Oxygen Sensor Question (differences in models)

  • Thread starter Thread starter Jamie
  • Start date Start date
J

Jamie

Looking at FCP Groton's site at O2 Sensors, can someone please explain
to me the differences when different sensors seem to be for the same
model cars?

My car: 1985 245 Wagon.

There's the $109 Bosch: Direct Fit Oxygen Sensor fits 85-88 240 Models
(This looks like what I have now)

And the $49.95 Walker Universal 3 Wire Oxygen Sensor fits all 85-92
and 1993 non California Models

And the $88 Walker Direct Fit Oxygen Sensor fits 85-88 240 Models

--- What's the difference? The Walker direct fit seems to be just
another brand, like the Bosch one - plug and play. The Walker
"Universal" 3 wire seems to be the same design as the Bosch direct
fit, but you have to do your own splicing and re-use the connectors or
get other ones.

Is that all there is to it? Or is there more? I am not sure if my
sensor is bad, I have to double or triple start my cold engine. I'd
like to pay the $49.95 - but would like to know more. I can imagine
that Bosch is better quality - but will all of these fit my car and
work?

Jamie
 
If your car is hard to start, look someplace else other than the O2 sensor.
A cold engine does not use the sensor to keep itself running. The sensor
has to reach 600 degrees F before it is used by the Fuel Control computer.

With ignition switch off, remove and clean the connector to the AMM. Also
look for vacum leaks via holes in the hose from the AMM to the intake
manifold, or loose or damaged vacuum hoses in general.

Test the tempurature sensor for the ECU.

And since this is an 85, is there damaged wiring coming from the connector
near the brake booster to the engine wiring harness?

Another problem in older cars is a bad check valve in the fuel feed line
wich allows fuel pressure to drop over a period of time which takes a few
cranks to get the pressure back up to spec to deliver the correct amouont of
fuel to the engine.

Add to that a dirty plugged up fuel filter not allowing proper flow and you
have a series of more probable difficult start causes than the O2 sensor.

In answer to your question, all three O2 sensors will fit and function. How
much you want to spend vs work you need to do and brand loyalty is up to
you.

Duane
 
Thanks Duane. I'd like to do a quick rundown:

The 245 started doing what my 1987 740 occasionally used to do, which
is fire right up, idle fine a few seconds and die - or die as soon as
you pump the pedal or shift into gear. After warming up - no problem.
This morning I started it, it died, I cranked again and pumped the
pedal to get it going. I let it idle 15 minutes, got back in and drove
off with no problem. No shift and die.

"> With ignition switch off, remove and clean the connector to the
AMM.

I did this a few days ago.

Also
look for vacum leaks via holes in the hose from the AMM to the intake
manifold, or loose or damaged vacuum hoses in general.
Click to expand...

I found a bad hose last week, but have not looked for other minor
leaks. I will do this.
Test the tempurature sensor for the ECU.
Click to expand...

I don't know how. Any instructions, please?
And since this is an 85, is there damaged wiring coming from the connector
near the brake booster to the engine wiring harness?
Click to expand...

I am familiar with the story about bad wiring harnesses - the mechanic
replaced the one on my 740 when we pulled the engine. This harness
looks good from what I can see, but I'd prefer to swap the harness -
but later. I'll look at this specific area.

Another problem in older cars is a bad check valve in the fuel feed line
wich allows fuel pressure to drop over a period of time which takes a few
cranks to get the pressure back up to spec to deliver the correct amouont of
fuel to the engine.
Click to expand...

I assume this is the check valve right smack on top of the fuel rail?
I'll inspect it.
Add to that a dirty plugged up fuel filter not allowing proper flow and you
have a series of more probable difficult start causes than the O2 sensor.
Click to expand...

The fuel is from the last owner's fill up in August 2006. I bought
this car recently and have been running the old gas out. I'm putting
new gas and seafoam in this week. I plan to change the fuel filter
soon.
I'll hold off on the O2 sensor for now. Thank you!

Jamie
 
Since you have an 85 with an automatic, your starting problem is "normal"
with that year and Electronic Control Unit where the Bosch Part Number ends
with 511. Green-Gold sticker on the ECU underneath the plastic cover on the
right side of the passenger foot well.

Volvo had a "fix" for a couple of years at that time which involved a kit
wired into the temperature sensing circuit for the ECU which is no longer
available. That kit tricked the ECU into thinking it was 10 degrees colder
than it actually was for about 10 minutes. If fuel pressure, idle or timing
are changed to "adjust" for the poor start, those changes are detrimental to
the emissions and running performance at all other operating parameters.

In later years, mid 1987 production run, they changed the ECU to "correct"
the starting problem, and substituted one drivability problem for another.
Starts fine but has sluggish acceleration and poor high RPM (above 3500RPM)
performance. That ECU Bosch number ended with 544.

They finally got it correct with ECU's that end in 554. Last 8 months of
the LH 2.2 Control units. Late production run 1988's. After that they had
to go to the 2.4 or 3.1 LH systems to meet new standards.

The 554 units can be found in salvage yards in 1988 200 and 700 series non
Turbo Volvos. Or any 1985 to 1988 of either series that has been serviced
by a very knowledgable mechanic and an owner willing to pay the $$$ (near
$900 or more) for a new ECU to correct.

I gained the above from a friendly dealership parts person shortly after I
bought my 85. I then "lived" with that starting issue for two years, then
the drivability of the 544 ECU for another year , until I found a 554 ECU
unit in a Pick-N-Pull yard from a rear ended 740.

I was getting ready to buy a refurbished 554 unit from a Bosch authorized
service facility for $365,(local Audi Independent Mechanic) when I lucked
upon the 554. Volvo Dealer ships do not like to sell refurbished and if
they do the price is better through an independent who has a direct
relationship with Bosch.

The starting problem is most prevalent between 55 and 75 degrees starting
temp. Let it idle for a few minutes before diving until the engine temp is
above 75 degrees when the starting temp is in that range would be your best
short (long) term solution until you luck upon a better ECU if you frequent
U-Pick-It type yards or are willing to pay for another ECU whatever route
the ECU becomes available.

If/when you finally do get the 554, you will need to "reset" all the engine
control settings to factory spec since most likely, every mechanic under the
sun has adjusted something to "correct" the problem, without success, and
those wrong settings will play havoc with the 554 running your engine.

Duane
 
Very informative! Thank you.

At lunch I went home and following up on what you said before, here is
what I found:

Check valve seemed OK. I cut a small section of the hose to the
manifold to better seal then taped it to be sure. The wiring harness
from the firewall to the connector had bad casing near the connector.
There was exposed wire for about 2 inches on all wires. I cleaned them
a bit and soaked them in liquid electrical tape. The wiring harness
side looked good. The small hose from the flame trap nipple slipped
off. I replaced it.

Because the liquid electrical tape had not dried, I did not start the
vehicle. Even if this makes no major improvement, these things all
needed to be done anyway.

Thanks,
Jamie
 
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