jturbo

I have not driven my '93 964 RS America for 6 months. I know this is never good, but the alternator belt broke and battery went dead 6 months ago and I never got to fixing the car before the winter months.

Anyway, I installed a new alternator belt and a new battery 770 Cold Cranking amps. Now the car will not hold an idle?

The car smoked a little bit when I first started the it, but fired right up. I took it for a drive assuming that the idle would return after getting up to normal operating temperatures. After a 5 minute drive the car still would not idle.

Any suggestions on why the car will not hold an idle?

BTW - I have only driven the car about 250 miles since I bought it in August of 2007. When I bought the car it was slow to hold an idle, but after a few seconds of fethering the throttle it would hold an idle.

ilko

First thing I would check is the ISV (idle stabilization valve). Take it out and clean it up, as shown here: http://p-car.com/diy/isv/

C4Russ

Sounds like a car that is searching for a full tune-up.

jturbo

Thanks for the website it looks like it has a lot of useful tutorials! I cleaned the idle stablizer unit with Mass Air Flow cleaner, however it did not resolve the idle problem.

I am wondering if the problem is not the new distributor belt that I installed. The new belt is 970 x 760, so was the old belt. However it looked like the belt "teath" on the old belt were much more narrow than the new belt. They are both stamped as the same size though.

Maybe I have the alternator belt installed with too much tension? Would this cause the engine to stall? I installed all 6 spacers in between the alternator pully halves which is the loosest tension setting using the spacers.

I did read that there was an update that Porsche made to the pullys and belts. The new belts are wider and the new pully halves have the spacers "built-in". Maybe this problem is a result of using the new alternator belt and the old pullys.

Any thoughts?

J richard

I'm assuming this was a typo and you really meant alt belt? I don't think you could get a belt so tight that it would stall the engine, I think the fan would be rubbing long before that...

I don't think a 5 minute warm up is enough after sitting for that amount of time, I think you should take it out and tromp on it for an hour or so, up at speed under load, blow the cobwebs out. Then if you still have an issue, I would start looking deeper. One thing to check first is that the floor mat hasn't bunched up against the acellerator pedal keeping the idle microswitch open...

and your right, it was very, very bad that you haven't driven it for six months...shame on you....

jturbo

Thanks Richard.

How can I locate this switch? I have never heard of it. I think running the car longer is a great idea.

I had thought that I should have driven it longer, but I didn't want to get stranded today. I had put Sabil fuel stabilizer in the tank before winter, so I think that the fuel is still good and there should not be much if any moisture in the fuel tank or lines. However it did sit for six months. Unfortunately before the belt broke I had just filled up the gas tank, so it will be an undertaking to drain the tank. Normally I would just add additional fuel to "revive the fuel", but the tank is at maximum capacity.

I'm hoping to get the car running for the Hershey, PA swap meet. i live 20 minutes away from the largest swap meet in the world. Its tomorrow.

RSGulp

Check every one of the hose clamps in the engine bay is tight enough. Just turn them to take up any slack - not too tight though so you don't stress the rubber. Make sure you check where the manifold meets the tops of the heads too. It sounds like you might have an air leak in the induction system due to a loose clamp causing your idle problems.

Then take the car for a good drive. Your ECU needs to refind it's settings. Find a good varied route - with different types of driving styles, town driving, freeway, etc, etc.

jturbo

I took the car for a long drive today for an hour and then stopped. Then for another 1/2 hour. The car still dies at stop signs? It will not hold an idle? I left the car sit for 6 or 7 months due to the broken alternator belt and the dead battery that needed to be replaced. I had put fuel stabilizer in the fuel tank right after the belt broke in early October, so I can't imagine that the fuel has gone bad? Do you think it is possible that the fuel accumulated condensation even with stabil dumped in the tank?

My next step is to change the spark plugs, but I don't think that will make a diffence though because the car runs fine other than when I get to a stop sign then it dies out. No idle?

Any suggestions guys?

MassGuy

How is your current battery? Is it fully charged?
Is the old fuel almost gone?
If the switch is staying open find it with your finger and press it. See if that helps.

tbennett017

The Idle switch is in the engine compartment where the throttle stops are. Look for the throttle cable, and where it connects to the lever arm at the throttle.There are two tiny switches that sense when the throttle arm is at "rest" (no tension, and against the stop) and when the throttle is WOT. They affect the engine settings through the computer. You might have a throttle cable that is too tight, thus not touching that switch. I would also see if you could get a Hammer or aftermarket unit to check for error codes, or look online here for how to read error codes.

http://members.rennlist.com/billwagner/CheckEngine.html

This might narrow your issues.

You will get it sorted. This is pennance for RSA neglect...

DAVISRILEY

Did you ever get a code out of it? It sounds like what my car was doing when I put the aluminum floor mats in I made, and they didn't let the gas pedal go all the way back. Iirc I got code 1515 out of it. Fixed mat, disconnected battery, did dme reset, and car has been happy since. But it would do that, hunt around for idle, and stall at lights. I agree with bennett, check the idle switch.

jturbo

Thanks guys. How do you reset the DME and where is it located? Also, does anyone have a picture of the switch?

jturbo

The gas is at 3/4 full still, so I am trying to run a little out each night. Its frustrating though stalling out at stop signs.

TEN DOLLAR

I've only owned my 964 for 12 months now, so don't have much technical knowledge on the cars. However you say your battery went flat and was recently replaced. Have you had a full adaptation done since then? Every time I disconnect my battery, my car wont hold idle and stalls every time I come to a stop at a junction. Once the car has been connected up to a diagnostics machine and a full adaptation performed, the car runs fine. I do find this a particularly irritating, as most jobs require the disconnection of the battery.

Just a thought, good luck with it.

TD

boxsey911

TD, you shouldn't need to do that. There's a DME reset procedure in the 964 DIY section. To save you searching, here it is:

DME RESET PROCEDURE