CAUTION big gremlins problems ahead

[xtreamvette69]

ok i dont know how much you guys deal with head scratching, hair pulling, tear jerking diognosis here or if this is the right section(if not move or remove).
i will warn ahead of time this thread will not be for the light reader(kinda lengthy) but i will do my best to summerize.

now for the basics:
*car is an 85 corvette 350 tpi auto(had running issues previously already (not fan issue just ran rich but then again fan circuit was bypassed )prev owner had cooling fan bypassed(for unknown reason, i originally figured because he wanted control).
*i have repinned the wiring harness from the original 870ecm with burnoff module to the 165 ecm with its individual maf power/burnoff relays.(wiring has been checked, rechecked and checked again. there are no problems with the repinning, its correct)
*tested out all the cooling fan wiring,relay and plug and found nothing wrong with it (no reason prev owner to rewire to switch except the fan was going bad and not working well. assume he thought running it more would help but idk) so anyhow i removed his switched hot wire jumper and his ground from the relay and wired it back as it was supposed to be, upon testing the circuit all works as intended.
*ok so i burn a chip using ARAP bin $6e def changing vats,egr, fan on @ 200* and a little timing(also same results with non modified ARAP bin with only vats turned off)

and now the good stuff errr... bad stuff
ok now i do know my tune is just a basic starter point so not even close to perfect but here is the odd issue.

the engine runs pretty decently with this chip when in open loop and decently even in closed but as the engine gets closer and closer to operating temp or fan turn on temp i should say it begins running poorer and poorer worst happening right around the 200* range before and durring fan turn on time.
it gets running so poorly that sometimes it just hunts idle, staggers , stumbles and dies and other times just insta dies as the fan comes on. i can go ahead and restart instantly after it dies but will only run untill fan comes on again(once i was fast enough to restart while fan was still running and the engine stumbled hunting idle through a wide range of rpm and managed to just bairly stay alive till fan off at that time it smoothed out till fan came on again to kill it.

ok so i was thinking some kinda feedback or ground issue in the circuit because when its stumbling around with fan on if i pull off the relay the engine smooths back to normal for the tune or lack of.
gets weirder because at any and all temps if i just leave the fan relay off and just jump +12v hott from the battery to the fan relay plug(wire going direct to the fan) the engine will do the same thing (stumble, idle hunt, surge etc only diff is at lower temp it will only come close to dying but not quite )

think thats about all i can tell you about the fan gremlin, also adding a couple log videos.
maybe just my tune 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.
http://youtu.be/qun4MJjgj14

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)
http://youtu.be/AkX3SoOx4aA

[delcowizzid]

looks like you are running real rich with blm pegged as low as it can go trying to pull fuel out.and looks like a lot of electrical interferance when the fan starts does it not scramble data if the fan is unplugged when its time to turn on the fan

[1project2many]

This happens at idle? Can you hold the throttle open and keep the engine running?

Suspect out of tune condition combined with additional load from fan is causing lower voltage at idle when warm as well as need for more IAC. Injector voltage corrections may be part of the problem. Attaching a strong 12V charger might keep system voltage high enough to confirm problem is not gremlin but the need for additional tuning. Alternatively, powering fan from external 12V source for short time might allow tuning to continue to get idle dialed in better.

[xtreamvette69]

looks like you are running real rich with blm pegged as low as it can go trying to pull fuel out.and looks like a lot of electrical interferance when the fan starts does it not scramble data if the fan is unplugged when its time to turn on the fan

yep running way rich especially once towards operating temp.
as for the interferance caused by the fan .. yes if i pull the relay all stays well at least as well as eye burning rich can be lol odd though is as i mentioned above even in closed loop when running best if i jumper 12v to the fan wire and start fan without the relay being there, just hot direct to fan the engine and scan does the same as it does when up to operating temp and ecm calls on it.

This happens at idle? Can you hold the throttle open and keep the engine running?

i belive i can although havent tried it recently, will try that .

Suspect out of tune condition combined with additional load from fan is causing lower voltage at idle when warm as well as need for more IAC. Injector voltage corrections may be part of the problem. Attaching a strong 12V charger might keep system voltage high enough to confirm problem is not gremlin but the need for additional tuning. Alternatively, powering fan from external 12V source for short time might allow tuning to continue to get idle dialed in better.

thats a decent idea, but isnt it odd that fan causes same issue even when its open loop and fresh start running decently? maybe not..

i thought this tune should have been close to what i needed seeing how its from a 89 tpi corvette..
oh and i guess i should also note that the car also has an aftermarket cam in it wish im thinking i wish i would have never done
adv dur 288/289, 215/224 at .050, lift is .444/.466 112lobe seperation .
cars timing is at 6*adv as stock but in chip it has about 2* added should note that car runs best with 10*+ with adv wire disconnected, think that may be part of the issue?
also shows best vacuum on vac gauge with 10*+adv

[EagleMark]

Tuning aside there is something wrong with the fan? Wiring? Ground? Electrical noise? Is it pulling so much power that Batt Voltage drops causing ECM issues? When voltage changes it also effects injector Batt Offset table, lower voltage also lowers fuel pressure at pump... What's voltage doing during this issue?

owner had cooling fan bypassed(for unknown reason, i originally figured because he wanted control).
*i have repinned the wiring harness from the original 870ecm with burnoff module to the 165 ecm with its individual maf power/burnoff relays.(wiring has been checked, rechecked and checked again. there are no problems with the repinning, its correct)

I'm not familar with this trick but it seems to be the cause of your fan issue? Maybe check at Thirdgen.org and the stickies, I'm sure if this is a legitimate trick it would be found there with good instructions. May not just be a wiring change, it could also need some hex change to code?

HTH!

[xtreamvette69]

Tuning aside there is something wrong with the fan? Wiring? Ground? Electrical noise?

agreed i figured was some issue here besides the poor tune/log results

Is it pulling so much power that Batt Voltage drops causing ECM issues? When voltage changes it also effects injector Batt Offset table, lower voltage also lowers fuel pressure at pump... What's voltage doing during this issue?

as shown in the logs normally running volts are about 14v at batt and 13.80v at the fp, when the fan kicks on they drop to around the 12.80v area but level back to normal soon as fans running(just an initial startup drop) in log files looking at the monitors though to me the voltage always looks dirty(not nice strait lines but bumpy constantly , not alot of range but not clean looking) of course i have no idea how there supposed to look

I'm not familar with this trick but it seems to be the cause of your fan issue? Maybe check at Thirdgen.org and the stickies, I'm sure if this is a legitimate trick it would be found there with good instructions. May not just be a wiring change, it could also need some hex change to code?

this issue as far as im aware is corrected, i put fan wiring all back to stock wiring going by the fsm all seems to check out correctly and works right. dont know original reason the old owner did it though maybe because the fan was bad(found blown fusable link for it had to replace) also new fan on it now and ecm is a new rebuilt did same with old ecm.

here is a screenie of a log in mon view showing just as the fan kicks on. as you can see even the tps jumps up but all other times it is steady and fluid.

[xtreamvette69]

also i did some further testing and playing around first i tried running car as is cold start fan relay out of the circuit and after ideling fine i jumpered 12v to the fan wire that goes directly to the fan.. engine reved then started searching idle reving up and down and borderline of killing(did even kill a couple times but far less likely to when cold)

also durring above test to answer a previous question.. yes i can give it throttle to smooth it out but if just ideling it runs this poorly till i remove the jumper.

[EagleMark]

Something is wrong, that is a lot of spikes in a lot of differant volts and I'm not sure what's what? What the heck is happening at 11;21?

[xtreamvette69]

lol i know right *scratches head*
anyhow at about 11:15 1/2 is where the fan comes on and the troubles begin 11:20 1/2 i cant remember if the car quit that time and i instantly restarted or not for sure(ok after looking at the log , no that is not where the car quit and i had to restart.. thats just all the activity that happens when the fan comes on and runs ). i could get a specific log with detailed info of whats happening and when if it would help.
i also had a large charger hooked up durring some other tests to keep voltage up and made no change.

here is log from same session further into it where the car quits(the same fan cycle as above but the ending right before engine quit)

[delcowizzid]

is the fan burnt out and taking a huge amount of amps to turn on does it spin easy by hand

[xtreamvette69]

pretty sure a bad fan was what the old owner had that caused him to blow a fusable link and then hook fan to a toggle switch..as the fan motor was still bad(slow and weak) when i got it. now it is wired according to fsm and i put a brand new fan on it.

[EagleMark]

Yeah that looks like it quit... post the log and ADX file so I can look at it live.

[xtreamvette69]

pretty scary squiggly line stuff in monitor mode but ok here it is.
in these logs i had initial adv bumped up (on balancer)just playing around learning and i manually jumpered the fan on direct to wire of fan with no ecm signal or relay in play.
the ones above are with it at 6* as intended and letting the ecm and relay trigger and run the fan.

[xtreamvette69]

full log from above youtubes fan kicks in about 12:00 on this one and i think has a couple on cycles and at least one off cycle. and on this one i know that 12:04-12:19 is an engine quit and restart

thanks alot for looking them over too

[xtreamvette69]

ok about time for an update to this thread i guess, been so busy and working on ZEDRATED's bin kinda distracted me a bit.

but ya i decided to streamline my bin a little, fix blm/int numbers and mostly see if my fan issue is nothing more then just a really bad tune(btw i did not write that initial tune) i tossed that one and this one i made as my base and looks much better already.

get this not only is it cleaner and not burn your eyes rich but the blm/int's look pretty decent and get this... wait for it........ YEP!! thats right fan works no issues without really so much as a glitch on the data.. amazing

i'm including log here and would appretiate anyone that has reviewed my other logs to review this one and tell me if its looking normal. my main question is should things like batt volts, maf, rpm, base inj pulse be jittery/static like that while others are strait like volt at fp, blm, int ? log and adx attached