Hey All ~

I've got an '89 240 DL Wagon. The kicker is that a previous owner installed a turbo set-up out of a 740 in the beast (I don't know what year the turbo is from).

The brick runs out great, but gas mileage isn't impressive (20-maybe 21 mpg on the road).

I'm cleaning the O2 Sensor, but am thinking I may need to look at buying a new one.

Questions:
1. Is the turbo going to screw up the O2 Sensor readings on a non-turbo car?
2. Should I get an O2 Sensor for the 240, or for the 740 the turbo came out of?
3. What's the best Make & Part Number of O2 Sensor I should get? The Sensor it now has is a Bosch 0258003006.


Your thoughts?

 

Are you saying that you have an '89 240 with a TURBO set up later added to the NA engine?

 

Yes, that is correct.

From everything I can see, he did it right - intercooler, exhaust & all.

 

If it runs great now, why mess with it? If you need to replace the O2 sensor just replace it with what's there now. The mileage is normal for a b230ft.

 

So 20 mpg - on the road - is normal/good for this car?

 

Yeah, amid what most people claim this as a gas saver, that engine gets at best 23 MPG in the city. That's what I get and I hypermile mostly.

 

Okay, thanks! I guess I was expecting a bit better highway mileage, based on the EPA rating of 20/25. Also, one of my sons had an '87 740 wagon with the 4-spd/overdrive. He got about 27-28 on the highway.


Again, my primary two questions about replacing the Sensor are:

1. Is Bosch okay, or is there one brand I should go with.

2. Considering that a previous owner installed the turbo out of a 740, should I get an O2 Sensor for a NA 240, or a Turbo 740? Is there a difference?

 

My guess is the only difference between the 740 turbo unit and the one for the 240 is the length of wire, from the pictures the 240 one is longer. I would stay with BOSCH since that's what was used at the factory.

 

Thanks Bubba. The one currently on the car has got about an extra foot of wire, so I wonder if maybe it's for a turbo 740.

Anywhoo... I kind of wondered if maybe the air/fuel/emission mixture would be different on a turbo model, and would require a different Sensor.

 

the B230FT engine has a different ECU and a few extra sensors, and has significantly lower compression. it has a higher flow rate fuel pump and larger injectors. the head has a different camshaft and sodium filled valves. the airbox etc is all different because of the air routing through the intercooler.

the only way *I* would put a turbo into a 240 woudl be to start with a complete B230FT from a 740/760/940and take the whole thing. oh, the turbo has a heavier duty transmission too, the AW71 instead of the AW70, and there's a downshift retard circuit fed by the ECU so you can stay in a taller gear and use the low end grunt of the turbo.

my 87 240 nonturbo has always gotten about 25mpg. 23 at the worst, 27 at the best.

my 92 740 turbo wagon has been getting about 18 around town.

 

Thanks for the good info, Pierce! Did you grow up in the oil pan of a Volvo, or what?

Actually, I don't honestly know what engine is in my Volvo. The previous owner may have just installed the turbo, or he may have swapped engines entirely. Is there any way to easily identify which engine it is?

I do know that it is an AW70 tranny, because I had to have it rebuilt awhile back.


Thanks again!