(_8*(l)Homer Posted November 14, 2015 Author Report Share Posted November 14, 2015 Yep, I think it's the MAF. It ran like crap, not much power when I just drove with MAF cleaned and plugged in, shifting was all wrong (auto) and turbo seemed to be not providing any assistance. With the MAF unplugged, the car had much more power, drove better, and idled smoother. Unplugged, codes 102 and 171 were thrown, as expected. Is it safe to drive the car without the MAF? Does it do any harm? Link to comment Share on other sites More sharing options...
volvoguy23 Posted November 14, 2015 Report Share Posted November 14, 2015 Should be fine but it may not start or stay running at times. I would just try not too drive it too much, visit your local junkyard and get a used for now until you can by a new one, they normally last a long time. Link to comment Share on other sites More sharing options...
(_8*(l)Homer Posted November 15, 2015 Author Report Share Posted November 15, 2015 Yeah, it won't even start now, regardless of weather or not the MAF is plugged in. It just cranks and cranks, doesn't even try to catch. Since the MAF was acting up, and the fact that it's a 98 wagon, I have no idea how much fuel is left in the tank. I usually refill every 300 miles, and I am at 305 now. I think the MAF issues dropped my gas mileage and the car is just out of gas... I hope so anyway. Link to comment Share on other sites More sharing options...
Flukey Posted November 15, 2015 Report Share Posted November 15, 2015 I have read all the comments and your description of your woe. I had the exact same experience with my 98 V70 lpt. It turned out to be the turbo compressor bypass valve. I remember that it cost me around 50 bucks to fix it with a rebuild kit I got from I think Kingua or some name like that. It is a place that specializes in turbos. Good luck with it. Link to comment Share on other sites More sharing options...
(_8*(l)Homer Posted November 16, 2015 Author Report Share Posted November 16, 2015 Bypass valve sounds reasonable. When I go into boost, the engine revs, but my speed drops and I can hear air flow quite distinctly. That would also explain the MAF error codes from what I read on Matthew;s Volvo and saw on youtube from that Volvo guy who makes all those videos. I had no idea a new bypass valve would be so expensive https://www.fcpeuro.com/products/volvo-waste-gate-repair-kit-271640. Do you know where I can just get the diaphragm, or is that not replaceable by itself? Link to comment Share on other sites More sharing options...
Saleen9091 Posted November 16, 2015 Report Share Posted November 16, 2015 Yikes that's expensive for new OEM. If it's a leak though, it's just a torn diaphragm. I think this will work for you. http://www.ipdusa.com/products/4898/114437-heavy-duty-compressor-bypass-valve There is a way you can check it though (I think). Take off the CBV line from the the source of vacuum (boost tree or intake manifold?) and suck into the vacuum line. If it doesn't hold vacuum, diaphragm is torn. Link to comment Share on other sites More sharing options...
Fudge_Brownie Posted November 16, 2015 Report Share Posted November 16, 2015 You're going in 12 different directions, by reading stuff and pressing on your gas pedal. I won't be surprised when this turns out to be a recently cracked hose, or a hose that came off. Have you checked your spark plugs to visually verify they are in good condition, and have remotely reasonable gap? If so, have you checked for cracks in the spark plug wires, signs of dry rot, and maybe watched for arching? Then move on to looking for cracked hoses or loose hoses. You can loan a vacuum gauge from Autozone. A rule of thumb is that it should be 18-20 in/mg when warmed up. If it's 12, you know you've got a massive vacuum leak or much less likely, low compression. Link to comment Share on other sites More sharing options...
volvoguy23 Posted November 16, 2015 Report Share Posted November 16, 2015 Bad cbv just causes turbo flutter, unless it's completely gone, even then the air is already metered by the the maf, a bad cbv should not cause what was described in the previous posts. Link to comment Share on other sites More sharing options...
(_8*(l)Homer Posted November 17, 2015 Author Report Share Posted November 17, 2015 So, I can pump up the turbo actuator arm, and it holds just fine. Since it holds, does that mean the diaphragm is not leaking? Link to comment Share on other sites More sharing options...
volvoguy23 Posted November 17, 2015 Report Share Posted November 17, 2015 The wastgate is not the same as a compressor bypass valve, neither of those are your issue. Check your ignition components and get a good used maf to start with. Link to comment Share on other sites More sharing options...
(_8*(l)Homer Posted November 17, 2015 Author Report Share Posted November 17, 2015 Yeah, it is definitely the MAF. I used one out of a friends car, and it ran like a champ. Boost was great, gas mileage was normal and there was no chugging or probs at WOT on the highway. I ordered a new aftermarket one on ebay, hopefully it will last. Link to comment Share on other sites More sharing options...
Saleen9091 Posted November 17, 2015 Report Share Posted November 17, 2015 14 hours ago, volvoguy23 said: Bad cbv just causes turbo flutter, unless it's completely gone, even then the air is already metered by the the maf, a bad cbv should not cause what was described in the previous posts. Two ways a CBV can fail. It can fail by not opening because of a missing vac line which will cause the turbo flutter. However, if it is a torn diaphragm, it's no different than a boost leak. You don't lose metered air but you are leaking air from after the compressor wheel to before the compressor wheel. Symptoms would be loss of boost target pressure but it wouldn't cause stumbling. And actually, you would also be hearing some turbo flutter because a torn diaphragm would prevent it from opening. That's good you found your problem. One of the best methods of troubleshooting is replacing parts one by on to pole out the problem. But if you are buying the parts instead of borrowing them, that's when it gets expensive and that's when I see most people ditch Volvo altogether. I know FCP Euro sells OEM bosch units. I've been told the MAF is definitely one of those things you want to make absolute sure you are getting OEM or you'll be replacing again. Link to comment Share on other sites More sharing options...
(_8*(l)Homer Posted November 17, 2015 Author Report Share Posted November 17, 2015 The MAF was $22 shipped, so I am totally not complaining. There are no local junk yards anymore (Cape Cod MA), just "auto recycling" places who do not sell parts, so I did the cheapest option I could. I know I will be buying an OEM MAF soon, even if I only get a few months out of the aftermarket one it's still worth $22. I got new plugs, cap, rotor, and wires (all OEM except the plugs, which are FR7DC) from FCP in the mail last night. The current wires are bougicord and plugs are Volvo OEM platinum and the cap/rotor are OEM. Everything was replaced in 2012. So even if I don't end up replacing everything this week (depending on how it all looks), I'll need the parts for later anyway. I think I need to replace the CBV as well, as I know I have some boost leak (I have since the last 80k miles), probably earlier. I rigged a boost gauge with a vac/pressure dial and can see that it under boosts, even after upgrading the TCV. Link to comment Share on other sites More sharing options...
Saleen9091 Posted November 17, 2015 Report Share Posted November 17, 2015 Boost leak can be anywhere and everywhere. Don't just assume it's the CBV, could be wasting your money. Link to comment Share on other sites More sharing options...
Fudge_Brownie Posted November 17, 2015 Report Share Posted November 17, 2015 1 hour ago, (_8*(l)Homer said: The current wires are bougicord and plugs are Volvo OEM platinum and the cap/rotor are OEM. Everything was replaced in 2012. I rigged a boost gauge with a vac/pressure dial and can see that it under boosts, even after upgrading the TCV. Any guess on mileage? If you're driving 15k/year, that's 45k. That's starting to reach cap/rotor territory. But honestly, if the OEM plugs you have in there now look good, check their gap and put them back in. Keep those coppers on the shelf for if you run in to misfires again, so you'll have fresh ones to troubleshoot with. Copper vs OEM is a pretty well debated topic on VS, and I'm a fan of the OEM plugs for relatively stock cars. They just last so long. What kind of vacuum are you seeing at idle, warmed up? And max boost? If you're only seeing 5psi, that's a decent sized problem worth pursuing. If you're getting a bit of boost fade at the top end, probably not indicative of a large issue affecting anything else. Link to comment Share on other sites More sharing options...
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