260000 1989 Ranger?

[Pono]

Aloha All,

I have owned a 89 Ranger for over 15 years and it has been a rock solid truck. A few questions as it approaches 260000 miles all original except for the transmission. I recently had the check engine light flicker and at the same time the truck missed a beat. The codes that it is throwing are 67, 41 and 63. #41 pertains to the 02 sensor sensing a lean condition and #63 is the TPS below min voltage. To trouble shoot I disconnected the 02 sensor and cleaned the TPS switch. Truck seems to run fine now. Thought I would replace the 02 sensor since it is probably original for starters. My question is with a truck with this many miles other than the normal tune up components what else would be good to replace or clean engine related?

Does the Ranger's gas milage change much with the 02 sensor disconnected?

Thank you,
John

 

[scotts90ranger]

The mileage will likely go down with the O2 disconnected.

Being an extended cab and an '89 and 4x4 (judging by ride height in the pic) you have a 2.9L, by then it should be pretty solid I think, I don't remember if the early ones or later ones were better but someone else might... Anywho, as long as it's staying cool I don't know if I would be too worried about much but yes I would change the oxygen sensor (there might be two, one per bank of cylinders). That year shouldn't have a MAF sensor so don't need to clean that as long as you've done cap, rotor plugs and wires recently it should be decent, about that time valve stem seals would likely be an issue but the valve cover gaskets are probably fried and leaking too, depending on how handy you are that shouldn't be too bad.

 

[SenorNoob]

I wouldn't run anything with the O2 sensor disconnected for any amount of time. (Think seconds.) Seen my dad melt the exhaust manifold off a Nissan that way. (IDK if there were other things wrong, he'd just bought it.)

That's a very clean truck. It still looks new from that angle.

 

[Cees Klumper]

I recommend you check for vacuum leaks and, if you're up for it, replace the fuel injectors with quality rebuilt (Bosch or similar) ones. Single biggest improvement I made to my 248K miles '90 Bronco II (in my apartment parking lot). Got mine off Ebay for about $120 for the set of 6, delivered. I think they are a bit more these days but, from a reputable place, well worth it in my own experience. This is where I got mine:

Pardon Our Interruption...

 

[Pono]

Yes it is a 2.9. I did replace the valve cover gaskets a few years ago. The gasket I would really like to replace is the oil pan gasket. It is hard and brittle just as you mentioned about the valve cover gaskets were. Looks like quite a project just to change the oil pan gasket.

Good call on the fuel injectors. Thank you for the link. Will do.

Thanks guys for the advise!
JM

 

[Pono]

Cees did you remove the plenum in order to remove the fuel rail?

 

[SenorNoob]

Most of the time, replacing an oil pan gasket means having the engine essentially removed. If the leak is serious enough I would probably try it with just the motor mounts unbolted and jack. That gasket is pretty flexible. With patience you might be able to do it.

 

[89longbed]

Removing the plenum to remove the injectors is standard procedure. I don't think you could get it done without removing it. Be prepared to replace the 3 gaskets.

If your injectors are not malfunctioning you can get an o-ring and filter kit for a fraction of the price of new or rebuilt injectors and clean them yourself. There are plenty of YouTube videos to see ways to do this. I used throttle body cleaner rather than carb cleaner because it's safer on things with electronics. It does take more time to clean them than just put in new ones. With the poor quality of some of the parts out there nowadays I try to stay with the original part, NOS or reliable brands.

Pono, I spent the past month getting an '89 to pass CA emissions testing. You may want to review my thread on Ranger-Forums titled 'Rich smog test reading at idle only', especially regarding that 67 code. Be sure you have your tranny in neutral (or Park if it's an auto) when you do KOEO or you'll get that code. You may also want to verify that your thermostat is staying closed until the engine gets warm by checking how soon the top radiator hose gets warm. You'll only have one O2 sensor on an '89. The computer will get more accurate data if it's less than 100k miles old.