PennyWise

This car (89 944S2) is like a drug lord..... I made me addicted in the first year, and now its making me pay for my pleasure..

I've developed a noticable vibration on the gear lever when I hit 3000 rpm. It stays there till 3200rpm and then is quite again. It happens it 1st, 2nd and 3rd (havent had space to test 4th & 5th) I've also noticed a slightly louder 'gear' noise when decelerating. I don't recall it being there before, but maybe I've become over sensitive since the gear **** started vibrating.

Context:
It only happens when in gear and accelerating (hard and soft). Other that the engine is smooth
I had all my belts changed about 1000m ago and are due for tightening in about 1000m
I've also had all the oils changed (gear/diff and engine)
I have noticed a louder belt whine around the same time the gear **** vibation started, mayby the belts are stretching and need to be tighted sooner.
All the work was done by an OPC that specialise in 944's etc so I trust their work
I tried pulling away in 1st and 5th with the handbrake on to test the clutch, no slipage.
I have a noisy/stuck lifter when the car is cold.

So... based on my initial process of eleimiation, It points to something in the rear of the car

Tube bearings?
Pinion gear about to pop?

maybe.. a balance belt slipped and under load it vibrates more?
maybe.. a cam belt sliped a tooth (hope not)?

I don't do burn-outs, drift, street race, DE or track the car, just a daily driver.

Any pointers would help..... I'm off to my OPC to see what they think...

Thanks.....

hosrom_951

Check the balance shaft belt, when my NA balance shaft belt wasn't aligned properly, it made a wonderful sudden change in exhaust note while accelerating and decelerating at 3,000-3,200rpms. A couple of weeks later, the fuel rail cracked (leaked fuel), the PS mount broke and the a/c compressor mount broke as well.

PennyWise

Just got back from the garage...... well... found nothing, except an oil leak from the front seals.... bummer.... car goes in tomorrow for new seals. They will have to R&R the belts so maybe that will fix the problem....

I'm starting think its the clutch.... as my changes are getting harder... and I'm getting a bit of wipping when decellerating... oh well.......

lucifer_sam

Hey! I have the exact same condition with my S2. A curious shifter vibration right at 3k rpm. Power delivery doesn't seem to change when the vibration is going on. It interferes with driving though, being that 3k is a nice rpm to cruise at and I have a tendency to either hurry past the vibration range or else leave the rpms under 3k.

Sorry, but I really don't have an idea what it is either. I CAN tell you that I'm just finishing up a belt and water pump job, and before I took the balance belt off I checked the sprockets and they appeared to be lined up correctly according to the marks on the belt cover, with the engine at TDC.

So what is "wipping" exactly? Before I started the belt job, I noticed that the car had a rather harsh way of going off throttle or coming on throttle. Basically when I first press the gas there is a noticeable (although not terrible) jerk and then once the throttle is open the rest of the rev range is smooth. It's the same for going off throttle, too - a little jerk when your foot comes up and the throttle closes. Is this what you're describing?

Hey if you find out what's going on - I'd love to hear!

sasilverbullet

Had this same problem once - it was the cv joints - put in new ones, the vibration went away.

btw, they didn't "feel" that worn, but they were...

black944 turbo

My Cvs where shot and did not feel worn at all. But once they where taken apart they here shot.

Peckster

Some Porsche mechanics screw up the balance shaft alignment, which causes the 3k vibration.

How many 944s does yours work on?

PennyWise

Spot on.. thats exactly what started about 3 days ago....


As for the CV's.... Thanks SasilverBullet & Black944 Turbo...... I'll give my guy the heads up.

I trust my guys...They only work on 944, 928, 356, and older 911's. They're even in your Porsche dealer manual. (Carrera Motors) Been around for yonks...so no problem there....

I'll post the answer when I get it fixed....

89AZ944

Hmmmm....Does the S2 have the "rubber donut" clutch?

Mark944na86

It does. (Hmmm. Donut... Doh!)

-Homer

lucifer_sam

yeah - just got mine back on the road. The engine revs silky smooth up to redline with the clutch in or when its in neutral, but going down the road, i get the 3k vibe.

so along with the wipping (not wHipping?), that pretty much rules out the balance shafts. plus, i installed 'em myself, so hey, they better be right, right?

CV joints - mine do click every so often, like when I'm going around a corner just so with just the right amount of throttle. usually at very slow speeds - coming out of a parking lot and stuff like that.

PennyWise

Whipping.... oops.. lost my 'h'. Sorry for the confusion..

Messed arround with the car at the garage.... it sounds like CV's.... they're going to check both.. will let you guys know....

PennyWise

Spoke to the garage today...... CV/Drive shaft joints are pitted and worn....

Cha Ching.....

944cruiser

I have the same problem on my 88 944S. I've looked into it a few times but have not had a chance to take it in to have the shop look at it, but I'm sure it's not belts (checked twice) or rear-end components because it persists with the clutch in or out. I'm inclined to think now that it is the exhaust hangars improperly aligned. Most days the vibration is heavy between 3100-3200 but very occasionally the vibration is gone. Let us know if you find the cause of your vibrations.

black944 turbo

It is an easy job, do it yourself and buy the axles from lindsey racing. They had great prices and had them to me with in a few days.