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MASTER TECH, Honda Service Technician
Category: Honda
Satisfied Customers: 5725
Experience:  28 years of Honda training and a master Honda tech
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87 Honda Accord LXi with 320,000 miles. Problem appeared in

Customer Question

87 Honda Accord LXi with 320,000 miles. Problem appeared in the last few days. The vehicle starts and drives normal when cold but once warmed up...occasionally at a stop light the vehicle's idle will be lower and slightly rough. If I blip the throttle the RPM's/Tach will drop and the engine will stall or the RPM's will drop, the engine will stumble and then rev up as normal. If it stalls I get no check engine light. If it does stall, it will generally restart in a couple minutes. Sometimes after the restart the problem is still there...sometimes it runs normal and then after driving the problem comes back. Sometimes turning the vehicle off and restarting will cure the problem but at some point it will come back. A new gas cap seems to have made the problem worse. The ECU showed a code 6 (ECT Sensor) but I reset the ECU over a week ago and no new code. The main relay was recently replaced which cured a previous thermal starting issue.
Submitted: 7 years ago.
Category: Honda
Expert:  MASTER TECH replied 7 years ago.
Hello welcome to the site
have you tried to readjust the idle yet.
Also a ect sensor will cause a lot of problems and should be tested
Customer: replied 7 years ago.
No...I have not touched the idle since it does not exhibit the problem all the time. The drive to work in the morning is flawless. And...often the drive home even when it's 100 degrees out is fine. I will have to test the ECT but I would think the a bad ECT would cause another ECU fault code....?
Expert:  MASTER TECH replied 7 years ago.
Not always we had a run of ect sensors causing no start in hot weather and the sensor was failed
Customer: replied 7 years ago.
It's probably easier to just replace the ECT...I believe it's located in the thermostat housing..? I don't have a manual other than an online workshop manual. Again though....the car starts flawlessly when cold and if it does stall when almost always restarts immediately or within a couple minutes. can be running poorly and a simple turning off and restarting will cure it for a time.
Expert:  MASTER TECH replied 7 years ago.
i will post a test for the ect. and yes it is located on the housing its been some time since i have checked one on a 89 lxi.but it will be a 2 pin sensor
also here is some info On all models with PGM-FI, the wrong ECT (engine
coolant temperature) sensor voltage may cause an
intermittent hot no-start without the MIL coming on.
To confirm the problem when the engine won't start
check ECT sensor voltage; if it's more than 1 V,
replace the sensor.
At normal coolant temperature, the ECT sensor
voltage should be between 0.5 and 0.7 V. If the ECT
sensor sends a cold engine signal (more than 1 volt)
to the ECM/PCM at normal coolant temperature, the
air/fuel mixture will be too rich, and the engine may
not start
Customer: replied 7 years ago.
Actually it's a 1987 Accord LXi but I would think the ECT would be the same.OK...I will have to go get my Fluke over the week end and test it or since the car is so high mileage I may just go ahead and replace it. The problem does seem to be worse when the ambient temp. is higher so an excessive rich signal would make sense. If you happen to know the wire coloring that would help although I thought the ECT was a single wire...I'll check and definately get back to you. Something had to make the ECU give the ECT Code 6 at some point...
Expert:  MASTER TECH replied 7 years ago.
since this is so old that honda did not digitzied the early car so the colors on some years vary but it is should be the only 2 pin connector
Customer: replied 7 years ago.
I will do some checking...:) It just baffles me since when it acts can be bad for a couple of blocks and then return to normal. And...specifically...if it is running rough exhibiting the weirdness but I have not stalled it by instead fast idleing it with the throttle at a stop light, I can turn it off, immediately restart it and it runs smooth as silk...weird. I'll definately stay with you and get back to ya...
Expert:  MASTER TECH replied 7 years ago.

no problem. i will wait for your results


Customer: replied 7 years ago.
I will not be able to follow up with you till after Thurs. as I'm a pilot and out of town. I assure you I will get back with follow up info. Thanks...

Expert:  MASTER TECH replied 7 years ago.
<p>ok no worrys i wanted to see if your needing my help still. take your time.</p><p>Dino</p>
Customer: replied 7 years ago.
Please excuse the long delay in getting back. I'm a pilot and have been out of town. The ECT checked out properly. I went ahead and replaced it anyway with a new factory Honda part from the dealer. I also reset the ECU. It had no effect on the problem. I will look at the ignition system next...
Expert:  MASTER TECH replied 7 years ago.

ok well sounds like we need to dig into the ecu since all the basis have been covered.

i will see if i can find any ecu testing for the code 6

Customer: replied 7 years ago.
The problem was somewhere in the ignition. Cap, rotor, wires, plugs and coil were replaced and car has run fine for over a week now. Take care...