Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post

gone.s2 · 03-26-2011, 01:36 PM

Hello - have been following this thread for some time and finally broke down and bought a few boarduinos to test with. After a bit of experimentation (see previous post) I managed to get the voltage comparator circuit initially submitted by schlorkist functional. A huge thanks to everyone who's contributed to the project, very cool stuff!

Wondering if anyone has any knowledge to share relevant to using OBDuino for diesel application. At first blush it appears I'm only getting data back for PIDs 04, 05 and 0C (load, temp and rpm) on my VW Mk4 TDI. If not, I'm hoping someone might steer me in the right direction as to where to start. I'm going to assume I need to assemble a list of supported PIDs but not really sure where to start there. I would love to make this work over OBD, but I fear a completely different method of estimating injected fuel quantity may be necessary due to the diesel engine's lack of a throttle blade.

And while I'm thinking about it, regarding the issue njakts was working on, you might also try commenting out:

Code:

#define do_ISO_Reinit
#define skip_ISO_Init
#define carAlarmScreen

as there appears to be an issue with ecu polling and / or the security screen. Mine will init successfully (only on the second attempt) when these are commented out, but never when using the default config (security screen enabled). Wondering if anyone with an ISO vehicle could try r187 and confirm?

Lastly, does anyone know the source of the "clunkiness" in the menu mode? It's almost as if the code is only seeing the rising or falling edges of the button transitions. Weird stuff. I would be willing to attempt to fix this but I've got a large laundry list ahead of me with the other issues mentioned, so any thoughts on this would be greatly appreciated.

UPDATE: it also appears I'm getting VSS. I think my problem may be timing b/c I'm getting no more than 2 pids / sec.

UPDATE #2: After configuring ISORequestDelay down to 10 ms I'm seeing everything I think I need. Now to hack something up for consumption - from what I've been able to gather the way others have done it uses PID 04 (Calculated Engine Load). This looks to be interesting b/c I noticed this number drops to 0 instantaneously during DFCO. Didn't I see mention somewhere about detecting DFCO in code? Wouldn't monitoring this PID work for that more simplistically?

03-26-2011, 01:36 PM	#641 (permalink)
gone.s2 EcoModding Lurker Join Date: Mar 2011 Posts: 15 der Öl-Brenner - '01 Volkswagen Jetta TDI Thanks: 0 Thanked 0 Times in 0 Posts	2001 VW Jetta TDI Diesel ??? Hello - have been following this thread for some time and finally broke down and bought a few boarduinos to test with. After a bit of experimentation (see previous post) I managed to get the voltage comparator circuit initially submitted by schlorkist functional. A huge thanks to everyone who's contributed to the project, very cool stuff! Wondering if anyone has any knowledge to share relevant to using OBDuino for diesel application. At first blush it appears I'm only getting data back for PIDs 04, 05 and 0C (load, temp and rpm) on my VW Mk4 TDI. If not, I'm hoping someone might steer me in the right direction as to where to start. I'm going to assume I need to assemble a list of supported PIDs but not really sure where to start there. I would love to make this work over OBD, but I fear a completely different method of estimating injected fuel quantity may be necessary due to the diesel engine's lack of a throttle blade. And while I'm thinking about it, regarding the issue njakts was working on, you might also try commenting out: Code: #define do_ISO_Reinit #define skip_ISO_Init #define carAlarmScreen as there appears to be an issue with ecu polling and / or the security screen. Mine will init successfully (only on the second attempt) when these are commented out, but never when using the default config (security screen enabled). Wondering if anyone with an ISO vehicle could try r187 and confirm? Lastly, does anyone know the source of the "clunkiness" in the menu mode? It's almost as if the code is only seeing the rising or falling edges of the button transitions. Weird stuff. I would be willing to attempt to fix this but I've got a large laundry list ahead of me with the other issues mentioned, so any thoughts on this would be greatly appreciated. UPDATE: it also appears I'm getting VSS. I think my problem may be timing b/c I'm getting no more than 2 pids / sec. UPDATE #2: After configuring ISORequestDelay down to 10 ms I'm seeing everything I think I need. Now to hack something up for consumption - from what I've been able to gather the way others have done it uses PID 04 (Calculated Engine Load). This looks to be interesting b/c I noticed this number drops to 0 instantaneously during DFCO. Didn't I see mention somewhere about detecting DFCO in code? Wouldn't monitoring this PID work for that more simplistically? Last edited by gone.s2; 03-27-2011 at 11:15 AM..