oddly unique querk? for lack of a better definition..

not sure if this should be in scan/tune or here but i think its mostly tech issue and not scan related but you be the judge.

guess you could reward the question of the thread to be car quits once it gets to operating temp, but i feel the log helps to better explain the happenings.

i'm using tuner pro rt v.5 .. and as alot of you already know this is on a 85 corvette that has been converted to running the 165 ecm ARAP bin $6e def mask.

i get a few random DA data errors while scanning but not many till car starts getting warm which i will explain in a bit
what are these errors and what causes them? i am assuming they pop up when for a split second the data isnt flowing and in a split sec it resumes its connection. but what causes this? or is it common? i read a few probs with the 165 ecm's and logging..

could this be a grounding quirk with the ecm or a power querk with the ecm? nothing leads me to belive either of those are an issue really but its possible because after further testing(only tested this far once so could just have been coincadense but i dont think so) anyhow the errors seem to get more frequent as the engine gets up to operating temp and even more frequent as it climbs a bit hot and at about 217-220*F tuner pro just stopped renewing data and just sat saying connecting... then shortly after the car just dies, restarts just like normal but dies after few seconds(will do this many times, i tried 3 )
also i used infered temp gun and engine was like 127*f by the ecs and around 130*f at the heads. any ideas?

also should note that once cooled off a bit all is back to normal. now i only had it do this once so far but also is the only time i have let it get that hot.

i would still would like to know what causes the few random DA errors as well.....

also should note this was all durring a recorded log, i dont know if that makes a diff or not in amount of errors or not but figured i would mention it.

 

ok so after alot of logging trying to watch this problem happen and alot of tracing and diognosis i think i am getting this issue simplified and cornered but now just cant seem to visualize why its causing the problem..

summery:
ok after trying out a new chip with lower fan on temp, i finaly think i have cornered it. the problem of engine running issues happens just as the fan kicks on(didnt associate it with fan turn on befer because fan was off waiting for replacment)
so yep seems pretty simple right, cts tells ecm temp and ecm checks and says ok time to turn on fan and sends the its signal to the relay and fan starts... this is the exact time the ecm starts running the engine all crazy(hunting idle, running rich, burning my eyes, stumbling idle, etc etc) eventually killing engine.
while the ecm/engine are acting up lets remove the fan from the situation(remove the fan relay) bingo.. engine goes back to running properly, log data goes back to normal etc.. plug relay back in and fan starts and engine and data go crazy again(once the car just instantly died the second i plugged the relay in...
now your thinking that seems simple enough right, but wait it gets wierd.... have the engine running with relay unplugged all is well, hook jumper from the battery + to the relay plug terminal that goes strait to the fan, fan starts but again engine goes wacky and log data crazy again..

so ok my conclusion is that the issue is that the ground side of the circuit is the problem, but where and why? is the current draw of the fan on the grounds just taking away needed ground to other things? ground for fan is right by in on crossmember which hooks to frame and battery has a ground that also hooks to same frame rail so i dont see much chance of this part of the ground circuit interfering with other things though..

any ideas now? any at all?

 

Please see if this helps:
http://www.scotthansen.net/images/fanrelay.jpg
http://www.scotthansen.net/images/fanrelay1.jpg

 

sorry, that doesnt help.. my relays are norm open and all working properly, the fan stays off till it is supposed to then comes on fine so fan operating correctly.


[maybe i explained wrong in my mail to you. fan only came on with key the once after the chip swap but i reset ecm and all was fine with that]

so anhow yes relay and fan work correctly but when it does kick on it makes the engine run poorly, data errors on log software like mad and eventually makes engine die.

also have log if that might help anyone, hard to catch whats all going on as data connection errors are going on too durring this time.

 

The IAC should anticipate the fan activation and add 5-10 counts to handle the additonal fan load.

Take a look at the fuel pump voltage signal in your datalogs when the fan is activated. This signal is the primary input to the injector voltage offset compensation, so if the fuel pump voltage signal is changing, the injector pulse width offset will also change. This may explain the rough running.

You can compare the fuel pump voltage signal the the battery voltage signal in the logs. Both should be similar, but if one signal is more stable than the other, it may be a better input for the injector offset.

You also may need to fine tune the injector offset table to improve the behavior, if you're getting a large voltage variation with the fan on.

 

hmm thanks very good info, just looked over my logs and compared with my notes of when every behavior was happening and my batt stays pretty steady at 14.00v (slight fluctuation as idle fluxuates)
and steady 13.80v at pump (slight fluctuation as idle fluxuates).

will have to do some more logging as time permits i guess taking better notes on the running times that things happen so i can catch the issue better.

 

It sounds to me like the quad driver for the fan relay is getting overloaded and signaling a high current problem. I don't recall offhand exactly what that means to the ECM code or hardware. I do know there is an interrupt from the quad drivers to the microcontroller, so it might be putting the microcontroller into a weird mode. Later years would generate an error code when there is a quad driver fault (and even tell you which one is having a problem), but we're not that lucky with the 1227165 ECM.

I suspect the ECM is turning on the fan, seeing high current and turning it off and then turning it back on again, setting up an endless loop of glitches.

Try replacing the fan relay and see if that fixes the problem. You could try measuring the resistance of the relay coil. Most of the relay coils in our cars are around 50 ohms. Anything much lower than that is a problem.

 

58.4 ohms
and maybe i didnt explain this well enough, the fan doesnt go on and off randomly, once the ecm tells it to come on it does but the engine starts running poor, idle hunting, surging, full rich... pull the relay off and engine goes back to normal smoothness.. oddest is that when i leave the relay out and just jump 12v pos. to the relay connector plug wire that goes to fan the engine/ecm still reacts the same running poor, idle hunting, surging, full rich... disconnect wire and clears up.

i also should note that this is a new rebuilt ecm i am using in it now and same issue as old one still

 

time for an update and some additional info i guess as i cant seem to figure this out... tracked wires, checked powers and grounds, even cleaned some grounds as well as even added some and still no improvment.. may be just my tune at the higher temps is just soo bad by then that the fan just pushes it over the edge?

anyhow like i said take the relay out of the equasion and the problem goes away but if you jumper hot direct to fan wire(relay still out of the equasion) problem still happens(although i never tested this jumping fan on at lower temp just once its up to the 200+* area)

anyhow here is a log with voice documenting and telling whats going on and when(how its acting and whats going on) but for some reason the audio seems out of sink(way late of the events) also its kinda long (20mins)so feel free to jump around.

this video documents everything from initial cold startup to the fan kicking on and killing engine then a quick restart up to fan coming on and killing it again.
and this one is a line trace version of the log playback(much shorter as i paused and scrolled through the traces trying to show problem areas only)