Guv Bob presented the following explanation :
Here are some photos of O2 sensor I'm checking out. I had a hard time
finding it from manuals - were either wrong or diagrams hard to understand.
Maybe this will help someone else.

Other sensors are OK - anyone know what each of the other 3 are?

1990 Mitsubishi Eclipse 2.0 DOHC Non-Turbo

Location of O2 sensor and connector
http://imageshack.us/photo/my-images/822/o2sens01.jpg

Sensor on inlet of thermostat
http://imageshack.us/photo/my-images/715/sensor1n.jpg

2 sensors below thermostat
http://imageshack.us/f/214/sensor23.jpg

Wrong group?

Here are some photos of O2 sensor I'm checking out. I had a hard time finding it from manuals - were either wrong or diagrams hard to understand. Maybe this will help someone else.

Other sensors are OK - anyone know what each of the other 3 are?

1990 Mitsubishi Eclipse 2.0 DOHC Non-Turbo

Location of O2 sensor and connector
http://imageshack.us/photo/my-images/822/o2sens01.jpg

Sensor on inlet of thermostat
http://imageshack.us/photo/my-images/715/sensor1n.jpg

2 sensors below thermostat
http://imageshack.us/f/214/sensor23.jpg

In article , guvbob2003
@yahooooooooooooooo.com says...

Here are some photos of O2 sensor I'm checking out. I had a hard time finding it from manuals - were either wrong or diagrams hard to understand. Maybe this will help someone else.



Are you using the Factory manuals (that your order from the dealer?)
Those sold at auto parts stores are useless for stuff like this...

In article ,
Bill wrote:

In article , guvbob2003
@yahooooooooooooooo.com says...

Here are some photos of O2 sensor I'm checking out. I had a hard time
finding it from manuals - were either wrong or diagrams hard to understand.
Maybe this will help someone else.



Are you using the Factory manuals (that your order from the dealer?)
Those sold at auto parts stores are useless for stuff like this...

Very true... (Unfortunately, not mfg's are equally adept at writing
manuals...)

Anyway here another place to check for for a factory shop manual (no
affiliation):

http://www.faxonautoliterature.com/

Erik

BTW, if when you ever buy a new car, as part of negotiations, get the
dealer throw in a set of of factory shop manuals.

On Sun, 01 Apr 2012 14:48:44 -0700, Erik wrote:

In article ,
Bill wrote:

In article , guvbob2003
@yahooooooooooooooo.com says...

Here are some photos of O2 sensor I'm checking out. I had a hard time
finding it from manuals - were either wrong or diagrams hard to understand.
Maybe this will help someone else.



Are you using the Factory manuals (that your order from the dealer?)
Those sold at auto parts stores are useless for stuff like this...

Very true... (Unfortunately, not mfg's are equally adept at writing
manuals...)

Anyway here another place to check for for a factory shop manual (no
affiliation):

http://www.faxonautoliterature.com/

Erik

BTW, if when you ever buy a new car, as part of negotiations, get the
dealer throw in a set of of factory shop manuals.

Always get mine on eBay.
Bought 4 sets so far, for cars +7 years old, which is what I drive.
All GM. Think the most I paid was about 30 bucks for a 2 volume set.
Sometimes you won't find them, so look every couple weeks.
They'll show up.
Here's one for the OP's Mitsu.
http://tinyurl.com/brsveha

I put all new o2 sensors on my daughters 2001 Eclipse.
Amazon had them for half the price of the local auto stores.
Bosch OEM.
Best to use OEM to avoid wiring problems with the so-called
"universals." ECU's are picky.
Don't think the '90 OBDI will give the codes like OBDII, so I can't
advise.
Besides, she had the 3.0 6-cyl, and the OP might have a 4-cyl.
I pulled codes for all 4 of her o2 sensors.
Two of them were about $170 each at FLAPS, half that on Amazon.
The other 2 were about half the price, and no deal from Amazon.
Shop around.

--Vic