ive got a gm 3500 chevy with a 5.7l motor.it is real doggy,it is supposed to be bored 60 over and a bigger cam not sure what the specs are.
ive got a gm 3500 chevy with a 5.7l motor.it is real doggy,it is supposed to be bored 60 over and a bigger cam not sure what the specs are.
What I find really weird is that this log was several minutes long and the coolant temp never changed. It stayed at 79 degrees for minutes on end even with driving. You need to figure out why it's doing that.
It's lean under load. Partial throttle the fuel trims start going to +15% or more and when you went basically full throttle the o2 sensors dropped to nearly nothing show that it's very lean on fuel.
Not knowing the specs of the camshaft and things like that doesn't help you. Being bored .060 over plus the camshaft upgrade is going to require lots of tuning to get the fueling correct. Wouldn't surprise me either if the stock injectors may not be large enough either.
For sure check for vacuum leaks, smoke test it and make sure fuel pressure is at spec for idle and under load.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
The stock injectors are good for alot more than a 350 with a cam. I made over 450 hp with them in a 383. 0.060 over does not change much of anything. My 383 ran pretty decently just changing cylinder volume and changing the MAF table to match my LS3 MAF.Originally Posted by 5FDP
He needs to start with a clean MAF, verify no vacuum leaks anywhere in the intake tract, then verify fuel pressure at WOT. I had to put a Racetronix Hotwire and a new Delphi pump on my 97 van when it was ~15 years old. The pump wiring is undersize and the factory square fuel pump connector is failure prone.
I noticed that the temp never came up,I?m gonna check the wiring on it and probably replace the sensor.I?ll smoke the intake and see if there?s any leaks.I checked the fuel pressure running and it was good but I?ll take it down the road and see if it changes under load
Stock spider shoud read 66 psi. The MFI spider 58 psi. This is under load. At idle it should drop 6-8 psi.
Last edited by Fast4.7; 12-09-2022 at 11:34 AM.
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