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View Full Version : '87 Accord still shakes with new mounts.



Tonysal123
11-16-2013, 12:55 PM
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
11-16-2013, 06:52 PM
What's your idle speed?

Tonysal123
11-16-2013, 09:25 PM
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
11-17-2013, 09:32 AM
Warped rotors?

Dr_Snooz
11-17-2013, 09:44 AM
Some things to consider in order of importance:


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

Tonysal123
11-17-2013, 11:12 AM
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
11-17-2013, 12:38 PM
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
11-17-2013, 08:44 PM
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
11-18-2013, 01:20 PM
Thanks for the insight, most appreciated. I'll give the Red Line a try.

T

Dr_Snooz
11-18-2013, 10:02 PM
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
03-22-2017, 09:32 AM
any resolution here? having a similar issue 86 accord lxi

Caleb Kelley
03-24-2017, 08:30 AM
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
03-24-2017, 08:38 AM
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!