H964

hey guys, just picked a clean low miles S2, so iam trying to work out the little few issues.
1- starting the car hot, sometimes i get a low rough idle for about 10 seconds then it clears. it seems to happen after each hot start.
2- i noticed the shifter vibrates a lot, and i get a rattle when decelerating, i am guessing the tranny mounts, but will listen to any suggestions, its also worse with the AC at idle.
3- there is a whine at all times, i might be low on steering fluid, will add some and see if it solves it.
thanks for your contribution

H964

i thought this was more active than the 964 section!

Fara

We are fairly active, but most of the members are not willing to weigh in on diagnosis of problems like this, because it's pretty intensive.

Your first point of contact should be Clarks.
http://www.clarks-garage.com/shop-manual/eng-15.htm

If the problem still persists, please list what troubleshooting you've done and what the results were.

H964

great link
thx

peanut

ok I'll take a shot at it

Hot start problems can be caused by quite a number of components . I would test the engine temperature sensor, the AFM , and the DME relay for starters.

Look on the Clarkes garage website in their workshop mamual for testing proceedures for AFM, DME, and ETS . if youare unfamiliar with these components I'll be happy to explain their operation and how to test them and why they effect your engine idle and starting when hot.

Re the whining sound . listen to the alternator, often the alternator bearing will dry up and start to whine in sync with the engine revs.This frequently happens after belts have been changed or tightened.Use a long wooden rod and place it on your ear and test various parts of the engine when its idleing to see if you can narrow down the source of the whine

My S2 whines all the time which is actually the air intake . it sounds a bit like an aircraft from outside the car .

ZR8ED

Tell us about the car and any work or diagnosis work you have done so far. Have you had the timing/balance belts replaced? where they done recently? Check the steering does the whine change when turning the wheel while the car is parked/stationary? check the fluid yet?

We need some more info. Please provide as much as you can describe. It may also help if we know a bit more about the car itself. Mileage? maint history? general condition? did you check the fluid level in the pwr steering first?

Please post back your results.

hamlin

This is not uncommon. Hot start symptoms as you describe it has been often found to be a bad diaphram in the fuel dampner. Pull the vacuum line from the dampner that runs to the underside of the intake manifold. If fuel is in the line the dampner diaphram is torn. Replace the dampner and the symptoms will disappear.

I encountered the same symptoms in 1996 at around 50,000 miles on a newly purchased 944S2.

Don't forget to have the valve cover pulled and the cam chain tensioner plastic ramps checked for wear and cracking if this has not been done. Ramps will crack and destroy the cylinder head.

The S2 is one great vehicle. Enjoy!!

H964

thanks for all the replies, the car has 63k miles, all maintenance is up to date, belts, new clutch....
my power steering fluid was low, added topped it but didnt stop the whining.. its not so bad though
Hamlin, i would your tip, but couldnt figure out which vaccum line you are talking about. can you be more specific? a picture would be great!
thanks again guys, will post pictures soon

N_Halbert

Even though the car does not have a lot of mileage the rubber parts are old and the center of the clutch is rubber. It breaks down and separates. That can cause shaking in the shiftier and harsh transitions on off throttle.

hamlin

Here are a few images. The Dampner is very easy to get to. It sits on top to the left of the intake boot. Pull the small vacuum line and if raw fuel is in the line or it smells of raw fuel the dampner needs to be replaced. Pictures should help. It is designed to suck the raw fuel into the bottom of the intake manifold if the dampner leaks thus preventing the possibility of a fire.

Let us know what you find.

David

peanut

its not the fuel damper (the damper dampens occilations in the fuel supply system)

its the fuel pressure relief valve or FPR like I said in my earlier post.

The FPR maintains a constant pressure of fuel in your fuel rail under all driving conditions . If there is too little pressure the injectors won't work properly . If there is too much fuel pressure then the ECU will shut down your fuel delivery system.

The FPR constantly relieves any over-pressure and allows some fuel to return to the gas tank via a seperate return fuel line which comes of the FPR.

The FPR valve has 3x connections.
Fuel in from the fuel rail
Fuel out to the gas tank
and vacumm connection.

The engines vacuum system is run off the cars inlet manifold and one of the things it does is to help the FPR valve maintain the fuel pressure at all engine levels from idle to full open throttle.

There are 2x aspects to this . Firstly you need to check all the connections and tubes in your vacuum system to make sure that there is no leaks (see your manual or Clarkes Garage site. Secondly you need to check the fuel pressure in the fuel rail to confirm that the FPR is maintaining the correct fuel pressure (again Clarkes garage or your manual) If you are unable to check the fuel pressure then you can substitute a known working FPR to check yours but substitution can become expensive ...better to test .


The Bosch fuel injection and engine management system is an extremely complex one and perhaps fewer than 1 in 1000 mechanics would have a working understanding of it sufficient to fault find problems . Most will simply bolt on new parts until the problem goes away or your wallet folds

H964

thanks guys for the support, i will follow your recommendations and let you know what i find.
peanut, i did not ignore your offer to help, if anything i am glad you guys are helping, i just havent had a chance to start the diagnose with the holidays

H964

update: it turned out to be a bad AFM connector. now car is running hot at times, i just posted a new thread, will appreciate any feedback.
will post pictures this weekend!
thanks again