Car falls on face right at 6100 rpm

[kinger]

@kinger I would just copy the midrange rpm #'s and paste them into the upper rpm ranges.


It will definitely pick up a misfire if there is in fact one present.

Thanks for the help!   I will try it and log for awhile and see

[gnx7]

Looking at the condition of the air filter (seriously nasty and mine have NEVER been that dirty ever)... you should change/clean your fuel filter and look at the basics.  All my LS swaps I've shifted north of 7000rpm.  I don't even know what a 6000rpm shift is.  With a performance cam even the smallest cam that is very low RPM shift point.  Check plugs (gap verify the electrodes), maybe a burnt wire (MSD wires pull apart very easily and are not great... most tuners hate them and we run stock wires on very nasty n/a LS engines.  Confirm all the intake bolts and TB bolts are tight (no vacuum leaks etc).  It will probably be something very simple. 

[kinger]

All good thoughts.  Filter has nearly 30k miles on it.  Looks good again after a recharge:




Plugs look decent if not perfect!





Will button it up tonight and take for a spin. 

New fuel filter will go in with new engine.


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[MPbdy]

I mean, if I’m honest my filter looked exactly the same when I checked it last lmao. It worked just fine and had no meaningful engine restriction. They actually filter better once they’re loaded with dirt (although the road grime is a bit extreme haha). My dad works for k&n they can take a lot before they’re plugged.

[kinger]

I mean, if I’m honest my filter looked exactly the same when I checked it last lmao. It worked just fine and had no meaningful engine restriction. They actually filter better once they’re loaded with dirt (although the road grime is a bit extreme haha). My dad works for k&n they can take a lot before they’re plugged.

Yeah I mean it's a driver, I drive it and it has been on there for 12 years now.  I don't think for a second it was plugged...This is a great filter.  Plenty of surface area for the engine.  I am impressed how it 'recharged' very cool. 

[kinger]

Got my scanner and WB talking and I noticed it’s going pig rich before cutting out.  Very strange.  I took some fuel out of the table and it didn’t do a thing.  It was going 10.4:1 and I got back to 12.5:1 and still same result. 

Turned on all misfires, logged them and none showed up.  Zero like there is a issue. I should have a bunch of fake ones. 


My map went up to 97-98 with the filter clean. I am running out of ideas now. May just swap the engine and forget about it.  434 will be here in fall. 


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[MPbdy]

Hmmmm so if it was misfiring it would go lean on the o2…not sure why it would start dumping fuel.

What did the o2 do once it hit the rpm it won’t pull past?

[FC3S Murray]

Generally when you are going rich for no apparent reason (meaning an easily identified mechanical discrepancy isnt discovered) it is a sign of power loss due to loss of engine efficiency such as compression degradation.


Have you done a compression check? Do you have excessive blow-by by chance?


Maybe borescope the cylinders and do a leak down check..

[kinger]

Hmmmm so if it was misfiring it would go lean on the o2…not sure why it would start dumping fuel.

What did the o2 do once it hit the rpm it won’t pull past?

O2 go off the gauge (it goes down to 10:1) and it pegs 10, in the logs I was seeing 9ish.  I held it once at that spot and it almost sounded like it was going to make it through it but I chickened out worrying about something letting loose.  I also revved it with no load (cringing the whole time) and it whizzed past 6100 to 6500 with no issues.

[kinger]

Generally when you are going rich for no apparent reason (meaning an easily identified mechanical discrepancy isnt discovered) it is a sign of power loss due to loss of engine efficiency such as compression degradation.


Have you done a compression check? Do you have excessive blow-by by chance?


Maybe borescope the cylinders and do a leak down check..

I actually have the motor sold and will do a leak down on it before I sell it just to make sure he still wants it. 

I think it needs valve springs, just my gut.  The plugs looked clean, but compression check wont hurt either. 

[jwvand02]

Generally when you are going rich for no apparent reason (meaning an easily identified mechanical discrepancy isnt discovered) it is a sign of power loss due to loss of engine efficiency such as compression degradation.


Have you done a compression check? Do you have excessive blow-by by chance?


Maybe borescope the cylinders and do a leak down check..

If you sell this motor before we figure out what is wrong it's going to torture me forever

I actually have the motor sold and will do a leak down on it before I sell it just to make sure he still wants it. 

I think it needs valve springs, just my gut.  The plugs looked clean, but compression check wont hurt either.

[kinger]

LMAO on torture you!  I played with it today again and its still going pig rich, smells like burning oil, and this time I held to the floor and it was slowly going past 6100 coughing and hating life.  It runs spot on perfect below that.  Going rich almost means to me its losing spark or something on one or 2 cylinders and its not burning the raw fuel being injected.  After it happens I shift and get back into the 5K range and it coughs for just a second like its cleaning itself out and AFR goes back to normal range.  Still no misfire codes though.   

What is everyone's favorite coil to use?  OEM Fbody, truck, or IGNA smart? coils??  I want all new coils for my new engine anyway (its getting all new everything sensors, accessories, etc) so I wouldn't mind getting new coils just to try and I can swap it over to my new motor in the winter. 

[jwvand02]

LMAO on torture you!  I played with it today again and its still going pig rich, smells like burning oil, and this time I held to the floor and it was slowly going past 6100 coughing and hating life.  It runs spot on perfect below that.  Going rich almost means to me its losing spark or something on one or 2 cylinders and its not burning the raw fuel being injected.  After it happens I shift and get back into the 5K range and it coughs for just a second like its cleaning itself out and AFR goes back to normal range.  Still no misfire codes though.   

What is everyone's favorite coil to use?  OEM Fbody, truck, or IGNA smart? coils??  I want all new coils for my new engine anyway (its getting all new everything sensors, accessories, etc) so I wouldn't mind getting new coils just to try and I can swap it over to my new motor in the winter.

I'm running truck coils which I think are plenty for an NA build, but if I ever had issues with them I'd probably go to the IGN1A coils, they seem to be the favorite option (or at least the best marketed one...)

[scuter83]

Raw fuel won't be picked up by an O2 sensor. 

[kinger]

Raw fuel won't be picked up by an O2 sensor.

Even if its being mixed in with other exhaust?