Spark plugs burning uneven - Pics Included!

ThreeHonks

ThreeHonks

Forum Member
I just got my motor back together and was checking a few things out, decided to pull the plugs and this is what I found:

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I have never seen anything like this before. As you can tell it is a DRASTIC difference. Please pay attention to #7 plug as it is soot black.

What could be causing this? The motor (and plugs) only have about 40 miles on them including some WOT pulls.

DETAILS ON MY SETUP:

-heads/cam LT1
-has the LS1 pcm conversion 24x system
-has NGK TR-6 plugs
-has 42lb. green top injectors
-tuned in speed density by Dr. Phil INTIMID8
 
Put new ones in and if they come out looking the same after a days driving then start to find out why.


If you did any tunning on these and they were used for the intially start up you cannot make tunning or condiational calls off them. Once you fuel load a plug it'll look that way for a long time.

ThreeHonks said:
they are brand new plugs that I put in after reassembling the motor
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igotaneed4speed said:
Put new ones in and if they come out looking the same after a days driving then start to find out why.


If you did any tunning on these and they were used for the intially start up you cannot make tunning or condiational calls off them. Once you fuel load a plug it'll look that way for a long time.
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I did no tuning on these and only drove the car for 40 miles/ about a day.

I talked with PHIL INTIMID8 and he said that if the fuel pressure regulator is bad it will cause the rear cylinders to run rich. I also confirmed this with Injuneer on Camaroz28. It makes sense to me because #7 cylinder is by far the darkest and it is the one that is closest to the pressure regulator
 
I'm not gunna diasgree or agree with that but I do have a questions for you.

Would you rather spend 20 bucks to put fresh plugs in it and re-check/verify the concern prior to changing any parts or just spend X amount of dollars on a new regualtor which I'm sure is much more than 20.00 and hope it fixes it?


They very much could be correct; I'm not arguing that just that I was taught a different way to approach things. If I'm wrong all you've done is spent money on new plugs which can be used anyways. If the regulator idea is wrong your out a much larger amount of cash.

"Anyone can throw parts at something on assumptions but a seclet few find the root problem before attempting to fix."

Gary Hienz - Ford Asset Professor.


ThreeHonks said:
I did no tuning on these and only drove the car for 40 miles/ about a day.

I talked with PHIL INTIMID8 and he said that if the fuel pressure regulator is bad it will cause the rear cylinders to run rich. I also confirmed this with Injuneer on Camaroz28. It makes sense to me because #7 cylinder is by far the darkest and it is the one that is closest to the pressure regulator
Click to expand...
 
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igotaneed4speed said:
I'm not gunna diasgree or agree with that but I do have a questions for you.

Would you rather spend 20 bucks to put fresh plugs in it and re-check/verify the concern prior to changing any parts or just spend X amount of dollars on a new regualtor which I'm sure is much more than 20.00 and hope it fixes it?


They very much could be correct; I'm not arguing that just that I was taught a different way to approach things. If I'm wrong all you've done is spent money on new plugs which can be used anyways. If the regulator idea is wrong your out a much larger amount of cash.

"Anyone can throw parts at something on assumptions but a seclet few find the root problem before attempting to fix."

Gary Hienz - Ford Asset Professor.
Click to expand...

I understand that, but this is my second set of plugs that have had this pattern, so I already "tried just putting new plugs in it"

Here is the first set of plugs (these were in the motor for about 400 miles), so after two consistent plugs burning strange, im sure there is some kind of problem. These plugs are not in order, but the white ones all came from cylinders 1,3,2 and the dark one was from cylinder 7.

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dave89iroc said:
well, you ever check for a leaking FPR?
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no im not really sure how. I took the vacuum line off and it kinda smelled like fuel (which can indicate a bad regulator), but it was not wet.

I remember I was testing for fuel pressure by just "keying it on" and I would have good pressure for a second or two and then it would bleed off entirely. Arent the lines suppossed to hold pressure? Could this pressure bleed off be because of the FPR leaking?
 
ThreeHonks said:
no im not really sure how. I took the vacuum line off and it kinda smelled like fuel (which can indicate a bad regulator), but it was not wet.

I remember I was testing for fuel pressure by just "keying it on" and I would have good pressure for a second or two and then it would bleed off entirely. Arent the lines suppossed to hold pressure? Could this pressure bleed off be because of the FPR leaking?
Click to expand...

key it up with the vacuum line off, see if it leaks fuel then
 
ThreeHonks said:
I understand that, but this is my second set of plugs that have had this pattern, so I already "tried just putting new plugs in it"

Here is the first set of plugs (these were in the motor for about 400 miles), so after two consistent plugs burning strange, im sure there is some kind of problem. These plugs are not in order, but the white ones all came from cylinders 1,3,2 and the dark one was from cylinder 7.
Click to expand...


That I didn't know as you didn't mention it.


ThreeHonks said:
no im not really sure how. I took the vacuum line off and it kinda smelled like fuel (which can indicate a bad regulator), but it was not wet.

I remember I was testing for fuel pressure by just "keying it on" and I would have good pressure for a second or two and then it would bleed off entirely. Arent the lines suppossed to hold pressure? Could this pressure bleed off be because of the FPR leaking?
Click to expand...


If there isn't a bleed back valve on the car no matter what pump it is it will bleed down pressure, unless the pump has one internal.


I'd check every injector circut with a noid to make sure none are stuck on via wiring/ecm.

Check leak down on the injectors to make sure one isnt stuck physically.

You can use a vacum pump with a brake bleed canister on the fuel regulator with the car runiing to check if it leaks thru the diaphram into the vac line.

Once those are ruled out...

Check for vacum leak around intake by the cleaner cylinders.

Check valve lash for consistance across all the clyinders

ect...
 
Thanks. Im going to take a closer look at everything. The weird thing about all of this is it seems like the car is running better than it ever has and it idles great and doesnt stumble or anything
 
ahhh its not uncommon to have distrobution issues with the lt1 intakes. Split block Learn multipliers being the most common offender of plugs looking like this.


does this car run in closed loop with O2 feedback ?
 
ThreeHonks said:
car is tuned in speed density. No O2's, no MAF
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well, something isn't right. if the fuel pressure regulator isn't leaking and the injectors are known to be good and balanced for flow. the tune needs work dealing with distrobution problems. If the intake has been ported it can make matters worse. There are a whole host of things that can and do cuase these problems.
 
Ok I'll ask agian. It has an LS1 P59 controller on an LT1 correct? you need to change the injector to bank assignment. I use one out of a 2002 express Van.
 
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