Resolved Violent shake at idle

[98gstJames]

This car man… these things make me lose hope. Anyways, so I’ve been fighting my idle and I went to test it out today and started driving and made it about 30 feet when all of a sudden I heard what sounded like my cam gear cover rubbing against the cams, then my car died, the engine is fine and everything’s good on that side, one of the bolts on my trans to the engine came loose so I tightened it back up, issue went away and then I went to just pull my car to park it and I made it like two feet and it did the exact same thing only it kept doing the loud whining until I shut the car off, the same bolt came loose again so I made sure this time it was super tight. The bolt didn’t come loose again but my my engine is sitting there violently shaking, I can feel it shaking the whole car from inside the car and I know it wasn’t doing that before, I have one bolt missing on the back mount to the trans but I didn’t think that would cause this much of a shake…

 

[BLACK'98DSM]

You have hardware missing and hardware coming loose... Seems to me like you need to run through it all and make sure everything is in it's place and torqued.

 

[98gstJames]

You have hardware missing and hardware coming loose... Seems to me like you need to run through it all and make sure everything is in its place and torqued.

Double checked all the bolts on the trans to engine and all the other mounts are nice and tight expect the back trans mount that has the one bolt missing, could this cause such a violent shake? I’ll check over everything again either tomorrow or Friday, I swear every time I fix something it seems like something else breaks… props to anyone that has revived these car from the grave, almost a whole year later and still have yet to be able to just get in the car and go without having some sort of issue every time.

 

[jesse12345]

Double checked all the bolts on the trans to engine and all the other mounts are nice and tight expect the back trans mount that has the one bolt missing, could this cause such a violent shake? I’ll check over everything again either tomorrow or Friday, I swear every time I fix something it seems like something else breaks… props to anyone that has revived these car from the grave, almost a whole year later and still have yet to be able to just get in the car and go without having some sort of issue every time.

You wanna talk about reviving from the grave. Once you've worked out all of the bugs you'll be happy you stuck with it. I've been through the ringer multiple times and every time it was well worth it. Just triple check all of your bolts like on the harmonic balancer, and anything that spins with the engine. If it's shaking like a misfire I'd check that also, it's hard to pinpoint when your not actually physically seeing what's going on. That's where I'd start and if you get frustrated take a break and then go back at it. Don't burn yourself out.

 

[luv2rallye]

You might try removing all the belts to see if shaking is still there (to help identify source). Also replace that missing tranny bolt and put loctite on the one that keeps coming loose. What did you work on last before all this?

 

[dwb]

Any CEL codes? Have you performed a boost leak test?

 

[98gstJames]

Any CEL codes? Have you performed a boost leak test?

Got a couple CELs, dual upper alternator fail (bad plug to alt), egr, evap code and yes I’ve done one, no leaks, I had a tiny leak from my outer tb gasket but I fixed that.

My engine runs fine. It revs perfectly, just the shaking seems to be from the trans area.

 

[spyderdrifter]

Is it auto or manual? Only asking because it sounds like an imbalance due to it being at idle. Check to see if the torque converter is secured, or clutch if manual.

 

[98gstJames]

Of course you can’t really tell in the video because my phone auto focuses the frames I guess to make it shake less on the video, but it’s bad enough where I can easily feel it in the car, I did have light vibrations before, but this is much worse than how it normally is. Also my car is a manual.

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[9 T GSX]

I have one bolt missing on the back mount to the trans but I didn’t think that would cause this much of a shake…

Is this the mount your missing a bolt from? If missing 1 bolt from this bracket isnt as bad as the mount below as you have 2 bolts but i would still put a bolt in there.

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or is it this one, specifically the 2 holes in the middle. If missing 1 bolt from either of these holes I would not drive car until both are in as those are the main bolts that hold the transmission in the car on that side?

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• You still have balance shafts? Have you checked the belt
• You can try the MAS sensor tap. if the car runs better or worse when tapping on the top it would be bad.
• Might want to take Timing cover off and see if your crank sensor has been damaged. Might be a sign of C walk.

 

[Dericsh]

You still have balance shafts? Have you checked the belt

Beat me to it, first thing I thought to ask about.

 

[98gstJames]

Is this the mount your missing a bolt from? If missing 1 bolt from this bracket isnt as bad as the mount below as you have 2 bolts but i would still put a bolt in there.

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or is it this one, specifically the 2 holes in the middle. If missing 1 bolt from either of these holes I would not drive car until both are in as those are the main bolts that hold the transmission in the car on that side?

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• You still have balance shafts? Have you checked the belt
• You can try the MAS sensor tap. if the car runs better or worse when tapping on the top it would be bad.
• Might want to take Timing cover off and see if your crank sensor has been damaged. Might be a sign of C walk.

No on the balance shafts, they’re deleted. I’ll check the crank sensor along with tapping on the top and also the motor has a rebuilt bottom end with only 32 miles on it so far, is c walk possible this early? Also the mount that has the missing bolt is the first pic, from the angle of the pic it’s the left side bolt in the back that’s missing.

 

[spyderdrifter]

I would say no, you shouldn't have crankwalk. As someone who defiantly has had crankwalk, you'd get a clicking sound every time you let off the clutch pedal, or at least in my case, that's how it went. It has to be one of the possibilities already mentioned. Since you have the balance shaft delete, did both shafts come out? If the one on the oil pump side was left in, you'd have unexplained vibration. Maybe a bad engine mount? In addition to the missing mount bolts?

Do you have a stethoscope you can poke around with to listen to things while it's running?

 

[98gstJames]

I would say no, you shouldn't have crankwalk. As someone who defiantly has had crankwalk, you'd get a clicking sound every time you let off the clutch pedal, or at least in my case, that's how it went. It has to be one of the possibilities already mentioned. Since you have the balance shaft delete, did both shafts come out? If the one on the oil pump side was left in, you'd have unexplained vibration. Maybe a bad engine mount? In addition to the missing mount bolts?

Do you have a stethoscope you can poke around with to listen to things while it's running?

Yes both were pulled out for the delete, and I’ll see if it can’t see a busted mount with it running and also I do have a stethoscope so I’ll definitely listen as well and see what I find.

 

[99dsmer4g63]

Looks like you’re missing a bolt on your driver side motor mount as well. I’d try putting the car together with ALL of the bolts first.
-Daniel

 

[98gstJames]

Looks like you’re missing a bolt on your driver side motor mount as well. I’d try putting the car together with ALL of the bolts first.
-Daniel

Only the one bolt is missing on the one mount, the rest of them are there, I didn’t have this shake before it just came out of nowhere.

 

[1990TSIAWDTALON]

Pull a plug wire one at a time and see if it gets worse or better or stays the same.
WARNING: THIS CAN SHOCK THE PISS OUT OF YOU. Plastic pliers or insulated ones help, or just man up and pull them by hand.
If I had an oscilloscope I would do a cylinder drop test instead of pulling plug wires, just to see the difference. We record the rpm drop on each one then compare the results to narrow down what cylinder to focus on, if it happens to be just one throwing the motor off. It is just a test.

 

[97egl]

Pull a plug wire one at a time and see if it gets worse or better or stays the same.
WARNING: THIS CAN SHOCK THE PISS OUT OF YOU. Plastic pliers or insulated ones help, or just man up and pull them by hand.
If I had an oscilloscope I would do a cylinder drop test instead of pulling plug wires, just to see the difference. We record the rpm drop on each one then compare the results to narrow down what cylinder to focus on, if it happens to be just one throwing the motor off. It is just a test.

Another way to do this without getting shocked is to pull the connectors off the injectors 1 at a time. Of course this takes more time since it's a pain to pull the metal retaining clips but I've been shocked by spark plugs too many times even when trying to be careful so that's how I always do it.

 

[curt-s]

Yeah I would sooner disable injectors one at a time before removing spark, just so that you don't keep dumping fuel into the cylinder without igniting it. Call me paranoid there
A constantly or intermittently bad injector or spark will cause a very noticable stumble but also throw off your o2 readings too. Revving will also likely be affected, causing hesitance.

How are your plug wires? Have you checked for cracks

 

[98gstJames]

Yeah I would sooner disable injectors one at a time before removing spark, just so that you don't keep dumping fuel into the cylinder without igniting it. Call me paranoid there
A constantly or intermittently bad injector or spark will cause a very noticable stumble but also throw off your o2 readings too. Revving will also likely be affected, causing hesitance.

How are your plug wires? Have you checked for cracks

Plug wires are brand new along with the plugs themselves, I pretty much replaced everything when I did the rebuild. I have a set of NGK BKR7EIX IX iridium plugs in the car, they were more expensive than just the regular ngk plugs you would normally get but they said to have a better ignition under high temps and what not so I wanted to try them out. Not sure if they’re the cause or what but I’d assume my plugs to be bad way before the wires. I’ll check each cylinder and see if any are misfiring.

 

[99dsmer4g63]

The normal ngk plugs are much better in these cars and are what most people recommend running and I do personally. The iridium plugs have their place but it’s not in the head of a 4g car. Not too mention you can buy two sets and probably be still cheaper.

-Daniel

 

[98gstJames]

The normal ngk plugs are much better in these cars and are what most people recommend running and I do personally. The iridium plugs have their place but it’s not in the head of a 4g car. Not too mention you can buy two sets and probably be still cheaper.

-Daniel

That’s what I had in it before and had no issues I just wanted to see if there was any noticeable difference, which I honestly couldn’t notice a difference.

 

[curt-s]

the regular copper plugs have proven themselves more than capable, anything else is just pointless. That being said, they would not cause idle issues when the strain and cylinder pressure is at a minimum.
Not unless they were defective but, again, you'd be seeing your trims out of whack because of unburnt fuel. How are your trims btw

 

[1990TSIAWDTALON]

Paranoid
The spark is never left off long enough to cause any issues to the cylinder walls. Been pulling them since BEFORE oscilloscopes and writing down RPM drop then going to the next one.
I do understand, but really, it's not going to harm the motor. Killing fuel is just harder because of the injector clips, but you do get the same data
One or the other.

 

[99dsmer4g63]

If the wiring harness is original there is no clips on the injector plugs. Pulling them is as simple as squeezing the release tabs and gently pulling on them.

-Daniel