2013 ram 1500 shutting down in boost

[hardeet]

truck runs fine under 14psi of boost as soon as the map sensor hits 28.1psi everything shuts down and i cant figure out why. hoping for some tips to get in the right direction.

running open loop
on3 7875 turbo kit
deka 80# injectors
6.4l cam
E85
3 bar MAP sensor 05149056AA


new PCM turbo 5 E85 map new scale.hpt
pcm cut.hpl

[N2speed]

the PCM can not read past 195KPA you need to clamp the map sensor

[hardeet]

is that a limit for this specific pcm regardless of MAP sensor?

[N2speed]

yes it is a hard limit but there are work arounds like clamping the map sensor

[hardeet]

so it seems i need to drop to a 2 bar map sensor and then clamp it to be able to use the full 5v sensor for best resolution and go over 14.7psi. is there another way around it with tuning or is clamping the signal basically it?

[jefo]

Either a 2 bar map with a clamp or 3 bar map with a clamp would be blind above 15psi with timing and fueling adjustments.

I'd think the bet would be using 2 bar map data with your 3 bar sensor, and scaling the WHOLE tune for fueling and timing with that in mind. Should allow you to bump up the kpa limit to 3bar - though the map readings will be 2/3 of what they actually are, or something like that.

Not sure if the ecu would somehow throw a fit doing this though - never tried it.

[hardeet]

Either a 2 bar map with a clamp or 3 bar map with a clamp would be blind above 15psi with timing and fueling adjustments.

I'd think the bet would be using 2 bar map data with your 3 bar sensor, and scaling the WHOLE tune for fueling and timing with that in mind. Should allow you to bump up the kpa limit to 3bar - though the map readings will be 2/3 of what they actually are, or something like that.

Not sure if the ecu would somehow throw a fit doing this though - never tried it.

im going to try this as soon as i get some time hopefully tomorrow and ill let you know how it goes, for science of course

[LilSick]

science?

its a known issue

2 bar max

call fuel tech and order a map limiter

wire it in in parallel (more like T it in) and its a wrap

adjust it til no more limp mode

done deal : )

[hardeet]

for science is a joke. scaling for 2 bar sensor with a 3 bar map sensor isn't a possible work around? and do the NGC4 ecus not have this issue?

[hardeet]

Either a 2 bar map with a clamp or 3 bar map with a clamp would be blind above 15psi with timing and fueling adjustments.

I'd think the bet would be using 2 bar map data with your 3 bar sensor, and scaling the WHOLE tune for fueling and timing with that in mind. Should allow you to bump up the kpa limit to 3bar - though the map readings will be 2/3 of what they actually are, or something like that.

Not sure if the ecu would somehow throw a fit doing this though - never tried it.

running the 2 bar map sensor scaling with the 3 bar sensor worked. had to make a lot of changes aside from the map sensor scaling but maintained control of fueling and spark. was able to hit 16psi with no issues

[LilSick]

if you had contacted fuel tech and bought their limiter, you would not now have complete control over what???

the last 1.3 psi?

[hardeet]

if you had contacted fuel tech and bought their limiter, you would not now have complete control over what???

the last 1.3 psi?

and the last 5psi if i decide to run 20psi

[jefo]

Nice! Sounds like it's a good workaround.