Volvo 960 2.0T 16v b204ft Issues

Hey guys, this is my first time posting on a car related forum, so please, go easy on me haha

I bought my first Volvo on October 2020, with only 90k km and in really good shape, and since then Im reading here to find help with my issues.

The problem is that the car feels really low on power, 1st & 2nd gear are good, but when Im either on 3rd 4th or 5th(M46), while foot to the floor, it hesitates a lot, its like Im not accelerating at all and after some secs power comes back again, usually happens more when going slightly uphill.
The consume is super high, I got 13L/100 doing 80-100 on highway.

Could it be that because the car was barely driven in the past, it drives so poor now?

The previous owner, one week before selling it to me changed all the filters and oils + timing belt(with 70k km).

I changed the sparkplugs (gap as I rode on the Volvo manual) and wires. Cleaned MAF sensor and throttle body. The hose that connects to the TB had some oil in it (is it normal?).

Today I checked the OBD and I got the following codes:

Fuel injection 3-4-4 & 1-2-1
TCU 4-2-3

Can you guys help me with this to get in the right direction?

Thanks in advance for your help and sorry for my lack of car knowledge, Im really new to this world.

EDIT: Idle stays usually high, between 1-1.5k rpm
Also, checked the injectors resistance and I got 2,7ohms on each one of them

My first suggestion would be to try to find some green book service manuals for your car. It's such a rare setup that it will help you a lot of have that information. It's usually for sale on ebay or many manuals are still available from Volvo.

I'd suggest checking the intank fuel pump as the problem happens when you have a high load on the engine. Try clearing the codes and see which ones come back. The oil in the hoses is normal. It's from the pcv system which dumps oily good into the intake. It's a good idea to take out the intercooler and drain the accumulation and also service the hoses and separator box of the pcv system. Check your engine over carefully for any cracked and damaged hoses. A vacuum leak aka intake leak can cause hesitation and also check the intake hose for the turbo to make sure it's not collapsing when you make boost.

3-4-4 EGT temperature signal absent or faulty << your car probably has a broken exhaust gas temperature sensor. It's located on the back of the exhaust manifold. Unfortunately this sensor is expensive and almost unobtanium... the TCM (turbo control module) needs this sensor input to regulate boost. If it does not get a good signal it will only allow mechanical spring/gate pressure and it will instruct the injection to add more fuel for safety which would explain the lacklustre performance and high fuel usage
If you want proper boost (max 18psi or so) maybe consider ignoring the TCU and installing an aftermarket (stand alone) electronic boostcontroller (like from Apexi or TurboSmart or Greddy, etc )
4-2-3 Throttle position sensor. Signal faulty. << this could be caused by bad adjustment or it could actually be broken
1-2-2 Faulty signal to/from Air Mass Meter << speaks for itself

dl242gt said:

My first suggestion would be to try to find some green book service manuals for your car. It's such a rare setup that it will help you a lot of have that information. It's usually for sale on ebay or many manuals are still available from Volvo.

I'd suggest checking the intank fuel pump as the problem happens when you have a high load on the engine. Try clearing the codes and see which ones come back. The oil in the hoses is normal. It's from the pcv system which dumps oily good into the intake. It's a good idea to take out the intercooler and drain the accumulation and also service the hoses and separator box of the pcv system. Check your engine over carefully for any cracked and damaged hoses. A vacuum leak aka intake leak can cause hesitation and also check the intake hose for the turbo to make sure it's not collapsing when you make boost.

Click to expand...

I found some books and manuals online, like The Gothenburg Bible/The Volvo Performance Handbook, but theres not much about B204FT, anyways still usefull info that helps me learn more.

I erased the codes but they all come back. I will check for leaks and try to service the pcv and intercooler this weekend.

Thanks for the advices!

Janspeed said:

3-4-4 EGT temperature signal absent or faulty << your car probably has a broken exhaust gas temperature sensor. It's located on the back of the exhaust manifold. Unfortunately this sensor is expensive and almost unobtanium... the TCM (turbo control module) needs this sensor input to regulate boost. If it does not get a good signal it will only allow mechanical spring/gate pressure and it will instruct the injection to add more fuel for safety which would explain the lacklustre performance and high fuel usage
If you want proper boost (max 18psi or so) maybe consider ignoring the TCU and installing an aftermarket (stand alone) electronic boostcontroller (like from Apexi or TurboSmart or Greddy, etc )
4-2-3 Throttle position sensor. Signal faulty. << this could be caused by bad adjustment or it could actually be broken
1-2-2 Faulty signal to/from Air Mass Meter << speaks for itself

Click to expand...

Is there a way to test that the EGT sensor is dead? I would consider ignoring the TCU(https://forums.tbforums.com/showthread.php?t=349043) and installing a boostcontroller, but Im really amateur and this job looks really tough for my skills.

Please explain ?speak for itself?. That means it has something to do with EGT?
Replacing the MAF sensor could be the fix for the 1-2-1?

If I had it at the shop, I'd smoke test it and find all the air leaks.

Inspect the MAF terminals for corrosion.

PaulBorsan said:

Please explain “speak for itself”. That means it has something to do with EGT?
Replacing the MAF sensor could be the fix for the 1-2-1?

Click to expand...

No. it means that the code discription is pointing directly to what is wrong with the AMM. It's either broken or not delivering a proper signal due to some issue like contact corrosionor maybe there is a wiring issue to the AMM.

How is the o2 sensor? When it was bad on my b204gt, it was also drinking the gas excessively and the performance was low.
For the idle...might be some leak. Try to pressurize the intake as suggested above.

Cleaned the terminals of the MAF, TPS and O2 sensor (also changed it with a new one). Deletee the codes and the only one that still pops up is the 344. Car still hesitates on full load, when Im 50% throttle it feels lot smoother.

Gonna make a smoke test ASAP, but I already can see a leak on the exhaust manifold.

Thanks for your help guys, will keep you updated!