Deanjo wrote:Get a cheap ODB II interface for your phone. It will save you hours of hunt and peck if you can read the codes. For $20 it is a worthwhile investment.
CB5000 wrote:So since it does run fine cold, I think ignition issues, fuel delivery issues can probably be assumed to be okay.
CB5000 wrote:As far as I can tell, there are no codes to even read. The check engine light has never lit up.
I could just go ahead and check for error codes though and see if there is anything stored in memory.
So it seems like the problem is something other than the possible errors listed on the error codes for the 1990 Honda accord?
It's also possible that the electronics are defective and the check engine light won't even come on. I can try disconnecting the MAP sensor or the EGR valve position sensor and see if the check engine light will come on.
Captain Ned wrote:Deanjo wrote:Get a cheap ODB II interface for your phone. It will save you hours of hunt and peck if you can read the codes. For $20 it is a worthwhile investment.
If the 1990 model year is correct OBD II is useless as it came in for MY 1996. He'll need an OBD I tool and those were mfg-specific as to pin-outs. Best thing to do is to follow these instructions:
http://www.smogtips.com/smog-question/1 ... ble-Codes-
spiritwalker2222 wrote:CB5000 wrote:So since it does run fine cold, I think ignition issues, fuel delivery issues can probably be assumed to be okay.
Aranarth wrote:Does this car have fuel injection and oxygen sensors?
sluggo wrote:The car is 26 years old - have you ever replaced the spark plug leads? I had a Lexus SC400 that started running rough at 90k miles, so I went through the ignition from cheap-->expensive. Rotor and cap first, then plugs, then ingition/coil lead. Finally hit bingo on the leads. It was stumbling and complaining on acceleration, but after the change it idled like a champ and pulled away willingly.
Usually you'll see these problems after a rain or just a spell of humid weather, but these cable were just worn out. It happens, and you can't always tell by looking at the jackets.
JustAnEngineer wrote:My 1990 Accord EX was prone to plugging up the EGR valve every 80-100k miles. You might be able to clean it up to unstick it or it could need replacement.
Losergamer04 wrote:I vote O2 sensor. At startup the engine typically uses pre-programmed map. I had a Jeep 4.0L that also went to a pre-programmed mapping at ~80% throttle. If you have an engine code/light it can often be an O2 sensor. My ford '91 300ci inline 6 had an "EGR insufficient flow" code. The EGR valve was replaced and it didn't go away. Turns out the O2 sensor was sending bad info to the ECU, making it think the engine needed more/less EGR.
TwoEars wrote:Could be old spark plugs, when was the last time you changed those? Maybe fuel filter, check that. Some heavy duty fuel system cleaning additive might be worth a shot. Could be EGR. Could also be you ICM.
JustAnEngineer wrote:On the spark plug front, I was most disappointed when I installed a set of the then just introduced expensive Bosch platinum plugs. The 90 Accord hated them. It ran great on the cheap NGK plugs.
Geonerd wrote:Interesting! My 1992 Accord developed very similar symptoms three days ago. I discovered this thread just now.
Idle and very light throttle are fine. I can cruise around town on ~40 MPH roads and ~1500 RPM just fine so long as I don't exceed a critical throttle application.
Any significant throttle below ~2400 RPM (varies somewhat with temp) produces mild to moderate misfire. Possible smell of rich mix.
Above ~2400, it runs perfectly. The transition from misfiring pig to Honda Powah! is immediate.
localhostrulez wrote:Little question for you guys with these old Accords - what refrigerant is your AC using? I thought those shipped with R12, which is banned nowadays.
Geonerd wrote:localhostrulez wrote:Little question for you guys with these old Accords - what refrigerant is your AC using? I thought those shipped with R12, which is banned nowadays.
Yup. While the unit will 'run' with modern refrigerant, it win't be terribly happy or efficient. I think (?) a proper conversion kit replaces the pressure regulating equipment to better tune the system to the new refrigerant's characteristics. If nothing else, do a complete purge when swapping R12 for R134 - the old and new oils don't always play well together.