Disco 2 Wastegate strange behaviour

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So with everything all connected as it should be, there is some resistance when you try to move the threaded arm back and forth?
 
Si Click said:
Previously you were seeing 550-600. Your new figure of up to 460 suggests low output from the turbo rather than pressure loss downstream.
Click to expand...

After my previous posts I was using the car without paying attention to the numbers (I had other issues to deal with anyway).

Yesterday when going up a hill in the motorway it dropped to 3rd with no reason and at that point I noticed a lack of power. When I checked using the nanocom I found out it went into overboost (this is a first). I cleared the fault and today on the same trip I was looking at the figures on the nanocom and I saw the numbers mentioned above (MAP up to 225kpa and MAF up to 460).

So based on this am I looking for a restriction/blockage after the turbo and before MAP sensor?
 
The MAP figure looks normal, which implies the pressure from the turbo is making it to the inlet manifold. Seems odd to me that you are getting enough boost to push you into overboost despite the low MAF figure. Have you checked that the wastegate and modulator are operating correctly and that there are no split hoses in the vacuum lines?
 
sierrafery said:
Read again post #19 , beside that make sure that the turbo hoses are not delaminated
Click to expand...
Same diagnose with the new info?
Si Click said:
The MAP figure looks normal, which implies the pressure from the turbo is making it to the inlet manifold. Seems odd to me that you are getting enough boost to push you into overboost despite the low MAF figure. Have you checked that the wastegate and modulator are operating correctly and that there are no split hoses in the vacuum lines?
Click to expand...
Modulator was replaced very recentry and I checked the actuator using a bicycle pump and it responded as expected.
I checked for split hoses and can't see anything suspicious.
 
It's not about split hoses but delaminated which is not visible cos the problem is inside... if they are still the originals that can be the case, squeeze them and if they are soft replace them with silicone or new genuine rubber.
 
sierrafery said:
It's not about split hoses but delaminated which is not visible cos the problem is inside... if they are still the originals that can be the case, squeeze them and if they are soft replace them with silicone or new genuine rubber.
Click to expand...
They aren't the original ones. They were replaced with silicone ones by the previous owner.
 
clamp the hose which goes to the wastegate valve and test drive it so...if it doesnt go to overboost it's not about wastegate at all but low boost for some reason, i have the same problem now which i hope it's a boost leak at the inlet manifold gasket cos it's gunked up around the ports but the boost leak on mine is obvious as the MAF exceeds 680 which means a lot of sucction while the MAP tops up at around 210 with clamped wastegate. Your's seems to have a restriction or management issue cos the sucction is low too... is the air filter new and good brand on your's? ... i forgot if it was mentioned or not but let's clarify:
1. is the EGR deleted?
2. is it 10P or 15P engine?
3. if it's 15P do you still have the CAT?
 
sierrafery said:
clamp the hose which goes to the wastegate valve and test drive it so...if it doesnt go to overboost it's not about wastegate at all but low boost for some reason, i have the same problem now which i hope it's a boost leak at the inlet manifold gasket cos it's gunked up around the ports but the boost leak on mine is obvious as the MAF exceeds 680 which means a lot of sucction while the MAP tops up at around 210 with clamped wastegate. Your's seems to have a restriction or management issue cos the sucction is low too... is the air filter new and good brand on your's? ... i forgot if it was mentioned or not but let's clarify:
1. is the EGR deleted?
2. is it 10P or 15P engine?
3. if it's 15P do you still have the CAT?
Click to expand...
I will try with a clamped hose to see if it overboosts and report back. If there is a restriction between turbo and MAP then it will still not overboost (I'm guessing).

Reusable K&N filter, cleaned recently. 10p, no EGR, no CAT.
 
So I went for a quick spin having the hose going to the actuator blocked and the thing kangarooed as soon as I put my foot down doing 30-40mph. No fault was recorded to the ecu.
 
It seems that it can build up the boost then... it's possible that you have a boost leak through the wastegate valve? that's the logical deduction but i've never seen that myself... you should replace the valve IMO .
 
Last edited:
sierrafery said:
Yes cos that' the one with the valve, it has a rubber diaphragm in it which might be shot... eventually read the MAP with clamped hose
Click to expand...
I tried to, it was shooting to 230+ and kangarooed. The strange thing is that no overboost fault was recorded on the ECU like it did a couple of days ago.
 
That's really strange, the stock overboost limit is at 1.42bar(142KPa) calculated by the ECM by extracting the AAP from MAP so to record overboost when MAP is at 230 you should have AAP 88, was it like that?...this thing is very hard to diagnose without a recorded live data log to analise all the air related readings(AAP, MAP, MAF) at the same time
 
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