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Low Idling Accord
11-23-2011, 12:17 PM
Hello, I have a 1998 Honda Accord Coupe with a 2.3L straight 4 with a 5 speed manual. Last night when I was driving home the car was idling at around 200 RPM when the engine was warm. And then this morning it started fine, ran fine, but as the engine temperature increased the idle decreased, as it should. But even when it wasn't fully at the proper temp it was idling at 500 RPM. When it warmed up to the proper temp it was idling at 150, yes 150. It was touching the 0 RPM line, but it didn't stall. It has had problems in the past with initial low idling, like when you disengage the clutch, but never constantly idling so low. Keep in mind that the idling hasn't progressively gotten lower over time. The problem just arose last night. Also, it accelerates fine, and the check engine light isn't on. What is most likely the cause?
11-24-2011, 06:30 PM
What is the maintenance history?
When did you last replace spark plugs, distributor cap, wires? When did you replace air filter? Was the throttle body ever cleaned?
11-26-2011, 07:33 PM
Is it actually idling that low, or is the tach having some issue? Most motors won't idle down past 300 or so without breaking up and stalling. And they usually hesitate taking the gas from idle if idling too low.
A '98 has two tach reference signals, one for the computer, and one for the tach gauge. If it was really idling that low the computer should be setting codes and lighting the CEL. Idle that low would definitely cause emissions problems, you should see all hella codes if it was actually idling that low....
Tach gauge signal issues are not that uncommon in Hondas though...
11-27-2011, 09:33 PM
I was reading it wrong. It wasn't going that low, but still lower than it should be. Sometimes the car has good runs without idling low, but then sometimes it does, and when it does it initially idles at 400-600rpm then increase to normal. But after 4 days of this happening a code did pop up. p1491 an egr insufficient lift error code. Should i replace the egr valve? I have alldata for my car and it has like 30 steps to figure out exactly what i need to do, but it doesn't seem like it's worth the time considering the step 4 says to install a known good pcm...
11-28-2011, 06:14 PM
I'd take the EGR off and see if it looks dirty, you can clean them up and sometimes they work fine again. Push the plunger all the way in and spray it out with cleaner and make sure the plunger seems to seat and seal well and check that the passages on the motor are clear. I'd always at least do that before replacing an EGR, they aren't cheap.
Sticking a little bit open could explain the low idle, so it may be related to the idle issue. Not for sure, but it might be your answer.
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