Boost Leak - Tried Everything :(

[WillT5]

Hi Guys,

Ive got a boost leak somewhere on my Volvo 850, its got a Rica 304 but ive never seen 17 psi! In second gear i get 14 psi spike which rapidly drops to 10 psi and holds and in 3rd, 4th and 5th it sits at a constant 14/15 psi

Ive got a DIY Rip kit with T bolt clamps on every join all extremely tight, i have a o-ring sealed turbo blanking plate, i have replaced the PCV system and put clamps on every pipe joined to the manifold. Also tested the BOV and TCS which are both fine

Would really appreciate any advice

Will,

[Jamest5r]

Actuator

[Jamest5r]

Also you won't see 17psi on a rica unless you have a mbc

[WillT5]

Thanks James, i did see that when researching will probably be my next part to try. Is it a common failing? mine is 90,000 miles

Isnt the boost set at 16/17 psi on a Rica 304?

[xllifts850]

Could be actuator seized, mine was stuck solid when I bought the car, also check the actuator pipe that goes across to the manifold mine was perished and split in the clamp that holds it in place on the block.

[WillT5]

I have checked the actuator and it does move freely

[Saaamon]

Someone mite be able to correct me here but pretty sure a good tuning company can test for leaks and at the same time check the actuator to make sure it's set correctly. Better off paying for this instead of aimlessly throwing cash at it.

[Jamest5r]

I have checked the actuator and it does move freely

It's supposed to be tight, a bit of pressure needed to pull it into position if it's moving freely it's knackered

[theflyingbrick]

ill bet a hundred quid its the actuator....I had excactly the same problem and although it felt ok when I fiddled with it, when I put the actuator adjustment tool on it (it has a gauge on it) I found it wouldnt hold pressure, swapped it for another and hey presto problem solved :-)

[T5frankie]

sounds pretty normal to me 1 st gear is limited boost wise as is 2nd but the fact you reach 15psi in 3rd 4th and 5th says its ok,

[WillT5]

Thanks for the input guys, i have asked all the breakers if they have any actuators just waiting to hear back.

Frankie - I had the same problem when using an MBC though so it must be a boost leak? Also i did check earlier and 3rd does creep down, when i hit 6,000 rpm its back to 10 psi. Its much better than second though

Ive previously tested it with my hand and it does feel ok. You've given me confidence theflyingbrick, hopefully this will work....boost leaks are a pain in the ass!

[T5frankie]

Thanks for the input guys, i have asked all the breakers if they have any actuators just waiting to hear back.

Frankie - I had the same problem when using an MBC though so it must be a boost leak? Also i did check earlier and 3rd does creep down, when i hit 6,000 rpm its back to 10 psi. Its much better than second though

Ive previously tested it with my hand and it does feel ok. You've given me confidence theflyingbrick, hopefully this will work....boost leaks are a pain in the ass!

yeah actuator if 3rd gear is dropping to 10 psi and it's mapped

[WillT5]

Hi Guys,

I finally got hold of a replacement actuator and the problem still remains. If i adjust the wastegate it will boost to 19 psi, is this normal? Surely the ECU overwrites the wastegate?

Also i was doing some investigation and found alot of oil in the intercooler pipes and alot pooled above the turbo compressor outlet (after 4 weeks of them all being clean) ive also lost alot of oil. No smoke that i can see coming from the rear and ive fully replaced and tested the pcv system

Any ideas?

Thanks,

Will,

[M-R-P]

You should need to pull the actuator rod out by about 4mm to get it over the peg on the arm (as a rule of thumb) if it hits 19psi then wind it back half a turn (maybe even a full turn)

There should be a thin layer of oil in the pipes - it means your PCV is working. If there's a lot of oil then some investigation is needed. It could be down to overboosting blowing some extra oil out of the block or compressor.

[WillT5]

Thanks MRP, ive wound it back now. It was overboosting after found the oil. This is a picture of the oil buildup, only been a month since clean:



Im wondering if they are related, should i try replacing the turbo?

[M-R-P]

Quite dark too. Has the oil been changed recently? Is what's on the dipstick the same colour as whats pictured above?

[WillT5]

It was changed less than 5,000 miles ago, i also have an oil leak that has no source. Ive replaced the PCV, turbo return pipe gasket and o-ring and the drain plug but it remains. I thought it was RMS but now im thinking turbo

Car is around 90,000 miles

[WillT5]

Ive now upgraded the turbo to a 16t and beaded the pipe that comes from the turbo outlet. In 3rd, 4th and 5th I'm now seeing 20 psi at peak and it holds at 18 psi afterward. Second gear also holds better but still leaks away to 10 psi when pushed. If i hold my foot at 50-60% throttle the boost will leak away

Ive also tried another actuator, new intake gasket and replacing rubber gromits around the intake. I am now going to try to test the tcv again and test the ecu to see if my tune is at fault. If thats not it I will also be replacing the intercooler (REALLY not looking forward to that....)

Ive read that the vacuum tree can sometimes leak, or maybe the FPR? Anyone have experience of this or have any ideas on something else to try? Rapidly running out of ideas....

Thanks,

Will,

[mitchyboy01]

If your seeing 20psi and holding 18 it sounds like everything is good. You won't hold boost on part throttle.

If you're still in doubt get a pressurised smoke test. Only 30 odd quid and will find the smallest of leaks.

[T5G]

I think someone suggested it to you before, maybe look for a local company that offers boost leak testing. Smoke testing should show up any obvious leaks you have. Don't be surprised if you see smoke coming out the bottom of the intercooler, it's from a weep hole that Volvo put there :-)