'87 Accord still shakes with new mounts.

[Tonysal123]

Have replaced all the motor mounts (including Dogbone) but car still shakes at idle (in Drive, less in Rev). It is a little better when car is warmed up, but worst when cold. Shakes even worst with AC on, any ideas would be appreciated. '87 Accord LX, carb model, 86k original miles.

Thanks,
T

[Dr_Snooz]

What's your idle speed?

[Tonysal123]

Thanks for your interest, idle is set to 900. But I had to increase it to 1100 so when the AC is on it doesn't shake as much.

T

[Gt-r]

Warped rotors?

[Dr_Snooz]

Some things to consider in order of importance:

1. Look for vacuum leaks
2. Check your timing
3. Do a tune up (spark plugs, wires, cap and rotor)
4. Make sure your carburetor is adjusted correctly (possible rebuild)

[Tonysal123]

Thanks for the info, most appreciated. I checked for leaks, all seems fine. Also put in new plugs, plug wires, cap, rotor. I'm in CA, so it just passed smog with flying colors- tech verified timing. Dealer installed new "Dog Bone" mount, I have heard that the rubber material used maybe too hard? Car has only 86k miles, could the timing belt be a factor in the shaking?
Car runs fine besides the shaking issue at idle, good acceleration.

Many Thanks,
T

[niles]

Mine shakes too at lower RPMs, I am wondering if it could be ignition related? Possibly the igniter on the distributor, or coil?

[g.frost]

These engines will idle smooth if everything is right. Sounds like you have covered ignition, what about valve adjustment? It could also be valve and/or combustion chamber deposits. (I had this once from using cheap gas for many years) Get a full bottle of Red Line SI-1 fuel system cleaner (must be something with a strong dose of PEA detergent) and put it in a full tank of gas. During this tank, get it fully warmed up and do some Italian tune up spirited driving to get it good and hot and burn off deposits. It may clean the carb some as well. This will clean dirty injectors too.

Congrats on the CA emissions PASS. Mine always comes though well below minimum as well.

[Tonysal123]

Thanks for the insight, most appreciated. I'll give the Red Line a try.

T

[Dr_Snooz]

tech verified timing.

To my knowledge, the test allows you to be a few degrees off and still pass. Not likely to be your problem, but you might still want to verify timing independently.

[profquad]

any resolution here? having a similar issue 86 accord lxi

[Caleb Kelley]

Mine is doing the same.

Also, if you're running the stock carb I know the butterfly valves are finicky. They are supposed to open when started and idle your engine a 2k rpms until it is warm, then it is supposed to close and lower rpms to 1k and just idle normal. Mine opens and idles at about 2.2k and never closes. Then when I hit the gas it lowers but it floods the engine and bogs it down. then it runs like crap the rest of the time it's on. I'm looking at upgrading to a Holley 5200 or Weber 32/36 so i'm not looking at rebuilding my carb. I have noticed though, that that makes my car shake like crazy as well. I would certainly start with looking at the carb! Best of luck to you!

[Caleb Kelley]

Mine is doing the same.

Also, if you're running the stock carb I know the butterfly valves are finicky. They are supposed to open when started and idle your engine a 2k rpms until it is warm, then it is supposed to close and lower rpms to 1k and just idle normal. Mine opens and idles at about 2.2k and never closes. Then when I hit the gas it lowers but it floods the engine and bogs it down. then it runs like crap the rest of the time it's on. I'm looking at upgrading to a Holley 5200 or Weber 32/36 so i'm not looking at rebuilding my carb. I have noticed though, that that makes my car shake like crazy as well. I would certainly start with looking at the carb! Best of luck to you!