Smokin

Jason,

Thanks for the tip... I may try that. How does it handle when cold? Do you still need to warm it up before it performs well? Did you clean out the ISV? What exactly did you do?

Please explain in more detail.

Thanks....

Rick

jagerocks

Works well in cold, it is 4deg cel here. I did soke the ISV in our solvent tank at work but was careful to keep it below the electrical. just soked the valve opening. Other than modifing the screw to be able to be adjusted all the time , that was it. the worst was getting the epoxy out. that is why I heated it up lightly 1st. I also installed a KN air cone filter at the same time, I;m not sure it made a difference with the valve, but maybe it helped it run better. all in all the whole thing was simple and cost 0 except the KN.

Jason

JasonAndreas

I've used methylene chloride to dissolve hardened epoxy and polyurethanes, you can probably find some at your local hardware store.

Smokin

Okay... This should probably be in a new thread but I'll ask the question anyway. I've searched the board but still cannot find the answer to this question...

If the ISV valve is meant to be cleaned and adjusted, why do they epoxy in a set position? There are plenty of ways to install an adjustment screw so it doesn't back out or move. Why the epoxy? They must not want you to touch it.

Any thoughts or comments?

Thanks,

Rick

Smokin

Okay... I just took out my ISV and cleaned it thoroughly. It wasn't caked with deposits but it was very sooty black. I burned up almost a whole can of carb cleaner on it. It looked darn near new when finished. I also took the chance to polish it up with a buffing wheel on my drill press.

I opened up the crimp type clamps with a pair of needle nose pliers and removed them. Carefully pulled the wire retaining clip from the plug and removed that. Loosened the screw clamp and removed it to clean. Reinstallation was the same except with new hose clamps.

I was very impressed with performance right off the bat. Normally, with the LWF, it was a bear to keep going when cold. This time I couldn't make it stall! Things were back to "normal" though when it warmed up. Unless I waited until it was below 2K RPM... It would stall out. The one thing it did do though was to take away part of the hesitation I would hear and feel when I "blipped" the throttle. It's now much more responsive.

I still have a few questions though...

1. How often should this be cleaned? I don't see anything about that in the manuals or the tech manuals I bought. (Full set off ebay for $100)
2. The 993 has set screws to keep the adjustment "locked" in place... After taking off the epoxy does the (964) screw still keep it's position when a change is made? I wonder if engine vibration is why they originally used epoxy?
3. My question from the above post still stands... Why use epoxy to lock this in place? I would assume that Porsche does not want you to fool with the positioning. What other reasons would a certified tech remove the epoxy and adjust the ISV?

As always... Thanks for the input.

Rick

Colin 90 C2

Jason,
Can you please post pics of your modified ISV.

I took mine off, removed the epoxy and now I see what amounts to a brass allen head screw. Is this the adjusting screw or is the adjusting screw below the brass insert?

KirkF

Well...
After reading 8 pages on this topic I am exhausted. But never the less I will put my 2 cents in.

I have an '89 C4. It has a LWF and is chipped to correct the stalling problems.

As many of you have probably noted in the past, if I happen along a post where someone is contemplating changing to a LWF I strongly recommend they not do so unless their car is going to be for track use only. Its a pain keeping the car from stalling. And the chips dont work.

But there are 8 pages of threads saying this so I will get to my point:

Jason,
You mentioned your stalling problem is corrected. Which sounds great. However before you jump for joy.... Turn on your A/C and see how well it fairs.

Like you I am also a canadian and I know its not warm out yet.

The stalling problem becomes more pronounced with the load on the engine. In warm weather, the extra load on the alternator with the cooling fans running and the a/c compressor clutch engaged is what sends my car over the edge. Its so bad I prefer to run with the windows open all summer.

One of these days when I get around to it I intend on ripping out the LWF and throwing it in a corn field where it belongs.

Kirk

JasonAndreas

We really need to figure out why some of us have no stalling problems while others do. If we can find an RS owner that is willing to open their DME control unit I'd be willing to send them an EPROM reader/writer. The RS eprom I have is not genuine. We know the genuine RS eprom will solve the stalling problem almost 100% of the time. If we can get an eprom image I'm willing to send it out to anyone with the problem, I was told it is NLA from Porsche.

jagerocks

I was told the eprom chip I installed was a RS chip... does this mean anything??

Jason
1990 C2

Adrian

Dear Jason,
I am sorry but where is the evidence a 964 Carrera RS chip will globally solve the problem?
The M64/03 engine does not have the load that a standard M64/01 engine does.
No power steering, no air conditioning and a lower capacity electrical system including battery.
The transmission loading on a C4 engine is significantly higher than the transmission loading of a C2 engine.
I believe that each 964 so modified with a LWF requires special individual attention.
I do not believe there is a one cure all solution to this problem otherwise tuners worldwide would be offering it.
I have checked with tuners from around the world and all are well aware of the 964 and its dislike of the LWF.
None offer any quick and cheap solution (well one did but they have gone bust).
Most tuners will not even do these modifications without moving down the path of aftermarket engine management systems.
I have been on this forum and its forbears for many years. Lots and lots of claims are made but not one person has ever presented a genuine solution.
I really do not care if an owner sticks lumps of welding rod into an ISV and claims the problem solved. What I care about is there is no before or after information, no follow up and no independent verification. You can all seriously damage your cars looking for a "Cheap fix".
What really scares me is that without one scrap of evidence other people are now following suit.
Would anyone here purchase a 964 with a lump of welding rod sticking out of the ISV?
I am sure Andial who created the USA edition of the Carrera Cup would not be offering the weighted LWF solution if there was a cheaper and quicker software solution to this problem.
However with that said I have asked a couple of RS owners I know already and they were very unwilling to consider opening their DMEs up for this.
I have another possibility which I will work on for you but it will have to be much later this month.
Ciao,
Adrian.

KirkF

I think Adrian has hit the nail on the head.

The key to the degree of stalling is the load on the engine:
Power steering, load on the alternator, Air Conditioning. Etc.

If I had no A/C in my car I would likely be telling everyone that the LWF conversion was fine in my car and it never stalls.

Kirk

Andy Roe

Would it do any harm to just remove the Air Con belt during the winter to decrease the load?

Adrian

Dear Andy,
First off all the air con does not load up the engine unless it is engaged. All the belt is doing is turning an unpowered clutch assembly.
Secondly the air con plays a critical role in helping to remove the steaming up problems when you hit defrost. I know that in winter where I live this is a very vital function.
LWFs are for racing cars and personally I see no point in having one in a normal road car.
Porsche abandoned LWFs on the 993 completely except for the GT-1 and the Clubsport versions of the Carrera RS and GT-2. Everything else had DMFs.
Ciao,
Adrian.

JasonAndreas

I thought the RHD Carrera RS had power steering? I understand why the air-conditioning (which can fixed in software) will have an effect but why the battery?

You can stall with the clutch pedal depressed so it shouldn't matter if your driving a C2 or a C4?


Knowing what I know about "tuners" I'm not the least bit surprised that only one had a working solution.

I'm still trying to figure why they sold a 12 pound flywheel with 7 pounds of weight welded to it when you could have bought a MWF directly from Porsche for a lot less money?

If we can find one I will send them an EPROM reader.

Whatever it is I look forward to it!

Adrian

Dear Jason,
The amount of electricity being drawn by the 964 has a direct and significant impact on engine load. The RS has a minimal electrical system including a significantly smaller battery which requires less time to charge up after each start.
Yes the RHD RS has power steering. Ever seen one? Most RHDs I have seen are the touring version which was fitted with the DMF.
I know of two RHD basic version Carrera RSs and they have stalling issues which are corrected by driving technique.
Many Carrera RS owners I know (who will not participate in this or any other forum) speak of low rpm stalling issues. I have experienced it myself in more than a couple I have driven.
You learn to keep the revs up in a Carrera RS. The basic Carrera RS is a club sports type racing car which is designed to be driven to and from the track. The Clubsport version is a full on racing car with a seriously nasty clutch for road use.
Ciao,
Adrian.