3.6 Varioram dying when I depress clutch at stops

[Polson89]

I have a 1970 RSR Clone with 3.6 Varioram.
On an increasing basis (about 50% of time now), when I come to a stop and depress the clutch, usually in 2nd, the car is dying. If it doesn't die, the it will almost die and return to idle. (like it's starved of fuel?)

Also seems like I need to give it more gas when starting from a stop (ie Stoplight)

Normal Idle is fine. (when I start the car it idles fine at 900-1000)
Not experiencing any power loss under little or heavy acceleration.

Fuel filter? Thoughts?

[MoreGAS]

This is not likely a running/tune problem but due to the transplant changes....With the loss of the dual mass flywheel from The 3.6(going to a 915 or 901 hope not ) there simply is not enough inertia and mass to catch the idle when decelerating at low RPM, especially if the clutch is pushed in for a quick RPM drop down in the 2000 rpm range.

There are folks that car reprogram the ECUs , but hopefully your's is not the 96 ECU which has a one time writable chip that cannot be re programmed and have not been avail.(chips) for years .
You can PM me and I can share experiences we have had w solving this by using one Co. or another as cost varies widely, as did results. There are also other band aids to try which may help that we have had varying results with, like use the AC idle kick up (there may be a low and a High like on a 964) to bump the idle up 100-200 RPM, or whatever Porsche planned for that. It involves grounding a wire in the DME harness, which is likely not being used presently after your engine was transplanted.

They could also try and tune around it by adjusting the closed throttle timing as you decelerate, but few have the hardware and software to do this. Many folks have done this V Ram transplant so likely one Co. or another has figured it out refining their approach over time...

Kevin
GAS Motorsport

[Kein_Ersatz]

^^^ This ^^^ DMF delete / LWF is also a common 993 idle problem.

[Polson89]

Thanks @Moregas and @Kein_Ersatz.

@Kein_Ersatz, sorry, what is LWF?

[Polson89]

Checked and my DME is '97, so maybe some options.

[Kein_Ersatz]

Light Weight Flywheel - nice RS upgrade that many 993 owners make when the clutch needs updating (Porsche RS or 3rd party flywheel clutch combos). Improves feel of revving up the engine . throttle response, but has the downside of stalling on stock OEM ECUs, so ECU "fixes" are then installed. May also increase cabin noise / vibration from transmission. Lots of 993 threads over the years on the LWF upgrade and issues and solutions to issues can be found on rennlist 993 forums.

[Polson89]

Thanks to both @Kein_Ersatz and @MoreGAS. I do have a LWF and after more discussion with local mechanic, could be a sticking ICV or vacuum leak given the problem has gotten progressively worse recently. My 97 DME has a Steve Wong chip and transplant was quite a while ago. appreciate the help.