FZJ80 Failed CO Emissions and Code 25

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Old Nick said:
Definitely double check your timing.

Also @BTLSHP is right on the money, I'm betting. The IAC on our 94 failed the FSM testing, as did the throttle position sensor (TPS). The idle in our rig was all over the place due to those two components failing. Replaced both, and advanced the timing to 6 degrees (something that you could do after you pass emissions), and it runs great.

Text the above components. If they are in spec, then they aren't your problem, and you've just saved yourself some money. If they are out of spec. replace them. Lastly, question... did you pull and reseal your distributor (new o-ring)? If you did, it's possible that upon re-install, it wasn't clocked properly (and that is something that's very easy to do).

I posted up in another thread earlier where a new owner was having similar problems (not the emissions part but starting/and idling). Haven't owned our '94 all that long, but if the IAC and TPS are original to your rig, there's a good chance that they are failing due to age.

BTW - the IAC for '94s is NLA. You can buy the IAC for the '95-'97 and it will work just fine.
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Checked the timing today when I readjusted the tps and it’s at 3 BTDC as it has been. I did remove the distributor for the o ring however I took a picture before of where the rotor was when it was at tdc and matched it up. When you tested your tps how did you know it was failing?

I was able to adjust mine to the point where it “deflects” I think as it just went over the ohm I had selected on my multimeter if that was wrong please let me know.

I’ll definitely look into testing the iacv as even though it’s smoother now the low idle is still annoying me
 
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FZJFirefly said:
Checked the timing today when I readjusted the tps and it’s at 3 BTDC as it has been. I did remove the distributor for the o ring however I took a picture before of where the rotor was when it was at tdc and matched it up. When you tested your tps how did you know it was failing?

I was able to adjust mine to the point where it “deflects” I think as it just went over the ohm I had selected on my multimeter if that was wrong please let me know.

I’ll definitely look into testing the iacv as even though it’s smoother now the low idle is still annoying me
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Hey, man. Off of the top of
My head I can’t recall the exact method for testing the TPS. BUT, there’s a step by step for testing it and the IACV in the FSM… all you really need
Is a multimeter. If you haven’t downloaded it yet, it’s a lifesaver (available for free in the Resources section at the top
Of the page here on Mud).

My TPS was, I’m fairly certain, the original unit as it still had touches of
Paint on the adjusting bolts and on the body of the unit itself (to clearly mark its correct position), the paint was a yellow/orange color. Anyway when I installed the new unit I put it
In the same position as the dead one and tested again… spot on.

The big culprit for my idle issues was a carbon filled throttle body and the faulty IACV. Cleaned up the TB, and installed the new IACV and everything was resolved.

Sorry for the long post, but I will also say that while the TB was pulled and a lot of other things, I replaced all of the hoses
In the engine bay.
 
Old Nick said:
Hey, man. Off of the top of
My head I can’t recall the exact method for testing the TPS. BUT, there’s a step by step for testing it and the IACV in the FSM… all you really need
Is a multimeter. If you haven’t downloaded it yet, it’s a lifesaver (available for free in the Resources section at the top
Of the page here on Mud).

My TPS was, I’m fairly certain, the original unit as it still had touches of
Paint on the adjusting bolts and on the body of the unit itself (to clearly mark its correct position), the paint was a yellow/orange color. Anyway when I installed the new unit I put it
In the same position as the dead one and tested again… spot on.

The big culprit for my idle issues was a carbon filled throttle body and the faulty IACV. Cleaned up the TB, and installed the new IACV and everything was resolved.

Sorry for the long post, but I will also say that while the TB was pulled and a lot of other things, I replaced all of the hoses
In the engine bay.
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I did same but neglected the vacuum test on the EGR control valve....Guess what eventually cured my 71 code?
 
BTLSHP said:
I did same but neglected the vacuum test on the EGR control valve....Guess what eventually cured my 71 code?
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O2 sensors?

I deleted my egr and pair. Total pain but worth it.
 
BTLSHP said:
Ours went to Denver......I did not think I could get away with removing that stuff.
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You would have got nailed and failed emissions. I’m sorry about that, man. Taking all of that garbage out made me feel a lot better… was worried about the engine harness. No need to worry about that anymore.
 
Old Nick said:
You would have got nailed and failed emissions. I’m sorry about that, man. Taking all of that garbage out made me feel a lot better… was worried about the engine harness. No need to worry about that anymore.
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Yes, it had been exempt in Maryland since 2017, they did not even have equipment to test pre-OBDII cars available here. So, driving out there was a bit of a crap shoot as to whether it would pass. It did not. It took us too long to focus on the inboard O2 sensor. Other than that, my daughter picked up a fully refreshed rig. Funny part is the woman 2 doors down was handed her dad's red '96 a month later. So, on one block in Denver two women who are both outdoor types have shinny red 80 Series in their driveways.
 
BTLSHP said:
Yes, it had been exempt in Maryland since 2017, they did not even have equipment to test pre-OBDII cars available here. So, driving out there was a bit of a crap shoot as to whether it would pass. It did not. It took us too long to focus on the inboard O2 sensor. Other than that, my daughter picked up a fully refreshed rig. Funny part is the woman 2 doors down was handed her dad's red '96 a month later. So, on one block in Denver two women who are both outdoor types have shinny red 80 Series in their driveways.
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Very cool! CO sure is a beautiful state.
 
IMG_8317.webp

Okay so as I was poking through the FSM again I found this which supports everyone’s assumptions for injectors, tps, or afm.

So I ignored what I said previous about not shotgunning more parts and decided to buy a new tps, fuel filter, and fuel pressure regulator along with injector seals and I’ll just pull the intake manifold to replace the last few vacuum lines along with the PHH while I’m there
 
BTLSHP said:
Test the AFM with your multimeter. Beyond this, I did nothing to clean the louvers.
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AFM is bad! Adding to the parts list. The afm ranges from 1200ohm > 1500 > 1180 fully shut > while opening max ohm > fully open.

FSM calls for 200-600 fully closed and 20-1200 fully open

This along with the fuel stuff and I have hope this next time I might actually pass :)
 
FZJFirefly said:
AFM is bad! Adding to the parts list. The afm ranges from 1200ohm > 1500 > 1180 fully shut > while opening max ohm > fully open.

FSM calls for 200-600 fully closed and 20-1200 fully open

This along with the fuel stuff and I have hope this next time I might actually pass :)
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Right on, man. You’re getting there.
 
FZJFirefly said:
AFM is bad! Adding to the parts list. The afm ranges from 1200ohm > 1500 > 1180 fully shut > while opening max ohm > fully open.

FSM calls for 200-600 fully closed and 20-1200 fully open

This along with the fuel stuff and I have hope this next time I might actually pass :)
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AFM is not an easy repair and it is no longer available. Post in Rising sun 4x4, I think Denver has a shop that knows the AFM. It is a Bosch device btw.

This is the rebuild shop I have heard does a good job:
www.bavrest.com

Air Flow Meter Service

Bavarian Restoration refurbishes all Bosch Air Flow Meters to meet factory specifications. Let me tell you that this is one of the most important sensors for your engine. After 10 or so years, these...
www.bavrest.com www.bavrest.com
 
BTLSHP said:
AFM is not an easy repair and it is no longer available. Post in Rising sun 4x4, I think Denver has a shop that knows the AFM. It is a Bosch device btw.

This is the rebuild shop I have heard does a good job:
www.bavrest.com

Air Flow Meter Service

Bavarian Restoration refurbishes all Bosch Air Flow Meters to meet factory specifications. Let me tell you that this is one of the most important sensors for your engine. After 10 or so years, these...
www.bavrest.com www.bavrest.com
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I’ve had a sister post on rising suns this whole time lol.

I just bought an eBay one that ima going to test when I get it to make sure it’s in spec then get my oem one rebuild when I have the time and money as my temp tag will expire in 2 weeks.

I know bavrest I’ve talked to them before about my e30! It’s cool to know they do stuff for the 80s in a way as well!
 
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Well new afm is bad right out of the box so now I’m outta luck.

By chance does anyone have a confirmed good afm they could sell me that’s not farther than hour - hour and a half from Denver?
 
FZJFirefly said:
Well new afm is bad right out of the box so now I’m outta luck.

By chance does anyone have a confirmed good afm they could sell me that’s not farther than hour - hour and a half from Denver?
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Look two posts up. You can get it rebuilt in Denver.
 
I am looking. I got a PM from someone in Denver when I was going through this off a Rising Sun post.
 
FZJFirefly said:
Well new afm is bad right out of the box so now I’m outta luck.

By chance does anyone have a confirmed good afm they could sell me that’s not farther than hour - hour and a half from Denver?
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A word to the wise of owners of 93 and 94 Land Cruisers. All the "new" AFM for sale on EBay are all made in China, and are total junk.
This is the very reason why i went ahead and bought and good used Factory Toyota AFM off of a Land Cruiser being parted out here on Mud. As time goes by this part will become harder and harder to find, and WAY more expensive if you can even locate a good used one.

​

 
Welp that eBay guy didn’t do anything but spray paint it and reseal it.

image.webp

Still reads 2000ohms at fully closed when it should be 200-600.

I have no clue what to do atp so if anyone finds a in spec afm let me know as otherwise it’s probably getting sold.
 
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