leonpiper69

iTrader: (3)

does anyone know could cause my engine to fire on 2 4 6 and 8 but not on 1 3 5 and 7?

it ran fine the other day. and my buddy just came home from iraq and wanted to check it out so i went to fire it and i could hear only one side firng and the pipes on the driver side were cold.

i checked the wiring and the pink wires on each coil are get 12 volts so i figure it must be a triggering type issue, but don't know what to check.

Teetoe_Jones

Are the coil pack harness connected to the correct pack on each cylinder?

Tyler

leonpiper69

iTrader: (3)

yeah and it ran the other day so i cant figure out what went wrong?

mmmchickenboy

Correct me if I'm wrong, but each bank of injectors has it's own fuse. So if the one banks fuse blows, the whole bank dies.

leonpiper69

iTrader: (3)

but its not the injectors. i checked it with a timing light and have no spark on the entire left bank. i just cant think of anything that would signal one side to fire and not the other. i hope my pcm didnt die.

leonpiper69

iTrader: (3)

if my batt voltage is a little low could that cause weird stuff like that? i have been running it without the alt connected here and there. and its reading just over 11 volts.

V8Rumble

iTrader: (9)

Pretty unlikely. You can charge the batt. to find out for sure, but I'd think that would affect both sides relatively equally.

I'm still on the "steep part" of the learning curve WRT these engines, but I'd say look at those things where each bank of the engine is handled by a separate part/sensor - things like like coil or injector harness connections, grounds, etc.

Honestly, the 1st question that comes to mind for me is "Has anything changed recently?"

EDIT: Here's a "dumb" question for ya - if you swap the coil harness connection over from one side to the other (or swap coils/parts), does the problem follow the swapped parts? (I'm still in the 'parts gathering' phase of my build, so if swapping coil harness sides isn't possible, try not to laugh too hard...)

Good luck.

leonpiper69

iTrader: (3)

the only thing diff since it ran is i relocated the part of the harness for the driver 02 sensor, because it was down by the alt and i "carefully" cut the old factory tape holding it together and rerouted that.

i looked for any cuts in the wire, my bud checked too and we found nothing.
plus even if i had cut one wire it would still run on the other 3 coils on that side, no?

next im going to trace the 4 wires that trigger each coil from the pcm to the coil and make sure i have a connection, it just drives me nuts cuz think that we will a waste because if one didnt have a connection, again the other 3 should still fire.

maybe i'll just pull my hair out, i need a hair cut anyway.

xssive

iTrader: (123)

Check the coil ground for that side. You could easily pull it off the back of the head when rerouting wires

V8Rumble

iTrader: (9)

OK, I'm not saying that you did anything wrong, but the latest change is almost always the best place to start. Doesn't sound like that should've done it, but...

Unless what was cut was a single path for a common ground, or something similar... (Again, I don't know, just thinking out loud...) If you're able to do a continuity test, that should tell for sure.

(Heh - xssive & I are on the same page...)

Maybe... (I really need to get a shop manual for the LSx engines...) I'm sure that someone will chime in soon who's got specific knowledge, & we'll both learn a bit...

leonpiper69

iTrader: (3)

where is the coil ground for that side? i thought all the grounds were the 3 pcm grounds on the back of the pass head?

leonpiper69

iTrader: (3)

i think my pcm is fried! i have good grouns and 12 volts at all coils. and i checked continuity from the pcm connector to the actual coils and its all good. so the pcm itself must not be telling the coils to fire?