1997 engine missfire

[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,,,)