ARC 2 - Cool start settings vs. Warm settings
03-05-2002, 12:17 PM
#31
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[quote]Originally posted by dlr944:
<strong>I don't seem to be getting my point across. The grey wire from the ARC 2 is a fixed resistance between 1.5k to 2k ohms. Therefore, the DME thinks that the temperature is roughly 72F. (You can figure out this by looking at the resistance vs temp. of the AFM in the 944 Manual).
Using the grey wire from the ARC 2 is fine if you live in a mild part of the country or use your car for the track. For track cars this is probably the perfered method because you now have one less sensor which could fail.
If you want temperature control, then you need to figure out a way to tap into the MAF assuming it has a temp sensor that's compatible with the DME or add independent temp sensor that connects to the DME. In either of these cases you just remove the grey wire (it's just there to send a fixed resistance to the DME) and connect the new temp senor to DME input. This is of course is my belief.
DLR944</strong><hr></blockquote>
Let's hope this isn't the case, because the Lindsey unit was being shot down by one of the "other MAF makers" for having a temperature sensor on their units.
<strong>I don't seem to be getting my point across. The grey wire from the ARC 2 is a fixed resistance between 1.5k to 2k ohms. Therefore, the DME thinks that the temperature is roughly 72F. (You can figure out this by looking at the resistance vs temp. of the AFM in the 944 Manual).
Using the grey wire from the ARC 2 is fine if you live in a mild part of the country or use your car for the track. For track cars this is probably the perfered method because you now have one less sensor which could fail.
If you want temperature control, then you need to figure out a way to tap into the MAF assuming it has a temp sensor that's compatible with the DME or add independent temp sensor that connects to the DME. In either of these cases you just remove the grey wire (it's just there to send a fixed resistance to the DME) and connect the new temp senor to DME input. This is of course is my belief.
DLR944</strong><hr></blockquote>
Let's hope this isn't the case, because the Lindsey unit was being shot down by one of the "other MAF makers" for having a temperature sensor on their units.
03-05-2002, 01:43 PM
#32
Race Director
were are the tuners? huntley/sfr/lindsey?
Ive seen this topic for about 3 days now, and theyre is even a a post on the main 944 list about this thread calling for the tuners help..
whenever i read a thread about supercharging an n/a they are all quick to brag and shoot each other down..where are they now..Im sure they have seen this thread or are following it..now chime in guys.
Ive seen this topic for about 3 days now, and theyre is even a a post on the main 944 list about this thread calling for the tuners help..
whenever i read a thread about supercharging an n/a they are all quick to brag and shoot each other down..where are they now..Im sure they have seen this thread or are following it..now chime in guys.
03-05-2002, 02:08 PM
#33
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Hopefully the tuners are all out tuning, but when they do return, I would like an answer / resolution to this. I am looking at a MAF or engine management for my summer project, and driveability, and cold start are both big issues with me. I've narrowed down my search to Huntley or SFR, as I like the idea of the ARC 2, I like the people who work there, and because I plan on making it a purchase of other things that these two carry. So when they do get in, and get around to answering this question, just think that you have a shot at "buying" a customer with knowledge.
03-05-2002, 05:06 PM
#34
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Oooo, oooo, oooo, I'm first to respond. The temp issue is really kind of funny. If we instructed all of the MAF owners to tune thier cars then pull out the ARM1 (mixture meter) they would never know that there was a difference in the mixtures cold or hot. The reality is that the early Motronic cars like the 944 Turbo do have different mixtures hot/cold because they just do, stock too. Those with no starts or very rough running have other problems which may be made worse with an MAF vs the original AFM. A good example of this would be: Lets say that a DME coolant temp sensor is starting to fail and is reading hotter than actuall temp. You tuned your ARC2 when the car was hot and was not effected by the temp sensor. You tune the car so that it has a nice lean idle when hot. The next cold morning start the car runs very rough and you turn up the low **** on the ARC2 which makes the car run better. But as the car heats up the idle becomes to rich and you turn it back down. This must be an ARC2 problem, right? With the original AFM it ran with a richer mixture at idle all the time so it's cold start was better. You can do the same with the ARC2 by just runing richer all the time. Of course having the ARM1 to SEE your mixture issue would kill that idea because it would bug you. These issues are why the great majority of people never have any cold or hot start problems, but those that do simply bandaid the real problem with a twist of the ARC2 and then blame the bandaid for the problem. Reiterating what I have said all along, MAF sensors do not need air temp sensors on these cars.
03-05-2002, 05:48 PM
#35
Racer
Thread Starter
[quote] “These issues are why the great majority of people never have any cold or hot start problems.” <hr></blockquote> Are you saying that the great majority of people don’t have issues because they can turn up the ARC 2 but chose not to because it would bug them? Could you explain why the great majority of people don’t have cold or hot start problems with a MAF?
Most importantly, the real question that needs addressing is what function does the original air temp. sensor serve? In other words, what does the DME do differently based on the changing resistance from the air temp. sensor? Why did Porsche include it in the original AFM? The DME uses this air sensor for an input to control or monitor something. Perhaps it controls an interrupt that starts up an enrichment routine? What exactly this input is used for I don’t know but I am sure the ARC 2 is feeding a fixed 1.5k or 2.0k ohm resistance to this input and the DME is expecting to see between 6.8k and 1.0k ohms depending on air temperature.
I would be delighted if you could address these questions, especially the question regarding the purpose of the air temp sensor and why it’s used in the first place.
Most importantly, the real question that needs addressing is what function does the original air temp. sensor serve? In other words, what does the DME do differently based on the changing resistance from the air temp. sensor? Why did Porsche include it in the original AFM? The DME uses this air sensor for an input to control or monitor something. Perhaps it controls an interrupt that starts up an enrichment routine? What exactly this input is used for I don’t know but I am sure the ARC 2 is feeding a fixed 1.5k or 2.0k ohm resistance to this input and the DME is expecting to see between 6.8k and 1.0k ohms depending on air temperature.
I would be delighted if you could address these questions, especially the question regarding the purpose of the air temp sensor and why it’s used in the first place.
03-05-2002, 06:06 PM
#36
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[quote] If we instructed all of the MAF owners to tune thier cars then pull out the ARM1 (mixture meter) they would never know that there was a difference in the mixtures cold or hot. <hr></blockquote>
No.. because the car will run like total *** when it is cold, and most if the time shut off from lack of fuel until it reaches a decent operating temp. In order to drive it, you need to turn the *****, or "band-aid" it. Going off the ARM-1 means nothing in this situation because the O2 sensor is not hot, and not functional. Even the ARM-1 sits with it's little orange stoich LED's lit, giving you no reading.
I know it is not a failed sensor. I replaced them before I attached the MAF. 2 times I took off the MAF and added the stock AFM to the car, and with the AFM, it ran perfect both times. With the MAF, even at 50 degrees outside, I needed to add fuel until it was warm.
Now.. obviously there is a probelem with the output of the ARC-2 to the DME, or the DME cannot figure out what the signal is. I don't think that we are trying to blame the "Band-aid" "turn the **** deal" as the problem. The problem is when the MAF is tuned to the car (when warm), it will not run very well if at all when cold. Both manufaturers say this is a perfect mod for the Street. Not if you need to adjust it every day. Sure.. it was a cool thing to do.. for about a week. Now that I have it mounted in the glove box, it is a pain in the ***.
So what are the values that the ARC-2 puts out to the DME? What are the values that the stock sensor puts out? There is not a temp sensor on the MAF correct? Then how did you design it to work if it has no idea what the air temp is? Can the ARC-2 work without attaching the lead to pin 22 and use the stock sensor in it's place?
Hopefully someone who designed the product can answer the questions.
No.. because the car will run like total *** when it is cold, and most if the time shut off from lack of fuel until it reaches a decent operating temp. In order to drive it, you need to turn the *****, or "band-aid" it. Going off the ARM-1 means nothing in this situation because the O2 sensor is not hot, and not functional. Even the ARM-1 sits with it's little orange stoich LED's lit, giving you no reading.
I know it is not a failed sensor. I replaced them before I attached the MAF. 2 times I took off the MAF and added the stock AFM to the car, and with the AFM, it ran perfect both times. With the MAF, even at 50 degrees outside, I needed to add fuel until it was warm.
Now.. obviously there is a probelem with the output of the ARC-2 to the DME, or the DME cannot figure out what the signal is. I don't think that we are trying to blame the "Band-aid" "turn the **** deal" as the problem. The problem is when the MAF is tuned to the car (when warm), it will not run very well if at all when cold. Both manufaturers say this is a perfect mod for the Street. Not if you need to adjust it every day. Sure.. it was a cool thing to do.. for about a week. Now that I have it mounted in the glove box, it is a pain in the ***.
So what are the values that the ARC-2 puts out to the DME? What are the values that the stock sensor puts out? There is not a temp sensor on the MAF correct? Then how did you design it to work if it has no idea what the air temp is? Can the ARC-2 work without attaching the lead to pin 22 and use the stock sensor in it's place?
Hopefully someone who designed the product can answer the questions.
03-05-2002, 06:28 PM
#37
Racer
Thread Starter
[quote] So what are the values that the ARC-2 puts out to the DME? Perry <hr></blockquote>
ARC 2 Grey wire is 1.5k or 2.k ohms to DME #22.
[quote]What are the values that the stock sensor puts out? <hr></blockquote>
Stock air temp sensor will output a resistance between 6.8k and 1.0k (0 C to 40 C).
[quote]There is not a temp sensor on the MAF correct? <hr></blockquote>
Good question!
[quote]Can the ARC-2 work without attaching the lead to pin 22 and use the stock sensor in it's place? <hr></blockquote>
It should if you connect an equivalent air temp sensor. After all that’s what was originally connected to this input.
Again the open issue is what is the purpose of the original air temp sensor? What does the DME do based on this input? It’s a basic I/O question. Derrek care to answer this for us?
ARC 2 Grey wire is 1.5k or 2.k ohms to DME #22.
[quote]What are the values that the stock sensor puts out? <hr></blockquote>
Stock air temp sensor will output a resistance between 6.8k and 1.0k (0 C to 40 C).
[quote]There is not a temp sensor on the MAF correct? <hr></blockquote>
Good question!
[quote]Can the ARC-2 work without attaching the lead to pin 22 and use the stock sensor in it's place? <hr></blockquote>
It should if you connect an equivalent air temp sensor. After all that’s what was originally connected to this input.
Again the open issue is what is the purpose of the original air temp sensor? What does the DME do based on this input? It’s a basic I/O question. Derrek care to answer this for us?
03-05-2002, 07:40 PM
#38
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I would assume it is for fuel enrichment. Add that with the coolant temp, and the DME knows what is happening. Perhaps once at operating temps, it ignores the air temp.
Well... unless one of the tuners can get a way to have the ARC-2 function correctly, or have an update in the software that will give the correct output, as per stock spec, I will attach my stock sensor to the MAF and say the hell with it.
Although it kinda hurts drilling into a $1300 peice of aluminum to make it work.
Well... unless one of the tuners can get a way to have the ARC-2 function correctly, or have an update in the software that will give the correct output, as per stock spec, I will attach my stock sensor to the MAF and say the hell with it.
Although it kinda hurts drilling into a $1300 peice of aluminum to make it work.
03-05-2002, 07:51 PM
#39
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[quote]Originally posted by Huntley Racing:
<strong>Oooo, oooo, oooo, I'm first to respond. The temp issue is really kind of funny. If we instructed all of the MAF owners to tune thier cars then pull out the ARM1 (mixture meter) they would never know that there was a difference in the mixtures cold or hot. The reality is that the early Motronic cars like the 944 Turbo do have different mixtures hot/cold because they just do, stock too. Those with no starts or very rough running have other problems which may be made worse with an MAF vs the original AFM. A good example of this would be: Lets say that a DME coolant temp sensor is starting to fail and is reading hotter than actuall temp. You tuned your ARC2 when the car was hot and was not effected by the temp sensor. You tune the car so that it has a nice lean idle when hot. The next cold morning start the car runs very rough and you turn up the low **** on the ARC2 which makes the car run better. But as the car heats up the idle becomes to rich and you turn it back down. This must be an ARC2 problem, right? With the original AFM it ran with a richer mixture at idle all the time so it's cold start was better. You can do the same with the ARC2 by just runing richer all the time. Of course having the ARM1 to SEE your mixture issue would kill that idea because it would bug you. These issues are why the great majority of people never have any cold or hot start problems, but those that do simply bandaid the real problem with a twist of the ARC2 and then blame the bandaid for the problem. Reiterating what I have said all along, MAF sensors do not need air temp sensors on these cars.</strong><hr></blockquote>
What about when it's really cold (ie -20C). Some of these MAF converted 951's ARE winter driven, and at -20C there's a LOT of enrichment required to get the engine to just fire up, let alone maintain a normal idle. For those people, do you suggest the "turn up ****" bandaid fix on winter mornings?
By the way, we now have 3 different positions on the MAF/cold start/temp sensor issue.
Lindsey : comes with it.
SFR : Says they use the stock one (confused?)
Huntley : doesn't need it
I do agree with Huntley in a small way though, most of the 951's aren't winter driven, and only used on warm days where this issue doesn't affect them, but it should be clearly advertised =).
<strong>Oooo, oooo, oooo, I'm first to respond. The temp issue is really kind of funny. If we instructed all of the MAF owners to tune thier cars then pull out the ARM1 (mixture meter) they would never know that there was a difference in the mixtures cold or hot. The reality is that the early Motronic cars like the 944 Turbo do have different mixtures hot/cold because they just do, stock too. Those with no starts or very rough running have other problems which may be made worse with an MAF vs the original AFM. A good example of this would be: Lets say that a DME coolant temp sensor is starting to fail and is reading hotter than actuall temp. You tuned your ARC2 when the car was hot and was not effected by the temp sensor. You tune the car so that it has a nice lean idle when hot. The next cold morning start the car runs very rough and you turn up the low **** on the ARC2 which makes the car run better. But as the car heats up the idle becomes to rich and you turn it back down. This must be an ARC2 problem, right? With the original AFM it ran with a richer mixture at idle all the time so it's cold start was better. You can do the same with the ARC2 by just runing richer all the time. Of course having the ARM1 to SEE your mixture issue would kill that idea because it would bug you. These issues are why the great majority of people never have any cold or hot start problems, but those that do simply bandaid the real problem with a twist of the ARC2 and then blame the bandaid for the problem. Reiterating what I have said all along, MAF sensors do not need air temp sensors on these cars.</strong><hr></blockquote>
What about when it's really cold (ie -20C). Some of these MAF converted 951's ARE winter driven, and at -20C there's a LOT of enrichment required to get the engine to just fire up, let alone maintain a normal idle. For those people, do you suggest the "turn up ****" bandaid fix on winter mornings?
By the way, we now have 3 different positions on the MAF/cold start/temp sensor issue.
Lindsey : comes with it.
SFR : Says they use the stock one (confused?)
Huntley : doesn't need it
I do agree with Huntley in a small way though, most of the 951's aren't winter driven, and only used on warm days where this issue doesn't affect them, but it should be clearly advertised =).
03-06-2002, 05:22 AM
#40
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i cant wait for the 4-5 questions to be addressed, and i drive my car when its between 0 and 32 degrees outside so that is somewhat why im interested as to the issue here also im getting lean on my arm1 at cold idle unless i turn the arc2 to 11:30 or higher to not go full lean (first red led on arm1) if the 11:30 or higher on the low setting then that question is answered but alot of people show their low settings at 9:00 or 10:00 or 11:00 and if i do that my car dies out completely 100 percent of the time from lack of fuel, i dont think i need 55 pound injectors to get enough fuel at idle with the maf#4 kit or do i? i even turned up the fpr to 60 psi w/ vac. line off but i still need 11:30 or more at cold starts to idle, also if i adjust my throttle body screw out my idle raises past 1000 and that aint good also i get more leaner so thats my problem, i got k27 autothority stage2 chips too, as far as perry' above post "Although it kinda hurts drilling into a $1300 peice of aluminum to make it work" ive seen some ricers add nos to the hoses that connect to their maf kits, so tap the kit at at a rubber hose maybe instead of the metal pipe and save yourself some money for testing this theory out for all of us, goto the local supermarket and look at import car mags this week youll see the nos setup into a rubber hose connector between metal pipes that he used, just a thought
03-06-2002, 05:29 PM
#42
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Thread Starter
I have a strong feeling that most users and tuners are unware that the ARC 2 (grey wire) sends a fixed resistance to the DME terminal #22. Additionally, it's also disturbing that no tuner has commented on the purpose of the original temp sensor or what the DME does differently based on the change in resistance from this input. Rather than send a fixed 1.5k or 2.0k ohm (grey wire) resistance from the ARC 2, why not send the DME the correct resistance base on air temp like the factory did? <img src="graemlins/cussing.gif" border="0" alt="[grrrrrrr]" />
If indeed it turns out this change in resistance controls/assists in timing or enrichment, then I would consider this a rather large application error. I plan to experiment once I receive an equivalent Bosch air temp sensor.
If your having similiar problems, please post a reply. It sounds like there might be more of us out there with this problem.
If indeed it turns out this change in resistance controls/assists in timing or enrichment, then I would consider this a rather large application error. I plan to experiment once I receive an equivalent Bosch air temp sensor.
If your having similiar problems, please post a reply. It sounds like there might be more of us out there with this problem.
03-06-2002, 05:38 PM
#43
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[quote]Originally posted by dlr944:
<strong>Additionally, it's also disturbing that no tuner has commented on the purpose of the original temp sensor or what the DME does differently based on the change in resistance from this input.</strong><hr></blockquote>
From investigations here by everyone on this thread, and based on my experience of fuel enrichment maps that are required for a cold car to start up and run smoothly, I'm certain that it's for fuel enrichment when cold.
[quote]Originally posted by dlr944:
<strong>Rather than send a fixed 1.5k or 2.0k ohm (grey wire) resistance from the ARC 2, why not send the DME the correct resistance base on air temp like the factory did?</strong><hr></blockquote>
Probably because the MAF conversion kits removed the temp. sensor that's housed inside the Vane Airflow Meter. Lindsey Racing seems to be the only ones admitting to the problem, and having a standalone temp sensor added to their kit to SOLVE (not BANDAID) the problem.
<strong>Additionally, it's also disturbing that no tuner has commented on the purpose of the original temp sensor or what the DME does differently based on the change in resistance from this input.</strong><hr></blockquote>
From investigations here by everyone on this thread, and based on my experience of fuel enrichment maps that are required for a cold car to start up and run smoothly, I'm certain that it's for fuel enrichment when cold.
[quote]Originally posted by dlr944:
<strong>Rather than send a fixed 1.5k or 2.0k ohm (grey wire) resistance from the ARC 2, why not send the DME the correct resistance base on air temp like the factory did?</strong><hr></blockquote>
Probably because the MAF conversion kits removed the temp. sensor that's housed inside the Vane Airflow Meter. Lindsey Racing seems to be the only ones admitting to the problem, and having a standalone temp sensor added to their kit to SOLVE (not BANDAID) the problem.
03-06-2002, 06:45 PM
#44
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I agree with rage2 on this one. If I am paying $1500+ for a MAF conversion kit, I would expect it to at least ~maintain~ the same functionality as the stock factory air box. Hopefully the aftermarket suppliers were not trying to save $50 on a $1500 kit by not including the air temperature sender. Why else wouldn't they include the air temp sender? The issue of fuel enrichment during cold starts is nothing new for EFI engines!
The reality is that many Porsches ~are~ daily drivers. Even if they are only driven on weekends, the notion of having to fiddle with the A/F ratio while driving would be annoying.
If I had to choose a system today, I would choose the Lindsey option because of the temp. sender.
The reality is that many Porsches ~are~ daily drivers. Even if they are only driven on weekends, the notion of having to fiddle with the A/F ratio while driving would be annoying.
If I had to choose a system today, I would choose the Lindsey option because of the temp. sender.
03-06-2002, 07:15 PM
#45
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Thread Starter
[quote] Rage 2 wrote: Probably because the MAF conversion kits removed the temp. sensor that's housed inside the Vane Airflow Meter. Lindsey Racing seems to be the only ones admitting to the problem, and having a standalone temp sensor added to their kit to SOLVE (not BANDAID) the problem.<hr></blockquote>
I realize that the factory temp. sensor has been removed. I am just surprised that certain tuners have not commented on why they chose to send a fixed resistance instead of a variable resistance based on temperature to the DME terminal #22.
Personally, I hope my research pays off and those of us that have this problem can correct it with an equivalent temp sensor. I must say this is quite an interesting find!
I realize that the factory temp. sensor has been removed. I am just surprised that certain tuners have not commented on why they chose to send a fixed resistance instead of a variable resistance based on temperature to the DME terminal #22.
Personally, I hope my research pays off and those of us that have this problem can correct it with an equivalent temp sensor. I must say this is quite an interesting find!