944 OBD Project (On-Board Diagnostics)
#466
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Cheers,
#467
Just curious.
With all the features you are adding do you think it’s possible to have enough data to troubleshoot shoot problems people have been having with the newer LR Mtune or utilize the Mtune hard for your future setup?
Unfortunately I am still behind with getting an engine back together but hoping it will happen sooner than later as I have so much stuff going on at the same time.
With all the features you are adding do you think it’s possible to have enough data to troubleshoot shoot problems people have been having with the newer LR Mtune or utilize the Mtune hard for your future setup?
Unfortunately I am still behind with getting an engine back together but hoping it will happen sooner than later as I have so much stuff going on at the same time.
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riouxc (07-16-2022)
#469
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I would appreciate it if someone that's pulled their DME from a turbo could explain exactly how it's supposed to be attached. When my son owned the 951 it went through several chip changes, and I think along the way it never got put back together correctly. I just installed the F9T Sport DME w/OBD+ (temporarily) and when I removed the DME it was only attached with one screw and speed nut (plus 1 screw that held the bracket for the alarm), whereas the PET indicates it should have 4 screws and speed nuts. Any images of how this is all supposed to go together would be great.
The Sport DME w/OBD+ is amazing as it's extremely useful to be able to view sensor outputs on real-time graphs. Looks like I have an issue with my NBO2 sensor as it always reads RICH at idle and never oscillates between RICH and LEAN like it should. I suppose this could also be an issue with the current chipset, which is from Transaxle Motorsports. If the fuel mapping is always too rich, then the DME might lack the ability to adjust the injection pulse width enough to lower the AF ratio. Joe has a nice video on YouTube to show how this is supposed to work:
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Thanks for any info.
The Sport DME w/OBD+ is amazing as it's extremely useful to be able to view sensor outputs on real-time graphs. Looks like I have an issue with my NBO2 sensor as it always reads RICH at idle and never oscillates between RICH and LEAN like it should. I suppose this could also be an issue with the current chipset, which is from Transaxle Motorsports. If the fuel mapping is always too rich, then the DME might lack the ability to adjust the injection pulse width enough to lower the AF ratio. Joe has a nice video on YouTube to show how this is supposed to work:
Thanks for any info.
#470
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I think I have the original 951 ECU chip somewhere... I could burn it to a 28 pin chip... PM me if you need it.
These chips are getting hard to get, I ordered 10 blanks from China...
These chips are getting hard to get, I ordered 10 blanks from China...
#471
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The 951 currently has a stealth MAF setup purchased from ProMax Motorsports in the UK back in 2005. It uses a Bosch MAF sensor and mounting adapter, which gets fed to the DME via a little converter harness that installs between the MAF sensor and the stock harness to the AFM. It's supposed to translate the MAF signal to mimic what the AFM would generate, but I've always suspected it may not be that accurate. The MAF came with the Transaxle chips. Prior to running this setup, it had Autothority chips w/banjo bolt restrictor, which was the configuration from the previous owner.
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Wow, just out of curiosity I looked up the P/N for a M44.52 DME from Porsche, 951-618-121-KX. Cost? Only about $1900 PLUS a core charge of $1595. That makes the F9T DME truly the bargain of the century
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Tiger03447 (07-29-2022)
#473
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I just ran my first log of my car and I am getting a Fly RPM Error 3. I did swap out new speed and reference sensors in May of this year and I have been getting a hunting idle sometimes. I also have been running lean but I was not sure if that was because of my setup or something else. Prior to getting the OBD+, i had put my FQS setting at the +2% setting. My WBO2 had a reading 15.8-16.2 at warm idle, 14.7-14.8 at 3k rpm and 10.8-11.2 at WOT.
I have not attached my WBO2 yet. It's still on my GFB EBC and I was monitoring it.
So my questions are: 1) what is the Fly RPM error 3 and does it have something to do with my lean condition, and 2) is there a virtual FQS or do I need to adjust it manually still?
I have not attached my WBO2 yet. It's still on my GFB EBC and I was monitoring it.
So my questions are: 1) what is the Fly RPM error 3 and does it have something to do with my lean condition, and 2) is there a virtual FQS or do I need to adjust it manually still?
#474
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The FQS is adjusted inside the DME.
My NBO2 sensor needs to be replaced as the voltage reading doesn't oscillate at idle but just stays in the 0.73-0.75 V range. I just got a new one from Porsche and will get that installed soon and see if that fixes the issue. If it doesn't then the fueling in my DME program (Transaxle Motorsports chip) may be too rich at idle and the DME can't lean it out enough per input from the NBO2.
#475
Posting in here since no one knows ODB exists yet for the 911 ;-)
Got my 911 DME with ODB.
Car's running, drove about 30 miles on it. No drivability issues.
I had the laptop with me and I noticed a couple of things.
1. RPM is off by quite a bit on the FocusODB program. It's showing much higher. Idle shows 1300 or so while car is showing 800ish..and shows like 2900 when I am at 2000.
2. Flywheel sensor vehicle switches between unknown and 944 constantly.
3. Flywheel tooth count is fluctuating between 128-130 constantly. I believe 130 is the right count.
4. Operating temp seemed off too. 240F on the program but it was below 200F on the dash.
Got my 911 DME with ODB.
Car's running, drove about 30 miles on it. No drivability issues.
I had the laptop with me and I noticed a couple of things.
1. RPM is off by quite a bit on the FocusODB program. It's showing much higher. Idle shows 1300 or so while car is showing 800ish..and shows like 2900 when I am at 2000.
2. Flywheel sensor vehicle switches between unknown and 944 constantly.
3. Flywheel tooth count is fluctuating between 128-130 constantly. I believe 130 is the right count.
4. Operating temp seemed off too. 240F on the program but it was below 200F on the dash.
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Sajan (08-25-2022)
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HI everyone!
I just posted a fairly big update to the FocusOBD Software on the website; it is now a v0.25.270. The main change is the Beta for ignition advance, however, there are numerous other refinements and bug fixes. I strongly recommend everyone download this build. A lot of code has changed, so please report back if you encounter any issues or have comments.
Ignition Advance (Beta)
This feature took much longer to implement than I had expected and taking a week of vacation pushed it out even further. Writing the code was actually fairly easy, but figuring out where true TDC was proved to be a challenge. It turns out the “Mark” flywheel sensor outputs a signal way ahead of TDC, but there are no makings on the flywheel to indicate how many teeth the Mark signal is away from TDC. Initially, I tried to physically count the teeth through the bell housing access hole, but I could not be 100% sure which tooth edge was at TDC. I then wired up the third flywheel sensor that is specifically for measuring TDC, but it has two studs that only encompass TDC, you still need to know which tooth and edge is at TDC. I finally ended up buying a digital timing light with an ignition advance feature. I then modified the FocusOBD software and firmware so I could data log the tooth edge count from the Mark signal to the ignition signal. I adjusted the advance on the timing light until the TDC Mark on the flywheel lined up with the bell housing. I could then see the ignition was consistently jumping around three discrete positions: before TDC, at TDC, and after TDC. The FocusOBD’s data log linked these three positions to three specific sequential tooth edges. Then, it was just a matter of using the ignition advance setting on the timing light to calculate how may tooth edges where advanced, and subtracting that number from the center tooth recorded in the data log.
I implemented this feature earlier than I had planned at the request of Richard T. Garcia, owner of Dyno-Comp in Scottsdale Arizona. He has been tuning his truly awesome 400+ horsepower 1989 Porsche 944 Turbo using one of my OBD+ DMEs and a TurnerPro/Ostrich setup. He needed a way to verify if the ignition advance he specified in TurnerPro actually translated into the DME hitting that target. I will be heading over to his shop in a week or two to play around with it and see if the FocusOBD software agrees with TunerPro. If everything looks good, I will take this feature off Beta status. One interesting thing about how the DME regulates ignition, is that it will only fire the ignition coil on a rising or falling edge of a starter ring tooth. This means the resolution for changing ignition advance is exactly 1.384 degrees on the NA and 1.363 degrees for the Turbo. Richard tells me that on modern cars he generally expects to adjust timing in 0.5 degree increments, but 1.363 is workable. The good news is that I should be able to overcome this limitation when I implement ignition advance tuning next year. Until then, I need to get back to MAF development…
-Joe Baumbach
I just posted a fairly big update to the FocusOBD Software on the website; it is now a v0.25.270. The main change is the Beta for ignition advance, however, there are numerous other refinements and bug fixes. I strongly recommend everyone download this build. A lot of code has changed, so please report back if you encounter any issues or have comments.
Ignition Advance (Beta)
This feature took much longer to implement than I had expected and taking a week of vacation pushed it out even further. Writing the code was actually fairly easy, but figuring out where true TDC was proved to be a challenge. It turns out the “Mark” flywheel sensor outputs a signal way ahead of TDC, but there are no makings on the flywheel to indicate how many teeth the Mark signal is away from TDC. Initially, I tried to physically count the teeth through the bell housing access hole, but I could not be 100% sure which tooth edge was at TDC. I then wired up the third flywheel sensor that is specifically for measuring TDC, but it has two studs that only encompass TDC, you still need to know which tooth and edge is at TDC. I finally ended up buying a digital timing light with an ignition advance feature. I then modified the FocusOBD software and firmware so I could data log the tooth edge count from the Mark signal to the ignition signal. I adjusted the advance on the timing light until the TDC Mark on the flywheel lined up with the bell housing. I could then see the ignition was consistently jumping around three discrete positions: before TDC, at TDC, and after TDC. The FocusOBD’s data log linked these three positions to three specific sequential tooth edges. Then, it was just a matter of using the ignition advance setting on the timing light to calculate how may tooth edges where advanced, and subtracting that number from the center tooth recorded in the data log.
I implemented this feature earlier than I had planned at the request of Richard T. Garcia, owner of Dyno-Comp in Scottsdale Arizona. He has been tuning his truly awesome 400+ horsepower 1989 Porsche 944 Turbo using one of my OBD+ DMEs and a TurnerPro/Ostrich setup. He needed a way to verify if the ignition advance he specified in TurnerPro actually translated into the DME hitting that target. I will be heading over to his shop in a week or two to play around with it and see if the FocusOBD software agrees with TunerPro. If everything looks good, I will take this feature off Beta status. One interesting thing about how the DME regulates ignition, is that it will only fire the ignition coil on a rising or falling edge of a starter ring tooth. This means the resolution for changing ignition advance is exactly 1.384 degrees on the NA and 1.363 degrees for the Turbo. Richard tells me that on modern cars he generally expects to adjust timing in 0.5 degree increments, but 1.363 is workable. The good news is that I should be able to overcome this limitation when I implement ignition advance tuning next year. Until then, I need to get back to MAF development…
-Joe Baumbach
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Last edited by Ftech9; 09-02-2022 at 11:21 PM.