Irregular idle speed

[Guest]

do all 964's have a little irregular idle? as opposed to a "modern" car where it is constant? I checked one out last night (in my hunt for a nice one) and being an absolute beginner in the porsche game I need all the help i can get. It seemed to be irregular in sync with a fan of some sort in front.

 

[Dave Wilkinson]

Darren,

I think the sort answer to your question is..... NO. In an ideal world the idle speed on a good condition 964 should be rock solid. However, there are a host of reasons why it might not be - some might mean there is a problem, some might mean it's been modified in some way which would affect the idle speed.

If the car is otherwise good condition it's an issue that should be investigated as part of a pre-purchase inspection (PPI).

There are (potentially) 2 fans up front - the oil cooler and the air conditioning condensor (if it has a/c). If the a/c was switched on (which would cause the condensor fan to come on slow) the idle speed might fluctuate a bit. If the a/c fan was bursting on high speed there may be a problem with the ballast resistor (a common problem) or, possibly, the fuse for the rear blower. Try turning the a/c off and check the idle speed again. The fans are electric of course but the a/c would place an extra load on the engine through driving the compressor.

Hope that helps


Best regards


Dave

 

[Elliot Davies]

Also make sure that the throttle cable is returning fully and hitting the idle control microswitch in the engine bay, its a tiny thing but it was my problem a while back causing eratic idle.
ECU been tampered with, lightweight flywheel ?

 

[vitesse]

Darren,

Our 964,80k miles used daily by Mrs Vitesse mainly in traffic ticks over very evenly with virtually no movement detectable on the rev counter.
It is even enough to trickle along in 5th in traffic with no throttle at 30mph or even lower with no hunting.

 

[Elliot Davies]

Remember to have a look at PCGB member John Mile's site at http://www.porsche964.co.uk/
read the running reports to learn what you need to know before buying

 

[Guest]

thanks people, it apparently has an RS flywheel and clutch (done in the last month). I have to say that some of the receipts in the history are quite scary in terms of cost...thousands and thouands of £££

is this part and parcel of porsche ownership? I can afford the car quite comfortably, but am not comfortable with having to fork out that kind of money for repairs and such.....maybe i'm just not ready for this?

the car has been looked after by porsheworx in london, are they good? anyone with any experience with their workmanship?

 

[Melv]

ORIGINAL: encomium

thanks people, it apparently has an RS flywheel and clutch

That'll be the erratic idle if the ECU hasn't been worked on.

I have to say that some of the receipts in the history are quite scary in terms of cost...thousands and thouands of £££

Budget on £2-4K p.a......

 

[Guest]

hi mel, does the ECU have to be remapped because of the flywheel and clutch? or jjust in general? and how much would something like that cost?

 

[Melv]

Yes and don't know -you need to talk to Geoff Everett, AmD or Weltmeister at Silverstone.

Needs to be done in conjunction with RR.

 

[Dave Wilkinson]

Darren,

This issue of using the lightweight flywheel is a constant on-going problem. At the moment there is a long thread on Rennlist on exactly this issue. Follow this to read it. There is no simple answer since it seems different cars react in different ways - some have no problem - some have incurable problems. It seems a general consensus that using the '89 C4 flywheel (at 19lbs) is a better solution than the RS flywheel (at 12lbs) because the 12lb flywheel allows the engine to respond quicker, particularly when slowing down, and the DME computer cannot react quick enough and often allows the engine to stall. None of which is at all helpful if you've recently had the RS flywheel installed. Changing it after the event is just a huge waste of money since the whole clutch mechanism has to be changed too.

Regards


Dave

 

[Guest]

wow...after reading the first 3 pages of that rennlist link, i really don't know if i'm ready for porsche ownership. I love the 964 and 993....but the amount of potential problems seems staggering!! I have a 94 BMW M3 now and it runs beautifully and it's a great car, but it still doesn't quite come up to the porsche experience (just my opinion).....

i will keep looking and reading.....just received my back issue copies of 911 & Porsche World (964 and 993 buyer's guide) and hopefully one day i will be ready to take the plunge

having said all that....i still want one...and this one i saw with the rs flywheel has no where near the problems that the guy on rennlist was/is facing....

 

[jr2015]

HI,
If the flywheel and clutch have been changed in the last month, why is the car for sale?caveat emptor I say.
Adrian Streather`s book "911 companion something or other" is an essential read if you`re after a 964( and is cheaper from the club shop than from 911 and PW).
good luck .
jr.

 

[Jamie Summers]

My 964 C2 has the RS clutch and flywheel and it does make the car quite hard work. The idle is fine and steady, the problems tend to be in low speed manoeuvering, especially going from 1st to reverse repeatedly trying to get into parking spaces, the revs fall off so quickly that it often stalls (stalled 4 times trying to get into a parking space last night !!), though curiously it is fine in stop start London traffic. The other place it can be a problem is decelerating and changing down from 3rd to 2nd at roundabouts - stalls quite a lot, though momentum bump starts it immediately. These problems are an inconvenience, but I am learning how to drive round them by using a few more revs than I would normally and shifting quicker. In due course I will have the ECU remapped and that should help too. It is not something that should put you off purchasing as it is no more than a minor, occasional inconvenience, though as mentioned above and in teh Rennlist thread it does seem to be a real insoluble problem on some 964s. You will just have to drive it and see........

 

[968CSReading]

Just reading through this post with interested because my 968 has an irratic idle speed. However, I have fitted a De CAT pipe so I wonder if that has any effect? Also, I have changed the DME relay so I may install the old one again to see if it makes any difference.

Encomium, have you condered a 944S2 or a 968. If you buy a good example it can be a good entry into Porsche ownership. You could then work your way upto a 964 or 993.