quickly shared my issue and he suggested changing the thermostat again since it seemed to be the coolant temperature that resolved the shifting. The last thermostat I put in only a few months ago broke at 170 F so I'm going to put in a 195 F and see if that resolves the issue.
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Tuesday, November 8th, 2011 AT 3:50 PM
Tiny
RIVERMIKERAT
  • MECHANIC
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Let us know what happens.
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Tuesday, November 8th, 2011 AT 9:53 PM
Tiny
IHBIGRED
  • MEMBER
  • 35 POSTS
I switched out the thermostat with a 195 F thermostat and nothing changed. I'm wondering since the only electrical components on the transmission that would be effected by the PCM's reading of the temperature are the solenoids that maybe they're weak? Even though their resitance comes within spec. Or another idea is maybe both PCM's I have are faulty? I have a car that I've been converting over from non-vtec to vtec and has a non-vtec automatic that does the same thing. I'm wondering if when I finish and am using the vtec PCM if it will continue to flare from 2nd to 3rd? Any ideas? Would a plugged up filter maybe cause this or if it was a faulty clutch pack why would the ECT sensor resolve it?
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Wednesday, November 9th, 2011 AT 12:45 PM
Tiny
RIVERMIKERAT
  • MECHANIC
  • 6,110 POSTS
Have you been able to rectify this issue yet? Did you have the valve body checked? Have you tested the fluid pressure? And especially during shifting?
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Friday, January 27th, 2012 AT 1:04 AM
Tiny
IHBIGRED
  • MEMBER
  • 35 POSTS
I have not yet resolved the issue. Here is what I've done since I last updated. Knowing the the engine coolant temperature effected the way the car shifted I troubleshot that area. I purchased a potentiometer that could get down the the range of resistance that the CTS operated in. I found that the CTS was around 200 ohms when car was at operating temperature and that resistance decreased and temperature increased. So I attached the potentiometer to the connector for the CTS and changed the resistance the ECM was receiving to 150 ohms. Wa-Lah! That fixed the problem! Shifted great every time no problems ever. So I figured the CTS was bad. I replaced it and it didn't fix it and I found that the CTSs are not designed to go down to 150 ohms at operating temperature. So I started to lean towards the ECM or shift solenoids again. I stumbled across another used ECM with 215k miles on it and that didn't fix it, so I swaped the AB shift solenoid pack out for another used set, and that didn't make any difference also. Another thing, I've got the other car that is doing the same thing running, the one I converted to V-TEC with non-V-TEC transmission, and it continues to also flare from 2nd to 3rd once warmed up. So I'm still searching and I'm almost positive that it's not an issue internal to the transmission. By the way, what is the purpose and what does the linear shift solenoid do on these cars?
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Friday, January 27th, 2012 AT 1:48 PM
Tiny
RIVERMIKERAT
  • MECHANIC
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I'm not exactly sure what that solenoid does or is for, but I've seen it referred to as the line pressure solenoid. Here's a link I found:
http://techauto.awardspace.com/transmission.html

Also, I didn't re-read the whole thread here. Have you have the trans pressure tested?

I also saw a few places where people have removed and cleaned the solenoids and the problem was cured.
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Friday, January 27th, 2012 AT 6:49 PM
Tiny
IHBIGRED
  • MEMBER
  • 35 POSTS
An update on what I have recently done. Rivermikerat, no I have not checked line pressures as I don't have a gauge for that. I cleaned the solenoid and checked the gasket for cracks and then reinstalled and car continued to flare so I ended up purchasing a Honda OEM linear solenoid to rule that out as the problem. After replacing the car seemed to shift better between all gears but continued to flare worse and worse as the car warmed up. I read a thread that someone had very similar issues to mine and replaced the linear solenoid and that resolved the issue for a few months till the solenoid went out and had to be replaced again for which it only went out again after a year. It was suggested that the PCM might have been bad and in turn causing the solenoid to be ruined over time. I tend to continue to swing towards the PCM being faulty because of being able to trick the PCM into thinking it's running warmer and thus it shifting just fine. What are the output voltages and from what pins on the PCM should I get for the linear solenoid and AB shift solenoids? I think this would be a good test to see what the outputs are to both the linear and AB shift solenoids at the point the car shifts from 2nd to 3rd to see if these are good outputs.
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Thursday, February 9th, 2012 AT 2:27 PM
Tiny
KHLOW2008
  • MECHANIC
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Are there any troubles codes now?
What type of transmission fluid was used? Is the fluid level correct?

A scan tool would enble you to monitor voltages. Since problem is not there all the time, only real time data analysis would tell you if there is anything wrong with the voltages.

A partially clogged fluid cooler inside the radiator can cause such problems.
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Thursday, February 9th, 2012 AT 10:02 PM
Tiny
IHBIGRED
  • MEMBER
  • 35 POSTS
No trouble codes. I took it to a tranny shop earlier on in this discussion and they checked for codes. I used only Honda ATF and fluid level is okay. I just deicded to pull some data with my multi meter from the pinout diagram. Shift solenoid B is at battery voltage till shifting from 2nd to 3rd. The voltage drops off cleanly every time even when it is flaring from 2nd to 3rd. The linear solenoid voltage sits at 1.15V while driving and just before shifting it drops to 0V. I noted when it flares it stays on 0V longer than any of the other shifts. I can't say it does that also when its cold and not flaring. I'm waiting for the car to cool down then I'm gonna go check that out. Maybe a plugged cooler section in the radiator, but that doesn't seem to tie with the ECT being directly related to the shift flare.
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Thursday, February 9th, 2012 AT 10:38 PM
Tiny
RIVERMIKERAT
  • MECHANIC
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Most stores like Autozone and Pep Boys will rent (cheaply) or loan transmission fluid pressure gauges that you can use to test with.
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Thursday, February 9th, 2012 AT 11:56 PM
Tiny
KHLOW2008
  • MECHANIC
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A plugged cooler can affect the transmission fluid temperature and line pressure. The transmission fluid temperature and ECT readings could be confusing the PCM to result in the flaring.
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+1
Friday, February 10th, 2012 AT 12:36 PM
Tiny
IHBIGRED
  • MEMBER
  • 35 POSTS
Rivermikerat, I will see if I can rent one or find someone with one. Also, I've never done that particular test, should I just pick the car up and run it through the gear to see the pressure readings?
KHLow2008, I'll pull the lines and throw some pressure at it to see if anything is getting through.
Last night, I checked some more voltage readings.
B1 - Power supply to linear solenoid negative electrode
B2 - Power supply to linear solenoid positive electrode

I check the voltage difference across B1 and B2 while shifting from 2nd to 3rd with the car warm and it was 1.15V just before shift. When I put the potentiometer in place of the ECT sensor (set at 150 ohms) the voltage difference across B1 & B2 was 1.25V. Seeing that an increase in voltage difference across those two PCM pins created a positive shift from 2nd to 3rd I checked each pins voltage to ground. B1 to ground read at -1.39V then dropped to 0V when shifting to 3rd and car was warm. When I put the potentiometer in place, B1 to ground was about -1.408V then dropped to 0V when shifting to 3rd. B2 to ground read 0.113V then raised to 0.5V when shifting to 3rd with car warm and with potentiometer in place B2 to ground read 0.115V then raised to 0.5V when shifting to 3rd. These readings seem a bit weird because their sums to follow the readings I got earlier when measuring across B1 and B2 but I used a PCM ground wire instead of the body (may be the problem). So it seems from the readings across B1 and B2 that an increased voltage difference across the linear solenoid made the car shift great. So I'm wondering what the linear solenoid really does? I know it only deals with high and low pressure (pretty vague, any help would be appreciated). So maybe by increasing the low pressure side voltage I'm allowing more pressure to build up before it shifts thus creating a better shift? (Trying to follow the flow process attached)
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Friday, February 10th, 2012 AT 1:29 PM
Tiny
RIVERMIKERAT
  • MECHANIC
  • 6,110 POSTS
Yes. That works. It'll be much easier than trying to do it on the road.
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Friday, February 10th, 2012 AT 10:56 PM
Tiny
BGORPY
  • MEMBER
  • 3 POSTS
Greetings ihbigred:

I have been following your situation over the last several weeks on this thread. I have a 1996 Civic EX with 102000 miles on it that I purchased recently. The vehicle is exhibiting the exactly same 2nd to 3rd gear shift flare that you describe. Trans shifts fine when cold but when the temp reaches normal, the 2-3 flare will occur and also only under light acceleration.
I have not gone as far as you have in my investigation yet. I have done a 3 x3 drain and refill with Honda's new DW-1 atf and saw no improvement in shift quality. I also removed the lock up, shift and linear solenoids, cleaned them, tested the operation and resistance. All were good and within the OEM specs.
I am posting not because I can offer you any insight but to show my support and to let you know that at least one other person out there has experienced the same issue as you have. I am hoping that you will be able to solve this problem and share your solution with others. Also, I wanted to thank you for all your hard work so far. Please know that what you have shared has helped me also, if for no other reason than to realize that I am not crazy in trying to solve this issue!
By the way, my vehicle has been serviced almost exclusively by a Honda dealership during its lifetime so, the car has been well-maintained.
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Sunday, February 12th, 2012 AT 12:23 AM

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