solareclpse2000

Ok guys i got my camaro for sale and would like to sale it running right but icant figure out this misfire. I have ran some coil tests and if I remember front to back driver side is cylinders 135 and 7 and pass side is 246 and 8.... so on cylinders 1 and 7 I have found very weak, erratic spark. So I ordered coils. I have msd coils but ordered stock jus to get it running. So I tookthe 2 "bad" coils and swapped them to other spots. And conducted another spark test. The coils tested fine, howeverthe cyliner 1 and 7 positions with "good" coils still tested weak. Cylinder 1 wouldnt even jump the 35mm gap in the tester most of th time. I have no idea what can cause this. Its deffinatly a spark issue but not the coil. A bad cps would show simliar results over all cylinders. Right? Im just not sure what to do next. What should I test next? It was running fine one day and while driving home it jus started out of nowhere. Serious spiting and sputter, barley idles, completely NOT drivable. Plugs, wires, and o2 sensors new. O also its a 2000 camaro lq4 lower end, ls1 upper
Ecu has been tunned accordingly. Ran great till just one day started doing this

solareclpse2000

ok so here is part of the ecu connector if i test the ign 7 and 1 wires what am i looking for as in a response in a volt meter? i know i can test this against the coil plug on ohms for conectivity. but how can i test each sensor that goes to the pcm to confirm tht the pcm is bad or a sensor? does anyone know the true old school method to do this?

97camaroguy

iTrader: (5)

Have you tried to put new plugs in it, rather than switch out the coil packs?

solareclpse2000

Yes. It has new plugs n wires. As soon as it started acting up those were the first things I replaced and it didnt change anything. I know from tasting that the 2 coils are not actually bad but on the 1 and 7 cylinder the signal to the coil is messed up, its not "telling" the coils to spark properly. I just dont know what causes that. I need to start testing back from th coils but dont know wht exactly to test or how

97camaroguy

iTrader: (5)

Are you getting backfire during acceleration?
My buddy had tightened his spark its down too much and actually cracked the porcelain on the plug which caused it to arc. Check to see if plugs 2 and 7 have any visible cracks on the porcelain

97camaroguy

iTrader: (5)

Sorry 1 and 7**

solareclpse2000

Th misfiring started before I changed plugs. But tht is still worth checking. Also I have a coil igh tester. Th type tht u pull th wire off th plug and plug th tester in ajd it has a clip tyt grounds it. There is a set screw to set th gap, in my case to 40mm. And u see if it jumos ty gap. My 1 cyl barly sparks at all and th 7 cyl has a slightly weak spark at idle but as u add throttle it has points where th spark misses 3 or 4 cyclew at a time. Maybe I can record the test this weekemd and post it on here. I have swapped coils around and still had th same spark results from th same cylinders reguardless of which coils I used.... including 2 new onee I got in today. So its like th pcm signal to th coil is all messed up or something. But th only codes I get are misfire codes. Im sooooooo stumped on this

01WS6/tamu

iTrader: (37)

Strip back the insulation at the pink wire on drivers and passenger side splice a wire on each bank start the motor and jump those wires directly to the battery and then go drive it see if the problem goes away.

IF it does go away then there is probably a wire breaking inside the insulation and it has very high resistance and under electrical load cannot supply enough power to the coils for them to fire properly. Then pm me and I'll see if I can point you toward the splice pack in the harness to begin troubleshooting from.

Been there done that got the battle scars high mileage and or old gm harness' suck these days you couldn't imagine the number of high mileage trucks that have gremlins from wires breaking inside the harness I've dealt with over the years

solareclpse2000

Ok ill give th a try. We r talkin bout pink wire.in th coil harness right? This i believe is th wire tht supplies 12v+ whn th ignition system is active? (key on)

solareclpse2000

gona try and post some videos of some testing. first. this is a pic of the coil spark tester i use. pretty simple most yall should know. set to 35mm gap for testing

solareclpse2000

this is testing a good coil. then one of the bad ones. but the coils have been replaced with no avail. the "bad" coils are brand new ones now. why im saying its not the coils it is th siglna from pcm

ok cant post so heres link, bad coil test http://s947.photobucket.com/user/haw...N2099.mp4.html



good coil test

http://s947.photobucket.com/user/haw...N2098.mp4.html

solareclpse2000

this is a test where is used 2 led lights pluged into the coilpack connector. so this is the flicker of the signal to coil from the pcm directly. the dimmer led is the cyl 1...... it is only slightly dimmer. the 1 cylinder seemed to be sparking better today than privious tests

http://s947.photobucket.com/user/haw...N2093.mp4.html


and

http://s947.photobucket.com/user/haw...N2095.mp4.html

solareclpse2000

and finally these are videos of it running. im so stumped guys and trying to sell this thing. if i can fix this issue i can get rid of it


http://s947.photobucket.com/user/haw...N2097.mp4.html

and

http://s947.photobucket.com/user/haw...N2101.mp4.html




guys im getting pretty desperate at this point. i didnt show an example of cyl 7 spark test but it completly cuts out for several cycles at a time. even at higher rpm

solareclpse2000

o also sorry also tried manual jumping pink wire in harness to no change. still the same. did further testing on the pink wire and also showed 12v the whole time

solareclpse2000

Found it. Busted valve spring, bent valve, busted rocker amd lifter. the valvetrain is all stock will it hurt anything to replace.jus th broken parts woth oem parts?