I have a lm7 5.3 with flat top pistons and 283/303 mutha thumpr cam, will not start or idle without the pedal pressed wide open, camaro base (pretune)2 (hope)1.2.hpt All factory except the pistons and cam, downstream o2 sensor deleted. please help
I have a lm7 5.3 with flat top pistons and 283/303 mutha thumpr cam, will not start or idle without the pedal pressed wide open, camaro base (pretune)2 (hope)1.2.hpt All factory except the pistons and cam, downstream o2 sensor deleted. please help
Last edited by Rabbitfp; 12-10-2020 at 10:14 AM. Reason: attach tune
How do I upload the tune? *edit* figured out have to do it on computer and not phone *duh*
Last edited by Rabbitfp; 12-10-2020 at 05:53 AM.
is the cam why you changed the firing order . sorry im new as well just comparing it to one of my factory 5.3 tunes . also just to clarify lm7 is gen 3 or gen 4 ?Originally Posted by Rabbitfp
Gen 3, I didn't mess with the firing order
thats strange because its different than stockhyukon base tune 122020.hpt
this is my relatively stock 2003 yukon tune and the firing order is different for some reason
The base tune I pulled from the truck the firing order is identical to what it is now, however the cam specs on Amazon list gen1 sbc firing order
try moving the table values for firing order over to the left 1 the firing order is correct just off by 1 in sequence it seems .
can you get a log file even if its a short one . will make it easier to see what it is doing
here ya go, the exhaust is not finished, may be skewing the readings camaro.hpl
Not having the coolant temp sensor working may be a partial cause, it's going to dump in more fuel than needed.
What is your fuel pressure?
What injectors are installed?? If they are stock you must upgrade them because they are too small for a camshaft upgrade.
Put your base running airflow back to stock, the table can not have the same value in every cell.
Unplug the o2 sensors if this does not have a complete exhaust, it's going to throw everything off if they are in open headers.
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.
fuel pressure not sure of, it is a walbro 255lph inline high pressure, factory injectors, what injectors should i upgrade to? not sure what is going on with the temp sensor, it is brand new, got a new one for a 2001 camaro z28 and it shows the same reading as the one that is in it now.
To be on the safe side I would run 31 or 33lb/hr injectors. The 31lb/hr are the stock 8.1 vortec size and the 33's are stock flex fuel truck injectors on the tahoe/surburbans of the early 2000's. The data can be copied straight from a tune with those injectors to make the swap super easy.
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.
No need to change the firing order. They are all the same. Some just start with a different number in the first position. The order remains the same. The number it starts with in the calibration has nothing to do with the engine running.
so as long as the order is correct the position doesn't really matter ? good to know just the first time i've had it pop up different in a compare
Reply With Quote