Vs Ute v8 problem

[Anson38]

Hi to all , got a issue with a v8 304 mild 355 stoker motor , mild cam , and a little head work done , new everything under the hood , except the dizzy , main problem is each time the tank drops below quarter of tank , I start it up and sounds like back firing and pinging then takes of and goes hard , things I have tried take it home let it cool down and do timing bridge 5 and 6 and start it up set timing do up dizzy double check then turn it of and pull pin bridges turn back on and it is sweet as reverse out the drive way and nail it no issues runs fine , part it up for 2 days , problem comes back reverse out and farting and piping like a backfire and comes good , just on take off it does it

 

[Anson38]

Only other thing I can see is when I bridge 5 and 6 turn the ignition on the engine light flashed 2 long 1 short in flashes like that

 

[BlackVXGTS]

DTC (Diagnostic Trouble Code) 21 is THROTTLE POSITION (TP) (SIGNAL VOLTAGE HIGH), but it doesn't seem to match with your symptoms:

"When a DTC 21 is set, the PCM does not receive the proper signal from the TP sensor, but it can still determine the TP sensor valve with a default valve based on MAP and engine RPM. If DTC 21 is set, the transmission will have: no TCC, high line pressure, harsh shifts and no 4th gear (if in hot mode)."

 

[Anson38]

Ok yeah it only flashes in series's 2 long one short and will keep doing that , yes the auto has a harsh overdrive lag but other lower gears nice and smooth put in hot mode brings the rpm up and changes are nicer , so what are thinking I should try to fix the issue I have , I haven't replaced the map sensor on fire wall ,
I'm still learning on your post Sorry if I don't understand fully what you are saying

 

[Deuce]

Are you sure it's not 1 flash and then 2?
12 is the standard 'nothing is wrong' code. Aka no codes.

 

[Anson38]

Ok I'll get new throttle body sensor , map sensor , O2 sensor , and a ob2 scan tool and let you know how I go

 

[Anson38]

One flash then another flash then a quick one

 

[Deuce]

Also, is it all a standard fuel rail setup? Pulse dampener and standard regulator?
Bigger pump and injectors obviously?

 

[Anson38]

What do you think the problem is ,I start it up runs fine revs fine just at the start user load pops then takes of , got new ignition module , coil leads spark plugs all new , I can smell like a fuel smell and when tank drops below quarter plays up , trying to add a few thing for everyone to see where the issue is ,

 

[Anson38]

No standard fuel pump and over size injectors software upgrade