help, got a 88 n/a fc, manual box
once its warmed up when you drive it there's a low pulsing noise when you press the throttle, doesnt happen in neutral or when the clutch is depressed, only when in gear and on the throttle, any idea's
also the noise seems to be coming from the front of the car and the passenger seems to think he can feel more vibration than normal through the floor on his side.

cheers

 

anbody?

 

from what you say, i would look at the motor mounts.

 

why would it only do it when in gear then?

 

and why only when warm

 

Diagnosing a sound on a web forum is pretty difficult since we can't hear what you hear. You may not find an answer to your question. The best you should hope for is that someone gives you a list of things to check, and that one of them happened to be the culprit.

 

Maybe transmission bearings, does the sound increase with engine load (throttle)?

 

it is louder with increased throttle but now also does it on idle in neutral,
but still only when warm

 

Sounds like Motor Mount to me also..If you put the car in Gear,then the Engine is essentially Attached to the Trans,Etc..it will make the engine jump up and down due to load,acceleration Etc..I Know this "Symptom" as I had one Break on me..I Swore it Wasn't broke,Until I went to change it out for New Poly Motor Mounts..The old mount just fell out in Pieces.

 

Is the sound a whirring/whining or a clunk?

A clunk may be the motor mount, the whine/whir is almost certainly a bearing issue.

Check your Transmission fluid level, it may be as simple as that.

My instinct tells me that a motor mount vibration should not make noise at idle in neutral with the clutch released and than cease to make noise when the clutch is depressed in nuetral.

The transmission countershaft is spinning anytime the engine is running and the clutch is up, this is a good candidate.

A good test is to place the car in gear, get up to speed, depress the cclutch and shut off the engine. if the noise is still there, it is almost certainly the countershaft bearings.

Hope this helped

 

if your at speed its there then if you depress the clutch it goes away,
if it is the countershaft bearing what does that entail to fix it?