FZJ80 Failed CO Emissions and Code 25

[FZJFirefly]

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.

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

 

[Old Nick]

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

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.

 

[BTLSHP]

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.

I did same but neglected the vacuum test on the EGR control valve....Guess what eventually cured my 71 code?