Thread: Intermittent Loss of Power

I was concerned about the fuel temp also. It is crazy hot here but that is high. Any thoughts on where I should start looking to rectify this?

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Will get rid of boost box and see how I go also. I know nothing about them and at this point don't really care about having a grunty rig. I just need the bloody thing to run properly.

One thing I will say is thanks to you guys & my friend Mr Google I've learned heaps that will help me if I get stuck out Bush at some point.
Sincerely thank you to all who have been helping me. Should any of you come through Alice the first round is on me. Lol

Sent from my LG-D802T using AULRO mobile app

Originally Posted by wobba79

Will get rid of boost box and see how I go also. I know nothing about them and at this point don't really care about having a grunty rig. I just need the bloody thing to run properly.

One thing I will say is thanks to you guys & my friend Mr Google I've learned heaps that will help me if I get stuck out Bush at some point.
Sincerely thank you to all who have been helping me. Should any of you come through Alice the first round is on me. Lol

Sorry, I was assuming that the MAF was wired into the boost box, but realised that majority of boost boxes only touch the MAP reading.
If the MAF is not connected via the boost box don't worry about disconnecting.

If, as Rok_Dr suggested, you should make a recording of the fuelling inputs or instrument mode while driving as it will give a much better idea of what the motor is doing.
Also worth checking for fault codes if you haven't done so already.

The fact that you are getting low readings with a brand new siemens/vdo MAF would make me suspect the issue lies elsewhere.

The MAF is supposed to top out at 680, if you can't get it past 370 then there is definitely something wrong with it.

RE fuel temp, start with the fuel cooler and go from there. Haven't had an issue of overly hot fuel temp on mine so haven't the foggiest on how to fix that, sorry!

The high fuel pressure temp can be due to coolant flow restriction in the fuel cooler, it has a built in thermostat which can be blocked or high reading sensor, you can see if the high FT is an issue by unplugging the sensor cos the ECM will go the a 60*C default which should improve things cos the FT sensor is important part of the addaptive strategy, AFAIK as the fuel temp increases, the ECM limits the amount of injected fuel: from 50 to 70 it's 43cc, at 71 degrees it drops to 41cc, then it drops with every degree increase so that high FT isue is something to be ruled out.

SF,

Where are those inject figures from? I don't recall seeing them before.

As you know i'm not able to dig within the brain of the ECU but during my prolonged research a guy who i trust told me that it's a table in the fuel map about that... i presume it's at the same place where the stored values for FT are too.... though in the unlikely case that the source is wrong i apologise

i had no reason to doubt that cos it's a fact that the lower the FT input is the better the engine is running

Originally Posted by sierrafery

... a guy who i trust told me that it's a table in the fuel map about that... i presume it's at the same place where the overheat protection is as well which cuts seriously the fuelling at 120*C.... though in the unlikely case that the source is wrong i apologise

Apology accepted. BTW If you keep up these whiny posts that refer to "brains of the ECU" I'm going to have to start each post with "I apologise in advance if I hurt the tender feelings of the Infallible Avionics Engineer who I know I should trust without question..."

There is a big difference between absolute limits which is what your friend is talking about and what occurs below the limiters.
Fuel density decreases with increasing temperature, so the amount of fuel injected is increased to compensate.
Conversely at low fuel temperatures injected quantity is reduced to compensate for increased density.


Fuel temp limiting and ECT limiting are completely unrelated. Your assumption on that point is incorrect.
FWIW Overheat limiting references roadspeed in addition to ECT, and the cut in point varies between 110decC and 115degC depending on how fast the vehicle is travelling. Maximum cut occurs at 125degC.