89 civic idle & torque converter issues

[Matt Gadient]

Hi. I recently bought an 89 civic (automatic) and it seems to have a couple little quirks...

First is the idle... every once in a while, i'll be sitting at a light and the idle will go up, and i'll have to push the brake fairly hard to keep from going into the intersection (or into the car ahead of me). I can't tell if temperature makes a difference. The idle stays high for awhile before finally dropping back down.

Second is a little stranger... When driving down the highway, once the car hits 4th, the torque converter frequently starts kicking in and out. It seems to get better as the car warms up, but it'll still do it every once in a while (and then it seems like it's "trying" to re-engage a few times, and then finally does). The time when it's worst is when the car first goes on the highway. As soon as the car gets into 4th, the TC kicks in and out every 1-2 seconds (almost rythmically), and then all of a sudden stops trying and the check engine light comes on. After that the TC doesn't engage anymore (and engine light stays on) until the ignition is turned off and on again. I checked the stored code from the check engine light and it was a '1'. I replaced the oxygen sensor, but it hasn't helped. I'm wondering if it's another sensor or if maybe the ecu is screwed up.

The only things I've tried to fix the above problems thus far are bleeding the cooling system of air, changing the oxygen sensor, and checking the EACV resistance and voltages as per the Haynes manual instructions.

Any help/ideas would be greatly appreciated. At this point, I'm completely lost, and it would be nice to get this thing running well. Thanks.

Matt

 

[Daniel Garrison]

my 86 accord was doing the same thing and a transmission job was not far behind. I belive there is a throttle position sensor on the tranny that tells the idle speed, you should check that, also your tranny oil, and all that good stuff. Generally that sounds pretty bad. You might want to find out about your lemon law or get them to check that tranny for you cause honda transmissions are F$#*ing expensive.

 

[Daniel Garrison]

my 86 accord was doing the same thing and a transmission job was not far behind. I belive there is a throttle position sensor on the tranny that tells the idle speed, you should check that, also your tranny oil, and all that good stuff. Generally that sounds pretty bad. You might want to find out about your lemon law or get them to check that tranny for you cause honda transmissions are F$#*ing expensive.

 

[Eric]

Hi. I recently bought an 89 civic (automatic) and it seems to have a couple little quirks...

First is the idle... every once in a while, i'll be sitting at a light and the idle will go up, and i'll have to push the brake fairly hard to keep from going into the intersection (or into the car ahead of me). I can't tell if temperature makes a difference. The idle stays high for awhile before finally dropping back down.

Is under any type of warranty. If so, then that might be the best way to deal with it. The throttle problem sounds like a safety issue sufficient to warrant the car's return or repair by the seller.

Second is a little stranger... When driving down the highway, once the car hits 4th, the torque converter frequently starts kicking in and out. It seems to get better as the car warms up, but it'll still do it every once in a while (and then it seems like it's "trying" to re-engage a few times, and then finally does). The time when it's worst is when the car first goes on the highway. As soon as the car gets into 4th, the TC kicks in and out every 1-2 seconds (almost rythmically), and then all of a sudden stops trying and the check engine light comes on. After that the TC doesn't engage anymore (and engine light stays on) until the ignition is turned off and on again. I checked the stored code from the check engine light and it was a '1'. I replaced the oxygen sensor, but it hasn't helped. I'm wondering if it's another sensor or if maybe the ecu is screwed up.

A code 1 doesn't necessarily mean that the O2 sensor had a problem. The following information is quoted from a Tech2Tech bulletin board.

"A code 1 is listed as an O2 sensor code, but in many cases is not actually a bad O2. Tons of O2 sensors get changed over a DTC 1 that are fine. What it really means is the O2 voltage does not have enough "activity".

If the car is running rich it will fix the voltage high, if it is running lean it will fix the voltage low. You need to determine if the O2 is not responding due to it being defective or is it due to a rich/lean condition.

Preferably get a DSO on the output wire, but a DVOM would work. See if the output is fixed... It probably is. You need to create a temporary rich and lean condition to see if the O2 will respond. If it does, the O2 is ok and you really have a rich/lean condition that is fixing the O2 voltage.

You can create a temporary rich condition by whacking hard on the throttle or flowing propane into the intake. You can create a temporary lean condition by letting the throttle slam shut from about 2500-3000rpm (uses the fuel cut strategy) or unplugging an injector. Since Hondas are speed/density systems, pulling off a vacuum hose will not create a lean condition."

Note that if you do this procedure with a DVOM, you'll need one with a fast sampling rate such that you'll get a good representation of the data.

The only things I've tried to fix the above problems thus far are bleeding the cooling system of air, changing the oxygen sensor, and checking the EACV resistance and voltages as per the Haynes manual instructions.

Any help/ideas would be greatly appreciated. At this point, I'm completely lost, and it would be nice to get this thing running well.
Thanks.

Have you tried replacing the transmission fluid? Some people here have recommended repeated draining and filling to eventually replace the whole fluid as it's not completely changed on one drain and fill. For example, drain and fill it once (you should get about 2.5 quarts of fluid), drive it a couple of days or so and drain and fill it again, and repeat a couple of more times. The fill capacity after rebuild is given as 5.7 quarts while the oil change capacity is given as 2.5 quarts. A rough calculation yields that after 4 changes 9.9% of the original fluid would remain while after 6 changes 3.3% of the original fluid would remain. Note that I don't know if the volumes given in the service manual include the ATF cooler so those percentages may vary slightly.

You may also wish to get a factory service manual from
http://www.helminc.com for better diagnostic advice. You can check out some online versions at http://www.honda.co.uk/owner/workshopmanuals2.html

Eric

 

[Eric]

Hi. I recently bought an 89 civic (automatic) and it seems to have a couple little quirks...

First is the idle... every once in a while, i'll be sitting at a light and the idle will go up, and i'll have to push the brake fairly hard to keep from going into the intersection (or into the car ahead of me). I can't tell if temperature makes a difference. The idle stays high for awhile before finally dropping back down.

Is under any type of warranty. If so, then that might be the best way to deal with it. The throttle problem sounds like a safety issue sufficient to warrant the car's return or repair by the seller.

Second is a little stranger... When driving down the highway, once the car hits 4th, the torque converter frequently starts kicking in and out. It seems to get better as the car warms up, but it'll still do it every once in a while (and then it seems like it's "trying" to re-engage a few times, and then finally does). The time when it's worst is when the car first goes on the highway. As soon as the car gets into 4th, the TC kicks in and out every 1-2 seconds (almost rythmically), and then all of a sudden stops trying and the check engine light comes on. After that the TC doesn't engage anymore (and engine light stays on) until the ignition is turned off and on again. I checked the stored code from the check engine light and it was a '1'. I replaced the oxygen sensor, but it hasn't helped. I'm wondering if it's another sensor or if maybe the ecu is screwed up.

A code 1 doesn't necessarily mean that the O2 sensor had a problem. The following information is quoted from a Tech2Tech bulletin board.

"A code 1 is listed as an O2 sensor code, but in many cases is not actually a bad O2. Tons of O2 sensors get changed over a DTC 1 that are fine. What it really means is the O2 voltage does not have enough "activity".

If the car is running rich it will fix the voltage high, if it is running lean it will fix the voltage low. You need to determine if the O2 is not responding due to it being defective or is it due to a rich/lean condition.

Preferably get a DSO on the output wire, but a DVOM would work. See if the output is fixed... It probably is. You need to create a temporary rich and lean condition to see if the O2 will respond. If it does, the O2 is ok and you really have a rich/lean condition that is fixing the O2 voltage.

You can create a temporary rich condition by whacking hard on the throttle or flowing propane into the intake. You can create a temporary lean condition by letting the throttle slam shut from about 2500-3000rpm (uses the fuel cut strategy) or unplugging an injector. Since Hondas are speed/density systems, pulling off a vacuum hose will not create a lean condition."

Note that if you do this procedure with a DVOM, you'll need one with a fast sampling rate such that you'll get a good representation of the data.

The only things I've tried to fix the above problems thus far are bleeding the cooling system of air, changing the oxygen sensor, and checking the EACV resistance and voltages as per the Haynes manual instructions.

Any help/ideas would be greatly appreciated. At this point, I'm completely lost, and it would be nice to get this thing running well.
Thanks.

Have you tried replacing the transmission fluid? Some people here have recommended repeated draining and filling to eventually replace the whole fluid as it's not completely changed on one drain and fill. For example, drain and fill it once (you should get about 2.5 quarts of fluid), drive it a couple of days or so and drain and fill it again, and repeat a couple of more times. The fill capacity after rebuild is given as 5.7 quarts while the oil change capacity is given as 2.5 quarts. A rough calculation yields that after 4 changes 9.9% of the original fluid would remain while after 6 changes 3.3% of the original fluid would remain. Note that I don't know if the volumes given in the service manual include the ATF cooler so those percentages may vary slightly.

You may also wish to get a factory service manual from
http://www.helminc.com for better diagnostic advice. You can check out some online versions at http://www.honda.co.uk/owner/workshopmanuals2.html

Eric

 

[jim beam]

for the transmission, is the cable that runs from the throttle to the transmission adjusted correctly? they are frequently "tweaked" to make the car shift more aggressively. the honda manual allows for only 3mm of adjustment between normal & "improved", but i bought one that had been adjusted nearly 10mm and that had lockup clutch issues like you describe. ymmv, but adjust it back to "normal" and see if that helps.

 

[jim beam]

for the transmission, is the cable that runs from the throttle to the transmission adjusted correctly? they are frequently "tweaked" to make the car shift more aggressively. the honda manual allows for only 3mm of adjustment between normal & "improved", but i bought one that had been adjusted nearly 10mm and that had lockup clutch issues like you describe. ymmv, but adjust it back to "normal" and see if that helps.