16v ECU acting up code 12s with jumper engine won't start

[zukitrek]

Like post says, my 16v is doing something odd. I can get 12's flashing engine off with jumper clip but will fail to turn on with clip inserted.

Runs fine, idle a bit too low, tried to correct it with bleed screw but Im not getting the 7v while setting duty, only 2.20v. TPS idle switch reads close to 0v back probed but reads 200ohms with a .020 feeler gauge. According to specs it should be 500ohms.

Need to remove ECU and do a visual inspection.

Thanks!!

[fixkick]

with the clip inserted, in the diag pins, and it dont start. did you, (does this hot and cold engine?)

1: try 5% throttle while cranking when it dont start , Diag jumpred.
2: check for spark, like , is spark gone?
3: if sparks ok, like that, then try "test fuel"? spray, start now? if yes how long it run or not at all. and with 5% right foot throttle?

these tests, prove what's up. for example is sparks gone, like that, then the ecu is bad.

why not look inside the ECU.? here are the steps.
http://www.fixkick.com/ECU/ECU.html#Removal_of_ECU:


pin 2 to 4 right? jump? not wrong pin... if you have 4 pin DLC then use. B to C pins, type DLC im search box.

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all clues and test matter.
like above. to prove a bad ECU.
and ECU that is crashing is random, the symptoms can be very obscure to total death. (noise on the main internal 5vdc logic bus, is bad news)
I think your ECU is first ever to do this, not start , DIAG jumped
most others the CEL is dead (llamp never glows)
or diag dead full time no matter what.
or 12s come out then die, then came back or misfire.
the not start issues is a first for me, and i scan vast numbers of forums world wide to see the, the odd , is interesting to me.

[zukitrek]

Yes thats what I thought, strange that is because I remember having clip inserted with engine on when I was having the error codes for EGR. Ok will look into that ECU as soon as possible.

Thanks so much!!

[fixkick]

DIAG + no start, is a first time.
never even a Rumor of this.
but i can tell you , i'd be all over spark and fueling and adding fresh air to see what the ECU is doing, wrong. with DIAG added.

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watch out for very tight ECU mounting screws, most are very hard to take out, first time. #3 philips.

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please make sure you are jumping the right pins.

[zukitrek]

1: try 5% throttle while cranking when it dont start , Diag jumpred.
2: check for spark, like , is spark gone?
3: if sparks ok, like that, then try "test fuel"? spray, start now? if yes how long it run or not at all. and with 5% right foot throttle?
Ok will try so tonight.

these tests, prove what's up. for example is sparks gone, like that, then the ecu is bad.

why not look inside the ECU.? here are the steps.
http://www.fixkick.com/ECU/ECU.html#Removal_of_ECU:


pin 2 to 4 right? jump? not wrong pin... if you have 4 pin DLC then use. B to C pins, type DLC im search box.
Yes, thanks for reminding but this has been done before. Mine is a 6pin connector.

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all clues and test matter.
like above. to prove a bad ECU.
and ECU that is crashing is random, the symptoms can be very obscure to total death. (noise on the main internal 5vdc logic bus, is bad news)
I think your ECU is first ever to do this, not start , DIAG jumped
most others the CEL is dead (llamp never glows)
or diag dead full time no matter what.
or 12s come out then die, then came back or misfire.
the not start issues is a first for me, and i scan vast numbers of forums world wide to see the, the odd , is interesting to me.
Old saying never fails: Theres always a first time for everything.

Like we discussed earlier in other thread. All this was about a month ago when trying to look for clues if I had a weak engine affecting tranny behaviour. I will try again tonight to see if this prevails.

Gracias!!!

[fixkick]

that is correct,
the #1 rule in electronics, is never diagnose logic, when the power bus is full of noise.
in fact its the first check,

one other common on cars, Noise wise, is the alternator with bad 3 phase diode pack, if one diode short, the alternator makes HUGE electrical noise
and if the ecu caps are not good, this gets worse.
can be heard on your AM radio , if present.(off station, between them.) IT sings a tone that rises with RPM,

[zukitrek]

TCM was jumpered last week and driven and only got 12's all the time. DLC was also jumpered 2 and 4 and got only 12's key on. I still have the engine shutting off with clip on. That one is still bugging. All fuses where checked sand looked ok.

Ill keep you posted.

Ok fix, this is a post I did from the A/T 4speed fails thread. What was happening to me before.
Now just a while ago, when I got back from work I tried the DLC jumper and 12's all the way but, what do you now? ... car started! So what could have prevented her from starting up last time?
Me, no idea. I did a video of it. Will send later on.

Now what would be next? Those TPS switch ohms look OK to you? I did it with a very warmed up engine. I don't know if that contributes or does not matter?

Javier

[zukitrek]

Here the video i did this evening.

https://youtu.be/pSvJVa7PWkc

Again I hope it sheds some light on this idle matter. You do advise to take a look at the ECU. Will do so on the weekend.

Good night!!

[zukitrek]

the wire is blue-white

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that is wrong.
the diag pin marked diag, must not cause the ECU to go crazy. ever.
both these?
" car would not start or start and shut off if diag jumper was in."
not start with added 5% throttle?

key on CEL always glows, every time?
if you insert the DIAG jumper, and engine stalls can person 2 save said stall with fast right foot actions?
are you sure the pins you jumper are correct, is it 4pin DLC or 6PIN at the battery.

as you can see with a dead ISC , the engine can run or start poorly, .

your ECU is bad. it fails my ECU test page. test 8 fails.
I told you , the ECU can be in diagmode flashing 12s can you can drive anywhere and the CEL flashes codes 12s all day.
this is a working ECU, that can do all its jobs.
if the ecu is crashing , it can not do all its jobs, (spark and fuel are top jobs, inside, but not the others, )
that means that the ECU acts funny , if over tasked.

i can't believe you have never looked in the ECU,
this is like 2nd check day one.
all 89./95 fail for bad caps... (1 time)
the main large corner cap may be leaking.


omg, bad steering wins , over ECU and idle, and brakes when all battles of logic and order.

i cant believe you have not looked in the ECU can.... use a number 3 Phillips to remove ECU screws, and throw them away and use hex heads, 6mm

the lid comes right off, after removal, and like all connectors they are locked and never force them, the lock lever depresses then wiggle the connector back and off ecu.

yes, too many things to do,,,, yes,,,, and old cars are just that.... hard hard work....


day 1: kick checks.
1: brakes ok,, fuel system not leaking , all fluids good. and belts. (hoses too, if 20 years old)
2: front crank pulley 17mm nut at 94 ft/lbs per TSB, or risk crank damage... $400 error.
3: ECU caps good. (look and if see green slime its bad, the if see words Rubycon on black caps, get them the hell out of there. ask for good brand for $1
4: CEL glows key on, turn off running.
5: can drive all day with diag pins jumpered flashing 12s all day... the proof that ECU is solid, and not gross errors. (this ecu can find minor errors ever, Egr excepted)

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the ecu can even , stop mid stride, flashing out a DTC code. the 12s (if it has 12s now) must flash out in perfect cadence.... not skipping a beat......
if skips, or dies, doing that, this means the ECU just crashed.
seen many do that.... and cured all.

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you do know, that limphome mode cancels idle ISC controls ,right?
since 12s fail, that means its in backup mode.
when the ECU fails it can go to limphome or backup. mode. both kill idle, but runs, some think running in both modes are fine, many do.... like lawmmower
burning fuel like crazy.
limphome mode is mimic mode, the ECU knows a sensor is dead, do goes to limp (failsafe)
but if the ECU main processes fail.... the ECU drops deeper down, to backup mode.

backup MODE, causes the CEL lamp to go DEAD. and most sensors are now simulated, and does this , so poorly that the engine floods, (your stall?)
backup mode is lawn mower mode, no spark advance, radical crude injection rates, even to the point of TPS angles = injection rates, yes, crude as hell.
backup mode is just last ditch effort to get the driver out of trouble. its not there to run to the store, or go on a trip.
its for like for , backing out of a snow bank and not get Carbon monoxide poisoning or the like.

Most these 90s (early) ecu have all failed already and are already fixed with new caps. 2nd reason to look day 1. is just that...... what is there, names....on those cans...(caps)
if yours is still original and virgin, i have zero hope for it. (not ungraded) (repaired)


now what happens with a dried out corner cap,
the on board, voltage regulator , drops out. this cause the 5vdc logic power to drop and return, then the processor reboots. (jumps to 0 addr)
or drops to backup mode, or failsafe. or bounce around in 3 different modes. lost... trying to recover for loss of main power.
this can happen many times a minute, and why the 12s drop off line. (means goes dead, or the 12 pulses are corrupted in some way)
the regulator can in fact drop out , in the middle of a boot cycle. and stall the engine.
really , having a bad power source to any computer is a very very bad thing.... (to you its just a bad ECU,)

exhibit 1:

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replace c103. if its black or shows signs of bulging or, cracked or see green slime below it.
or replace it for JUST Cause.
it is polarized ,means it solders down only 1 way, plus to plus. (minus to minus)

this drawing , identifies all major parts that fail, caps and all output drivers. (driver transistors can blow up, easy,)

some caps just dry out, with no warming, or signs at all (visual)
my ESR cap meter finds them bad, 0uF, crazy high ESR.

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many parts on this PCB can not be bought today.

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the idle switch is GOOD.
but the ECU is bad.
my duty page lists over 18 ways for the regulation of idle to fail. lots of ways.
but if you had a scan tool?
and it was connected.?
you'd see communications going dead. as car ran. (this is the ECU CRASHING)
just like that deal with 12s failing, that too is crude form of communications (human to ecu)

ISC is last , to work on all Suzuki's these year.
dead last.
and is because we are ignoring all other bad signs. code 12s and the stalling.

if the ECU does not like the diagnostic jumper, that means it got ISSUES.
the ECU does jobs (tasks) on priorities. (how ever crudely) If the ecu crashes (caps bad) the ecu reboots and sees thin rpm very high (its running still (coasting to stop possible) its first job is to get spark online, then fueling, back
and the Diag pin is on the last end of list to work. and can skip this.

the Diag mode failing tells me the ECU is overtaxed, (crashing tops list)
we have seen 12s even skip mid stride. 1/2 flashed out. and doing that over and over...

we should not even bother with the ISC, on this sick ECU,
idle controls are the last thing to calibrate... dead last. and we must not try.
not now.

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time to start a new post
my 16v ECU is acting up. code 12s, fail, code 12s, on demand cause engine to stall. Diag mode FAILS.

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bad caps
and with gross damage from leaking caps, due to acid spill inside ecu. as is common.

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your doing great.
got new tranny
new steering.
now we can fix the ECU..... everyone does this 1989 to 1995
i had a brand new, ecu (nos, new old stock) not long ago, in hand, a 1992, and the caps were all good.(tested)
this ecu sat in and air conditioned warehouse for (20+ years)
it had rubycons on it, and were the first ones I ever saw to be still good this old. (id still replace then with nichicons)

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Please do start new thread. Remember I did get 12's flashing but with engine off. It was only when attempting to start that it would not. Odd that is.

Some more results from TPS Idle switch.
Without feeler gauge=130ohms
With .020 feeler=202ohms
With .026 feeler=infinite.

Will read your last post later on. Got go to work. Thanks!!!!

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look close at the caps.
some have tiny cracks, , top bulging, bottom rubber plugs ruptured,, ?
seen tiny side volcano's on them. see them explode(have photos) some versions mounted (no X on top) too close to PCB can explode. (aka; violent rupture)
the green acid spill (boric)
the acid eating copper traces, turning green too.
traces missing below cap.. (traces are the copper circuit paths)
the name rubycon, and the hit the trash fast.... and Nichicons stuffed in, low ESR, high temp rated.
these original caps have no X's on top of cap. the X are weak points added later, after 1995, ? "a better design"
the X's are to cause the acid to go UP. and not explode, and to hopefully send the acid to the lid and not to copper traces.
so the X Tops, are much better, if not there already.

always buy new stock caps.
do not buy NOS, 2000' year caps, as that was the bad caps years, (china cloned knock off)caps. that all failed. this is covered in a long WIKI.
buy new ones from MOuser. (fresh as a daisy)

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i told you why, the ECU is vastly more busy, running, key on, it (ecu) does almost nothing.....
the processor just loops, key on, doing almost nothing.
your ECU is bad.
it fails , running , not key on, running is what matters, with the ECU very busy...
id guess, c103 is bad.
replace, it for a buck and see.....

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12s must flash key on,
and 12s must flash running, endlessly and not break up code 12, the cadence is perfect.... flash, pause flashflash, repeat, no skips or hickups,(or other codes too. takes careful watching ....)
even all day running,12,12,12, endlessly. all ECU do this (usa <1996)
if not the ECU is BAD !

(well, the ground to the ecu might be bad, or power feed to it bad. even loose rusty fuse powering the ECU can do this) ig-coil and FI fuses
if power to ecu is good. the ECU is bad.

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the ecu has many pins
one guy had a car with hacked wiring (remote start bs) pin a2 cut.
and the start pin on the ecu was at 12vdc all the time (wrong)
this causes the ecu to think, gee, cranking all time time....
it started but this logic pin, was wrong, confused the ECU.
some times, all pins on the ECU need to be check for wrong logic, or levels (sensors))

my ecu page links to this page,
that covers all that

http://www.fixkick.com/ECU/16v-ecu-pins.html

[fixkick]

the TPS page explains that.
ok, the switch is not really a gold contacted switch
its a carbon, switch, (never reads 0 ohm like gold does. )
but reads less that 500 ohms... it only needs to that.
the voltage at zero , wins all bets, as that is what the ECU uses, volts. E= I x R. (the I part, is very low current)

the jumper is harmless... the ecu just takes that as a side job, (do all else first. (spark , inject ,etc) and do this diagnostic as side job , it must never stall the engine ever.
if it does, (is spark gone? is fueling halted, is the engine flooding? 1,2,3, I check that fast. to see what's up.