Eric Kessel

I've had my 90 C2 for about 4 months. It's had a full life before I got it, and had been fitted with a "chip" of some sort, a LWF, AC has been converted over to the modern gas, secondary bypass, and B&B free flow primary muffler.

It's my third Porsche, and first where the AC actually works. Problem is, if you put the clutch in, it immediately stalls. When I first got the car, I replaced it O2 sensor, Idle Stabilizer, Head Temp Sensor, and it was very drivable, once it warmed up.

Now with the summer, if I use the AC, the car is basically undrivable.

I'm planning on pulling the engine, send the flywheel to Andial, and have them put the weight on it, making it a Mid Weight Flywheel.

Finally my question.

Will the car still have stalling problems? Has anyone first hand experience (or good second hand) with this setup? Will I need a new chip?

Figured i'd ask before I pull the engine. I could put a dual mass flywheel in, but that would be more expensive.

I try to commute with the car, and actively autocross it during the summer.

Thanks for reading this far.
-Eric

GP964

Hi Eric,

I too have similar set up on my 90 C2 (LWF (12lbs), R-134 retro, Autothority MAFS w/ custom chip, dual outlet euro muffler. My car only stalls if your letting the rpms drop drastically with the A/C on. I hear to fix this problem is to get an adj. ISV available at Windward Performace.
Thats gonna be my next proj after I install a larger throttle body which is coming this week. Anyways I don't race around with my A/C on. hehe

GP

Cupcar#12

also call Rennsport Systems in Or - as they customer burn chips for LWT flywheels and other mod's.

Randall G.

If you search the 993 archives (is the search function working yet?), you'll find a DIY for adjusting the ISV to cure stalling. It has worked well for several '95 993 owners.

GP964

I pulled my ISV off 3-4 months ago trying to drill out the factory glue, instead stripped and broke the adj screw (sh*t), just put it back and hoping i didn't mess it up internally, got it back on and it works. Does anyone have a extra ISV? or possibly and adjustable one? hehe

Thx
GP

johnfm

Eric & GP

Randall's right - the 993 guys seem to have come across a good ISV adjustment. Seems a helluvalot easier/cheaper than replacing the flywheel!!

joey bagadonuts

You might also give Todd at Evomotorsports a call. I have their standard chip which I have been very pleased with but they offer one for LWF owners as well which they seem confident will fix the problem.

From their website:Of course, having a custom chip dyno-tuned is the ideal solution but this may be the next best thing. They also offer a 30-day return period, so it may be worth a try.

Again, just a satisfied customer ... no other affiliation.

Adrian

Guys,
Before you go off trying 993 fixes please understand that the 993 uses a different engine management system to the 964.
The stalling is caused by the reduced mass of the flywheel causing a rapid loss in momentum. The engine management system of the 964 cannot react quickly enough to the rapid loss of rpm and you stall. I have seen many electronic attempts to fix this problem and none have ever worked 100%.
To avoid the stalling issue once and for all, you need a flywheel weight of 19 lbs. Maybe one day somebody will start with 19 lbs and then start shaving off some weight and see what the lowest weight is. Andial, RUF and others recommend 19 lbs.
Ciao,
Adrian
911C4

johnfm

Adrian

is the ISV on the 964 completely different to that on the 993?

Adrian

Dear John,
I have never had a 993 version apart to compare them physically but that was not my point. My point was take care when looking at 993 fixes and trying to apply them to a 964. I cannot tell you and nobody can with any clarity that the signal provided to position the 993 ISV is the same as that used in the 964. Messing around like this can cause more problems that they solve. My warning was to take care about using other model fixes for a 964 fix.
Ciao,
Adrian
911C4

PS: I also believe if the fix was so simple that somebody would have worked it out a long time ago for the 964 including Porsche and companies like Andial.

Eric Kessel

Thought i'd follow up. I just finished installing the LWF with the Andial add on weight, and the stalling is gone. I drove around with the AC on, and the car would not stall. The car still revs quick, just the engine speed doesn't drop down nearly as fast towards idle.
-Eric

DJF1

I confirm the same results with my 1995 993 which is a closer relative to the 964... Great LWF...