GMWTUK

My 3.2 Carrera (89) hunts for about 10-15 seconds on startup from cold. It settles down and ticks over perfectly after that.
I have only had the car for a couple of months and it's my first P car .
Is this normal?
Regards
Graham

art

I would start by checking for vacuum leaks, intake manifold gaskets, etc.

Giantman

Hi Graham, my 83SC does exactly the same thing. To those in the know, could this also be the result of a faulty warm up regulator?

Chuck Harmon

my 89 3.2 does the same thing... I'm thinking the Air Flow Meter.
It really does not bother me much and it goes away after a minute or two,
then everything is fine.

Chuck

art

An SC has a warm up regulator which can cause this, but a 3.2 does not.

danoberer

My 89 3.2 does it too, but not always. I haven't worried about it. By the way, love your cars - we should have an 89 3.2 pic fest!

GMWTUK

Thanks for all the replies Guys. I have taken the opportunity to speak to to my local Mechs (Porsche Specialists) who serviced the car recently and their response was that this is a pretty common thing with 911's that are not used regularly. It also applies to 964's and their view is that it is not an induction or vacum problem but an electrical one/Symptom.
Their suggestion/prognosis is that on start up from dead cold, there are so many electrial demands from the systems all at the same time from what is a battery that is at slightly less than full charge (keeps alarm and immobiliser etc trucking away all of the time) that it takes a while to get the system up to speed (up to 30 secs)
This car is used once or twice a week ,weather permitting, here in the UK , so the suggestion is that to avoid this, put it on a battery conditioner/ trickle charger.
I am not going to do this at the moment as I reckon my use will increase as we are heading into our summer, but I will monitor this symptom in relation to my useage and will report back.
Their explanation makes some logical sense to me particularly after the initial splurge, it runs like a dream,but I would be interested to hear what some of the more experienced and learned Porsche enthusiasts here think about this.
Only been here a while (couple of months)but can I just say great site, great advice, and great value...I'm a freeloader at the moment and I am now gonna pay my dues, coz its more than worth it.
regards from the UK
Graham

Gost

Hi Graham and welcome to your 911. My 85 has done this for 7 yrs when cold AND when it sat for a week or two. Goes away in 15-20 seconds and runs perfect. I notice that when I run her after a week let's say and drive for over and hour or two and return to bed her down for the night, the next morning when cold it will not do it and starts perfectly. This would coincide with your wrenches explanation because the battery is now fully charged from the jaunt the evening prior. So I'd say Fuget'bout-it and drive the car alot and enjoy her.

Gost

ClubsportSP

Graham

I believe 10-15 seconds of hunting is fairly normal.

There might be a problem if it continues to do this after reaching normal operating temperature. Mine does this, occasionally, and from what I've read on this forum and on Pelican, sounds as though my cylinder head temp sensor needs replacing. The part is approx £70

SP

scottb

You might have your wrench take a look at the mixture.

DonMo

If you adjust the idle and mixture to factory specs and do not have any vacuum leaks, the hunt goes away. It is a fine line. Also, Steve Wong's chip makes it go away also. My guess, if not perfectly tuned, the combo of the O2 sensor and idle control valve work against each other until the system is warmed.

lperkins

I had the same problem, adjusted the air fuel mixture and the problem went away and has not returned.

Julia

My 1980 911SC does the same thing. It appears from all the records I have that several mechanics have tried to fix it, but it still does it. I just replaced my battery and I did notice that it doesn't hunt for as long. Maybe 30-60 seconds. Before it would doit for about 2 minutes! It runs perfectly when warmed up and starts fine after the initial morning start-up. I do not use my car for a daily driver. Next week I plan on taking it to our mechanic for an A/C recharge and a brake line check, I'll have them take a look at that as well.

Peter Zimmermann

Julia: Your "hunt" is a completely different deal than the 3.2 cars experience. Your hunt is GOOD - because it protects the airbox. Your SC (and all CIS cars) has a warm-up regulator. That part is adjustable, and controls cold control pressure. Cold control pressure can be set, as per tha factory manual, to a specific number, usually within the parameters of a graph (shown in the factory manual). When the cold control pressure tilts toward rich, a short-term idle hunt after cold start occurs. For example, my '82 hunts for between 5 and 20 seconds in winter, and only a few seconds in summer. Your car is probably set a touch richer than my car, but that's OK. The slightly richer mixture seems to extend airbox life, my original went 192K miles (with NO toilet bowl, sorry, pop-off valve). My advice is to leave it alone and let it settle itself into a smooth idle, and enjoy hesitation-free start outs!
Pete

JBO

Just curious Peter - why didn't you (of all people!!) have a pop-off? Do you have one in your new box?