 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
Car Forum / Honda Cars / June 200799 Accord Has Me Stumped
For almost a year I have been struggling with a recurring problem that appears to be triggered by sustained driving on the highway. It has come up three times now and I thought I had it fixed after the second episode so I don't know what to try next. It's a 99 Accord LX 4 door 4 cyl 5-speed, 184,500 miles (lots of highway driving). The problem is after the engine hits operating temperature, it cannot idle at the bottom end -- when you slow down it just drops off to zero RPMs and dies unless you feed it gas with the clutch down. It first happened during an all-day drive last summer. I had just changed the oil, filter and air filter for the trip. To try to fix it, I replaced the spark plugs and the PCV, ran some injector cleaner through, and replaced the coolant and the ignition coil. That seemed to help a little and the car stopped dying so much but still ran uncertainly at low RPMs. Then I took another long drive (this time a warm day in December) and the same problem came back. This time I switched out the ignition wires, distributor cap and rotor. Lo and behold the car seemed almost back to normal. I have driven it up to 50 miles at a time without incident. But this weekend my son drove over an hour on the highway (warm abient temps, too) and sure enough, it started dying again. There are no trouble codes being activated. I'm looking for a good idea on what to try next and this group is a great help. Thanks in advance for your suggestions. I am no expert, but I suggest you look at ignition and fuel (filter, timing, plugs, module). When was the last time you tuned it up? > For almost a year I have been struggling with a recurring problem that > appears to be triggered by sustained driving on the highway. It has come [quoted text clipped - 22 lines] > on what to try next and this group is a great help. Thanks in advance for > your suggestions. Thanks, Spam. The fact that it always waits to start dying until heating up suggests to me that something electronic is happening that causes the computer instructions on where to set low idle get interrupted somehow. The ignition, timing and idle all work perfectly fine while the car is warming up. Also, they have been working fine on short trips for the last few months. The problem only re-occured after a longer drive at high speeds. >I am no expert, but I suggest you look at ignition and fuel (filter, >timing, plugs, module). When was the last time you tuned it up? [quoted text clipped - 25 lines] >> on what to try next and this group is a great help. Thanks in advance >> for your suggestions. > Thanks, Spam. The fact that it always waits to start dying until > heating up suggests to me that something electronic is happening that [quoted text clipped - 34 lines] >>> idea on what to try next and this group is a great help. Thanks in >>> advance for your suggestions. Maybe you should monitor the reference voltage going to the Throttle Position Sensor(TPS)and the TPS output voltage.Perhaps the ref V is dropping(it's source is the ECU),or the TPS output is changing (bad TPS)and telling the ECU to lower the idle....to a point where it will not run properly. Take a "cold" reading on the reference V,then another when the engine starts to stumble. You'll have to backpin the connector. Or maybe the igniter (in the distributor)is the problem;perhaps altering the firing of the coil once it warms up.  SignatureJim Yanik jyanik at kua.net Thanks, Jim. Your suggestions sound promising. Would high or low voltage out of the TPS trigger a trouble code? (I haven't had one with this problem.) The igniter also sounds like a possible answer, especially given it's closeness to the hottest part of the engine. But replacing it will be a $130 gamble. Is there any way to test the igniter? > Maybe you should monitor the reference voltage going to the Throttle > Position Sensor(TPS)and the TPS output voltage.Perhaps the ref V is [quoted text clipped - 7 lines] > Or maybe the igniter (in the distributor)is the problem;perhaps altering > the firing of the coil once it warms up. > Thanks, Jim. Your suggestions sound promising. > [quoted text clipped - 4 lines] > closeness to the hottest part of the engine. But replacing it will be a > $130 gamble. Is there any way to test the igniter? yes. it's written up at tegger.com. but if the vehicle runs at all, it's unlikely to be the igniter. bottom line, if working on the distributor scratched the itch, and it seems to have, keep poking about with that. suggest removal, cleaning, and thorough inspection. read all of tegger's write-ups on ignition problems. also, make sure you use denso or ngk plugs. >> Maybe you should monitor the reference voltage going to the Throttle >> Position Sensor(TPS)and the TPS output voltage.Perhaps the ref V is [quoted text clipped - 7 lines] >> Or maybe the igniter (in the distributor)is the problem;perhaps altering >> the firing of the coil once it warms up. >> Thanks, Jim. Your suggestions sound promising. >> [quoted text clipped - 7 lines] > yes. it's written up at tegger.com. but if the vehicle runs at all, > it's unlikely to be the igniter. there's an IC and a switching transistor in there that could be affected by heat or temperature sensitive.IIRC,there's white heat sink grease used to help heat transfer from the ceramic substrate of the igniter to the metal of the distributor.maybe that grease is missing? > bottom line, if working on the distributor scratched the itch, and it > seems to have, keep poking about with that. suggest removal, > cleaning, and thorough inspection. read all of tegger's write-ups on > ignition problems. > > also, make sure you use denso or ngk plugs. Someone else mentioned using only OEM Honda distributor cap/coil and rotor,that aftermarket parts caused him a lot of wacky trouble. >>> Maybe you should monitor the reference voltage going to the Throttle >>> Position Sensor(TPS)and the TPS output voltage.Perhaps the ref V is [quoted text clipped - 7 lines] >>> Or maybe the igniter (in the distributor)is the problem;perhaps >>> altering the firing of the coil once it warms up. SignatureJim Yanik jyanik at kua.net > Thanks, Jim. Your suggestions sound promising. > > Would high or low voltage out of the TPS trigger a trouble code? (I > haven't had one with this problem.) the OUTPUT is supposed to vary with throttle position,0-~4.5V.If the Reference input V went high(more than 5V),I suppose that could "set a code",but I doubt it. A code is probably generated if there's NO output V from the TPS. Like if the ref V input failed or the TPS went open. If anyone knew the value of the variable resistor in the TPS,one could sub a pot for it and see if that fixed(steadied) the idle. Maybe a 10K or 50K linear pot. > The igniter also sounds like a possible answer, especially given it's > closeness to the hottest part of the engine. But replacing it will be > a $130 gamble. Is there any way to test the igniter? Scope it's output,with an oscilloscope. See if the pulse train is too jumpy or erratic. Since most people don't have those instruments,the only other way is to swap it out with a good one. >> Maybe you should monitor the reference voltage going to the Throttle >> Position Sensor(TPS)and the TPS output voltage.Perhaps the ref V is [quoted text clipped - 7 lines] >> Or maybe the igniter (in the distributor)is the problem;perhaps >> altering the firing of the coil once it warms up. SignatureJim Yanik jyanik at kua.net >> Thanks, Jim. Your suggestions sound promising. >> [quoted text clipped - 16 lines] > Scope it's output,with an oscilloscope. See if the pulse train is too jumpy > or erratic. if it is, it's unlikely to be the igniter. the igniter's just an electronic power switch. like most other semicons, they usually either work, or they don't. kinda related to this, i'm a big fan of premium coiled core spark plug leads. they suppress a lot electrical noise under the hood that the rubber core leads don't. this means less noise for the sensor inputs to filter and i think it makes the vehicle run much more smoothly all ways around. > Since most people don't have those instruments,the only other way is to > swap it out with a good one. [quoted text clipped - 10 lines] >>> Or maybe the igniter (in the distributor)is the problem;perhaps >>> altering the firing of the coil once it warms up. >>> Thanks, Jim. Your suggestions sound promising. >>> [quoted text clipped - 20 lines] > electronic power switch. like most other semicons, they usually > either work, or they don't. Since the igniter contains an IC to adjust the "dwell" time of the transistor that is the actual power switch,it's possible for that IC to get flaky at a high temp,or even at a narrow temp range.With electronics, "either works or it doesn't" is not always true. also,doesn't the igniter feed back data to the ECU,thru the tach output? SignatureJim Yanik jyanik at kua.net >>>> Thanks, Jim. Your suggestions sound promising. >>>> [quoted text clipped - 22 lines] > flaky at a high temp,or even at a narrow temp range.With electronics, > "either works or it doesn't" is not always true. the added complexity compounds the problem, not mitigates it. ever had computer componentry flake on you? one minute it's there, next it's gone. pow. > also,doesn't the igniter feed back data to the ECU,thru the tach output? no, the ecu relies on the sensors in the distributor for rpm input. if you think about it, the tach line is just a phased version of the ecu's own output - not much good for ecu feedback purposes. Jim Yanik said the following on 6/13/2007 12:01 PM: >> Thanks, Spam. The fact that it always waits to start dying until >> heating up suggests to me that something electronic is happening that [quoted text clipped - 45 lines] > Or maybe the igniter (in the distributor)is the problem;perhaps altering > the firing of the coil once it warms up. I had a similar idle problem with a Dodge Caravan (3.0 liter Mitsubishi Engine) that turned out to be a gummed up throttle body. There were no engine failure lights, the idle speed would just drop to zero. > For almost a year I have been struggling with a recurring problem that > appears to be triggered by sustained driving on the highway. It has come up [quoted text clipped - 22 lines] > what to try next and this group is a great help. Thanks in advance for your > suggestions. check for the great ignition switch recall. applies to your year. [low revs cause vibration which can make the switch contact "noisy". always return the key to the "run" position by hand, don't rely on the string to return it fully. and make sure you have no other heavy objects on the key ring.] Jim, You're right. I had the recall service done at the time it was announced. Thanks. > check for the great ignition switch recall. applies to your year. |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.