AnoxieGTO

iTrader: (3)

Pulled all the plugs and 7 and 8 look like ***.....black as ****......getting no miss fire codes.....this all started yesterday after noon....right after alittle spirited driving....car sounds like crap....(old farm truck sound) sputters and just isn't running worth a crap...... I searched and I'm guessing most of you are gonna ask if its ticking.....but it's always ticked pretty good....so I figure most of you will call bent pushrods or something...but they are brand new (1k miles or so Texas Speed Hardend rods)
Well any other ideas?

Steve Bryant

iTrader: (1)

It sounds like plugs 7 and 8 are oil fouled and you are only running on cylinders 1 through 6 and that's the source of the old farm truck sound.

This kind of diagnostic question should really be raised another forum other than the Advanced Performance Tech Forum which is intended to be reserved for broad theory types of discussions. Take a look at the guidelines for this forum https://ls1tech.com/forums/advanced-engineering-tech/396223-what-forum-please-read-before-posting.html.

A number of us (including me) will be glad to help you. I'd suggest the LS1/LS6 Internal Engine Forum https://ls1tech.com/forums/generation-iii-internal-engine-5/.

Steve

gametech

iTrader: (1)

The last time I had a problem like that was on a '69 cutlass with a high volume oil pump and worn valve guides. If my oil pressure went above 50psi, too much oil accumulated in the back of the heads and drained into the back cylinders. Vehicle acceleration kept the problem out of the front 6 cylinders.

AnoxieGTO

iTrader: (3)

Pulled all the plugs and 7 and 8 look like ***.....black as ****......getting no miss fire codes.....this all started yesterday after noon....right after alittle spirited driving....car sounds like crap....(old farm truck sound) sputters and just isn't running worth a crap...... I searched and I'm guessing most of you are gonna ask if its ticking.....but it's always ticked pretty good....so I figure most of you will call bent pushrods or something...but they are brand new (1k miles or so Texas Speed Hardened rods)
Well any other ideas?
Any solutions?

BADBOYZ28

iTrader: (228)

Check to see if the plug that goes on top of the injector came off!! Its suppose to have clips but if you like me non of them are there for some reason.....lol
I'v had the same problem a few times where they pop off and car runs & sounds like crap.

Steve Bryant

iTrader: (1)

AnoxieGTO
It appears that cylinders 7 and 8 aren't firing. You need to determine whether it is an ignition or a fuel problem.

Tell me about the plugs. Do they have oil on them or are they just all carboned up?
If the car is running and you pull the plug wire off either the coil or the plug, does it change the way the car is running or not? Check this for both #7 and #8 Cylinders. Also, attach a known good plug to the spark plug wire for cylinder #7 and ground the plug to the valve cover or some other good ground (you could use a jumper cable to hold the plug and ground the other end). Do you get a good spark? Now repeat with plug 8.

If you have spark and the plugs are not oil fouled, it's time to look at fuel. But first tell us about the condition of the plugs, etc.

Steve

AnoxieGTO

iTrader: (3)

The 2 plugs are a dry and sooty black....I dont think it's oil foul...they look about the same as some plugs looked one time when the 02 sensors came un plugged......just a dry blackness....

Steve Bryant

iTrader: (1)

If the O2 sensors go bad, are unplugged, etc. the mixture goes rich. If the pintle valves in the injectors aren't moving back and forth, they could be unseated and not cycling causing the mixture to go rich and soot things up too.

What mods, if any, have you made to the car? If you have the stock injectors and are running a bigger cam, you could be exceeding the injector duty cycle enough of the time to damage the injectors.

However, before we blame the injectors or anything else, find out if your plugs are firing.

Steve

AnoxieGTO

iTrader: (3)

Pulled valve covers tonight....a rocker arm on cyl. number 5 was off its rod and all fucked up......I need a rocker arm and the little plate that all 8 rocker arms sit on...drivers side......where can I get these!?

Steve Bryant

iTrader: (1)

I'd check a local salvage yard or just go to a dealer. There are several discount sources that sell parts on line. Was the rocker arm bolt loose? Are the threads in the rocker arm boss where the bolt screws in stripped out?

With this new piece of information, my gut feeling is that the rocker arm issue is the main problem as to why your car sounds and runs like a farm truck. It is running on seven cylinders. Now, from the sound of things (like the plug sooting on 7 and 8), the rocker arm is not your only issue.

BTW, when you install the stock rocker arms use some blue thread locking compound (Locktite, etc.) on the threads and torque them all to 22 pounds feet and rotate the crank half of a revolution. Then repeat the rotating and torquing three additional times. This relieves the valve spring pressure on each bolt completely at least one of the times that you torque.

Steve

AnoxieGTO

iTrader: (3)

good info on crack rotation....thanx.. I don't know about the 7 and 8 problem...........maybe just a ill-effect of the #5 problemo......maybe a tuneing problem.....I dont know....maybe .....

Steve Bryant

iTrader: (1)

What mods if any do you have? Is your car bone stock?

I doubt that the plug sooting problem is related to cylinder 5 or tuning for that matter. The AFR is adjusted for the engine as a whole with the exception that the closed loop function is controlled by the #1 primary O2 sensor for the left bank (Cyl 1/3/5/7) and the #2 primary O2 sensor for the right bank (Cyl 2/4/6/8).

Steve