My 454 Rebuild

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Carlaisle

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The injectors GM used on this engine are famous as junk for a good reason. It is not possible to rebuild them. Now that your fuel pressure has been corrected, those are the most likely suspect. Two drop in replacement options are: 1) Ford yellow tops used on the 1996 4.6L V8 Mustang (0280150556) and 2) the GM injectors used on the 1999 5.3L Silverado (17113582). Many others will fit and can be made to work, but those have exactly the correct flow rate at our fuel pressure and can be installed with no tuning required.
 

Spareparts

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I did have new 5 O motorsports injectors installed less than a year ago. Ran perfect in the old engine.
Installed them in the new engine and last weekend Installed cleaned, rebuilt whatever they do to them stock injectors with another FPR. Still runs pretty much the same with either set of injectors. Driving feels exactly the same.
Something is telling the ecu the engine is rich. There is never a gas smell like leaking injectors cause, exhaust smells clean and does not burn my eyes like unburnt fuel will.
I'm thinking i need to check for a ground that got overlooked, maybe a pinched wire, wire plug not fully seated
 

Spareparts

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Have a appointment at 1pm today to get it put on a scanner, Drive and diagnose today. Hopefully they can figure it out as apparently im not smart enough to do it and i getting tired of working on it every weekend
 

Spareparts

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Was at the shop on a scanner for about a 1/2 hour. Pretty much told me what i already knew.
For some reason it is pulling fuel out. Duh, I know that, that's why im here im thinking.
It has 0 misfires.
He did suggest changing all O2 sensors for a start as they are 25yo as far as i know.
He also suggested the miss i think im feeling is something out of balance. Well the Flex plate is the original one but the Harmonic balancer is a new one supplied by the machine shop that did the short block.
Maybe it is the wrong one?
Matching it up with pictures of new ones mine looks the same as near as i can tell without taking it off and matching it up to a known good one. Looks like it is a Dorman brand.
I don't think that's it though because sometimes it feels worse than other times.

So anyway i changed all 4 sensors and reset the ecu fuel trims. Went for about a 20 mile drive and the trims are the same.
Here is a pic of the 4 O2 sensors. The white ones are pre and the black ones are post.
Do they offer any clues to the problem?
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Mangonesailor

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Maybe the tune is just not ideal for the cam?

You're totally sure the injectors are sized correctly? I don't recall this sorts of issues swapping to 5.0 injectors. Are they blue-knights or are they the Ford Yellow-tops? I want to say I remember a member either on Fax or here had a fit with the blue knights.

I have my old Yellow-tops still, but IDK if they'd be worth a try. I'd hate for one to be stuck open and flood a cylinder.
 

Piratehunter

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Try to get the invoice that has the harmonic balancer part number to compare to. they were hard to find last year when I did mine. Not saying that is the problem, but try comparing to RockAuto or other vendors.
 

Spareparts

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Cam is pretty much a stock cam.
No tune. It has the old black box ecu for now.
I don't think it is a fuel issue, well it is but not because of bad injectors or FPR or ignition.
Could be Plugged/bad cat's, Bad Mass airflow sensor, Bad vapor canister.
Cat's i don't know how to check. Mass airflow i can replace, Vapor canister i can just unhook for testing i think.
 

Spareparts

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Watched a few vids again and with a temp gun i measured both cats temp at the inlet and outlet.
Both measured around 390F at the inlet and outlet. Supposedly that means they are both working properly.
 

Mangonesailor

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When you reset the fuel trims/reset the computer does the idle hunt a little when idling and then smooth out and gets in control?

Have you tried using dash command to check the IACV counts?

Can you try making a log through torque or dash command and posting it? I suggest logging from a warm engine (around 120°F), let it idle a smidge, and then drive it up to about 50, cruise, and then stop the log?
I suggest:
Ignition timing
RPM
Vehicle speed
ECT
LTFT banks 1&2
STFT banks 1&2
TPS position
Crank/cam offset (if possible)
MAP InHg vacuum
MAF signal (in Hz)
Battery voltage
 

Spareparts

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Ill see if i can figure out how to get a Dash Command log file posted.
 
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