S80 T6 '99 Down on power, but only a post O2 code

Post by **boosted5cyl** » 02 Mar 2010, 10:52

So over the last few days ive been checking the OBD codes, on a couple of occasions (ie not very often) a TCV code has popped up. Good news in a way I guess. I was going to swap the TCV with the one on the T5 (Same part) however the pipe are pretty moulded on there, decided to leave it be.

I pulled + shorted the battery terminals to reset the ECM, however im not sure if it was actually successful. I think it only cleared the OBD cosed. The trip odometer and radio stations were still stored.

Took it for a drive and held it in different gears while pulling from lower RPM on full throttle. It seems to pull up to 2500RPM or so then I can hear the wastegates chirping and boost being released. Why would it release boost at this stage? At best it pulls for 3second before letting go. If I hold the gas down for long enough while its producing no power it will misfire.

Also noticed in another thread on volvoforums.com, a guy who brought his NA S80 in to the dealer had the folllowing info from them "Found no codes sotred in system. Monitored ETM using VID. Found reading normal. Checked mass air flow sensor readings. Found readings very high, 25 kg/hr at a steady 640rpm. Repaced mass airflow sensor and remove engine control module to reset fuel trim adaption. Reinstalled ECM and rechecked mass air flow readings. MAF readings are now normal at 14kg/hr. Vehicle now idles smoothly. Road tested to verify proper operation"

Looking at the earlier idle readings that I posted above, My motor was flowing .4lb/s at idle, this translates to 10.88KG/min. seems quite a difference in % terms. I know it might be different for a turbo, but thats quite a difference. Does anyone have some information on what airflow I should be seeing a different RPMs (no load I guess) or even at idle with the T6?

Time permitting, I'll try resetting the ECM again, cleaning the MAF, re-route the CKT sensor lead, fit new airfilter and replace the spark plugs. I have the pre-cat O2 sensor on order as well.

The mystery continues.... I think I may end up sucking it up and going to the dealer, but I want to elimiate as many variables as I can before doing that. I'm not really in a position to start chucking money at sensors so I need to be prudent.

Post by **vegasjetskier** » 02 Mar 2010, 13:45

boosted5cyl wrote:Took it for a drive and held it in different gears while pulling from lower RPM on full throttle. It seems to pull up to 2500RPM or so then I can hear the wastegates chirping and boost being released. Why would it release boost at this stage?

Bad TCV?

Post by **boosted5cyl** » 02 Mar 2010, 14:24

That would be nice. It sucks not being able to drill down to the measuring blocks like I can on a VW with VAG-COM. I'll take another look at the V70, if theres enough piping to cut the TCV off (pretty sure ill break the TCV if I just try and pull the pipes, they are pretty solid.) Ill pull it tonight and swap em out.

Its just annoying knowing you could end up replacing a load of parts, spending $$ and still not fix the problem

Post by **boosted5cyl** » 02 Mar 2010, 23:01

Some progess made today...Have about 60% of the power back, its a veritable rocket compared to before. Now its surging at higher RPMs and overboosting. I have an overboost code now, never thought id be happy to see one! The reason for the overboost code is below.

So heres what I did today:-

Fitted new air filter (old one was not clean, but not exactly pristine either)
Removed battery in an attempt to clear the adaptation info in the ECM (Trip odometer still had a reading, so Im not sure if this was actually successful
Fixed coolant leak on rad pipe on transmission side where it joins a metal pipe towards bulkhead.
TCV solenoid service: removed TCV. cleaned with carb cleaner, excerized with 12V charge, cleaned again, repead, tested good.
Checked all the pipes to the TCV, no leaks found.

Now heres whats interesting and it explains the overboost code that developed today (now that its making some power). While checking all the TCV\Wastegate plumbing I blew on the TCV pipe going to the wastegates and I could hear the air leaking somewhere, big time. Poked around a little and discovered there is some red electrical tape covering about 2.5" of the metal pipe as it turns and makes its way to the #2 turbo (Cyl 4,5,6) and the air is leaking out there. Looks like a pig to get at so I'll tackle this at the weekend probably.

Next test will be in the morning, hopefully it will be more drivable from cold than it has been since all this started.

gunner · Post by **gunner** » 03 Mar 2010, 06:13

My 99 s80 t6 is -with exception of oil loss above doin same thing , runing rich scan shows po335, crank circuit , p1238 , po136, p0036 which are trans & o2 sensors , as result of p0335. I removed crank position sensor after testing in car , found dirty , corroded , cleaned and re-installing till it can be retested ... it can cause missfire and cause flooding and more - my car will barely crawl in this mode... Mitchell on demand tests show voltage signal ok, but when we did a resistance test it failed "specs" ...hense the new crank sensor also known as engine rpm sensor .

My car had extended crank and a service bullitin says re-routing battery cables can help - my car had this done - and tach still jumps randomly ...and I found battery cable laying tightly against crank sensor , now relocated , will advise on if the crank sensor repairs this ....film at 11 .....

Some good advice , watch oil & fluid levels , these nasty leaks will still be needing repair long after a good tranny or engine are destroyed ... my advice is check it daily , chart milage till you know for fact what range it takes to loose a quart (litre to us Canadians) and top up immediatly ....oil is first on sceen for heat protection , and absolute vital to transmission to prevent seals & clutch discs from getting cooked , a state from which they will never recover !

Clean "wet spots " with brake cleans (WHEN ENGINE IS COLD ) - and short road test , inspect whan engine -trans up to temp & see where it is leaking from , repair as required ... leaking oil can fan out to areas with air flow , so cleaning entire area , and short drive are vital with follow up inspection .... hope it helps

Post by **boosted5cyl** » 03 Mar 2010, 06:30

Car was drivable this morning, I can accelerate to 30 or so without fear of it stumbling. So something helped, might have just been the re-run of the adaptation (I removed the battery when I service the PCV).

@Gunner if moving the battery cable doesnt help the crank sensor, you can try shielding it with aluminum foil. I've been tracking milage, issues and maintenance on my iPhone with an app called Car Care, so I have hard data on what was done, when and how many miles it's been since. T6 used 3/4 quart last week, over the course of 305 miles to be exact. Not stellar, but better than the 10+ quarts it would have used before I checked the PCV.

Post by **boosted5cyl** » 03 Mar 2010, 08:12

In the event I might need to replace the metal wastegate plumbing, does anybody know what its description or P/N is? Im out of ideas!!

gunner · Post by **gunner** » 03 Mar 2010, 12:14

Well , my stalled/limp in mode after aggressive merge with traffic problem is related to a loose turbo hose blowing off , for sure , we cleaned the crank sensor on top of bell housing behind cyl head , relocated battery cable laying next to , fixed the tach jump/ extended crank , car ran after crank sensor cleaned - cable moved but panted like a out of breath traffic cop , thats when we opened our eyes and beside l/f rad /intercooler , noticed a piece of intake loose, secured that , roadtest , perfect .... what time is it now? ..........A quick oil change to protect engine from being flooded with fuel (ruins rod bearings , pistons & these two windmills ) and we should be ready for a real trip !

Post by **boosted5cyl** » 03 Mar 2010, 12:43

Sounds like we are both on the right track....T6 is a nice motor. Screamers for the track, luggers for the road as I say.

RE fuel in oil+oilchange. Surely the ECM will cut the injection time to compensate for the missing boost/airflow.......Or were you getting clouds of black smoke?