JTOTHAP

Okay guys I am open for ideas. I have a 1999 C5 with an LS1 and its running on Cylinders 1,2,3,4 and not on 5,6,7,8. You can smell raw fuel and the car is running very rich. It sounds like there is a massive cam in it. I have changed the plugs and wires to see if that was the problem. I scanned it and I found out about the cylinders not firing. All the injectors are working and all of the coil packs are plugged in. There are no codes being thrown at all.

Im open for ideas and/or suggestions. Hopefully somebody on here has had this issue and knows how to resolve it. Thank you in advance.

slowpoke96z28

iTrader: (2)

there's got to be a fuse or something blown if the coil packs are plugged in good at the coils and at the big white connector.

JTOTHAP

Checked the fuses too. I have no clue what is going on. Its frustrating. No Codes, No Lights nothing.

ss_slowmaro

unplug all of your plug wires from the plugs, once this is done have a buddy get a spare plug and attach it to a wire. then have him put it to a ground with you turning it over to make sure its got spark(make sure he isnt holding it if its a GOOD friend). turn the motor over to see if you have spark. repeat the process on all 8 plugs.

If you have another friend with an Ls1 swap over the coil packs to ensure thats not the root of your problem.

Mine did something similar and i had burned and o2 wire on my longtubes and it caused it to miss fire bad

Just my .02

mxjs

iTrader: (13)

My engine was doing the same thing. It was fouling the spark plugs on the drivers side. I opened the spark plug gap from .040 to .055 and they stopped fouling.

JTOTHAP

We did that as well slowmaro and they all sparked. I even swapped the coil packs around and it still did the same. I have no clue brotha. It is really frustrating.

slowpoke96z28

iTrader: (2)

check both fuel injector fuses too then. FWIW, how do you know one bank is good and the other is bad?

cam

iTrader: (9)

Did this just randomly begin or just after you did some mods?

Alt

iTrader: (6)

Hmm, I had an issue like that after I installed my Mac headers for the first time, I totally forgot to hook up my coilpacks on one side. Granted if you're getting spark from each cylinder there's only fuel left to check?

... They are plugged into the right coils yes? I've seen that as an issue as well.

cam

iTrader: (9)

Who tuned it?

jman54002

iTrader: (11)

has there been a fix to this ... I have the same issue... did you find the problem?

eseibel67

iTrader: (10)

If you're running on 4 cylinders, it's usually either left or right since the power supply and grounds for the coils and injectors are split bank1 and bank2.

But you are only running on the front 4 cylinders - 1,2,3,4. Are you sure? This is very unusual.

jman54002

iTrader: (11)

don't mean to high jack just haven't seen the answer yet. but yes it seem the back four holes on my car are not running compelete. The header tubes stay luke warm and the front ones get burning hot right away in 5 to 10 sec.

jman54002

iTrader: (11)

just found the problem ...broken valve spring on #6 cylinder. thanks for all the input guys.