JasonF

Along with my top end rebuild last year, I had my trusty independent install an RS clutch and LWF into my OBD1 '95 Carrera 4. After reading every post regarding the infamous stalling issues with our '95s I decided to push ahead anyway and make adjustments if necessary.

Steve Weiner originally suggested that I install a new ISV along with the mods since the ISV is a wear item, but I decided to hold off and see if my car was even prone to stalling. Well, wouldn't you know it, but I stalled my car about 5 times on the first trip home after the clutch was installed.

Thoroughly cleaning the ISV every few months along with bumping the idle a bit did cut down on the stalling, but my car would still cut out if I downshifted into a turn while my headlights were on and I applied the brakes (seems like a limited scenario, but it was still very annoying).

Recently, my idle seemed a little rough and the stalling was becoming more frequent. Rather than fiddle with the idle speed on the old ISV once again, I purchased a new one from Sunset and installed it earlier this week. This new ISV was setting my idle at about 450 rpms...way too low for my car with the LWF. After bumping the idle to 750 it is now impossible to get my car to stall under any circumstance and the car just plain runs much, much smoother.

So the moral of the story is that any '95 owner's experiencing stalling might want to consider simply putting in a new ISV (assuming there are no vacuum leaks). For me, it seems to have smoothed out the car's idle and it operates much more efficiently.

One note of caution, you need to remove the protective epoxy coating covering the hex bolts in order to adjust the ISV. For an old unit subject to thousands of heat cycles, chipping the epoxy off isn't very difficult. However, it was virtually impossible to get the epoxy off my new ISV. I had to eventually resort to cutting slots through the hex-head and use a screwdriver to loosen the bolts.

AOW162435

Great info. A new ISV is quite expensive, right?


Andreas

JasonF

I got mine from Sunset for around $320. Someone mentioned that Autohaus AZ has them for less. They must have stocked up on them before the price hike, since I believe Sunset sells for only true cost +10%.

fast_freddy

Thanks Jason. Me thinks I'll be doing this soon on your old car.

CaptainGSR

Thanks for the info. I have few more questions for you:

Did you notice anything else besides the stalling issue? (Noise/vibrations)

What about doing something to the ECU to combat the stalling? (it was mentioned before on this forum)

How is the driving experience? Much Better overall? Not worth all the trouble?


Cheers,

JasonF

How's she running Fred?

JasonF

Johan,

My car didn't feel quite as "crisp" and the old ISV'S ability to catch revs before a stall was deteriorating. I didn't notice any noises or vibrations.

Just before I had the clutch installed, I put in a Steve Weiner/Rennsport chip that was programmed for a '95 with a LWF. I haven't put the old chip in since the LWF install to see if the chip makes a huge difference or not.

The driving experience is better in that I don't have to be obsessed with making sure my revs are below 1,000 rpms before engaging the clutch to downshift. It takes 5 minutes to install the valve, so the only hassle is getting that epoxy off to bump the idle if that's necessary for you. For the $260 or so, it's worth a shot to see if that improves your driving experience.

TheOtherEric

AFAIK nobody knows how to fix the stalling via chip programming. Maybe some 964 guys had some ideas but I don't know if it's ever been found to work on 993's. Simply bumping up the idle rpm doesn't completely work, but it helps a little.

95 C4 993

I havent stalled in a 3 or 4 months worth of driving. After about 5 years of a LWF, I just gave up trying to resolve the ocassional stall. Its like the common cold in my opinion---there is no cure. If there was a cure, it wouldnt be a topic of discussion any more.

fast_freddy

She's running great! The Ersatz RS conversion gets completed this weekend sans several pieces. Basically, the suspension is a full on RS upgrade and then some, no more back seats nor AC and heat blower. All easily reversable jobs. She's a quick one too. With street tires I get to within .25 second of the same class cars on Hoosiers, not too bad for a 14 year old car versus pimped out with cages, bigger intercoolers, more boost, R compunds, etc. EVO's/STI's, FFR Cobra's and Lotus Exige's. I'm tempted to get the aforementioned tires but it's just an Auto-X and I'm there to learn, not make mistakes and not know about it because of the R compounds.

JasonAndreas

it did...

TheOtherEric

Has anyone explained what they did, or is the solution proprietary? I thought you had speculated about making the ECU think the a/c was on or something like that.

So who is selling chips with this fix? Any performance chips, or simply factory-programming with the LWF fix?

95 C4 993

FWIW, I noticed something and it could be way off track pertaining to the 95 and the LWF. The stalling seems to be less when I have less oil---less as in between around 1/2 on the dip stick (or a little less) --rather than upwards of 3/4 + on the dip stick.

This is a right field observation and I have no idea if the amount of oil in a 993 has any relation to the mechanics of a flywheel. I tend to analize things and this is something I thought of after 1.5 glasses of Jip Jip Rocks Shiraz (from down under) wine while cooking dinner.

Steve Wong has mentioned a chip that brings things back to stock but some have claimed it has reduced or eliminated the stalling. Im not endorsing it but some have said it has helped. However, I will take a stall now and then in combo with a performance boost.

Another 2 glasses of wine and I may have a cure for the common cold.

nile13

Jason, fess up, what did 964 people do? :-) Stalling makes things pretty upleasant.

Other Jason :-) can you explain what slots you had to cut to get to the adjusting screw? Any pics?

JasonF

I'll try to take some pics this weekend. The "fresh" epoxy on the new ISV was so difficult to remove that my Dremel bit rounded out part of the hex bolt head, making it impossible to use an allen wrench to remove it. As a result, a small Dremel cutting attachment was used to make a slot in the bolt head so I could use a screw driver to back out the adjusting screw. The perfectly fine bolts from the old ISV are now on the new unit.

I didn't have this problem with the old ISV, probably since the epoxy was exposed to thousands of heat cycles which made the epoxy brittle and relatively easy to chip away.