Engine vibs???

[Fast 3.4]

My engine seems to shake while I am stopped.
I heard of putting a chain around the front manifold and bolting it to the chassis. But won't this cause damage to the manifold over time, with the pulling action when I drive the car? I know cars like the Lincoln Conty, have a bar type thing to reduce vibrations, what is a safe way to reduce vibs in our SHOs???

 

[stephen newberg]

Once the engine on mine reaches operating temperature, it has virtually no movement at all at idle. If yours is shaking under those conditions, I think something else is wrong, perhaps in the motor mounts, and it would be worth checking out before going to something like straps.

pax, smn

 

[Fast 3.4]

The only way to check the mounts is to pull the motor right? Well the vibs arent harsh, the motor will shutter then its smooth, shutter then its smooth. Just a slight vib.

<small>[ January 31, 2003, 11:12 AM: Message edited by: Fast 3.4 ]</small>

 

[SHOZ123]

You can visually check the motor mounts from under the car. The chain has slack in it and is only active under the initial moment of acceleration.

 

[E1]

Have you looked into operational problems with the motor? Flakey coil or something? did you pull any trouble codes?

 

[Fast 3.4]

Yeah I had all that stuff checked(coils and such)
Maybe its the mounts, I just notice the vib, my passengers don't feel it. But I do.
Back to the chain, if it has slack in it, and you take off, isn't it pulling on the manifold then? Over time I would think that all the pulling would cause a problem?

<small>[ January 31, 2003, 02:56 PM: Message edited by: Fast 3.4 ]</small>

 

[mholhut]

Just remember, not all faulty coils will throw a code. '96's threw them all the time, but the '97 and up model years seem to be a bit more reluctant to throw misfire codes. The best way to find out if you've fried a coil is to test them with a volt/ohm meter. Even then, that method is not 100% accurate.

IIRC (and Paul and Kirk might be able to verify) if the wiring harnes on the back bank of cylinders gets too roasted, you could have a random misfire. I've seen plenty of these harnesses now that have been melted. Without any treatment, I'd bet some sort of misfire might have been the result.

I just wouldn't readily dismiss this as a motor mount issue.

 

[stephen newberg]

Hey Mike, I read that they are going to seriously upgun the power output and retune for greater stiffness the suspension of the LS for this year. You going to trade up?

pax, smn

 

[mholhut]

Steve,

Not to get off topic, but the '03 LS has a new 280 hp variable valve timing V8. They bumped up the HP to the '03 V6's as well, but I don't have those numbers... 230-240 I think. I haven't paid too much attention to the other 100's of improvments but they were quite extensive. Am I going to trade up? Sure.... in a few years when I can afford one I figure the '03's will be about $20K in two years or so.

 

[SHOZ123]

Back to the chain, if it has slack in it, and you take off, isn't it pulling on the manifold then? Over time I would think that all the pulling would cause a problem?

These manifolds are heavy cast iron. And are bolted to the head with 8 bolts. It is probably one of the strongest area on the motor. If there is any stress that develops then I would think it would make itself know audibly due to an exhaust leak.

With the ATX, once you are on the throttle and the slack is taken up on the chain there is tension on the chain until you lift the throttle.

There is actually very little slack maybe a 1/4 inch. With so little distance to move before the chain is tense the motor does not get to build up much inertia.

<small>[ February 01, 2003, 04:21 PM: Message edited by: SHOZ123 ]</small>

 

[stephen newberg]

"I figure the '03's will be about $20K in two years or so."

Must admit that thought had occured to me also. I am going to drive one next week for a day or two to get a feel for it. From the reports I have read thus far, they seem to have taken care of all of the things that I felt needed changing on the car when I last drove one a year or two ago.

But I have gotten really fond of the SHO, so I suspect I will hold off until it needs to be replaced, no matter what.

pax, smn

 

[MikeMike]

i know this may be off the topic, but on the SHO i am looking at it is a 97 and when i am around 20-30mph there is a low rumbling coming from the front tires.. could it be the CV joints ot the tires?

 

[stephen newberg]

This was a fairly low mileage '97, right? At low miles I would not think CV joints, though it could be. More likely would be tires, or perhaps wheel bearings. I have replaced by front wheel bearings twice now, I believe, the first time at 46K km (about 30K miles), and the second time just recently at about twice that mileage, so they do seem to be high wear components. The way I drive, anyway.

pax, smn

 

[SHODWN]

Coil pack
Vacum leak
bad plug
Bad Injector
Stuck secondaires (to much air)
Faulty IAB
Dirty Maf
shorting wiring harness
warped runers not sealing
Used gaskets after a cam weld and not being properly torqued down.
Cam sprocket loose not making noise changing the timing of one bank of valves.
Carbon on the valves not letting it seal properly

Anything mechanical will not throw a code, and as Mike said the obd-2 blows for throwing codes untill its to late.

all will cause some of the specified conditon.

 

[MikeMike]

thanks a lot, well the car is 97k miles not too bad