1997 engine missfire

[MP2]

howdy, I just bought a 97 Pontiac sunrunner 1.6 16v. ive been trying to repair an engine miss. it runs flawless at idle and pulls good to any gear or rev in neutral, to about 4300 rpm then the ses light flashes and the motor cuts out, it comes back on in an instant and misses again, if I hold the throttle down it will rev to 55oo+ at this point with all the missing the exhast smells pretty gasy. I tried to capture the miss on a live link dtc reader, but as soon as it misses the data stops. it has lost communication twice with the reader and is very slow to set up a link. ive installed new ngk wires and gapped the plugs. the issue disappears as soon as the revs drop below that 4300 mark and all is well.
as the miss is a complete 4 cyl non fire im looking at things common to all 4 cylinders, like bad crank sensor, ignition coil, etc. or could it be computer rebooting? only dtc logged was for p0400.
thx j

[fixkick]

in retrospect, my not asking for photos if this engine, engine serial number, and VIN was my failing..... I do know better.....

howdy, I just bought a 97 Pontiac sunrunner 1.6 16v. ive been trying to repair an engine miss. it runs flawless at idle and pulls good to any gear or rev in neutral, to about 4300 rpm then the ses light flashes and the motor cuts out,
SES flash, is a warning that the CAT is about to burn up. (never seen this on a canada car, ever. but is a USA spec, ECU feature)
It means gross misfiriing and or very rich running. (this can melt the CAT fast)
Do you even still have a TWC CAT?

it comes back on in an instant and misses again, if I hold the throttle down it will rev to 55oo+ at this point with all the missing the exhaust smells pretty gasy. (rich black smoke, gross misfire, it is)

the ECU will P0300 (or close) live, or in pendings section of scan data.



I tried to capture the miss on a live link dtc reader, but as soon as it misses the data stops.
BINGO (lost electrical power !) you need to monitor vehicle main electrical power, I bet its NO GOOD. these cars have no dash voltmeter like newer cars.
this is a bad thing, no gauge. so add one, one way to do that , is put a pig tail, lead, cigligher plug into the cig lighter, port.
then the wires connected to any voltmeter. DMM set to 20v scale?
now when it misfires, see that voltage drop like a stone, this kills the ECU, and the scan tool, neither can work much below 9 to 10 v.
the lowest voltage allowed on cars is 8v, the starter solenoid , on all cars, die at 8v. but the ECU can die before that. point. (old cars)
the top failure for all kicks is on my power page, bad power. ever see that? at the fuse box on right fender.
http://www.fixkick.com/electrical-failure.html



it has lost communication twice (LOST 12v power !!!!!) with the reader and is very slow to set up a link.
my 96 the scan tool works 100% just key on , not running,,and will run like that for ever, battery willing...(or charger connected)


ive installed new ngk wires and gapped the plugs.
the issue disappears as soon as the revs drop below that 4300 mark and all is well.

as the miss is a complete 4 cyl non fire im looking at things common to all 4 cylinders, like bad crank sensor, ignition coil, etc.
or could it be computer rebooting?
only dtc logged was for p0400. (egr, just defeat it ,
make sure the EGR closes 100% and defeat it closed, until such time as you fix real problem)
thx j

bad power. for sure.

I have a special fuse (ATC) that allows me to monitor voltage at the fuse. or current
I then monitor the IG-COIL fuse, this is ECU power. and ignition.
your ecu gets power from the blue-black wire feed, (pins12/13 ecu) the FI fuse in the fender fuse block supplies that.
The IG-coil fuse in 96+ runs spark , and the main relay, if IG-Coil fuse drops volts the main relay drops out with load CLANK, engine dies, and dash goes dead.
So IG coil power dropping out MAIN, kills dead FI power. see that fact off 1 of 3 pages on my schematics page.
this page is called LEFT (fully horsed up, with comments,,,)

[MP2]

thank you for this reply, ill see what I can do to monitor voltage, would there be a better place to pick up volt reference from
j?

[fixkick]

the 97 , ECU/PCM has changes. they moved the TCM , on board the old ECU. no more stand alone TCM in 1997
also ABS makes big changes, if opted.
none the less
the ECU will crash if fuse 2 fuse feeds drop voltage, (bad connections or even bad battery terminal lugs. for rusted fuses.
fuse FI on the fender box, called box1 or MAIN by GEO ro Suzuki.
the IG-coil fuse is above left knee (LHD) and must never have voltage drops. bad connections.

The scan tool will crash too, for these reasons: DLC is that which the scan tool plugs into, 16pin OBD2 DLC is what that is.
1: lost ground at DLC (pin 4/5)
2: lost power at DLC PIN 16 VIA fuse 11. (this is scan tool power.)
3: lost power from IGcoil or FI feeds, will cause the comm lines to drop dead, as THE ECU goes OFF LINE. (AND misfires, and or stalls.)

[MP2]

what about just running another +12v fused from the battery to pins 12/13 and a separate ground from the battery to the correct grnd pins in the ecu (which pins are ground?). this way ive bypassed all the potential bad spots.

[hatchetman]

never ever hot wire any ECU. (that is rule one, why risk it, its $500 used and $1700 from suzuki new)/? why zap the most expensive part in the car.?

there is never a reason to do that.
and you missed most the pin there are many that need power. not just 2.

ever use a voltmeter before?
connect it and watch it.
if it glitches as the ECU drops dead, and the scan tool drops. then move the test lead upstream.

Id bet if you look under that fender fuse box, it's a mess. right? all salt belt KICKS fail for this. all of them... (shock tower can leak salt water there)
you are in the salt belt. right? all roads ROCK salted with NACL , on the winter roads?

just inspect all connections from battery to the fuse box, under box. across fire wall and then to fuse box 2 in cab.
is there damage, and the green slime? or hackers damage, i inspect my cars for any thing like that. I look for abnormal first.
may cars this old are hacked for a long list of crazy reasons.
remote starts
audio
alarms.
tachometer hacks.
the list goes on, but in 5min i can see that damage, oops, another hacked up car. (electrical)

that is first. then the battery minus lug off next
then looking under the main fuse fender box, oops, the green slim of salt hits copper......
suzuki even still sells the box new. amazing , and dirt cheap. unlike most other things.
like $15

[MP2]

the vehicle has been continuously registerd in alberta canada since new. I don't believe we are part of the salt belt. will hook up the dvm and see what it shows. thx

[fixkick]

this does not have to be hard
if the power glitches or drops in the cab, the check the FI fuse at the fender for that drop
if it drops on the inputs side of the fender box.
then its bad battery cables or grounds. (all grounds must be good , off my bad grounds page)
even a bad alternator can glitch out the main fuse box. because it sits right there.(has its own fuse, drive with it pulled? for 10min)
if the main is good (fender) no glitching and say the ECU sees glitching
this can be a bad ignition switch (got 100 keys on a ring> guaranteed to wreck any ignition switch)

if the IGN switch out side is good, it can be the MAIN relay is dying.
input to MAIN relay good, out bad. (12v across coil full time)
The voltmeter will find the 2 points of proof, good here, bad there ,so the part between is bad. (voltage drop)
I hope this helps you.


my comments are for cars worth more that $50 and is not a swamp buggy or field hand stump puller, and that it has great value to you and you don't want to make it wor$e.
some folks may have other ideas. that is ok too.

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between 0 and -10 degrees Celsius Alberta for example uses SALT.
ok, how to find the glitch.

i connect my meter with a long wire to the battery minus cable, this allows me to see GROUND FAILURES INSTANTY (keep it there at all times testing)
then connect the red lead of said meter to the CIG lighter. (using a std, adaptor , got a box of old CEL phones. and 100 car adaptor, bingo free parts...) i save them all, those cables, just in case.
The cig center pin is hot, the shell is ground, for get this ground.
red meter to center cig. pin, the center is HOT. test there.....!!!
key on 12v. (12.6v is perfect) is this a 2 door rag top car? is the fuse holder corroded from driving in the rain?

engine running. (14.6v (no lower that 13.3. or alternator is dead) 800 or more engine RPM.
engine misfires, did voltage drop below 12v at any time,, that is a glitch if below 10v, big time bad that!!!!
if the Cig goes dead. or drops or glitches ,that means the power is bad, new cars have a gauge and you see the needle drop fast.

we have 2 paths here.
its ok, or not ok.
lets work not ok, it gliches. IF the CIG glitches that tells me , MAIN FUSE box is GLITCHING.
i check the fender box next.
http://www.fixkick.com/power-elect/96fuse-map.jpg
see that?
see FI ? if FI glitches, DOOM. a hopeless case and future, it will get worse. all bad connections love to get , worse (entropy always wins , car, or Black holes, etc)
The red test lead is clipped to , the FI output wire.
then fuse 3 IG this wire runs the whole cab fuse box, neither can be allowed to glitch.
glitches are only legal 1 way and that is cranking, we are not cranking we are running and voltages are 13.4 to 14.7 , in that band at all times. out of that band is a GLITCH.
the word glitch means an abnormal voltage transition. (a drop out ?)
if you look close to the fender box. there are many connections to it, it runs the whole car. every inch.

when power is bad, in any car the first place to look and test (after the green slim inspection , SALT DAMAGE and HACKER damager)
is to look at chapter, 8A-10 called power distribution.
its here (at ACKs FAQS)
http://www.acksfaq.com/96-FSM-v2-8A-10_pdf.htm
see that first page? see the fuse box?

see the white-green wire at pin 2, that is IG. (main to cab)
see the black-red wire that is FI, (main to cab)
neither of these, must be allowed to glitch, do not accidentally ground out any of these wires, or the hard to find fuse blows or it catches fire. there is 600 AMP there. respect those amps.

ever kick ive ever seen or touched or helped on,
I pull the battery minus, lug.
then invert that box #1 , and look for the green SLIME, this any time, i see main power glitching. and if in a SALT belt , times 1000 that idea.
really. in fact it should be in the service list.

if those 2 points dont glitch then it must be in the cab wiring.
repeat the tests at (red test lead on meter)
at
IG-COIL, a glitch here, is a bad ignition switch. see fuse marked IG-coil see wire with color marked. black-white ( black solid with white stripe, dots dont count)

if this wire glitches, try a new fuse. here. they can look ok and not be ok, for sure.

looking at the same FSM drawing above, see that wire from IG, going to the ignition switch., if it glitches and the white-green input to said switch is good, then the switch is DOA.

I will not pretend to know what is bad, any thing can fail (entropy is a beach, no?), but the tests are easy if the car fails fast. more random failures takes patience.

now lets talk bad grounds.
if the ECU case reads (red test lead touching it) more than 0.5vdc at anytime,then the grounds in the car , are bad.
that is a whole other set of tests.

look for melted body grounds. g105 or 6? that means the battery cables are failing and this weak ground burned up in do to the electrical law. of currrent seeks the least path of restances.
the starter to batter minus cable is bolted to the top starter bolt ,if the salt is bad, this fails and the other grounds smoke.
here are the critical grounds, and varies by body type ,not stated.

http://www.fixkick.com/Good_Bad_Ugly/com...lures.html

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got slime, the green death of copper oxide?

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when you drive north, this happens.
snow/ice and salt

i spent a long time at sea, fixing navy electronics, its 1000 times worse.

[MP2]

I have batt volt 14.4. this is at cig lighter and other points, no glitch when missing. I checked fender fuse, there was a minimal amount of corrosion on fi fuse I cleaned this no change. I jumped a 15 amp fused power to the cold side of the under dash fuse panel, this should eliminate any chassis wiring, ig switch, etc, no change. where is the main ecu relay located? could this be a bad ignition coil? an open circuit at a certain engine rpm frequency? although that wouldn't likely be as consistently intermitant as this is.

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found the issue!!!!! with the help of the most excellent fix kick .com site!!! I was looking into limp home and crank angle sensor info. I was looking for a cas on top of the starter, and here it hides under the front crank snout. so as a lark I unplugged it, and it started, ran fine, ses light was on, logged a code for no cas, pressed the rev pedal, and bingo 6500 rpm no misses!!!! so just to confirm my crap luck, I plugged the sensor back in and 4300 rpm ses comes on and a gross misfire, unplugged it again and revs free. off to buy a new crank sensor. thank you very much for your help.
j

[fixkick]

Contratulations! I hope.
The ecu will report a bad CKP, crank sensor, if it is hard failed or 1 misfire in 8 signal.
P0335

this new sensor added in 1996, is what allows the ECU to see misfiring and report it, P030x (0 = random, 1,2,3,4, cylinder specific)
this failure will not correct bad communication to your scan tool , (clean 12v does that)

unplugging CKP, that may cause limphome, and in limp home, the ecu will use all new tables, and such. hiding other serous errors.
CAS crank angle sensor, or CAS cam angle sensor is CMP. a dead CMP kills all spark, a bad CKP, can be only limphome or cause misfire. a dead CKP will not kill starts.

case in point:
motor is way lean , and misfiring.
force limphome, and motor goes rich hiding the TRUE failure.

may folks fail to realize what limphome is, or how it works.
take the case of a good maf, and a huge air leak,
motor is lean, (big leaks here; do that)

so owners unplug the maf, this in fact does 2 things. it causes limphome, and MAF mimic that is a virtual MAF simulation ! and goes way rich, (BY design)
the reason limphome goes rich, is because it cant go perfect with no maf, so goes rich to avoid engine KILLER LEAN.

by design. they have no other choices.

but pulling the CKP is a great test , too is the ECU many not show a fault for all types of CKP failure, what if it sent too many pulses?
I think too many pulses, cause, P300s. (keep in mind the CKP is what measures crank velocity , the key player)

What if the timing belt was never changed at the 60k limit. and is now slipped. and compression is low. (ever do compression?)) not at 170clog or 185psi warm to hot>
and then the CKP is not firing totally wrong. due to cam timed wrong. The ECU can not figure that out, not now , not ever.
the compression is the first test.
so is checking spark timing, and unmolested engine, will in fact show huge spark time errors when the belt slips.
in cases where the PO found that error in dist. timing and corrected, that, he just hid the cam error and 2 wrongs dont make a right here,
that folly, is way my helper made the sneak-a-peak page, to check cam timing, while ignoring the dizzy.

limphome does go rich
limphome does mimic bad sensor
limphome just to do 1 thing , limphome .

without limphome, many or most EFI failures would result in engine stall. (or worse) (like racing ECU's , they only work when all is perfect)


since comms are/wer lost, i bet you missed most of the errors the ECU was sending you... I tend to fix that first, so Im not working blind.
ive only seen one comm loss ever, and only a few from friends (1996 ecu and newer) bad DC power. in all cases . (or crap scanner (china no name , missing the term resistor R36? )
did you know there are vast ELM327 China illegal clone scanners missing R36, (buy a real scanner) its the term resistor for comms.
i run scantool.net (have all 3{wired/blutooth-wifi) scan tools. and they never ever fail. (zero cloned parts, inside!)


i do hope the CKP fixes this , i do








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