Datastream-ing from 1226026 ECM

[KANE]

So I've swapped the '84 auto ECM into my '82 so that I could actually get datastream level information out of the Vette. The '82 ECM is not supported by my Actron CP9185 and some other scan tools these day.

Anyway, here's a smattering of the data I pulled during open loop and closed loop. I'm really happy that I can actually get data from the ECM, monitor it real time, and put it to use.

Open loop-

• Engine temp: 172 degrees
• Idle: 1,000 rpm
• IAC: 25
• BLM: 128
• Integrator: 128
• MAP: 1.12
• 02 (mv): 670
• TPS .65

Closed loop (just a few of interest)-

• BLM: 111
• Integrator: 126
• IAC: 38

NOTE: above are summaries of snapshot in time values to provide a sense of what is available- NOT actual averages.





It was really neat to watch the ECM trim the fuel and to see all of the adjustments happen real time. Perhaps for the crossfire folks this sort of thing is interesting...

 

[Hib Halverson]

(snip)

Closed loop (just a few of interest)-

• BLM: 111
• Integrator: 126
• IAC: 38

(snip)

Your system is rich so the ECM is pulling out fuel. Block learn (today it's called long-term fuel trim) is below 128 and your integrator (or short-term fuel trim) is just a tad low.

 

[KANE]

Your system is rich so the ECM is pulling out fuel. Block learn (today it's called long-term fuel trim) is below 128 and your integrator (or short-term fuel trim) is just a tad low.

Like I said...

I'm really happy that I can actually get data from the ECM, monitor it real time, and put it to use.

 

[KANE]

Your system is rich so the ECM is pulling out fuel. Block learn (today it's called long-term fuel trim) is below 128 and your integrator (or short-term fuel trim) is just a tad low.

Yeah- my instincts tell me the fuel pressure may be a bit high. If I remember correctly, a low number in the integrator could be a sign of incorrect fuel pressure as it is delivering a bit too much. I am in the 13-14 range on fuel pressure.




ADD: Hey Hib- remember that TPI swap a few years ago with the code 43? It took a while to figure out that 6 degrees base timing wasn't going to cut it. 6 degrees wasn't enough for the ECM to advance itself and achieve knock- thus passing its self test. Once I set it to 12 (the max advance was 32 on the engine) it all worked out great.


I don't seem to get the easy challenges, do I?

 

[82ColEd]

Kane,
glad you're getting the data out, but stupid me is not sure why you couldnt with the 82ECM? I've plugged my car up to the laptop a few times and get data. :confused

:confused Is there more then the 82 on a 84 chip?

One tip: Dont leave the laptop on the passenger seat when you need to stop, it might take a flying leap, though the looks of the people seeing a 31 year old car with a laptop connected are priceless. :L



Stefan

 

[Hib Halverson]

The problem is not that the 82 didn't send data. It was that the scanner he has did not support the 82's communications protocol...a common problem with OBD cars.

One good thing about OBD2 is that it standardized the communications protocol.

The software-based scan tester "82ColEd" talks about obviously does support 82s

As for the problems with the 82...while it is possible high fuel pressure is causing the system to be rich, that would not be my first choice.

Lastly, be careful with the idea that the 82 system is doing things in "real time". The 80-85 systems had clock speeds so slow they were benchmarked with sun dials.

Not everything in those systems in "real time". Spark control, fuel delivery occur fairly rapidly but other things, such as fault detection, changes in block learn (long-term fuel trim) and update of the serial data stream may not.

 

[82ColEd]

Ahh, ok. Thanks Hib.. Yeah old style OBD readers work. Especially the software ones that I am using on an old WinXP laptop..
And now I learnt something too regarding the timing of the "real time" as well . Good point.

 

[Wegone]

Interesting, I have never hooked my scanner up to the 82, Now I will have to see if it works.

 

[82ColEd]

Interesting, I have never hooked my scanner up to the 82, Now I will have to see if it works.

Steve, i am using Joby's WinALDL with the OBD1 cable to USB hooked up to my WinXP mini laptop to collect data. Am a PC geek, so that worked best for me to have the data on my PC to 'try' and read it.



-Stefan

 

[Wegone]

82ColEd,

I'll give my scanner a try its a Genisys EVO 2012 5.0 I have not had the 82 out in over a year I start it and let it run once a month. Thanks for the info.

 

[Hib Halverson]

Ahh, ok. Thanks Hib.. Yeah old style OBD readers work. Especially the software ones that I am using on an old WinXP laptop..
And now I learnt something too regarding the timing of the "real time" as well . Good point.

Speaking of reading data from the older cars, anyone here still using "Diacom-Plus"? It was an old DOS-based program for scanning pre-96 systems.