1998 V70 T5 with delayed Boost

[driesbabe]

Hi guys,

I have had my 1998 V70 T5 for about a year now. The car has done 169000 miles. Lately I have an issue where the boost only starts to develop at between 3000 and 3500 RPM. I tow a trailer, and it makes towing a little slow getting away especially on an hill. When it dose come, it comes strong most of the time, but sometimes it feels like it's not boosting properly and the car almost feels sluggish.
I have no traceable vacuum leaks, and the Inter cooler hosing seams fine also.
What should I start looking at replacing.

Thank you
Andreas

[JRL]

Adjust the wastegate rod (tighten one turn for starters)
There are plenty of threads on how to do this on almost all Volvo sites, do some searching

[boosted5cyl]

I agree with JRL, I'd start with the wastegate. However my advise would be to purchase a hand vacuum pump. Something along these lines....


If you already have a cooling system pressure test pump it can be used the same. I don't have the pressure figure to hand ( I think its 4.5PSI), but it is listed in VADIS. I believe IPD have a video on youtube of the process of setting this up also.

This method will ensure two things.. 1) That its set correctly and 2) That the diaphram for the wastegate is actually holding pressure!
Once you verify that the wastegate is set correctly and that the diaphragm is not leaking, we can look at other suspect areas. Sluggish TCV solenoid for example.

Heres a pic of me setting the pressure on one of the turbos in my T6. This does not require the turbo to be removed, so don't panic

[boosted5cyl]

OK just noticed you are in Nambia, buying the pump from HF maybe not so practical but I would urge you to get a similar pump with a pressure gauge when setting the wastegate actuator pressure.

Also, how are your plugs, leads, distributor cap/rotor and soforth? If they have not been done I would highly recommend you get them done as you will loose power without necessarily getting rough running.

[db130]

could it be a faulty boost control solenoid?

[JRL]

I guess you are not absorbing what we all said
Adjust the wastegate first and go from there
You can do this by hand not using a pump or gauge for purposes of testing
Tighten (shorten) the wastegate rod ONE turn only and see how it runs after that

[driesbabe]

Thanks for the input guys.
I will try the waste gate rod trick and let you know how it's going.
I do however think that my plugs might be on there way out also. I will check them. All the cords and rotor are new with +- 6K miles.

[KSUMMEY]

The above are great things you need to try FIRST! If you still have issues with the car being sluggish I can think of 3 other things to check.
1 make sure you don't have a boost leak blown hose or something like that. I know it may look fine but pressure test it . Pop the hood have someone stand beside the car put it in gear and for about 5 seconds give it part throttle. If you have a boost leak you should be able to hear it. Its rare you will ever see a blown hose its usually more so a minor hole that leaks a lot of air.

2 The compressor bypass valve could be blown. It's located on the turbo it job is it bypasses boost when you lift on the throttle. Its under a round stamped plate with a 3 bolt triangular bolt pattern its directly on the turbo. You can use a vacuum pump to check it. Remove hose from the plate connect vacuum pump and see if it will hold a vacuum. If not its most likely blown

3 Check to see if the catalytic converter is starting to stop up. Some good signs its stopping up is rotten egg smell, and total over all boost at wide open throttle is lower than normal. The Car will not always set a code for converter efficiency because its stopping up. It is a 3 layer converter and if like in my cars failure case the first layer can turn to a molten blob but the 2nd and 3rd layer cleaned the air enough to prevent any codes to set.I