sk8kat1

hey guy I have a question .. actually two

I just bought an 86 944 na w/ 81K org miles ---
I have ahd a few 914's and a 911 but this is my first 944

here are the only two ( crossing my fingers) issues I can find w/ the car

1) at start up from cold , in nuetral the car s-s-hakes until it warms up then it runs even and smooth . if I go for a drive and I park for 30-45 min same thing for a little bit . If drive away like that it is very sluggish. at a stand stil it makes no difference if teh clutch is depressed or not.

if it was d-jet FI on a 914 I would say bad head temp sensor or bad MPS ( manifold press sensor )

any ideas ...

2) the car has a a whir sound from the engine - sounds super charger -ish . it sounds like a belt and is from the drivers side -- sounds like it may be the alternator but not sure ---- it is from that general area ... the belts are good no cracks or anything --PO had timing belt and water pump replaced -- is it posible teh belts are too tight .. is the alt going bad --

-- any ideas here

thanks for the help -- and glad to be apart of the 944 club !

V2Rocket

1) cold starts will make it idle at a lower speed than optimum temperature. the lower speeds will make it harsher and shakey because the large four-cylinder engine naturally vibrates. its just how things turned out with the design of the crank etc. once it gets up to speed it goes away because the vibration pulses are closer together

2) that's the balance shaft belt; it has teeth on both sides and the belt spins at twice engine speed (if your tach says 5000RPM the balance shafts are moving at 10000RPM). these shafts spin the opposite direction of the crankshaft and are supposed to neutralize some of those vibrations i talked about earlier.

MAGK944

Could be a combination of problems. First two I would check are the ISV (under the manifold) and the TPS (on the throttle). Then the vacuum lines and also the engine mounts as they might exagerate the problem on idle.

There is good info on this site: Clarks Garage

As for the noise, I would change the balance & timing belt, water pump and rollers if you haven't got definative info on when they were last changed

M

sk8kat1

ok tps = throttle position sensor
isv =-?

knfeparty

idle stabilizer valve

On clark's there's a "right" way to test the throttle position sensor, which is pretty easy to find. It's right under the throttle body like you'd expect. The ISV is under the intake manifold around the middle-ish. Replacing it is more money and cash than it's worth. If the TPS is bad, you'll get weird stuff like you'll step on the gas and the correct fuel map doesn't come on right away so it's really really sluggish and then suddenly kicks on or it's hard to modulate the difference between foot totally off the throttle and just barely into throttle.
There's a throttle reseal kit that is cheap and well worth it- if you remove the throttle and clean it (easy except for one hard-to-get-to allen screw) and replace the o-rings, you can also easily replace the TPS. You may need to follow the clark's directions for bypassing the ISV with a jumper wire and re-setting the idle air bypass screw on the throttle. If you've ever tuned a carb it's really easy in comparison and you can probably get rid of that rough idle. The ISV is supposed to alleviate idle troubles at various temperatures but all it really does is get stuck and cause idle dip. Have fun! And yes the supercharger sound is pretty normal. If it's really bad, re-tension the belts. I re-iterate that if you don't know how old the wp/belts/rollers are, go ahead and replace them as well as front engine seals.
Have fun!

MAGK944

idle stabilizer valve

sk8kat1

so i should just perm bypass the isv?