FJ62 questions - O2 sensor and EGR (1 Viewer)

[tstockto]

I think the list of things I want to do to this truck have resulted in many, many late nights reading these great forums and not a lot of effort on my part to keep track of what i read... Apologies for asking something I know has probably been covered multiple times.

anyway, have owned this truck for about a month or so. it is a 1989 fj62. truck idles rough, gets about 10MPG and I pulled codes 28 and 71 recently (although CEL only comes on if I drive on the freeway for more than about 10 minutes and will go off after a day or so).

Seemed like swapping O2 sensors was a decent start - figured it was something I could do, even with my limited mechanical abilities. Had Jim Dickey do a fair amount of work recently, but I wanted to at least prove to my wife and kids that I can do more than just fix the broken window lock switch...

ordered 2 of these denso 234-4056's from amazon (https://www.amazon.com/gp/product/B000C5WCM2/). Then realized what a PITA it is to get at the sensor with the wire that runs up above the transmission.... well, it also turned out that someone prior to me looks to have welded the bolts to the exhaust. should have really inspected that first i guess. But I still have a few questions.

Q1 - I know a few people here have suggested to access that second sensor from above, from inside the truck. Can anyone explain how that's done exactly? How much interior disassembly is required, etc?

Q2 - It felt like the wire running from the sensor up on top of the transmission was literally just draped over the transmission. is that right? or did it come out of a hanger or some sort? When i reached up there from below, it felt like a mess of wires up there and a lot of dirt and grease. It seemed like a bad setup.

Q3 - code 71 looks to be a tricky one, first thing recommended was to clean out the EGR valve. I'm not able to find any good references for how to do that exactly. I've poked around the pdf FSM's I've found here but maybe I'm looking at the wrong manual... any advice would be appreciated.

Thanks to anyone who has some time to chime in - looking forward to lots of family adventures in this truck - grateful we finally got to a place where we could purchase one (something I've wanted to do for a long, long time!). have had some interesting "adventures" so far just getting it home and to a place where the kids and wife are safe riding in it but would like to have real adventures too. or maybe owning a land cruiser is mostly those other mechanical adventures...

 

[morganism]

for EGR, You should get truck up to temp, put a longer piece of vac hose on the top connector of the egr "tophat", and suck hard and quick on it. You may hear carbon rocks rattle down tube, and truck will try to stall, so do it quick, but do it a few times.

I have found most toyotas run better without o2 sensors even connected. Their is a fallback program in the ECU, that is the default run mode, and if your timing is set correctly, and the vacuum lines are correct, and no major vac leaks, truck will run better without 02's.

That said, you need to disconnect the batt for a while, and i like to turn key on/off to drain any capacitance in car comp. Drive for an hour or so, and truck should smooth out and gas mileage should go up a bit.

 

[tstockto]

for EGR, You should get truck up to temp, put a longer piece of vac hose on the top connector of the egr "tophat", and suck hard and quick on it. You may hear carbon rocks rattle down tube, and truck will try to stall, so do it quick, but do it a few times.

I have found most toyotas run better without o2 sensors even connected. Their is a fallback program in the ECU, that is the default run mode, and if your timing is set correctly, and the vacuum lines are correct, and no major vac leaks, truck will run better without 02's.

That said, you need to disconnect the batt for a while, and i like to turn key on/off to drain any capacitance in car comp. Drive for an hour or so, and truck should smooth out and gas mileage should go up a bit.

Thanks for the reply!

so what happens to these carbon rocks? where do they go? is that a dumb question? i am searching youtube for an example of this sucking thing. sounds interesting...

if i disconnect the o2 sensors, will the CEL come on? the people's republic of california may also frown up on that?

 

[OSS]

My experience with EGR valves is that they can build up carbon deposits internally that are very difficult to remove. The only way to clean out the insides of an EGR valve is to remove it from the engine and then go at it with Mr Muscle Oven Cleaner on the insides (not the rubber diaphragm) and wire pipe brushes/metal pick/small screwdriver scraper. The MMOC is pretty nasty stuff, so wear thick rubber gloves and have forced air ventilation. Actuate the valve a lot with a hand actuated vacuum pump when it's removed and you're cleaning it to ensure the piston moves freely without sticking and the bottom metal valve seals off the chamber tight. Takes some time to get it all clean again. Soak the carbon encrusted parts (not the upper half) over night in MM.

 

[tstockto]

Q1 - I know a few people here have suggested to access that second sensor from above, from inside the truck. Can anyone explain how that's done exactly? How much interior disassembly is required, etc?

Q2 - It felt like the wire running from the sensor up on top of the transmission was literally just draped over the transmission. is that right? or did it come out of a hanger or some sort? When i reached up there from below, it felt like a mess of wires up there and a lot of dirt and grease. It seemed like a bad setup.

figured i would bump this to see if anyone has any advice on Q1 and Q2...

 

[Kleatus]

figured i would bump this to see if anyone has any advice on Q1 and Q2...

Q1 - remove the auto trans shifter housing and boots from transfer case shifter, remove door jam and footwork trim pieces and either peel back or remove front carpet entirely (back to seat brackets - then you will see the cover panel to be removed not that bad of a job really.

Q2 I think there is plastic clip on top of the trans for the wire. If you’ve been grabbing up there blindly you may also find the auto trans vent nipple and hose.

You can buy new 2-bolt flanges for the OEM style O2 sensors. If your old stuff is rusted into oblivion the best thing to do is put in new flanges (and pipe as needed.) I can also assure you the truck will not run better with the 02 sensors disconnected..

As to the EGR, you may find the nuts on the EGR pipe hard to turn - spray some
Penetrating oil on the the threads when it’s hot, I found it easier to to break loose the one at the manifold and take the whole valve/pipe out as one. You have to twist and turn it around to clear things but it will all come off/out as one.

You might also have an issue with the modulator or VSV or vacuum lines and not the valve itself.

 

[tstockto]

thanks @Kleatus that is a great starting point for me! I think I am going to bite the bullet and order the new carpet kit that @dnp is peddling so this goes hand in hand with the o2 sensor access. I still have a feeling this is beyond my abilities and toolset to fix though. The EGR cleaning I feel more confident about.

Thanks for all the replies!

 

[tstockto]

So I finally got the time to take the EGR off and attempt to clean it out. Much easier to remove than I thought it would be. Check out the pics... I'm not sure if this is normal looking? Do I need to disassemble this at all to clean it out or just soak and wire brush? and i assume cleaning out the intake off the engine is good to do also? thanks for the advice so far @OSS

 

[houstonfj40]

sold the 62 recently but this may also be Cat issues. But with the cats you sometimes get the rich/lean codes at same time. I think the are 24/25. On plane and don’t have notes with me. My cats were original it looked, heavy as hell when taken off. New ones welded in and no issues afterwards. Easy to bypass EGR also, just pull the elbo bent vacuum hose underneath and cap both.

Ran so well after this felt bad selling.

Marc

 

[tstockto]

figured i'd post some "after" pics of the EGR valve. Cleaning it was a pretty satisfying task. Mr Muscle oven cleaner did the trick, just took like 3 days of soaking/cleaning/brushing/cleaning. the rough idle resolved itself after cleaning and reinstalling the EGR valve!

as for the o2 sensors... ended up taking that to mr. dickey who had to fabricate new o2 sensor mounts and redo most of the exhaust. it turned out the cats were garbage and needed to be replaced as well... so much for my simple attempt to just change out o2 sensors.

truck runs better than it ever has now. super smooth. unfortunately code 71 keeps coming back. will be tackling replacing all the vacuum lines this weekend and testing other things like modulators and temp sensor.

 

[dannyd]

Hey tstockto, im a little late to the thread. I just picked up a FJ62 with CEL on permanently because of O2 sensors. Did your CEL turn off after you installed them? What type of job is that cost wise?

Thanks!

 

[tstockto]

If there's one thing i learned going through all these CEL codes, it is that there is almost never a single thing that is definitely the culprit... what code are you getting? This thread was maybe my first post on mud, and i had a lot more after this in tracking down the codes 25, 26, 41, 51, 71.

As for replacing the o2 sensors, i gave up trying to get at that one where the suggestion was to go through the trans tunnel from inside the truck. Plus those things were permanently attached due to science at that point in life. Just beyond my abilities. The mechanic basically put in all new exhaust from the manifold back including new cats and muffler. he fabbed new o2 mounts as part of that job.