Vibration Problem

[Tim Stevens]

My brother bought an 86 951 turbo and is having a strange vibration under the gas pedal under acceleration in first and second gear. It starts around 3000 RMP and goes to 4000 RPM. You can also here it in the engine compartment. There is a rattle at Idle as well. Also he is running at 1 bar of boost is that what he should be at? Any thoughts???

PS – he is also looking for some performance upgrades. What would you recommend first.


Thanks - Tim

[Lawrence Coppari]

Check all your heat shields including the one around the brake fluid reservoir. There are at least two bolts on the bottom.

One bar boost.....what does the gauge say when it is floored and doing about 3500-4000 rpm? Stock, you should be reading about 1.8 bar. The gauge reads in absolute units.

[Tim Stevens]

The gauge reads 1 when turbo is at full boost. Also anyone in Atlanta that would recommend someone for a 944 T. Thanks for all the help - Tim

[Lawrence Coppari]

Either your gauge is wrong or you are not getting any boost at all. Turn on the ignition switch without starting the engine. It should read 1 bar, the atmospheric pressure.

I do a lot of track events at Road Atlanta. One shop sets up a tent there and helps out with the cars. They are very knowledgeable. Group is Performance Imports in Doraville, GA. Bob Sanderson runs the show I think.

[944TurboHB]

I also seem to be having the same problems of low boost (actually the bar needle jumps/wobbles backwards as I step on the gas after just barely going forward of the 1 a couple fo wobbles, it for the most part seems to want to go backwards, havent really gotten to open her up as this was done with the rear wheels off the floor and also due to the fact that also just like you said for your 951, I have to step lightly on the pedal, like mid to low...otherwise it seems to want to stall. I also have the problem of it being rough at idle but once I give it a little gas it smooths out but once I let go of the gas it idles rough again....
As far as my vibration is concerned, I think the problem may lie in the balance shaft woodruff keys, I did the job with an experienced mechanic who had I think up to that point never worked on a 944. We replaced the water pump and timing belt/ balance shaft belt and all the rollers and such...When we put everything back together (pretty well in fact) we only forgot to note the position of the keys so it was a guessjob when we put them back in. I had read some post on here that this would be the cause of a lot of vibration at higher rpms (over 2500 to be exact i beleive it said) (the post is on this site).
Could you please get back to me with some info on what ended up being the solution? What you did that made the problems go away?? I am thinking for now it may be a vaccum leak somewhere in a cracked line but haven't gotten to check...and seems like I've got my work cut out for me. Thank you in advance for your help.

[Tim Stevens]

I believe it was plumbing for the turbo that was leaking. The vibration was never fixed and he no longer owns the car

[944 Ecology]

Originally posted by Tim Stevens
I believe it was plumbing for the turbo that was leaking. The vibration was never fixed and he no longer owns the car

Did he sell it to someone in Queens?