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Discussion Starter · #1 ·
Hello All,

(I apologize for how lengthy of a first post this is)

I am new to this board and new to the world of R's! I have been perusing this board for a few months now to learn as much as I can about these cars before I pick one up...I have wanted a V70R for a long time. I finally found one a couple weeks ago and jumped on it. I got a 2006 V70R Black/Nordkap with 81k miles on it. I am located in MN and the car was in Naples FL, I found a local Volvo shop, they went and looked at it and it turned out to be one of their customers car. They vouched for the quality of the car and had all the service records since 2009 including the timing belt, pulley(s), and water pump were just done 3k ago. It is stock except for some aftermarket wheels and a Snaab intake from the air box to the turbo. I thought everything was good...it made the 1800 mile drive home without any issue.

Only Pic I have that I can Post


Then a day after I made it back I was just driving it around town and the idle started surging from 800 up to 1200. I did some research and decided to clean the MAF and the throttle body, even though it has the better Bosch one. That did nothing, in fact it then started to backfire like crazy, I could hear it popping in what sounded like the plastic intake tube. I reset the ETM after cleaning by turning the ignition to II, waiting for the calibration to stop, then turn the ignition off. It also was idling real low, around 500 RPM, almost like it was ready to die, and really chugging. I did some more research and wanted to do some maintenance work anyway, here is what I thought it might be and what I replaced:

-Volvo plugs
-Bosch coils
-Replaced K&N air filter with a Mahle stock one (Not a fan of K&N and the oil)
-Bosch MAF sensor
-Mahle fuel filter

I thought all of this would help, especially when i took the coils out and all of them had cracks in them. Now it isn't backfiring but the idle is still surging and the drivability it horrible, it also surges when driving at higher RPMs and makes it almost undrivable. It seemed to smooth out a bit when warm, but then when I would come to a stop the idle would drop real low (600 RPM) then surge back up to 1200. Also, it sounds like the turbo is making an odd noise. I have to admit this is my first turbo car as an owner, but I am pretty familiar with them and this doesn't sound quite right. Does it sounds like a hose is loose, or a vaccum line is bad, or does it sound like the turbo is having issues? (I really hope that isn't the case!)

I have posted some videos below of the the actions in the car. I really appreciate any input! I really like this board so far, seems like a lot of dedicated owners that know there stuff and are willing to help. I admit I dont know the ins and outs of these cars yet but I am learning more every day. I am looking forward to getting this issue taken care of and driving this car like it was meant to be.

Surging Idle

Turbo Noise (I think at least...) (You'll have to turn up the volume to really hear it)

(I will make a formal introduction post with more info about myself and pics of the car later, I am consumed by these issues right now and want to get them addressed)

Thanks,
Scott
 

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Ensure that the intake pipe is securely mounted to the turbo, the Snabb intake pipe is difficult to fit and will cause these symptoms if disconnected.
 

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Discussion Starter · #5 ·
Thank for the advice guys!

I have tried unplugging the MAF, and there was no change, so I probably didn't need to replace it but wanted to be sure.

I've seen a few things about the FPS possibly being bad, is there a way to check it and make sure it is faulty before replacing it? I would rather not spend the $$ on it if it isn't bad.

Thanks Austin, I think that sounds like a logical culprit! One thing I have noticed is the upper torque mount and the bushings in the support bar are totally shot, I can grab it and really twist it with little force. This may be causing a lot of motion at the top of the engine, possibly slowly working the connection of the Snaab intake loose at the turbo, that's why it made the journey home, almost all freeway miles, and then became loose during more stop and go driving in town.

Is there a way to get to that connection from the bottom if I jack the car up? I have looked down at it from the top and it looks really tight, is that the only way to get at it?

Thanks,
Scott
 

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Could be a FPS issue, when it goes bad it starts creating bogus readings, and since the pump is electronically controlled by the signal it will cause the real fuel pressure to fluctuate and cause issues.

I know it causes stall issues sometimes, though in this case it could be the idle control having a hard time dealing with a near stall.

If you have the same issue with the MAF disconnected chances are pretty unlikely its your new intake pipe causing the issue.
 

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A disconnected intake pipe at the turbo looks like a MAF issue because the true volume of air into the system is much different than the MAF understands and the Electronic throttle body expects, especially at low engine RPM.

Unfortunately there's no easy way to access it. Disconnect the battery, Remove the airbox, disconnect the + battery cable and harness from the Fuze box, and reach your hand back there to feel / see if the air inlet is attached the the turbo. It's not a tough job, just be patient and expect to spend a few quality hours playing with your car. Use a good flashlight / floodlight and get 6, 7, and 8mm, 1/4" drive sockets, a 1/4 drive long extension, and a 10mm ratcheting box end wrench to make your life easier.
 

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Discussion Starter · #8 · (Edited)
Update

I methodically went through the whole air intake system from air box to throttle body. Took the whole Snabb intake out, the connection at the turbo was solid, however the connection between the tube and the elbow on the turbo seemed to pull off pretty easy without even loosening the clamp, so I started thinking this could be a leak point. I cleaned everything up, it was pretty nasty inside the elbow on the turbo. I checked all the vacuum lines too, and didn't see any problems with them. Reinstalled the intake.

I think looked at the turbo to IC pipe, cleaned it up and found a crack/hole! Its right by one off the mounting tabs.


As a temporary fix I laid some fiberglass over it to seal it up. I then checked the pipe from the IC to the throttle body, looked good and all connections were tight. I let the fiberglass cure and then reinstalled that pipe. I reconnected the battery, let the ETM reset, and then started it up. NO LUCK! Idle started to surge, and was still stumbling and wanting to die.

I checked the pipe repair, no leaking. I think unplugged the MAF and the car smoothed out, but since it was running rich it was backfiring a little, which I think is normal, right? So what does unplugging the MAF, and the idle gets more smooth, very rich, but no surging, mean? Does this mean my brand new MAF is bad and the previous one wasn't?

Is there something that I need to do after making all these repairs to reset the ECU or something? I am disconnecting the battery while I work on the car, reconnecting it, let the throttle body re-calibrate and that's it...anything else I should be doing?

Could it still be the FPS? Unplugging the MAF cleaning up the surding really threw me for a loop, considering doing that did nothing before I replaced it...

Thanks,
Scott
 

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Fps only goes 75k max or less for me 50k-I am now on my 3rd at 130k --when was yours last replaced ? They are a cheap part , will remove that factor
 

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^^ my fps died at 80,000 on the odometer, had similar symptoms to what you have--but that hole was probably also part of the issue.
 

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Update

Unplugging the MAF cleaning up the surding really threw me for a loop, considering doing that did nothing before I replaced it...

Thanks,
Scott
Unplugging the MAF sensor forces the ECM to use a default fail safe fuel map as it doesn't have info on the airflow anymore.
 

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Discussion Starter · #12 ·
I have a few questions about the FPS-

-Is there a way to check it before replacing? Or is it just a part that just needs to be replaced?
-Can I hook up a gauge to the Schrader(sp?) valve on the fuel rail to see whats going on with the fuel pressure when its running?
-When the MAF is unplugged does the ECU ignore the FPS, hence smoothing out the idle?

Thanks,
Scott
 

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Yes, you can look at the running pressure via the shrader valve. Should be a steady value at idle, but if you see a change precede the idle issue that would point to the FPS.

Does the idle issue go away with the MAF unplugged, or just get less bad? If less bad then its not the MAF. If you still have your old MAF why not swap it to see how that effects things too.
 

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The way I check them is running a fuel pressure gauge off the fuel rail. Pressure is generally 4 BAR or 58-60psi. Using Vida I check the fuel pressure sensor output which is usually 400kpa. If the FPS is fluctuating and the fuel gauge attached is steady, you probably have a bad sensor. By fluctuating I mean it widely swings.

When the MAF is unplugged it not that the ECM ignores any particular sensor. It just uses pre programmed fail safe data and does its best to keep the engine running long enough for you to either get to safely off the road or to a repair shop. I have seen MAF sensors cause the vehicle to not run at all and by unplugging the MAF the engine would then start.
 

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Discussion Starter · #15 ·
Stealthy - When I unplug the MAF the surging completely stops, and it idles at a consistent RPM. However, it still is idling pretty low and sounds pretty rough, there are a few backfires too.

I am going to pick up a pressure gauge today and test it tonight to see what its reading at idle. If the pressure is actually fluctuating then it would point to the FPS being bad and if it is solid then the problem would be elsewhere, correct?

Thanks,
Scott
 

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If its low and backfiring something is obviously still wrong, so even though the problem changes with the MAF disconnected, its likely not the cause if something is still wrong.

Have you checked the car for codes? They may be able to tell you exactly what is wrong.
 

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Discussion Starter · #17 ·
The car currently is not throwing a check engine light, or any warning messages.

Could it still be storing codes? I was under the impression it needed to throw a CEL to be able to read codes.

Thanks,
Scott
 

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He's asking if you've hooked it up to VIDA/DICE to check for issues, not just OBDII codes.
 

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Discussion Starter · #19 ·
Ok, thanks. I have not hooked it up to VIDA/DICE yet. I will need to find somebody, or a shop, that could help me with this.

Thanks,
Scott
 

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Double check the spark plug number. Should be 30751806. Other plugs will fit but the R plug is longer. The shorter plugs can cause backfiring and surging like you describe.
 
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