3.5 TMAP reading are off (+/- 5psi) on JB4

oVeRdOsE

Private
Jun 12, 2024
42
15
0
I saw only 1 single post on that, and no solution.

- inb4 '' get rid of jb4'', yeah , but not yet. Work fine for my needs.

Spec : N54 , ST, MHD BEF, Maps on JB4 G5 (lasted ST firmware), 3.5 Continental TMAP N20 w/ wiring reversed order , BMS 600CC meth kit.​

Issue : Ive noticed 48°F iat @ 27psi on a 5.5'' stepped IC. Quite low !

I've added a external boost gauge and BINGO ; it read 22 psi, while JB4 read 28psi (peak) !


reached Terry, he doesn't know.

He told me to put TMAP :
- Setting to 1 : No , I ve a check engine and a 7.8psi readin on IDLE !
- setting 2 : same behaviour
- Setting to 3 : bingo, idle reads 0psi ( or vacuum) , but Ive a +/- 5 psi offset


ONLY 1 person reported Setting 3 did the trick, but he never validate the REAL boost pressure !

Any way to ''calibrate'' it?




here Setting 1 at idle :
fetch