S40: V40 2.0t '01 Underboosting

[ww1dm1]

Originally Posted by bobe84

I have turbo whine from 1500rpm and turbo lag.
Turbo was serviced due to compressor started rubbing housing, but techician said it was minor and no damage was done.
2 weeks after turbo service car ran great, had so much middle range power i was amazed.
Afther 2 weeks dreaded whining started coming back and with that sound i started loosing power in midrange.
Now i have whine and boost lag.before that lag was not noticable at all.
Techician said cbv was fine on inspection and wg actuator arm was loose so he titghened it.
Basicaly car ran amazing for 2 weeks after service and it is now same as before. PIA in town to drive. And turbo whine.
I have negative fueltrim on acceleration and negative fuel trim on coldstart.

Well, if the problem behind the whining before was the compressor rubbing the housing, it was fixed, everything was great for a while and then the exact same whine returned, shouldn't you focus on that? No point in digging for fuel trim problems if your turbo is making all kinds of odd noises. Rich or lean mixtures won't make the turbo whine.

[bobe84]

I'm afraid that is probably true.
Whine sound is like ambulance sound going up and down with engine load.
Anyhow i talked with service guy a week ago and i will be driving my car to that service after new year.

[bobe84]

Originally Posted by ww1dm1

Well, if the problem behind the whining before was the compressor rubbing the housing, it was fixed, everything was great for a while and then the exact same whine returned, shouldn't you focus on that? No point in digging for fuel trim problems if your turbo is making all kinds of odd noises. Rich or lean mixtures won't make the turbo whine.

I was trying to determine whether i have boost leak with fueltrims.

http://www.volvoforums.org.uk/attach...4&d=1482746461

Is this hose done? Should i buy new one?

[Ginga]

Originally Posted by bobe84

I was trying to determine whether i have boost leak with fueltrims.

(...)

Take a look at this: https://www.youtube.com/watch?v=oRX2V6_a3dc

There's a lot of videos explaining the basics. If your trying to solve this on your own, they might help

[bobe84]

Originally Posted by Ginga

Take a look at this: https://www.youtube.com/watch?v=oRX2V6_a3dc

There's a lot of videos explaining the basics. If your trying to solve this on your own, they might help

Actually already watched this particular video.

[cheshired5]

Originally Posted by bobe84

Is this hose done? Should i buy new one?

Test it...... and the other vacuum hoses and the actuator as already suggested.

Stop guessing.

[skyship007]

Originally Posted by bobe84

Car performed poorly for about a year.
I had sort of turbo "whine" on acceleration and it lacked middle range torque(1500-3000RPM)
This september turbo started making more horrible noise(compressor just barely touching housing) and turbo went to service. After service everything was super for about 2 weeks.
No turbo whining or perhaps boost leakage.
I have OBD2 cheap chinese elm327, during that period of 2 weeks car was boosting to 155kpa from 95kpa atmosferic pressure. It was able to peak in boost in third at a little over 2000RPM. Really strong pull.
After 2 weeks whining sound started coming back, and started performing poorly in middle range.
Today i tested for boost leaks. I pressurized hose from turbo outlet to the throttle body. Apparently nothing was audible. Had about 1.5bar pressure.
Guys any sugestions?
My observance at cruising and using light to medium throttle i have negative shortterm fuel trim... it goes to -15%
It suggests i have leak but i cant find it.
Now i have to wait to hit peak boost of 60kpa (0.6bar) at 4000rpm. Really laggy medium rpm.
Some directions please for debugging.
Thanks!
Forgot to say, during that period of 2 weeks car didn't misfire and was running really happy at high boost on 40C outside temp.

What exactly did the turbo service include ??

If the vane really was hitting the housing, they might have used a Fleabay insert of just hammered it out. That could result in a temporary improvement before it started failing again.

If a turbo fails because the oil feed pipe is obstructed with varnish and another turbo is fitted without replacing that pipe (It might be in the fitting kit), the next one can fail very quickly. Same applies to a sludged up oil pump intake screen.

When the turbo is replaced, it makes a lot of sense to use a good fitting kit and to replace both the hose and boost control valve IF they are the same age.

[ww1dm1]

Originally Posted by bobe84

I was trying to determine whether i have boost leak with fueltrims.

http://www.volvoforums.org.uk/attach...4&d=1482746461

Is this hose done? Should i buy new one?

As I mentioned, if the hose is giving you doubts, just wrap it with some serious duct tape and look for trim changes. However it seems like you have bigger problems at the moment.

[bobe84]

As time goes by im also more convinced that problem is in the turbo itself.

Whining noise is same as before(before the turbo started screeching). It is more prominent on cold engine.
I reach targeted boost but it is PIA, i have to floor engine and wait to 3500rpm to reach 0.5bar.
When turbo was working correctly after service i had no problem reaching 0.5bar boost at 2200rpm.
Will investigate more...
When turbo was taken of the engine i tried to wiggle compressor there were no noticable movement. Maybe 1milimeter max.
Anyway guy that rebuild it swears it is not the turbo and said it was not damaged that much.
After new year i will drive the car to the shop and let them deal with it.

My O2 sensors were never changed. I belive they also could be hidden culprit to all these problems.
To many variables here.
Will start from the basics.
But as time passes by i realize actually that turbo is in same condition as before service.
During those 2 weeks it worked really good but it had no whine. Just induction noise over 3000rpm on high load.

Anyway i'll keep you guys posted on this subject.

[bobe84]

First, happy holidays to everyone!

Whats new....
It is -10C here in serbia, for tonight announced -20.
Today i started car and hooked it to the laptop. eeem....
longterm is +1.6%
shorterm was +-3% at idle, almost same on load.
ECT could go above 90C only if idling. If i drive it it goes like 87C(bear in mind it is -10C)
I read somewhere on forums that T4 will only allow full boost when it reaches over 90C engine temperature... Is it same with T3?
If i kick the throttle and ECU gets 87C ECT will it boost to 0.5bar? Or is it like this once the ECU reads 90C and flags engine as fully warmed up?
Other posibilites, could it be that since i dont have plastic protection under the engine that snow and ice blocks boost leak? Or perhaps something like water improves some ground under the engine?
I was flooring it but DSA was limiting torque all the time, but i could reach 145kpa with more ease then before.

Anyone some suggestions? Boost leak blocked by ice? Hoses so cold that dont split under pressure? Some engine ground stuff like that(electrical)?
Definitely as soon as i can i will go under the car and do careful inspection.