2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Engine shakes alot

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Old Jul 16, 2012 | 12:57 PM
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Engine shakes alot

Hi!

I have being annoyed over this for a long time, and now its time to make a post about it!

My engine shakes alot, I'm afraid it will kill the engine mounts bit by bit. I don't have a BAC (someone got a TII S5 BAC? ), so idle is adjusted up towards 1500-1800, it doesn't shake there, but it shakes when I turn it down to 1000-1200. Reason I am saying X-X is that it goes up and down, slowly down, and then jumps up, I bet the missing BAC is the reason for this But anyways, what can make my engine move so much? You feel it in the whole car, and you see the gearlever move, the proper description would be an electric *****

Cheers for any tips!
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Old Jul 16, 2012 | 01:52 PM
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Potentially broken engine mount(s). The passenger-side mount is typically first to go due to all the heat off the turbo. Get a pry bar between it and the subframe, and see if you can separate it.
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Old Jul 16, 2012 | 02:29 PM
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Sounds like engine mounts to me as well. Helped my engine shakiness.
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Old Jul 17, 2012 | 12:19 PM
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Will harder mounts like the mazdaspeed ones be very shaky as well? Why not upgrade them when I have the change, I'd say...
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Old Jul 17, 2012 | 12:34 PM
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I put Mazda speed ones in my girlfriends car because hers oem mounts were worn and shaking. Engine might vibrate a little bit, but it no longer shakes. No vibrations felt through the body. The mounts do its job well. I got some poly mounts from banzai for mine. I plan on having some "spirited" driving. I have yet to try it out as the motor is on a stand.

Last edited by tuscanidream; Jul 17, 2012 at 12:42 PM.
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Old Jul 17, 2012 | 01:43 PM
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The engine going up and down I assume you mean the engine revs?
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Old Jul 17, 2012 | 01:49 PM
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Yes, I mean it revs itself. Probably cuz of no BAC. I made another thread, but can just as well ask here: Does the S4 and S5 BAC swap without mods? I got a friend with many S4 BACs, but no S5 BACs, so would be easy to go to him next week and fetch one.
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Old Jul 17, 2012 | 03:19 PM
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Probably because the tps is set for idle and the engine is running higher than 1k, so its doing it fuel cut on decel thing.
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Old Jul 17, 2012 | 03:55 PM
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Ah ****! Same as when you rev it to a certain point, the engine sounds like it's having diarrhea? That is fuel cut? Isn't that bad for the engine? Or is it just the 14PSI ohfuck-fuelcut that is dangerous?
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Old Jul 17, 2012 | 07:39 PM
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Its all bad, its certainly not good, your tps could be bad (could just be bad connection if blue corrosion is on it) , if its not able to be adjusted to spec it needs replaced,.

fuel cut in general is bad,.but the tps will cause backfire (i believe), not fuel cut.

New motor mounts are a must, the harder the mounts the less the engine will shake, and youll get more power to.the wheels(possibly less wheelhop), on.the downside the car will vibrate more from harder (solid mounts), leds with softer ones (rubber)
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Old Jul 17, 2012 | 09:08 PM
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Well the fuel cut isnt that bad I'd guess on that low rpm, but anyways the plug to the TPS is good just changed it to 6 separate plugs. The symptoms of bad TPS plug is far worse than just some backfire and stuff. It just doesn't work at all the car, drives liek ****.
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Old Jul 17, 2012 | 09:44 PM
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With that I mean compared to total fuel cut on one rotor through higher RPMs due to too hgh boost
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Old Jul 18, 2012 | 08:53 AM
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Fuel cut is bad, id think no matter what rpm, it can cause detonation, which will have a chance of breaking your apex seals.

Ive had a bad tps connection on my old na, it would constantly backfire on decel, until i replaced the bad connecting plug.
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Old Jul 18, 2012 | 09:41 AM
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For me the car jerked, was unresponsive, backfired on decel, had no throttle response.
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Old Jul 18, 2012 | 11:44 AM
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It could have more of an impact on a turbo car, im.not sure.

Clogged fuel filter? Clogged up.injectors?
Have you replaced your fuel filter? Maybe try fuel system cleaner when.you put a full tank of gas.

Id check ecu for error codes, dall my grounds and connections,vacuum lines, throttle body (see if secondary plates are stuck) , sounds like you could have a short somewhere, something obviously isnt right.


Just try to.go.over everything and rule out whatever you can for being the cause.
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Old Jul 18, 2012 | 11:56 AM
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Already done those when my TPS was fouling. The car runs great above idle, no error codes I am 100% sure. Except intake temp sensor, but it is 20 degrees outside, so the default of 20 degrees fits me perfect. That is celcius.
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Old Jul 18, 2012 | 01:45 PM
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Clogged cat?
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Old Jul 18, 2012 | 01:51 PM
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I killed the cats! One is removed, the other is blown out I think. I can get 0,9 bar on it without any problem, car still accelerating, so I doubt it is the cat.
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Old Jul 18, 2012 | 07:26 PM
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Gotta be something electronical
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Old Jul 18, 2012 | 11:34 PM
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It's gotten a tad worse. Points to engine mount after all.
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Old Jul 19, 2012 | 07:55 AM
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Yea thats something u should of already replaced, theyre easy
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Old Jul 19, 2012 | 08:46 AM
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I know, I checked them I took out the engine for a rebuild.
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