Hi all

I have a KKL code reader and so have bought a MultiECU license so I can plot out my expected and actual pressures as I am still having problems with loss of boost.

I am getting a difference between actual boost pressure and desired pressure.

The actual pressure sits at around 1000 mbar with no throttle, and doesn't always seem to rise in correlation with expected.

The temperature was 14 degrees this morning, so wasn't too bad, as the symptoms get worse as the ambient temperature increases.

MultiECU gave a sensor reading of about 40 degrees this morning, which while obviously higher than 14, shouldn't really cause an issue should it?

I will keep monitoring the issue, and have exported a graph of all the pressure related options i could find, and would love for somebody to have a look who might be more experienced in these things but can't upload it here.

Anyone have any ideas on how to get the graph uploaded?

Craig

You need to post those graphs.

Something isn't right.
What sensor was reading 40 degrees?


Post the graph as a picture

Unsure as to what sensor reads air temperature, its just an option on the graph parameters.

I've attached screen prints when idling and on boost, hopefully someone can make sense of them

Hi,
What engine do you have? Something is clearly wrong with the sensor signals, but I don't have enough information. I'd suspect the manifold pressure / temperature sensor If it has one (MAP sensor on multijet). The air temperature signal needs to be sorted first as it does make a big difference. The air density decreases with temperature and the ECU compensates for this.
Robert G8RPI

Cheers G8rpi

Its a T-Jet 150.

The temp was an ambient 22 degrees this afternoon, and the sensor was reading 27-28.

I believe it takes the reading from the inlet manifold pressure sensor, but could be wrong on this.

OK,
I don't know the T-jet so can't help much. I'm also out of the country but if no one else chips in I might do some research.

Robert G8RPI

I know on other car the outside air temp sensor is in the wing mirror
A small bulge on the underside could check yours to see is it the same?

OK,
Let me shed some light on the situation:
-The t-jet only has a MAP sensor (NO MAF); the MAP also includes the air temp sensor; it's located in the intake manifold.
-there is another pressure sensor on the pipe that goes from the intercooler to the throttle body. This is where MES is a bit confusing: if you select the "Boost pressure" parameter you will see the values from this sensor.


The "Desired boost pressure" value should be compared to the "intake manifold pressure" value.
Here is some info to support my claim, look at the idle.pdf you posted:
-The "Boost pressure" value is at ~1024 mbar that is ~atmospheric pressure because there's no pressure in the line from turbo-to intercooler-to throttle body.
-The "Desired boost pressure" value and "intake manifold pressure" have similar values close enough => no error


Check intake temp early in the morning , or pretty late at night, after the car has been still for 5-6 hours. The sun will easily make those temp readings vary.
Best way to check would be in a garage, overnight, with the hood opened , check in the morning, without starting the car, a few degrees difference is still acceptable (~5).

While running the intake air temps will rise:
-in city traffic/standstill you will easily see 60 degrees C... on a nice sunny 20 day degrees C ambient temp.
-highway driving, you will see 30-35 degrees C
-hard pull 45-55 degrees C


After looking at your graphs, i'd say there's no problem.... the small differences are caused by inertia and they are fine and to be expected.

Make some graphs with the temps as well; coolant and intake.
Always include RPM and Speed so we can tell which gears is engaged..because it matters.

Cheers Aurick86, i will get on it this week and post the results

Craig

Hi again, please see my new post on fuel pressure regulator as I believe this may actually be my problem.

Craig