Fixed My LWF Stalling Problem - New ISV
08-04-2012, 11:37 PM
#46
Race Car
I've heard the ultimate LWF solution is going to a Motronics replacement ECU as opposed to just using a chip.
Not sure what the cost is on that, but the gained adjustability and Hp from an aftermarket ECU would be a no-brainer for me if I was doing a LWF on a track car. For a street car you can even run tandem computers (I think CupCar is doing this) so you can pass smog with the flip of a switch.
Should I be ducking?
Not sure what the cost is on that, but the gained adjustability and Hp from an aftermarket ECU would be a no-brainer for me if I was doing a LWF on a track car. For a street car you can even run tandem computers (I think CupCar is doing this) so you can pass smog with the flip of a switch.
Should I be ducking?
Its not quite a flick of a switch but is a 10 min job to switch from the Original ecu to the aftermarket one .....
08-05-2012, 12:23 PM
#48
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BTW--the score card proves that I win this debate---factuals, facts, statics, surveys, polls, and user feedback states that LWF's are problemmatic and you are 70% (lets give or take 20% to be fair) more likely to have a vehicle with stalling problems with a LWF than without one. You drive a race car---unless your driving that car around as a daily driver in the streets---totally different experience. I would hope you would have a LWF in a race car---I'd have one 2 if I was racing.
Im sure we all agree that the LWF is problemmatic---even with your 993. To the average person, telling them their car has a 60-90% chance of stalling with a LWF probably wont sit well. As I did, I thought maybe (just maybe) I may be one of the lucky ones but I was dead wrong. Im no Porsche nut---just an average driver who is not all that thrilled with the LWF and disappointed that the industry has no fix for 60-90% of those on the road. To try another route, in my opinion, is throwing good money at a bad cause. I have spent many of thousands of $$$ and many trips to the shop and it still stalls time to time. It just gives me a big woody every time it happens!
Im sure we all agree that the LWF is problemmatic---even with your 993. To the average person, telling them their car has a 60-90% chance of stalling with a LWF probably wont sit well. As I did, I thought maybe (just maybe) I may be one of the lucky ones but I was dead wrong. Im no Porsche nut---just an average driver who is not all that thrilled with the LWF and disappointed that the industry has no fix for 60-90% of those on the road. To try another route, in my opinion, is throwing good money at a bad cause. I have spent many of thousands of $$$ and many trips to the shop and it still stalls time to time. It just gives me a big woody every time it happens!
Again, your poll showed that over one quarter of all '95 owners do not have stalling issues with the LWF.
I was going to quote you in the thread that mongrelcat posted, but decided against it. However, since you brought up your own post, I'll also quote this one from you:
I daresay your close-minded approach is willing the car to stall in order to cause you to think/not think/think/not think about it.
I absolutely knew you were going to say that part of the 30% were incorrect or lying
, but I didn't want to be accused of putting words in your mouth. Since you have gone ahead and fulfilled that prophecy, just remember that it was your poll results and that 15% of people have not had an issue.
You also can't say that a portion of the people who said that they didn't stall were wrong, while 100% of the people who said that they had stalled are all correct. Moreover, how does missing your poll only affect the results of the respondents who never stalled? The percentages are based on the people who responded, not the entire population of Rennlisters or the total number of 993 owners.
Like I said, you've lost a great deal of objectivity on this.
Oh, full disclosure: my car stalls from time to time, but it's just not a big deal to me. Maybe that's why I haven't had it stall in over four years; sounds like the ghosts gave up on me and decided to haunt you since it bugs you so much.
I was going to quote you in the thread that mongrelcat posted, but decided against it. However, since you brought up your own post, I'll also quote this one from you:
I daresay your close-minded approach is willing the car to stall in order to cause you to think/not think/think/not think about it.
I absolutely knew you were going to say that part of the 30% were incorrect or lying
, but I didn't want to be accused of putting words in your mouth. Since you have gone ahead and fulfilled that prophecy, just remember that it was your poll results and that 15% of people have not had an issue. You also can't say that a portion of the people who said that they didn't stall were wrong, while 100% of the people who said that they had stalled are all correct. Moreover, how does missing your poll only affect the results of the respondents who never stalled? The percentages are based on the people who responded, not the entire population of Rennlisters or the total number of 993 owners.
Like I said, you've lost a great deal of objectivity on this.
Oh, full disclosure: my car stalls from time to time, but it's just not a big deal to me. Maybe that's why I haven't had it stall in over four years; sounds like the ghosts gave up on me and decided to haunt you since it bugs you so much.
08-05-2012, 02:24 PM
#50
Rennlist Member
BTW--the score card proves that I win this debate---factuals, facts, statics, surveys, polls, and user feedback states that LWF's are problemmatic and you are 70% (lets give or take 20% to be fair) more likely to have a vehicle with stalling problems with a LWF than without one. You drive a race car---unless your driving that car around as a daily driver in the streets---totally different experience. I would hope you would have a LWF in a race car---I'd have one 2 if I was racing.
Im sure we all agree that the LWF is problemmatic---even with your 993. To the average person, telling them their car has a 60-90% chance of stalling with a LWF probably wont sit well. As I did, I thought maybe (just maybe) I may be one of the lucky ones but I was dead wrong. Im no Porsche nut---just an average driver who is not all that thrilled with the LWF and disappointed that the industry has no fix for 60-90% of those on the road. To try another route, in my opinion, is throwing good money at a bad cause. I have spent many of thousands of $$$ and many trips to the shop and it still stalls time to time. It just gives me a big woody every time it happens!
Im sure we all agree that the LWF is problemmatic---even with your 993. To the average person, telling them their car has a 60-90% chance of stalling with a LWF probably wont sit well. As I did, I thought maybe (just maybe) I may be one of the lucky ones but I was dead wrong. Im no Porsche nut---just an average driver who is not all that thrilled with the LWF and disappointed that the industry has no fix for 60-90% of those on the road. To try another route, in my opinion, is throwing good money at a bad cause. I have spent many of thousands of $$$ and many trips to the shop and it still stalls time to time. It just gives me a big woody every time it happens!
I may respond later since I'm posting from my iPhone.
08-05-2012, 03:06 PM
#52
"but until you try and prove that a new ISV won't work"
A waste of money! The original DME ECM firmware was not written to contend
with the rate of change of the RPMs when a LWF is installed resulting in an
undershoot of the nominal idle RPM. There is no external fix, e.g. Mickey
Mouse chips, a new idle valve, A/C on switch grounded, etc., that will solve the
problem reliably short of re-writing the DME ECM firmware.
A waste of money! The original DME ECM firmware was not written to contend
with the rate of change of the RPMs when a LWF is installed resulting in an
undershoot of the nominal idle RPM. There is no external fix, e.g. Mickey
Mouse chips, a new idle valve, A/C on switch grounded, etc., that will solve the
problem reliably short of re-writing the DME ECM firmware.
08-05-2012, 03:14 PM
#54
"but until you try and prove that a new ISV won't work"
A waste of money! The original DME ECM firmware was not written to contend
with the rate of change of the RPMs when a LWF is installed resulting in an
undershoot of the nominal idle RPM. There is no external fix, e.g. Mickey
Mouse chips, a new idle valve, A/C on switch grounded, etc., that will solve the
problem reliably short of re-writing the DME ECM firmware.
A waste of money! The original DME ECM firmware was not written to contend
with the rate of change of the RPMs when a LWF is installed resulting in an
undershoot of the nominal idle RPM. There is no external fix, e.g. Mickey
Mouse chips, a new idle valve, A/C on switch grounded, etc., that will solve the
problem reliably short of re-writing the DME ECM firmware.
08-05-2012, 03:28 PM
#57
Rennlist Member
As for too many posts, all we need to do is eliminate non technical discussions from the technical discussion folder.
08-05-2012, 03:50 PM
#58
"what parameters are available for tuning by the aftermarket folks?"
It's not a tuning issue, i.e. tuning is nothing more than basically changing
numbers in a spreadsheet, which won't solve this problem as the routine
controlling the rate of RPM decel is not part of either the fuel or ignition
maps.
"Can the minimum engine speed to allow fuel cut be increased? What about ISV commanded opening vs RPM during decel?"
Both of these variables can only be changed as part of a firmware routine
re-write and just a simple one or two variable change most likely won't
solve the problem. The basic idle algorithm must be re-designed.
It's not a tuning issue, i.e. tuning is nothing more than basically changing
numbers in a spreadsheet, which won't solve this problem as the routine
controlling the rate of RPM decel is not part of either the fuel or ignition
maps.
"Can the minimum engine speed to allow fuel cut be increased? What about ISV commanded opening vs RPM during decel?"
Both of these variables can only be changed as part of a firmware routine
re-write and just a simple one or two variable change most likely won't
solve the problem. The basic idle algorithm must be re-designed.
08-05-2012, 04:09 PM
#59
"what parameters are available for tuning by the aftermarket folks?"
It's not a tuning issue, i.e. tuning is nothing more than basically changing
numbers in a spreadsheet, which won't solve this problem as the routine
controlling the rate of RPM decel is not part of either the fuel or ignition
maps.
"Can the minimum engine speed to allow fuel cut be increased? What about ISV commanded opening vs RPM during decel?"
Both of these variables can only be changed as part of a firmware routine
re-write and just a simple one or two variable change most likely won't
solve the problem. The basic idle algorithm must be re-designed.
It's not a tuning issue, i.e. tuning is nothing more than basically changing
numbers in a spreadsheet, which won't solve this problem as the routine
controlling the rate of RPM decel is not part of either the fuel or ignition
maps.
"Can the minimum engine speed to allow fuel cut be increased? What about ISV commanded opening vs RPM during decel?"
Both of these variables can only be changed as part of a firmware routine
re-write and just a simple one or two variable change most likely won't
solve the problem. The basic idle algorithm must be re-designed.
Agree, changing the base fuel or ignition maps is useless for this issue. Is that the only thing tuner folks have access to? On the other hand, the opening of the idle valve has a direct impact on MAP, hence rate of RPM decay with either fuel on or off, no?
08-05-2012, 05:02 PM
#60
"changing the base fuel or ignition maps is useless for this issue. Is that the only thing tuner folks have access to?"
That's it. Besides the '95 993 EPROM basically just stores data for the maps,
and the majority of the firmware is mask/flash coded in the microcontroller
where the idle routine most likely is.
That's it. Besides the '95 993 EPROM basically just stores data for the maps,
and the majority of the firmware is mask/flash coded in the microcontroller
where the idle routine most likely is.