Napster134

After finishing up on some adjustments to my ECM tune I parked the car and took out 4 spark plugs, 2 from each cylinder bank.

I noticed the two spark plugs that were removed from the passenger side were really lean, they were bright yellow/green color while the two spark plugs that were removed from the drivers side were very rich/dark and damp looking.

I was wondering if it would have to do with the injectors, one may be giving more fuel than the other? I have had my injectors sent off and pressure cleaned and flow rated about a year ago and run only premium.

Another thought I had was that the drivers side does have a PVC and the other just has a filter on the valve cover so not sure if it would matter much to cause this.

I am also using a TBI adapter to carb spacer by dctrumpet with a 454 TBI w/ a FP block off and regulator feeding 18psi to it and bolted onto an edelbrock RPM performer intake if it matters any.

and my last thought would be mis-adjusted roller rockers

I dont have much time or money at the moment and just wanted some opinions as to what the problem may be more and likely so I could get a starting point

Justin89Formy

iTrader: (26)

hmm well the ecm is batch fire and sends injector pulse to the entire left bank and entire right bank at the same time. Sounds like something (wiring/tune?) are goofy

Napster134

I do have the EBL flash ECM although I would have to look into the guide to see if there is anything in regards to the way the injectors pulse. I will also check the voltage and ensure each lead to the injectors is getting the correct voltage.

I was thinking of swapping the injectors onto the opposite pods to see if it would cause the passenger to go rich and vise versa

RBob

iTrader: (1)

TBI set ups (2-bbl) fire each injector alternately on each spark plug firing. The actual period of time they are firing can overlap between the injectors.

With the Performer RPM intake each side of the engine has 2 cylinders feed from the same side of the plenum. Put another way, each side of the plenum goes to 4 cylinders, 2 on each side of the engine. Of course, can cut the dividing wall down some, and/or run an open adapter plate. Both of which will cause the plenum to be more open.

To see which cylinders are fed from which plenum need to follow the runners.

As for yellow/green on the plugs, maybe some sort of fuel additive is causing it. For the dark plugs, it may be that the intake gaskets a leaking a little and oil is being pulled from the valley.

RBob.

Napster134

Well I guess it doesn't help that im color blind so I thought I'd take a few pics. I don't have any fuel additives so the yellow green may how I see the lean ones. The colors don't seem to be as exaggerated in the photos as they really are.

The spark plugs are in order as if you were taking them off standing in front of the vehicle. (the hardest plugs to take off stayed in)

Do look like something to be concerned about?


I did notice the runners, seems like the two runners on the outside go to the two outer intake ports on each side.

Then the two inside runners, run underneath and to the opposite side intake ports that are closest to the center of the engine.