Thread: Wastegate adjustment and Nanocom

Originally Posted by rapserv

Just for interest, I am virtually at sea level, driving along the foreshore only a couple of metres above the water.

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Then check the ambient pressure reading at idle cos it should be close to 100KPa, if it is and it drops to around 86 as in your first post replace the air filter or check for any restriction in the intake the AAP should not drop more than 5 units under load if everything is OK, if it's low at idle too check the real pressure with a barometer and compare cos they should be the same, eventually clean the AAP sensor with contact spray or MAF cleaner.

Originally Posted by sierrafery

Then check the ambient pressure reading at idle cos it should be close to 100KPa, if it is and it drops to around 86 as in your first post replace the air filter or check for any restriction in the intake the AAP should not drop more than 5 units under load if everything is OK, if it's low at idle too check the real pressure with a barometer and compare cos they should be the same, eventually clean the AAP sensor with contact spray or MAF cleaner.

Ok.. I drove down to the beach one metre from the waters edge and nanocom shows ambient pressure as 90.13Kpa and manifold turbo pressure as 102.63Kpa (at idle). Before taking these readings I checked for restrictions in the air input (also have silicone hoses throughout) ,replaced the air filter, cleaned AAT sensor and plug contacts with contact cleaner along with MAF.
The vehicle seems to run ok but at 80kph on flat road, inlet air at 40C and vehicle loaded fairly well with all my tools etc. I have a egt of around 650C !!!
This seems to be an excessively high egt.
When adjusting the wastegate rod, should I be in fact watching the egt instead of my boost gauge?
If my main concern is high egt's am I doing the right thing by adjusting the wastegate?
I made mention in a previous message that I have a boost box installed, I should also mention that the ecu has also been reprogrammed for more power and I have also upgraded the intercooler.
Am I also better off bridging out the wastegate controller and running tube directly from the lower pressure outlet to the actuator as they tend to do on defenders?

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First of all the difference between the AAP and MAP readings at idle is too big, shouldn't be greater than 1 - 4 units tops though as long as that boost box is there it might affect the MAP reading all the way cos it's linked to it's signal, nevertheless, the AAP seems too low to me at sea level though, the EGT should not grow together with the boost for the contrary it might drop with higher boost

IMO you should rule out that AAP reading, compare it with a barometer reading before you change the sensor cos it's expensive, a bad input from the AAP can affect the EGT especially if your's is with the 4 pin type which has a temperature input too not shown by fueling data...the AAP reading being lower than real pressure the ECU will go to altitude compensation mode without being necessary which means overfueling.

no need to bypass the wastegate modulator as long as it works OK cos it improves the throttle response at lower revs by restricting the boost from the wategate valve

Curious problem you have - many of us here have done the same mod as you and only experience positive results. Where is your EGT probe installed? I quickly scanned your previous posts but didn't see comment about it so probably missed it. FYI my EGT's reduced with wastegate adjustments to increase boost. My VDO analogue guage which is tee'd off the wastegate actuator pipe (not ideal i know) peaks at 22psi. Also I have a straight pipe in place of my once clogged intermediate muffler so she now breathes a lot freer but that was in place before my boost mod.

onebob

This seems odd , as others have said . By increasing boost your egt should come down , especially as with a low reading aap this will reduce fuelling even more , ( we will have to disagree on that sierrafery)
What does your egt read under load up a hill ? Is there a chance that the cam timing is out (recent head work etc) or that the egt gauge is not reading right

Originally Posted by discorevy

This seems odd , as others have said . By increasing boost your egt should come down , especially as with a low reading aap this will reduce fuelling even more , ( we will have to disagree on that sierrafery)

We dont disagree, i apologise cos my statement wasn't the best, i didnt actually mean that the overfueling will be the direct result of the ECU altitude compensation(as you are right, at higher altitude/lower AAP the ECU reduces fuel). I meant that higher EGT is the the result of the fact that the ECU ''thinks" the presure is lower while it's not then the driver will compensate instinctively that lack of fuelling through the throttle but on the higher driver demand the MAP reading is lower than expected due to the false low AAP so more fuel will come and so on ... i've seen that with my own eyes diagnosing a friend's car and it was almost the same, the AAP reading was lower than real pressure measured with barometer and there was black smoke, i only presumed that the EGT was higher than normal cos he didnt have a gauge but usually black smoke = higher EGT for me ... though this whole theory might be wrong just that after replaceing the bad AAP sensor the black smoke dissapeared

interesting , did your friends car have the 4 wire aap sensor , I'm wondering if it did that the temp sensor side of it might have been giving very low temp readings as well as the driver demand combining to cause the black smoke. Can't remember what the default readings are for aap but it might be higher than current readings in which case it may be worth unplugging and going for a drive , this is assuming the egt probe isn't sitting right in the flame. Those egt levels at mid throttle would usually mean buckets of black smoke