suggestion needed plz? intermitent reduced performance. no code, no message

[proton]

2005 xc. Sometime, my car fell like if I had push an "eco" mode button like in my wife's car. The engine run very well but just slow to get speed, like if I have less HP. Sometime it is normal and the car has a lot of pull. like yesterday moning, going to work it was ok, my day trips was ok and lose it at the ride home. But in the evening , I got out to bring my son at his lesson and on the halfway, I got it back normal.... I notice that when I'm in "eco" it seam the rpm and the speed I have look weird. Not matching,too much rpm for the speed I get. Like to have your opinions on where to check first. sparkplug 10k km and airfilter about 5k km. No codes. no messages

[Astro14]

Maf

[JRL]

Usually if a MAF becomes that bad it will throw a code

[howardc64]

I had a bad MAF that could cut out the engine entirely without throwing a code. During early stage of failure, the engine would cut out suddenly but not shut off and sudden comes back to life. At later stage of the failure, the engine would randomly cut out completely coming to a stop.

The biggest problem for DIY is how do you know without putting in a new MAF (cheapest is ~$150 Bosch from online stores, do not buy no brand aftermarket. I tried 2 and both were defective) to find out? I was able to swap it with my other Volvo (also P2 same year) and found the problem. If you know someone with a P2 (believe MAF were slightly different on various years, search online for other P2 cars you can try from) and have a 5 point security bit to remove it, its relatively easy and quick to try. I've read there are some MAF testing procedures but I'm not familiar with them.

There are 2 air intake sensors on this car. MAF is before the turbo and MAP is after the turbo and intercooler. I've seen 1 MAP failure before and it produced a code. I don't recall MAP failure's behavior as it wasn't my car. I'll ask the owner and see what they remember.

UPDATE: Spoke with the owner with the MAP sensor failure. The car would bog down once in awhile and wouldn't produce a code. Anyhow, thats another source to consider.

[proton]

the evening before, with the pedal to the floor, I got a few hesitations and then buuuuuuu sick, no power juice. I did not get it bac since. Still no codes. Look at my turbo boost pipe and it look good. Here is my torque screenshot at idle in my office parking. Somethin abnormal? any info you'de like to see.

http://imageshack.us/a/img824/5930/an9p.jpg

[guyeye]

Really can't tell much from this data. Idle isn't gonna tell you much since this isn't when your symptom presents itself.
I had this happen to me before. I was stumped until a neighbor (who used to be a Volvo mechanic) cam over and started yanking (hard!) on all my pipes in my induction system. Turned out that the pipe coming out of my intercooler was loose. The pipe clamp stayed in position, so you couldn't tell from just looking at it. Whenever I hit the throttle hard, it would blow the pipe off the intercooler and I'd bog down and sometimes stall. When I let off, the pipe was lined up so perfectly, it sucked itself right back on!

TLDR: All my problems have been from loose pipes.

My advice? Yank your pipes! Squeeze them too- all along your entire induction system to look for cracks. If that renders nothing, find someone with a dice unit and run the ETM diagnostic (the DICE is also going to tell you if you have other problems and give you a much more complete data set than your smartphone app). If that looks good, buy a can of CRC MAF cleaner. I have a feeling though, that if you ran an actual Vida-DICE scan, you'd find some stored codes. Then you might be able to better decide whether or not to invest in a new MAF unit.

[howardc64]

the rubber hose between turbo and the charge air pipe is well known for being corroded with all the oil that settles there. The oil comes from the PCV system dumping oil vapor into the fresh air pipe (the pipe between MAF and turbo). So definitely check that weak point.

05's ETM is likely okay. I read somewhere that 02+ ETMs have 1 resistive TPS and 1 hall effect (contactless) TPS so a lot more robust than the 01s. But ETM test on VIDA/DICE would probably be a good checkpoint if that test runs on 02+ (I've never ran it on anything but 01s)

Research how you check MAF and MAP sensors. But failures in these 2 sensors are often intermittent. I'd imagine even if you can test it. It might be good while you are testing it. Talk about a hard problem to hunt down. Might need to do what I suggested and borrow a sensor from a car that isn't being used.

[Forkster]

Or the Turbo Control valve is starting to fail. Usually replace it at age 10 + all tubing.

[proton]

tubing look good, main turbo pipe is IPD silicone changed about 2 years ago. Can the pcv system do that. I just did the latex glove trick and it look like it is not blowing as not get aspirated too. I've cleaned the MAS and will see tomorrow if it did something on the road to job. fuel drinking is sky high. Got that out. For the headlight I know, work well, just not stock (EST). cnt downpipe and obx exhaust if it can help for interpretation

http://img28.imageshack.us/img28/2913/5koq.png (http://imageshack.us/photo/my-images/28/5koq.png/)

Uploaded with ImageShack.us (http://imageshack.us)

[proton]

3 days since I've clean the MAF with the CRC MAF Sensor Cleaner. no change at all. So Ive bought the IPD HD TCV and silicon vacuum tubes. will see...this car is killing me......it is paid but still have a terms...:confused:

[proton]

oxigen sensors changed, mass air flow changed.....still the same crappy volvo. I notice that the car is running well at cold temperature. It is when it is att normall temp that it stat to go bad. Still have bad mpg too.

[Thames]

Have you changed the O2 for OEM or "universal" ones ?

[proton]

bosh for the mas and ngk for o2

[howardc64]

sorry to hear you are having such a tough time with this hidden problem.

one suggestion is to look for another vehicle and compare diag tool readings. Most of us have no factory training to understand most of the sensor readings. But if you compare 2 cars for differences, you might find signs of what to chase.

Since you note fuel consumption is high + reduced performance, I'd start with looking at fuel flow rate and ignition timing. These cars are electronically triggered ignition so they can fire it at anytime during the compression cycle to advance or retard the ignition timing. I believe retarding the timing usually reduces power and have more unburnt fuel and is often used as a safety precaution to avoid engine damage when problems are detected by the ECU.

I believe knock sensors are used on modern engines to auto tune ignition timing. Read here for more info

https://docs.google.com/viewer?url=http%3A%2F%2Fwww.wellsve.com%2Fsft503%2 Fcounterp_v4_i4_2000.pdf

I battled a 2001 ETM failure awhile back and got engine reduced performance. I'm speculating that ECU also retards timing significantly upon seeing a bad throttle body readings to avoid engine damage. Just my speculation, didn't go through Volvo tech training :) Again, your 05 likely don't have the high occurrence 2001 ETM failures.