MAP Sensor/Boost Issues

[YO ZAH]

Hey guys I have a 2007 1KD Lux
I've been facing a problem for a while with My turbo overboosting, my boost will consistently hold between 20-27psi but the fuel will not match it, alot of boost and no power (Accompanied by a high pitch whine but I've had this before any problems)
I've been trying to find the issue for nearly a year and half, now I do have a fmic, unichip ECU and 3 inch Exhaust straight through exaust fitted with my egr completely blocked, I've Had no problems for over 2 years with these mods until I let my car sit for 3 months started with boost leaks then once those were fixed the EGR started playing up, and holding open letting boost leak, which is why I deleted it, now my current issue with too much boost and lacking power I've been mucking around with different Map Sensors which is where the problem may be, I brought 4 different sensors, including one off a Hilux similar model and an $250 OEM replacement, they all give readings that are Too high
Some read 200kpa at idle and throw P0069 code when started and then throw P1251 & P0106 codes when I give it some boost , the OEM sensor reads 160kpa at idle (engine warm) and doesn't throw P0069 when started but will throw all codes when boost comes on causing limp mode, even when I run a diode to keep the volts below 4.7 it will throw a code
The weird thing about this is the original map thats in the car works fine but is possibly the reason that my car is overboosting ? At idle the original sensor sits at 90kpa which is alot better than 160kpa
Iv so far replaced MAF and IAT Sensor and done an intake clean out,Air filter replacement, triple checked vaccume lines and throttle body, pressure and smoke tested intercooler piping (no leaks) & removed the unichip to test (same issues) am I missing something with replacing the Map? Do they have to be programmed or something? Or is it something further down the line like the stepper motor or even the turbo could it be SCV, I'm not to sure on all components that could effect a map sensor
I just find it weird that the original sensor works and no replacement works, im still yet to find someone with similar issues so this is a nightmare to track down the problem and help is greatly appreciated

[ptommo59]

Hi YO ZAH,

Did you get your issue sorted?

[YO ZAH]

Nah not yet, seems to be I had a small leak on my throttle body, but even with that fixed I can't run a new map sensor, just going to keep replacing parts until the issue resolves itself, I'll update here if I find what was causing it

[ptommo59]

Hi YO ZAH

If you have access to Techstream or Scangauge etc have you compared the MAP sensor reading and the Atmospheric Pressure (from sensor in the ECU) at ignition on? The Workshop Manual I have access to from a slightly later model indicates these should be within 8 KPa and close to the actual externally monitored barometric pressure if everything is working correctly.

If there is a significant difference you may have a 5V ECU generated reference voltage or wiring issue assuming the MAP sensor is correct part for your engine and working properly. The 5V reference is also used by other sensors so be careful trying to use a diode to alter the value as it may throw other readings off and make things worse.

There was an area on here where you could put a snapshot from Techstream/Scantool of all your readings at idle and/or faulted condition after warm up and one of the more experienced guys would give you an idea of what readings are off and potentially causing the issue. May be worth exploring.