Another power loss under load thread!

[DaveM-sport]

I know there's loads on overboost problems but not sure if Monroe exactly the issue.

Before fitting the VNT. I was getting typical stuck actuators with limited revs a 3K under load and sudden power loss at around 4K if you built revs up slowly under light load.

Would feel like limp mode but be fine again once you backed off for a few moments and then grand again until you pushed it too hard once again.


When fitting the VNT, it was perfect even when towing heavy loads and would pull to 4K no problem under full load.

This morning however, it's at it again albeit not as bad as it was with the old turbo.

When under too much load, it'll lose power until I back off for 4 or 5 seconds and ok then again. I don't have to restart it or anything or nothing shows up on the dash.

Will throw out a shot of black smoke too when it hits the point of dying too as to say its not getting enough air and overfueling at full load/boost.

Don't have a MAF bypass yet but have boost box.

Just wondering if its maybe a MAF or MAP sensor problem or maybe the cheap Britpart silicone hoses are collapsing

 

[sierrafery]

is it D2 or Defender?

anyway this is a guessing game untill you plug in a tester and watch live data when the symptom occures cos there could be many issues

what do you mean "MAF bypass" ? ..and do you still have EGR?

 

[DaveM-sport]

Defender.

By MAF bypass, I mean a bypass pipe to allow the MAF not cause it to go into limp by the VNT overboosting.

It's been fine since Sunday now again though with no future issues. It did die for no reason at all Sunday evening though but once started, it was fine again. There was a tiny bit of oil on the ECU plug alright however so I dried that up before I started it again. Changed the injector harness since and there's no faults showing up on the nanocom.


If it happens again, I'll plug in the nanocom and keep an eye on anything that looks a little off.

 

[sierrafery]

i think you confuse the MAF with MAP then cos MAF has nothing to do with boost pressure

 

[DaveM-sport]

If you say so...

 

[sierrafery]

i was just trying to help m8, it's not me who is saying so....it's the reality, but if you can explain how comes that "bypassing"(which i dont see how is possible) the MAF will protect the system from overboost i'll stand corrected(as the MAF is there mainly for EGR management)

 

[DaveM-sport]

Yea, I understand and appreciate the help of course

I'm pretty sure both MAP and the MAF are used for inputs though.

With a boost box, you fool the ECU in thinking the MAP sensor is happy with whats going on but with alot more air than what would normally be needed, the MAF can throw a fault. Sometimes, it can cause it to go into limp mode. By how much it causes a problem can vary though as some will need a bypass or a boost box that takes care of both and some won't have any problems.

 

[DaveM-sport]

Discovered the problem
It was getting worse again and as bad as before with the old turbo and was typical stuck wastegate actuator with the 3K rev limit as well as very dead in the low end and unresponsive at low rpm. I knew it had to be either a MAF or MAP sensor issue so I disconnected the MAF the other night and it was perfect.


Only trouble is, the next morning it started missing very badly to the point it won't even run now. No fault codes but injector balances are all over the place.

It feels like bad diesel, water in the fuel or taking in air somewhere.
Will change the injector harness as have a new one that I've been meaning to fit as very slight bit of oil in the ECU plug and will change the fuel filter too to rule those out.


Feels like bad diesel though as just filled it up the previous day it started missing and disconnecting the MAF possibly would make bad fuel more evident due to default over-fueling.


Bit of investigating over Christmas it seems