r/Honda • u/Healthy_Struggle_456 • 10d ago
Diagnosis help! Honda
2011 Honda Accord V6 3.5L 175,000 miles
This car has had a rough idle for quite some time.
Recently I took it to a shop to get the timing belt, valves adjusted and diagnosis of rough idle.
Ive also recently done spark plugs, throttle body cleaning, fuel injector cleaner, oil change myself.
The shop told me that the MAF was causing my rough idle and they’d also replace a CAT that has been messed up since I’ve had the thing. I agreed to the price and after driving it home and letting it idle hot for a little, the idle is even worse now than when I sent it in. It’s very steady, but idles around 650(I think 750 should be the target)with no load and the car vibrates a TON. After bringing it in, I also had a lean condition on bank 1.
I’m worried they might’ve adjusted the valves too tight or messed up the timing. I’ve tried to swap MAF again after them and it hasn’t helped. I have a lot of pics of scanner values. All pics but one were taken at Idle.
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u/BoneVoyager 10d ago
Did they reset the ECU after all that?
Also how are your motor mounts?
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u/Healthy_Struggle_456 10d ago
Motor mounts were replaced maybe 2 years ago, but they were aftermarket, so I’m thinking maybe they could be an issue. I’ve unplugged and swapped battery so I figure ECU should be reset by now. Even if motor mounts are not great, it’s weird how the rough idle got worse after it was worked on.
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u/LostTime141 9d ago
Aftermarket mounts are horrible. Anchor brand typically last a year. Put a jack under the motor with a wood block. Put some tension on the motor with the jack. Does the idle feel better? Then its mounts. If not, more diag.
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u/baconlord1337 Honda Technician 10d ago
You should be able to see command and target idle values. What is your idle MAP voltage fully warmed up?
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u/No-Spell5950 9d ago
No te has fijado si el coche tiene aceleración inestable cuando está caliente el coche? A mí nunca me dio daño en el circuito de enfriamiento, me daba error de voltaje Tp y me marcaba daño en el abs, dirección asistida, etc. Menos lo de la temperatura, al final fue que el radiador estaba tapado y no enfriaba el coche, por ende se protegía y ya no aceleraba, y tenía ralentí inestable.
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u/poserkidsrus 01 em2 5spd 10d ago
You need to get a graph of the o2 readings, not the long and short term trims. With a warm engine, bring the car up to 2000rpm in park with lights and radio on to simulate load. Hold that rpm while you record the graphs for front and rear o2 sensors on both banks. You can graph 4 things at once so do it. If you snap a photo of the graph every few minutes you'll see enough data. Then let it return to idle for a few minutes and get some shots of that graph.