Split injector O-ring
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Joined: Feb 2010
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From: Metairie LA
Split injector O-ring
I've been data logging and tuning (with mseven's help) since I changed over to the Stealth Ram. My BLM's are 128 finally, but I have a wideband O2 in the passenger long tube collector (same location as the stock O2 - which is now heated). The wideband is almost always on the lean side, 15-16's. I resealed the collectors last week and rechecked the whole exhaust system. No leaks - no noises.
Decided to do a little investigation this afternoon to find out why. Went to pull the passenger side plugs (Autolite 3924 as per head mfg.) and noticed that the fuel injector o-ring for #4 is completely split and the others are all cracked and splitting. These are the o-rings that can be seen where the injectors enter the manifold.
Would this cause lean running? Isn't there another o-ring further toward the tip?
How does the #4 plug look?
The others look similar - dark on one side and light on the other
Decided to do a little investigation this afternoon to find out why. Went to pull the passenger side plugs (Autolite 3924 as per head mfg.) and noticed that the fuel injector o-ring for #4 is completely split and the others are all cracked and splitting. These are the o-rings that can be seen where the injectors enter the manifold.
Would this cause lean running? Isn't there another o-ring further toward the tip?
How does the #4 plug look?
The others look similar - dark on one side and light on the other
Last edited by cgantner5150; Jan 8, 2012 at 03:16 PM. Reason: Redirected photobucket link
Thread Starter
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Joined: Feb 2010
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From: Metairie LA
Just spoke to Jon at FIC. The o rings in question are not a problem and according to Jon are probably not needed on the Stralth Ram (injectors don't need to sit as high as on a TPI or LT1 - good info to know that I didn't find anywhere else). The lower o ring (unseen in the manifold) provides the seal. He did offer to send me another set.
Going to try without and see.
Thanks again Jon for answering my questions and easing my mind. It's good to learn at least one new thing per day.
Now, on to the look of my plugs? Any input.
I have a feeling I am running a bit lean.
Going to try without and see.
Thanks again Jon for answering my questions and easing my mind. It's good to learn at least one new thing per day.
Now, on to the look of my plugs? Any input.
I have a feeling I am running a bit lean.
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From: Overland Park Kansas
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Yeah...the light color on the tip of the side (ground) electrode is on the light side. Seems to indicate a bit lean. It might also be burning a bit of oil as indicated by the black on the outer ring.
Is this an L98 where you're getting 128 BLMs from the DS O2 feedback -- while getting higher AFR thru a WB on the PS?
How do the plugs from each bank compare to each other?
Is this an L98 where you're getting 128 BLMs from the DS O2 feedback -- while getting higher AFR thru a WB on the PS?
How do the plugs from each bank compare to each other?
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Joined: Feb 2010
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From: Metairie LA
It was an L98 - now its a 385 Stealth Ram. This is the second set of plugs so far since the rebuild (start up 02/11). The first set with the converted LT1 intake looked the same (they are dark on one side and light on the other). Not missing any oil or water - no smoke or odd smells out of the pipes. No missing or stuttering - runs damn good. Vacuum gauge at idle is 14-15. Wondering if my wideband or narrowband is accurate. The only way I can get idle to calm down is if my BLM's are 121 in cell 0 - then the wideband shows 14-15. Smells pretty good at idle, too. They do seem to agree but not in the same range - if that makes any sense. It seems that if my BLM's all were at the 120-121 range the WBO would be at 14.7.
Played around with the tune some more today (AE fueling) after removing the broken O ring completely. All is good - checked for vac and fuel leaks - none found.
Going to change plugs one again this weekend and take a look.
Played around with the tune some more today (AE fueling) after removing the broken O ring completely. All is good - checked for vac and fuel leaks - none found.
Going to change plugs one again this weekend and take a look.
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Race Director
Joined: Nov 2003
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From: Overland Park Kansas
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Wondering if my wideband or narrowband is accurate. The only way I can get idle to calm down is if my BLM's are 121 in cell 0 - then the wideband shows 14-15. Smells pretty good at idle, too. They do seem to agree but not in the same range - if that makes any sense. It seems that if my BLM's all were at the 120-121 range the WBO would be at 14.7.
Played around with the tune some more today (AE fueling) after removing the broken O ring completely. All is good - checked for vac and fuel leaks - none found.
Going to change plugs one again this weekend and take a look.
Played around with the tune some more today (AE fueling) after removing the broken O ring completely. All is good - checked for vac and fuel leaks - none found.
Going to change plugs one again this weekend and take a look.
OTOH, are you looking for 14.7 with ethanol? Is your tune set for 14.7 or 14.1 (as ethanol would dictate). If it's set for 14.7, it might actually run "better" at the richer 121BLM....as it could mean it needs more fuel to hit stoimetric burn.
What fuel are you burning?
I agree with Jon that the lower O-ring is the only one that matters.
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From: Metairie LA
I was just reading about lowering the AFR to 14.2 for the E10 that has now taken over in Louisiana. I thought corn was for eating? We are also one of the biggest oil refining states - at least our fuel is cheaper here than most places. Filled up today with 93 octane for $45.00 at Chevron. Decided to read the label - may contain up to 10% ethanol - which means that it probably does.
I thought I knew all about computers until I ran into a car from.... 1986. Who would have thought?
The plug colors are a mystery to me also. The rears on both banks are universally darker than the fronts. I really don't think that I am burning oil, but who knows. They just appear to be burnt - the dark brown looks like burned porcelain.
I thought I knew all about computers until I ran into a car from.... 1986. Who would have thought?
The plug colors are a mystery to me also. The rears on both banks are universally darker than the fronts. I really don't think that I am burning oil, but who knows. They just appear to be burnt - the dark brown looks like burned porcelain.
Le Mans Master
Joined: Jul 2007
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From: Tampa Florida
Intake leak(s) usally will affect the idle a bit. If you don't find any exhaust/intake leaks - now that the "tune" is closer - clean the entire plug(s) up or just swap'em out for a fresh set and run them for a bit then pull'em again for a better "read".
How old are those plugs your showing us - the electrode looks almost brand new?
"Almost always on the lean side" - does that include WOT?
How old are those plugs your showing us - the electrode looks almost brand new?
"Almost always on the lean side" - does that include WOT?
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From: Metairie LA
The plugs have been in for about three months of weekend tooling around.
No WOT throttle yet - one pull at about 3/4 pedal for about 2 seconds - data log showed 3.1 volts on the TPS and the narrow band volts were low and even went to double digits for an instant. Thats why I started fooling around with AE. Every time I get a little spirited with a takeoff it drops like a stone - both O2's
Gonna grab new plugs today.
No WOT throttle yet - one pull at about 3/4 pedal for about 2 seconds - data log showed 3.1 volts on the TPS and the narrow band volts were low and even went to double digits for an instant. Thats why I started fooling around with AE. Every time I get a little spirited with a takeoff it drops like a stone - both O2's
Gonna grab new plugs today.