95 C4 993

I have done a lot of upgrades on my 993 and I would have to disagree that Im closed minded when it comes to vehicles. My 993 isnt exactly a stock car. Its a solid car and runs very well.

One person stands up and says "Praise the Lord, 4 times driving with my new ISV and no more stalls!!" I thought the same thing after numerous trips to the shop and months down the road, I get a stall.

I'll let a dozen or so people replace their ISV's, watch the feedback from several hundreds drives over the course of the next 12 months and see what happens. Thats not closed minded, thats letting someone else be the guinea pig. Find a few virgin 993 owners to go down that path. I was all giddy up doing upgrades and probably didnt think the LFW through they way I should have for the most part.

I'm not closed minded to a new ISV, just not seeing any stats or facts to back it up today. If ISV's are to fix all issues, 50-90% of those with LWF's and 95's should replace them because God forbid, they work just fine with a DMF.

And my no means will I had down a piggy back chip that is being discussed---I have my Steve Weiner chip installed, Im cool with it.

Beautiful day in Park City---Arts Festival, decent weather (a few sprinkles) and damn I have seen some kick ***, very expensive exotic sports cars driving around today. And to top it off, no stalls!!

matt777

My reading comprehension is good. Really.

Theory...because the old ISV was slower to react than the new ISV.

Alan 91 C2

My 1991 C2, exhibited the same issues. Stall with LWF and A/C on. Solved with DMF. But I miss the engine response.

In my 944 readings, learned the ECM cuts off fuel in deceleration (to prevent backfire). Seems like higher RPM fuel enabled could solve the problem. Maybe a little ISV action to soften the hard idle stop.

Bottom line, the LWF modifies the rotational inertia for the engine deceleration. With LWF the RPM curve slows faster than the ECU and ISV were programmed to react.

Old school solutions are to raise idle stop, or add dashpot to throttle linkage (slowing slightly the actual closed throttle, dampened action)

Want my LWF back, but not the STALLING.

jakfrost

'Heel and Toe'...at every stop.

Its so ingrained that it is automatic, not even aware I do it anymore, unless I forget and get one of those '1 in a 100' stalls .

Jim

IXLR8

You're new here.

You are not supposed to admit to that. You will be burned at the stake and your RL membership will be withdrawn.

Just as wheel rub does not exist and the some other topics.

cavlino

That was funny

Alan 91 C2

Actually, my girl drives the 964, sometimes. So trying to teach heel and toe, will likely kill our relationship.

Seems like a simple fix, now that I understand the ECU code issue.

But, I do not want to anger the "Gods", RL or in my car.

Or I can go back to the 944 turbo S group, they are very inclusive, and we sing Kumbaya.

Bmk3

2005 993 c2, LWF, RS clutch, Steve Worng chip, sill a massive stalling issue...
After reading everything I could on this and other forums, working with Steve Wong (great guy but located 3K miles away from me, so direct support was not possible) and my local shop, the following worked for me.

I pulled my ICV, cleaned it VERY well, it was totally jammed up with carbon. I then marked the current position of the valve and after removing the resin and loosening the Allen screws, adjusted it to a more closed position. 3-4degrees. I then disconnected the battery for 60 minutes, reconnected and let the car idle for 25 minutes. To relearn to idle under the closed ICV condition. I then drove with no stalls, but was getting an intermittent no start. (likely due to the ICV being too closed) I then adjusted the ICV back to the original position. The car now thinks the ICV is in a more closed position, and when it opens I get even more air, so when my Steve Wong chip tries to catch it prior to a stall, it is more exaggerated. The only time I will get a stall now is if there is a big electrical draw putting a load on the alternator (headlights, radio, wipers, ac) and I put the clutch in at a high RPM, but even stalling in that condition is very random/seldom.

Perhaps the ICV adjustment helping is in my head as I just don't know enough about how it works with the ECU, but it certainly seems like disconnecting the battery and lletting the computer reset and relearn goes a long way to help alleviate the stalling issue.

I hope this helps someone else pulling their hair out like I was.

cavlino

^Thanks for the update. Since I added Steve Wong's chip mine hardly ever stalls but I am still going to replace the ISV to see if it cures it 100%.

95 C4 993

The bullet proof resolution is go back to a DMF and now the MWF is coming into play. The industry experts and those who sell flywheels will recommend the MWF over a LWF, in my opinion.

Years of tuning (Wong/Weiner) replacement chips, tuning, ISV cleaning/replacement, ect, ect still have not resolved the stalling issue with LWF's with 95's and other years.

Good luck to those seaching for a cure , industry experts now pusing the MWF, and may your 993's never stall.......again.

michel j

Like many others, I have tried many things to eliminate the stalling on my 95 with LWF ( Wong chip, clean ISV, plugs, checked vacuum, etc.). Thus far, the biggest improvement was with ISV adjustments. In the counterclockwise direction (making opening bigger), I tried moving rotating with an arc of 1.5 mm, 2.0, 2.5, 3.0, 3.5, and 4.2 mm. After each rotation, a drove the car for a few days to give the ecu time to learn the new settings, except on the largest value, 4.2 mm, the engine kept oscillating and never stabilized. The 3.5 mm seems to work the best for my engine (my rough calculations tell me that is about 6 degrees of rotation). It has been at this setting for 2 or 3 weeks and I have yet to experience a stall even with AC, blower, and lights on. That makes my VERY happy. There is still a small problem when engine is warm, on quick closing of butterfly where the idle will jump up and down a couple of times before settling down.
In the near future, I plan on experimenting with a dash pot to try to slow down the last part of the throttle closing. I have searched and could not find any information on anyone trying this for a fix.
Will keep you all posted.

matt777

Steve Wong updated my chip this winter (LWF3 ??). If you can relay to him the particular issues he can make sure you have the right/latest update. It seems best to just phone him.

michel j

Matt,

I understand Steve is very busy. I think I will call him as you suggested.

FYI, here is a photo of my chip from Steve. I'm curious to what version I have.

matt777

Older I would say but ask Steve. I think he has different variations.