I may have solved my rich running issue, 1993 FZJ80. code 26 (1 Viewer)

[ITRJ]

I bought my first 80 a little over a year ago and have been slowly fixing all the little issues and baselining. After owning it for about a month it started to idle a bit rough and seemed to be down on power. The O2 sensors looked original so I started by replacing those with 1995 Denso sensors. Bank one had some corrosion in the connector so I thought for sure that was the issue. At this point the issue became worse. The engine had no power, misfired and would barely run with the O2 sensors plugged in, but runs well with them unplugged. If I drove it long enough with the O2’s connected, it would throw a code 26 rich mixture. I tried reinstalling the old O2 sensors and replacing with a 2nd new set but no difference. I replaced most of the parts relating to the fuel mixture and tested the rest per the FSM but no luck. The O2 sensor voltages were .6 on bank 1 and .8 on bank so slightly rich and very rich. Long story short, I decided to send out my injectors for testing/cleaning. 4 of them are leaking and need to be replaced. I have ordered a set of Bosche “upgrade” injectors from Cruiserparts.com. I will report back with the results once a receive them. I wanted to write this thread as I’ve seen a few similar threads on this issue with 93-94 cruisers but no definitive solutions. Here’s a list of things I did to get to this point.

-1995 Denso O2 sensors, deleted PAIR and relocated.
-checked sensor signals at the ECM per Fsm
-replaced ECM
-ECT sensor Replaced
-EGR deleted
-all Vacuum hoses replaced, VSV’s tested
-VAF tested per fsm
-replaced VAF with eBay junk (don’t do it! Wouldn’t even run). Reinstalled old unit.
-spark plugs
-fuel pressure test
-regulator replaced
- compression/leak-down
-valve adjustment

 

[Malleus]

 

[csanders]

Not sure if the O2 sensors are the main reason you're running rough, but the 95-97 O2 sensors are different from the NGK 93-94 O2 sensors on the 1FZ-FE. Try replacing the 95 O2 sensors with some NGK 24080s. One of the two OEM Toyota O2 sensors for the 93-94 is NLA, but I believe people have had some success with the 24080s as replacements or using 89465-69115 in both locations.

This is just me, but I'd also keep all the injectors the same, rather than 2 original and 4 "upgrades." You can still buy original injectors ($$$) if the cleaning/flow service didn't fix them.

 

[ITRJ]

NGK 24080 is discontinued. There was a thread on mud about using the 95 spec Denso sensor and a bunch of people reported success. I ordered a set of 6 upgrade injectors. New injectors are $250 cad each x6 plus tax so not the most budget friendly option. Remanned Denso are available for about $280 USD/set. I considered that option but decided to try the upgrade. The difference is 4 ports/injector vs. 2 ports.

 

[csanders]

NGK 24080 is discontinued. There was a thread on mud about using the 95 spec Denso sensor and a bunch of people reported success. I ordered a set of 6 upgrade injectors. New injectors are $250 cad each x6 plus tax so not the most budget friendly option. Remanned Denso are available for about $280 USD/set. I considered that option but decided to try the upgrade. The difference is 4 ports/injector vs. 2 ports.

Gotcha, I thought they might still be floating around somewhere. I think I did see a thread where someone de-pinned and backdated the Denso O2 connectors, but if you're able to plug and play, that should help narrow things down. Good call on the injectors, curious to see how those do. I think the updated 1FZs in the 105 came with 4 port injectors.