ECM Command,signal sequence and values measured and applyed

[rooster]

Im looking for a reference to GM  computer commands, there sequence, make and model
applications, for instance  a command from the ECM will trip a relay at a certain temp, a
command from ECM will discontinue voltage when a certain temp is reached. Where
might I find this type of information?

[jaybee]

Don't know what kind of engine you're using but there's a wealth of information at ls1tech.com .

[rooster]

Don't know what kind of engine you're using but there's a wealth of information at ls1tech.com .

Ill check them out, thanks.

We used to be able to get a chart telling points gap,plug gap, timing , ect. Those kind of things can be found in a haynes manual for a certain car, what about all these electrical gismo's that the computer operates, cooling , ignition,charging systems and much more, I have a new book by haynes called OBD2, it tells about what sensors do but dont say what car it applys to.

For instance a few weeks ago I started a post about making a Fan running light, quickely we got into why I needed it, there were alot of suggestions of what temps the car should be at when a ele fan would start and stop. There were also info on what sensor would signal the computer to start the fans relay to start the fans moter.
The Hayens manuals just dont cut when it comes to the kind of answers im looking for. I have 2 different Haynes manuals and neither one has a wiring map for our 95 olds cutlass, the best one I got is the old one.

[UGLY OLDS]

Try nosing around Here:


http://www.diy-efi.org/gmecm/



Or Here...


http://www.moates.net/phpforum/index.php

( This one gets kinda hairy...Lots of info though...Just gotta keep lookin')

Bob....

[wayne petty]

Im looking for a reference to GM  computer commands, there sequence, make and model
applications, for instance  a command from the ECM will trip a relay at a certain temp, a
command from ECM will discontinue voltage when a certain temp is reached. Where
might I find this type of information?

that info is written into the software....    

you can view the output command with a scan tool...

it will say Fan 1 on or Fan 1 off.    thats about it.. because the fan and other data in the ecm effects emissions you generly cannot get access to it  

most applications turn the fan on at 215 to 226F
IT IS WRITTEN.. in the code that is

there are ways around it.. like a custom prom or reflashing the memory.. depending on the year...

(prom= programable read only memory) this is a removable chip that can be reprogramed with an eprom burner and a pc and hours of work... maybe months of work...

there is a list of normal operating data values that you normaly see.. this allows you to visually see something out of place in voltage readings ...

if you want to see more you will need a minimum of a 200 buck scanner to play with.,...
if you have a pc laptop you can get  pc software and an interface cable  but those cost a lot more than the innova equis scanner from csk... if you intend on buying one check back with me for an exact part number.. so you dont get the wrong one...

feedback carbs and fuel injection drivability is one of the things i do a lot of......

pm me direct  if you need more info.. and be sure that you do not back probe the relay pigtail with anything except a digital volt meter...you can let the smoke out of the ecm in a second...and never know it...


and do you have a pep boys near you???  they have a 20 buck infrared non contact temp pen ..too limited in the range for what i use. but designed exactally for a/c and cooling systems...-20F to 260F.

pc and palm based scan tool software and cables can be had here...

www.aeswave.com


imperial  the same people who make cooling fans and fan clutches sells an ajustable fan thermostat that has a bulb that fits into a hose or behind the radiator to control the cooling fan.. the only problem with that is that on some systems  there is a feedback wire from the fan to tell the computer the fan is on and turning under power... cads have this system..  perhaps other cars..  (this system failed a lot on cads which is why i know about it and why a lot of cads have the cooling system relays bypassed.. 85fwd to 92-93??maybe newer.. the data has to be seen with a scan tool.. the cads have a built in scan tool by depressing the off and warmer buttons at the same time and having a proper balloon trouble shooting flow chart...
and a complete understanding of their display values...

where the heck am i going,..?

oh yea... just what are you trying to do???  turning on the fan to get the extra push...  ever wonder why zoomies on top fuel and funny cars are pointing back at that angle???  to help with the downward thrust..  if they aimed them back a little farther they would probably pickup a few miles an hour... but then nhra would need the pilots to get a rocket car license...

is it possable that the impeller blades are eroded off of your water pump???  yep..     and ..   the oil pump drive o ring  leaks because the oil pressure galleys are right next to it..  do to a change in design on the 60 degree blocks the dist housing fits outside the intake mounting area and has been lowered to a pad just above the cam shaft bores.. but like a small  and bigblock chevy one of the oil galleys passes around the housing. this is what the notch in the v8 housings was for..  but it was way down by the gear.. since this drive is shorter and mounted directly on top of the oil galley there is oil pressure on the bottom side of the oring.. the thermal cycling wears/shrinks the oring and it starts to leak... on one 2.8 cad cimmeron the customer wanted to reseal the timing cover on the front of the motor...  i fixed the oring and he was  really happy.. in fact most of you have seen him..   he was the old man who got the girl and the porsche from the desert store in the dr pepper commericial.. and guess what.. he could not drive a stick.. he stripped the gears out of that 356...

[rooster]

Quote Wayne:
that info is written into the software....

you can view the output command with a scan tool...

it will say Fan 1 on or Fan 1 off. thats about it.. because the fan and other data in the ecm
effects emissions you generly cannot get access to it

most applications turn the fan on at 215 to 226F
IT IS WRITTEN.. in the code that is

================================================================

I know I have seen the type of information I seek, but I cant remember where, it was a
mapped procedure with sequnce, with alot of  "then if" statements in it. Trobleshooting
info is written like this.
If someone is writing programs there must be basic instructions for different kinds of cars
sense there not all the same.
You asked "what am I trying to do" , I want to study the procedure or instructions that the
computer (OBD 1 1/2 ) in our 95 Olds follows, involving its cooling system, from the
beginning to the end of its cycle, and anything inbetween!.
The Scantool is the only way to access our 95's Olds system, and it must be OBD1 1/2
capable. I have been looking at Actron cp9150, kit.
The car is a diffent topic and im trying to not go there in this topic. We dont see alot
about computers and cars at RRT.
Thanks for the input.

[wayne petty]

ok   now i know what you want...

internal programming is out of my range..  it is avaialble probably at the other sites.. or can be had on that model by possable finding a copy of the reflash data and tearing it apart line by  line..    

as far as i know the fans are commanded on when it reaches a certian temp and run for a timed legnth....  there are some models that  have an ambiant temp sendor out in front of the radiator and i seem to recall on some older dodge models a temp sensor behind the radiator in the air flow...


i would think that  the programers on these have used a lot of imputs to vary the fan timing .     like ambiant temp, vech speed, a/c on,  ...

i bet there are some papers written at sae.org

on cads when they first came out with the electronic shift trannys customers were compaininig about a quick turn from a stop  and while waiting to merge the tranny upshifts to 4 gear  and locks the converter... during a meeting to discuss this problem a jr engineer from a differnt department was there and suguested why not use the lateral accelerometer data to hold back the shift... as the story goes these transmission engineers look at him like he was from mars and said what laterial accelerometer data..   on monday he gave them a program that used that data and he fixed it.  oh where do you get that data...just in case you are curious..  airbag srs sensors above the rear view mirror... that data in a cad is all fed into the bcm.....


here is the link to the actron system you are looking .. this is the owners manual..

http://www.actron.com/publish/2005/07/22/pdf_english_16143.pdf

i have not had  time to read it and i am on my back up puter.. during a friends puter restore job...

[wayne petty]

i have not had a chance to open this diagnostics page yet...
too many downloads filling my hard drives...

http://www.goodwrench.com/_res/pdf/EnginePdf/Strategy%20Based%20Diagnostics.pdf

found it on the goodwrench site...

[rooster]

i have not had a chance to open this diagnostics page yet...
too many downloads filling my hard drives...

http://www.goodwrench.com/_res/pdf/EnginePdf/Strategy%20Based%20Diagnostics.pdf

found it on the goodwrench site...

Thanks, Wayne for the link. I read it all and makes sense to me, in fact it brings up a few
things I need to check out. Rear window defroster don't work! Haven't checked the air
filter. Also found I have a after market alarm in the car that we didn't know we had.

I have done some searching in the links provided by you guys and only found pieces of
the info I seek, most of it is in general , don't know if it applies to a certain car or not,
here's a example:

http://www.gearchatter.com/viewtopic11753.php

After a suggestion from Tom im going to go to the library and go to all- data and see what
they have to offer.  Its the computers game plan that im after, for this particular car.

As of right now I think my computer is nuts or mis-informed by its sensors. I would like
to know the exact number witch triggers the "hot light" in the dash . I have a sensor
simulator where I think I can trigger the light and record what resistance it occurred at ,
then compare to a chart, but im going to stay away from that until I can get a scan tool.

The ol Skool gauge is up and running a timer was added, so far as I know fan will come on sometimes when eng is not up to operating temp. Cooled water reaches the new gauge, and starts responding to change with in 20 seconds after the fan does start at operating temp(about 220).  The wifes got the car for a few days just to keep the piece, she dont like the pickup with camper shell, parking lots and xmas shopping . go figure!

[wayne petty]

sorry but i did post that i had not looked at it...

it was late and the other stuff i was downloading looked good...

i was overly hopefull...


try this link...  it has tbhe best info i have found.. still not exactally what you want but at least have a look...

http://www.mefi4.com/sc/toplevel.asp?cat=2 there are a bunch of differnt pages in there..


i will now be quiet for a while....

waynep@servsite.com

[rooster]

sorry but i did post that i had not looked at it...

it was late and the other stuff i was downloading looked good...

i was overly hopefull...


try this link...  it has tbhe best info i have found.. still not exactally what you want but at least have a look...

http://www.mefi4.com/sc/toplevel.asp?cat=2 there are a bunch of differnt pages in there..


i will now be quiet for a while....

waynep@servsite.com

Thanks for the links Wayne, I did get some info from the alldata at the libary.

Question, does your scanner have the abilty to turn the fans on?

Heres the first offical test in the picture. During the last week in DRIVING CONDITIONS the fan running lights comes on earler, but not very ofter the fan comes on at all with the temps at around 205-210 on capullary gauge.

[wayne petty]

the otc and snap on scanniers i have used,  have on most later applicatons, have the ability to override the fan control...for testing...

i have a cheep scanner from actron.. up to 95...  my model is obsolete... but i have not tried to override a later model gm with it...

i use it to look at live data .......

wayne....