2001 C70 T5 Coupe low boost issues

perkunas · Post by **perkunas** » 17 Nov 2013, 15:16

Hello everyone,

Recently I have purchased a C70 Coupe. Great car in many perspectives and so far I love working on the engine. Being a 12 year old car, it needs some attention. Also, I like my cars to be in a perfect condition, therefore I personally check that everything works fine. So far I have done these things: replaced a bad thermostat and coolant, cleaned the ETM (nasty layer of grime inside), had the belts, oil and all the filters changed at a shop, also winter rubbers mounted on the wheels. However, it feels like the car is lacking power, especially in the higher gears (in gears 1 and 2, STC warning lights up on the dash if pushed to the max). I have started tinkering with the components of the turbo. I have removed and checked all the intake hoses and they seemed fine. When assembling, I did up the clamps properly too. Today, I found a hole in the red vacuum hose near the TCV due to rubbing to the airbox. I will replace all the vacuum lines ASAP.

The real question here is:

The car came with the MAP sensor blown out of the tube and just hanging on the wire, not installed on the intake tube which goes from the IC to the ETM. When I noticed this, I immediately reinstalled the sensor. After that, I have pushed the engine hard multiple times. Recently, it has developed a woosh when boosting (or maybe I'm just paranoid). Anyway, should I expect to face more serious problems due to overboosting by the previous owner or maybe even myself? If the vacuum hose had a hole in it, this would mean that the wastegate doesn't even open properly. The car doesn't really burn any oil or coolant, and there were no CEL's except for one that said the engine was running rich (possibly fixed by the ETM clean).

P.S. I temporarily repaired the hole in the vacuum hose with electric tape, but it didn't change much.

Post by **jblackburn** » 18 Nov 2013, 07:11

I thought mine sounded weird coming back to it - turned out there was a hole in the rubber hose directly attached to the turbo. Moral of that story - check all of your rubber intercooler hoses for cracks and make sure they are snug at the clamps.

If you can boost hard and then hear a weird fluttering sound when letting off the gas at 4000-5000 RPM, the compressor bypass valve is bad and leaking boost.

perkunas · Post by **perkunas** » 18 Nov 2013, 09:27

Well, sometimes there is a woosh sound when accelerating around 3000 rpm (which got worse after some hard driving recently). All the charge hoses seemed fine when I removed and checked them afterwards. The one that I didn't remove was the one closest to the turbo because I was having a hard time getting to the clamp. It seemed fine from above, after removing the OTE pipe, except for a small amount of oil inside it. Also, I hope it isn't the intercooler that is leaking, but it did come with some damage, that is, some bent fins, nothing too serious though (I think). Also, I don't think that the leak would get worse in the intercooler after hard driving, but maybe the hoses would.
Right now, I don't want to push the car hard, but I will try to replace the TCV lines tomorrow if I can get to the turbo nipple.

perkunas · Post by **perkunas** » 16 Dec 2013, 08:11

I have replaced the TCV lines.
The turbo line had a hole in it. Now the car pulls better, but sometimes it does and sometimes it doesn't. I would suspect a faulty TCV. I suspect it hasn't been changed.

perkunas · Post by **perkunas** » 13 Jan 2014, 06:57

Sorry for multiple posts, but I wanted to bump the thread.
I went to a local independent volvo shop and they gave me these codes:

ECM-262A, lower limit. Any help for this one? It has been bugging me for a while. There is a lot of white smoke on idle, around freezing temperatures (I know there is more smoke when the weather is colder), however there is still plenty of it when the engine has warmed up, which means a rich condition. Oil level is fine, did not need to top it up in 3k km, so it's not a leaking turbo. I now suspect the EVAP vacuum lines (in a pretty poor condition, hoses flaking, especially the one that goes to the intake hose), PCV vacuum - Looks fairly good, but it's a major PITA to inspect well.

To make things more complicated:
If I remember correctly, 2 months ago, before I found a leak in the TCV lines, it had a code for the system being too rich. Is the new code for the system being too lean? If so, could the new code be set due to the Lambda sensor being contaminated from the previously rich condition? I'm really confused right now. Also, the car didn't start from the first time a couple of days ago, but I think it might be the antenna ring.

According to VADIS: Hint: Air leakage in the intake system can occur through the canister purge (CP) valve, the secondary air solenoid valve and power brake booster.
Power brake vacuum line seems in a great condition. There is no SAS system in the car. Should the canister purge valve be my main suspect?

CCM-414 - I will be cleaning the sensor in the near future.

Post by **kcodyjr** » 13 Jan 2014, 08:05

I like to use carburetor cleaner to hunt for vacuum leaks.

If your MAF was hanging by its wires, it's junk. These things die like drunken flies. Replace it with none other than the correct OEM part. Check whether yours is Bosch or Denso; I believe it'll be a Denso. Doesn't have to be the blue box Volvo branded one, just has to be exactly the same part from the same manufacturer.

The MAP sensor in this car (altitude sensor) is located over by the washer fluid reservoir. They go much more rarely. A good cleaning, especially in that hole it has, might be a good idea.

+1 your TCV solenoid is probably sticky. The aftermarket HD versions from IPD or ARD are said to be more reliable and definitely have better latency, allowing the ECU to push it a little harder without risking overboost.

Most importantly though, have you been resetting the adaptives? It's done by draining the last bit of charge from the ECU. Disconnect the negative battery lead, and either short it to the positive post for 10 seconds, or walk around and step on the brake pedal. That'll wipe out its long term trims and a bunch of other fiddly numbers, and force a relearn. It's best practice anytime you do something that can affect mixture, boost, or ignition.

perkunas · Post by **perkunas** » 13 Jan 2014, 08:23

Isn't the MAP sensor the one in the plastic pipe between the ETM and the intercooler? There is no atmospheric pressure sensor in my car.

Also, I guess that cleaning the faults won't force a relearn? I have noticed that it takes much longer (~100km of driving) for the CEL to reappear if I disconnect the battery for an hour or so and today, after the diagnostics, the CEL came back in like 15km of driving.

However, when looking for a C70, I test rode one with an intermittent atmospheric sensor fault. Later it turned out that it had a blown headgasket. Shame, it was a great car.

In the attachments, I have a couple of pictures. The first one is the location of the sensor. The second one is a random question: do you know what connects to the two holed slot on the driver's side of the car?

Thanks for the info!

Post by **kcodyjr** » 13 Jan 2014, 08:49

No. Between the ETM and intercooler, should just be a hose with an idle air control valve.

The MAF (mass airflow) sensor is in the plastic pipe between the airbox and the inlet.

The MAP (manifold absolute pressure) sensor is over by the washer reservoir and has only a wire.

Clearing codes does not force a relearn, only an emissions retest.

perkunas · Post by **perkunas** » 13 Jan 2014, 08:51

Uploaded some photos!

There are two sensors in my car on the plastic pipe: air temperature sensor and manifold pressure sensor.

Also, here is a photo of my MAP sensor located on the Intercooler-ETM charge pipe.

I have to note that when I bought this car, the sensor was removed from its slot in the pipe (possibly due to an overboost when a hole developed in the red TCV hose??). Maybe it would benefit from cleaning.

Post by **kcodyjr** » 13 Jan 2014, 09:09

See that bracket next to the blue filler cap? That's where the MAP is mounted on mine.

See how it's just stuck onto a peg where it is, not actually screwed down? Also, it makes no sense to me for the MAP to be sensing post-boost pressure. It's supposed to be monitoring ambient pressure.

I'm going to have to defer to someone that has a 2001. Did they move the MAP?