Tomin

Hi,
cliffyk: I agree with you. Just only for info I add: ELM is slow because there is a timeout for subsequent packets at all.
On Ford's PWM bus you can achieve much faster data transfer. 100-150 pids/sec. in question/answer technique and 400-600 pids/sec. if you can use batch mode.
Take a look at this http://www.youtube.com/watch?v=X0c8deyX6S8

cliffyk

I have set the timeout to the most aggressive mode, and specified the number of expected responses, and find that on my '03 GT the very best rate I can achieve (using a 115k baud interface to the ELM) is 25 to 30 PIDs/s before the ELM hangs.

I have Ozen's CAN (1610) and J1850 (1210) simulators and find that when using the J1850 simulator I can reach 95-100 PIDs/s with my software--but connect it to my Mustang and 25/s is the practical limit.

This is with the V1.4 chip--if someone is exceeding that on the EECV J1850 PWM bus I would love to see their code, or exchange some "real" email messages.

On the CAN bus rates of 150 to 300 PIDs/s are common, on the simulator or with a vehicle...

cliffyk

I just realised that the engine in that video is a Duratec HE, which uses a CAN bus "black oak" PCM. 145 PIDs/s is average, or a bit slow, for that PCM...

Tomin

about your test on ELM: It is strange. I did not test ELM heavily, so I can not disagree with you, but I think there must be big time gap somewhere. Some timeout on RS232 or so. The best practice is hook oscilloscope on PWM ...

About video: it was taken on Duratec with blackoak, but on PWM bus. Blackoak (in the Europe, I don't know about USA) has both busses and for diag there is used PWM bus (on cars from around 2000-...)
But this video is taken in batch mode - no question/answer sequence, but "loading pid map to ECU" + "start sequential transfer from ECU" (without need to more questions)

cliffyk

I am not aware of any "batch mode" supported by either the ELM327 or the EECV PCM (US versions), do you have any further information regarding this?

jcthomas

I'm running AeroForce dual Interceptor gauges off the OBDII port on my 2005 Mustang GT. Just bought a ELM327 cheap bluetooth device ($18) and an OBDII Y cable ($16) off Amazon. Hooked it all up, gauges still worked, and the Torque Android app connected with the ELM327 device.

But... the Torque app reported that it was unable to talk to the ECM over the J1850 protocol. I went back to read the notes in the Google Play store for the Torque app, and followed the link to their site. It said "I would recommend avoiding this adapter if you intend to use it on a Ford vehicle with the J1850-PWM protocol."

I googled "ODBII bluetooth Ford Mustang" and found a reviewer on Amazon (http://www.amazon.com/ELM327-Bluetoo...ews/B0051CAE1C) that said it worked on his 2005 Mustang, so I ordered it ($30). We'll see...

I'm keeping the first one I ordered. I plugged it in to my 2010 F150 SCrew and it worked fine!

cliffyk

Most of these things are junk, ELM327 ripoffs. They tell you to "avoid the J1850-PWM" because the 41.6 kBaud interface cannot meet their claimed specs.

The fact is that for all practical purposes 10-12 PIDS/s is plenty fast enough for tuning, the engine's control parameters just do not change much faster than that...

Chasingponies

I have a 2001 mustang gt i can pair to the obd2 device but it wont connect to ecu why is that?