com port or USB

[Gorman]

Hi Guys; for data logging purposes...will the com port be quick enough or is USB a must. Does it depend on the laptop ? I read the com port type are unreliable...is that true ? Just looking to start monitoring the ecu with with an old laptop under then seat. cheers BigG

[bensenvill]

speaking only from a computer aspect, serial ports are much more reliable than USB [in fact if it offers you the choice, the USB is almost certainly using serial port emulation anyways].

a serial port is relatively slow for transfering data and I'm not sure how much data is really transfered with the data loggers but I can only guess that it is well within the abilities of a serial port.

[Gorman]

Cheers for that T. "a serial port is relatively slow for transfering data and I'm not sure how much data is really transfered with the data loggers but I can only guess that it is well within the abilities of a serial port." Anyone have any idea of data rates and how big files can get over say a week ? Thanks G.

[DemonSVT]

Well answered already.

A serial port is very limited in the amount of total polls per second it can log. (i.e. transfer rate) Expect to be able to log 5-6 categories at multiple polls a second. Anything slower then this is not worth datalogging. This port is very reliable and consistent.

A USB interface does not have this limitation but is also less reliable/consistent.


I've had no problems datalogging with Alex Pepper's OBD-II setup and it uses a serial port connection.

[bensenvill]

Well answered already.

ya, I was all excited, its probably going to be the only question in the tuning section I will ever be able to answer.

[Gorman]

Thanks DSVT; for the clarification; 5 or 6 parameters will probably do, to start with. I can't imagine the data; over a week, would overflow the 20G hard drive....unless someone knows otherwise. cheers G.

[bensenvill]

no it wont get anywhere close to that.... and if it does, you'll have more data then you'll ever be able to analyze

[Gorman]

Hi T. i was hoping to check out the A/F ratio and see if I'm running rich/lean thru the rev. range...the motor rev's OK, but it seems to lack real urgency. First step then..get connected... cheers G.

[bensenvill]

no, keep us posted, I'm going to be picking up some datalogging equipment in the next few weeks so it will be nice to know answers to these questions also [that and the laptop I'd be using only has a 850meg hd]

[cpapashley]

:mad: :mad: :mad: :mad: :mad:

Oh how I wish it was that simple for me.....

But please post some details. I think it will be full of surprises :eek:

Will be looking on with interest.

[Gorman]

:mad: :mad: :mad: :mad: :mad:

Oh how I wish it was that simple for me.....

But please post some details. I think it will be full of surprises :eek:

Will be looking on with interest. Hi A. from what i'm reading..only four wires are being utilized on the OBD port interface. You must have a four pin plug under the hood which is used for diagnostics. You could use that and make your own connections to the ECU by cutting the end off an interface cable. One wire is power, one is ground...how hard can it be. You need to know which protocol you have ie vpwn pwn or an ISO standard etc. Look on ebay for OBD interface cable, @$45 AU.....just thought i'd tell you what i've seen...good luck...G.

[bensenvill]

you should really take some photos of the wiring process... that stuff always flies right over my head.

[cpapashley]

Hi A. from what i'm reading..only four wires are being utilized on the OBD port interface. You must have a four pin plug under the hood which is used for diagnostics. You could use that and make your own connections to the ECU by cutting the end off an interface cable. One wire is power, one is ground...how hard can it be. You need to know which protocol you have ie vpwn pwn or an ISO standard etc. Look on ebay for OBD interface cable, @$45 AU.....just thought i'd tell you what i've seen...good luck...G.

Well actually it is a 25 pin plug much like the MECS plug. I agree with you that this should be so simple. Apparently if it is an OBDI which I am being told, the code and details are all internal and so you have to get into the actual PCM and put in a "tweecer" type system that reverse engineers the code and allows access to all the info. I have the rep from tweecer getting this checked out for me. I also have been starting to look at cheaper alternatives from MOATES and tunerpro that provide a similar thing to tweecer.

However you do make me think that just buying an interface cable and trying for myself might just get me some results. Once I buy my new laptop PC for christmas I will certainly be giving it a go now. You have given me some encouragement to continue on in this journey. Thanks big G.

In the meantime of course I am still watching on ebay for a Greddy, but the cost is just too much at the moment with four children and christmas on its way.

[cpapashley]

you should really take some photos of the wiring process... that stuff always flies right over my head.


Now that there is a good idea ;)

[Gorman]

Hi A. something else i forgot to say.....if in your travels you get to look at the OBD plug on a flasher unit, see if you can get a photo or note the position and number of utilised pins. By comparing an interface cable with a flasher, we should be able to deduce which pins are used for writing to the ecu. The goal is to end up flashing your ecu from your laptop..eliminating the need for a flashing unit. Has anyone got the schematic of the OBD port..it seems to missing from my manual, cheers BigG

[cpapashley]

Hi A. something else i forgot to say.....if in your travels you get to look at the OBD plug on a flasher unit, see if you can get a photo or note the position and number of utilised pins. By comparing an interface cable with a flasher, we should be able to deduce which pins are used for writing to the ecu. The goal is to end up flashing your ecu from your laptop..eliminating the need for a flashing unit. Has anyone got the schematic of the OBD port..it seems to missing from my manual, cheers BigG

umm, I think I understand. Problem is getting a good look at a flasher unit and getting a photo.

I would also think from my understanding it is the code that is sent to the ecu that then primes it for action (reflash) as well as ensuring the right pins are used. At least in my case. As the obdii protocol is a standard method of communication, getting the correct software to reflash the ecu is (as far as I understand in US) fairly straightforward (ie PRP of SCT among others). But I am still doubtful that I can get access through the diagnostic port on my vehicle easily. Having said that, obviously Mazda have the ability. I am going to try to find someone in the trade (mazda dealer) who can help me on this matter once I finish my essays for the subject I am doing externally (finishes 13th December).

If there is any prayers out there pray that I finish on time. My mind is not working to well at the moment (a legacy of a burnout 8 years ago) :confused:

[Gorman]

Hi A. Good luck with the essays, we're rooting for your success. :gitrdone: I've discovered my OBD port uses pins 2 and !0 on an ELM 320 interface cable to communicate with the ECU (pwm). All i need to do is find a flasher and see if the thing has connections in those positions. The interface cable ELM 327 u or c will apparently work with all protocols in the Ford duratec range including later CAN bus types. Hope this info helps those interested. G.

[cpapashley]

Hi A. Good luck with the essays, we're rooting for your success. :gitrdone: I've discovered my OBD port uses pins 2 and !0 on an ELM 320 interface cable to communicate with the ECU (pwm). All i need to do is find a flasher and see if the thing has connections in those positions. The interface cable ELM 327 u or c will apparently work with all protocols in the Ford duratec range including later CAN bus types. Hope this info helps those interested. G.

I was having a look at a pdf file describing the use of the elm 327. It looked interesting (considering my total newbness in this area). But if I understand it correctly it would just be a matter of connecting the pinouts from my diagnostic pin (assuming it is one of those protocols). Of course I don't hold my breath as I have been told that it cannot be done without expensive diagnostic equipment, but I guess it could just be something similar to the elm327 ;)

So with your cougar using pwm protocol, I was reading somewhere that Mazda's (in Australia) up till 2002 used the 9141 protocol or something like that and read that the elm 327 also works with this protocol. So that cerainly gives me encouragement at least for datalogging. Having said that my previous discussions with the elm distributor over here in australia were very unfruitful. So I think I have a few options before me to investigate :) so thanks for the input big G.

Just one thing have you looked at tunerpro the pc program that allows you to update parameters?? I am a little unsure how that works but might be worthwhile especially if the end goal is to get some base tuning maps that we can interchange.

I think I have a lot to learn before I will be much use in this area. But I am probably more fortunate than most at my age getting another chance at life with pretty well a clean slate after being out of life in the mainstream for 8 years.

BTW thanks for the encouragement on the essay's should get them finished :banghead: mind you it does remind me of banging my head against a brick wall or was that brick books :rofl:

[Gorman]

Originally posted by cpapashley Just one thing have you looked at tunerpro the pc program that allows you to update parameters?? I am a little unsure how that works but might be worthwhile especially if the end goal is to get some base tuning maps that we can interchange. Hi A. no I hadn't, but have now, cheers. One of the features of the Tunerpro was; running your car from your laptop, using it as a surrogate ECU. That could be really useful and it's only one step from actually installing it. Not sure what happens if you hit the brakes hard and the laptop connection is lost in some way :ugh: . I followed one of the links in the software to find a re-mapper for $150 US. and wideband O2 sensors. I think i need to start logging and take it one step at a time. The ELM 320 comes with logging software, so i'm starting there. Perhaps; when you know where to plug in to your ECU, you'll join me. Hope so.....it would be good to talk to someone who's looking at the same software. G.

[cpapashley]

Originally posted by cpapashley . Hi A. no I hadn't, but have now, cheers. One of the features of the Tunerpro was; running your car from your laptop, using it as a surrogate ECU. That could be really useful and it's only one step from actually installing it. Not sure what happens if you hit the brakes hard and the laptop connection is lost in some way :ugh: . I followed one of the links in the software to find a re-mapper for $150 US. and wideband O2 sensors. I think i need to start logging and take it one step at a time. The ELM 320 comes with logging software, so i'm starting there. Perhaps; when you know where to plug in to your ECU, you'll join me. Hope so.....it would be good to talk to someone who's looking at the same software. G.

Whatever way I go first up will be the datalogging. Hopefully I will be able to get something done soon. have a big weekend of study planned so all should be done by next wednesday and then it will be.......datalogging by Christmas one way or another. I am very tempted to get the wideband sensors next year sometime. Just think that will help in the process with more accurate measurement of the a/f ratio.

Looking forward to hearing more about your progress, I have been eyeing off the ford mondeo over here as a second car. They have the 2.0l in them wonder if it is difficult to get a 3.0l installed into them, but that is another issue altogether :biggrin:

Anyway good luck with the elm320, hope it gives good data. Let us know how it goes.