O2 sensors replaced...now rough start...99 T6

[boosted5cyl]

Interesting thing is that the O2 sensors have no bearing on startup as the ECU is operating in open loop. In open loop mode the O2s have no bearing on running. Once the criteria are met for closed loop (coolant temp and other factors) the ECU switches to it starts using the signal from the (upstream, ie nearest motor) O2's

Are you sure a vacuum line or turbo pipe wasnt knocked when the O2's were replaced? Is your CEL on? You could do a fuel system readaptation. Disconnect the battery for 30mins. When you re-connect it, the key should be in the ignition and at II position. You will need to recalibrate the climate control fan too (turn full on then back to full off).

Heres the abridged adaptation process:


Set parking brake, start engine in P or N. Warm up motor until it reaches normal operating temp or until the cooling fan cycles
Allow to idle for one minute in N, then select D and allow it to idle for one minute.
Accerlerate at normal hrottle position (20-50%) until vehicle shifts into top gear
Cruise at light to medium throttle
Decellerate to a stop, allowing vehicle to downshift and use brakes normally.

BTW where did you get the sensors and were they a direct fit? I might need one for mine......

[boosted5cyl]

Mechanic called me, car is throwing 4 new codes one regarding coolant temp, one for MAF, and two for Turbo circut. I'm going to get the car shortly and taking it to my volvo mechanic. If that info helps in anyway, please inform me. I have had a low coolant light pop up within the last couple months, and added coolant. Didn't think much of it at the time, now I wonder if it was more significant.

Possibly a bunch of "unsettled connectors". Get the specific code #s. If you want to drive to st paul LMK

[boosted5cyl]

To be honest I'm not 100% sure what hardware he is talking about or what he means by "acting as a ground". To me it doesnt strike me as something that would require replacement of an electronic device, but rather checking or ground cables or perhaps reflowing of dry joints inside whatever box he is referring to. I know how you feel about the love\hate thing. Trust me.

Clear the codes, drive it some more, see what comes back. Coolant temp by itself is enough to cause erratic running. In fact it may explain your need to replace the two O2 sensors.

[precopster]

When you say ETM do you mean the Electronic Throttle Module??

The S80s shared the Magnetti Marelli unit from the V70 series of the same era as yours; certainly sounds as though it might be one of the affected ones.

There are a set of copper contacts on the throttle module which wear out. They are associated usually with operation of the throttle in a certain area of throttle movement ie 2/3 to full throttle when you are taking off. Highway cruising uses a different area of the contacts therefore the car behaves. Have a look at this post:

https://www.matthewsvolvosite.com/volvo- ... le-fiasco/

[boosted5cyl]

A new/repalcement ECM is going to cost you an arm and a leg. For now I think I'd disconnect the MAF sensor and see if it makes it drivable until you figure out whats going on. An internal short in the ECM would suck, but I would guess theres a lot of other places it might short out too.

Come to think of if, this issues came up after the O2 sensors were replaced....Hmmm

[boosted5cyl]

You're welcome. Us early-edition S80'ers have to stick together. See if you can have Kline bring the price down on that a little, perhaps "hesitiate" on getting it done. You could try a PM to jimmy57 to see if there are cheaper options for replacing the ECM.

That sucks man, I think If that happened with mine I'd have to part it out, much as it would kill me.

[boosted5cyl]

Win

[boosted5cyl]

Hopefully they'll do the right thing and cough up the dough. Its probably not going to be easy though. On the upside you have a T6 with a new ECU and rebuilt transmission.