2000 s80 2.9L idle and fuel trim issues

rigozzi · Post by **rigozzi** » 10 Oct 2017, 22:56

Need some advise on the next step with my 2000 s80 2.9. I recently picked up this car for just about free. Of course it had no service records but a VIN search showed no major accidents (reported of course) and that the ETM had been replaced under the recall. It had some brake issues but thanks to the forum I was able to repair the ABS module successfully restoring brakes and resolving brake issues. So I started attacking codes. To date I have replaced the following components:
ETM with pre programmed xemodex unit
MAF sensor (Bosch)
Crank Sensor
Fuel injector seals
Fuel filter
ECT sensor and Thermostat
IAT switch/sensor (on air-box)
All vacuum lines in the engine compartment
Spark plugs and coils (Volvo)
All 4 o2 sensors (Bosch)
Oil trap (and hoses)
CVVT Solenoid
Intake/phlenughm gaskets
Cat/exhaust flange gasket
Engine management relay
So after replacing all these parts I'm still having the same issue and it is about to cost me my sanity. After a hard reset the car will either a) start and idle high for 5-10 seconds and then settle and purr like a kitten until warm or b) run like dog poop before stalling and then repeat 2-3 times before achieving a terrible idle. In scenario "a" once the car reaches operating temp, it starts to act as if it is in a misfire condition shaking and sputtering in what I call a "machine gun" idle. If I engage the accelerator the engine will smooth out only to return to machine gun idle. When attempting to drive the car, it will accelerate decent but almost always"bog down" around 2000 rpms sometimes clearing up but sometimes I have to let off accelerator until rpms reach idle and then normal acceleration will return until it bogs down again. The most frustrating part is that it will not throw any codes, or at least codes that I can pull with my scanner but I know it is faulting bc if I clear the codes while accelerating, I can notice an extreme difference in performance, momentarily, but no codes are being shown on scanner. The live data is showing what should be considered acceptable fuel trim data with the exception of B2S2 consistently reading N/A. The other strange thing on the live data is the IAT reading reads, and always has, -40°F. Every so often it will generate codes : P0134, P0154, and P1171 which are all o2 sensor and ETM related codes. I have inspected all the wiring between o2 harnesses and ECU and metered them out with no opens and no shorts showing. One thing, when I replaced exhaust flange gasket I noted the catalytic converter has been gutted. Is it possible that the absence of the catalyst is causing the front and rear o2 sensors to have the exact same readings in turn throwing off the ecu and causing bunk fuel trim and throwing 134 and 154 codes? Also an occasional P0171 code. I have been working on cars for 25 years and Volvos for about 5 and this is hands down the most frustrating troubleshoot of my life. Any insight will be greatly appreciated. Additionally, fuel pressure and compression checks are flawless on all cylinders. ETM update from dealer? Fuel pressure damper? Injectors? Thanks guys.

rigozzi · Post by **rigozzi** » 22 Oct 2017, 14:33

Add fuel injectors to the list of replaced parts. Same issue. Now throwing codes for bank 1 sensor 1 and b2s2 o2 sensor no activity. Is it possible that they are plugged in the wrong ECU plugs?

rigozzi · Post by **rigozzi** » 22 Oct 2017, 21:36

Swapped o2 sensor plugs and it runs like new.........not that anyone gives a shit

Post by **June** » 23 Oct 2017, 01:14

rigozzi wrote: ↑22 Oct 2017, 21:36 Swapped o2 sensor plugs and it runs like new.........not that anyone gives a shit

Congratulations on figuring out that strange problem. I wonder how the plugs got switched to begin with? Don't expect much from the online Volvo community. The 1999 through 2006 S80 2.9 and 2.9 T6 apparently have a GM transmission which being made by GM makes it bad by default according to the experts on here. Therefore not many on here have any interest in these cars. Not to worry, in the 16 years of driving S80 T6 equipped cars I have yet to have any trouble with a transmission. In fact the 2004 S80 T6 has been a excellent car for 14 years and 146K. I have completely enjoyed owning it. Now that you have it running great enjoy your car! June

rigozzi · Post by **rigozzi** » 17 Jan 2018, 13:49

3 months later I will reply June, thanks for the info. I'm assuming the previous owner had swapped plugs, he must have mentioned a half a dozen times that it needed o2 sensors. I have had zero transmission issues in the Volvo or any GM vehicle I have ever owned. Matter of fact, how would it be possible that a Ford owned Volvo (at the time of production of my s80) would end up using a GM transmission? I just hit 200K and the car runs and drives great. I am going for a million miles with this one. Previous record is 750,000 on an Oldsmobile 98 with a 3800 in it..... I think the Volvo can make a mil no problem thanks again June

Post by **June** » 18 Jan 2018, 12:42

rigozzi wrote: ↑17 Jan 2018, 13:49 3 months later I will reply June, thanks for the info. I'm assuming the previous owner had swapped plugs, he must have mentioned a half a dozen times that it needed o2 sensors. I have had zero transmission issues in the Volvo or any GM vehicle I have ever owned. Matter of fact, how would it be possible that a Ford owned Volvo (at the time of production of my S80) would end up using a GM transmission? I just hit 200K and the car runs and drives great. I am going for a million miles with this one. Previous record is 750,000 on an Oldsmobile 98 with a 3800 in it..... I think the Volvo can make a mil no problem thanks again June

I'm now at 152k and no end in sight. Daddy had a 1972 Buick Electra he bought new and various family members passed it around until it threw a rod at 412k. She was referred to as The Red Bomb among my family. My Aunt Janet has the factory wire wheels in her garage to this day.

Nothing Volvo has made since drives as good as our S80 T6 cars in my opinion. If you are not running 93 gas, you have not really felt how much power these cars make. Both of my T6 engines had noticeably less power on 87.

These engines are though, my son showed me videos of two S80 T6 engines being locked up on YouTube in the cash for clunkers program and the length of time both ran with engine cease and no oil was five times longer than any Honda, ten times longer than most 350 Chevrolet engines. If you want to see the US government at it's most wasteful type in cash for clunkers Volvo on YouTube. June