Does anyone know how to test if your engine mounts are doing their job properly?

I have an issue with "bucking" right at the beginning of the throttle movement from a closed plate to it just being open with small pedal movement. (It's not driver related so rule that out completely. Read here if you wish https://www.s2ki.com/forums/index.ph...f=22&t=262519)

Anyhow, I have a feeling it could be engine mount related. Allowing the engine to rotate a little too much affecting the minute throttle inputs which is transferring it as a spring type action through the driveline causing oscillation too easily. (jerking the car, no pun intended .)

This is my fist experience feeling this in an S2000, and it has been apparent from birth (since I have owned this car). My previous S did not have this problem nor have any others I have been behind the wheel in.

I have a feeling it could be engine mount because have felt wheel hop now with the colder wet temperatures. I don't remember the rear hopping before as easy as it does now. I know wheel hop is a HUGE issue with FWD cars and soft engine mounts.

I earlier thought it could be the MAP, dirty injectors, dirty air filter, plugs, dirty TB all combined to limit small throttle inputs close to the off position but all that checked out ok. It's ONLY when you go from an open to closed plate. Throttle adjustments from 1/4 throttle to 1/2 to full have no issues. It's ONLY when you transfer from a closed to barely open throttle plate.

I almost want to get rid of this car and get another one.

 

Should be a simple check. Are they tight, are they leaking? If the answer to both of these is no, your problem likely lies elsewhere. Hope you can get it figured out.

 

Just an update. Most of my problem (90%) has been fixed now after running some "Fuel system cleaner" though.



I'm assuming this formula contains more concentrated chemicals than the regular injector cleaner does.

My other question concerns drive shaft play. With my car in neutral, ebrake released on a hoist. If I pick a point on my driveshaft i can rotate it about 1/4" from one direction to the other before it will start turning the wheels. (I.e. i load it up in the fwd direction and switch to the reverse direction i can turn it about 1/4" of an inch before it

 

That's about normal slack in the driveshaft.

Checking the mounts is pretty much a visual check, rev the motor and watch to see if the mount has seperated.

 

[QUOTE=Jasonoff,Nov 1 2005, 07:15 AM]Anyhow, I have a feeling it could be engine mount related.

 

What you're describing is not a problem, its normal. Its from something called Deceleration Fuel Cut-off. Whenever you close the throttle when you're in gear (not idling) the fuel injectors cut off. This is for emissions purposes. Back before there was decel. fuel cutoff (with carb. engines), whenever you lifted off the throttle to decelerate it would create a rich condition and you heard the typical "exhaust popping." That rich mixture is bad for emissions so to fix that the fuel injectors cut off during deceleration.

When you open the throttle again, the fuel injectors have to turn back on and thats what you're feeling. Its the transitioning of the fuel injectors cutting on or off. The feeling is probably just more pronounced in the S compared to a more luxurious car with softer motor mounts.