cc93cruiser
CRUZAHEAD
Now that these sensors have been in your trucks for some months now, any updates? Just bought 2 denso units for my 93 and a out to do this mod.
ARCHIVE Repurposing 95-97 Oxygen Sensors for 93-94 1FZs
- Thread starter NLXTACY
- Start date
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Now that these sensors have been in your trucks for some months now, any updates? Just bought 2 denso units for my 93 and a out to do this mod.
All good here. No CEL, passed CO emissions, truck running great.
No issues as of late, meaning no check engine lights.
cc93cruiser
CRUZAHEAD
Well, I was not so fortunate as far as repurposing the Denso 4153's into my 93. It never ran right. At first, I swapped the blue and the white terminals as per instructions on this thread. About 20 miles later, I got a code 26. So I uninstalled the new o2's and repined back to how they came from factory. The truck ran even worse, no code but no power at all. Couldn't even reach highway speeds. For the past month or so, I had been chasing a bad idle, stutter etc. I replaced TPS sensor, efi relay, fuel pump, checked all vacuum lines including air intake hose. Cleaned the IAC valve/throttle body, nothing! Still ran the same. That's when I thought I would replace the o2 sensors with the Denso units, but as mentioned that didn't work out. Swapped the old units back along with a new ECT sensor. Problem all along was the ECT sensor that communicates with the ECU. But just wanted to mention that the repined Denso units did not work on my 93.
Lextronix
SILVER Star
I had a similar experience when trying to repurpose the Denso sensors. I wasn't able to observe any rich/lean switching on my Toyobd1 reader. It would show full lean or rich depending on the orientation of the blue and white pins. I was pretty excited about this retrofit, any electrical gurus have ideas?
So in the end are you running your original o2 sensors with the fixed ECT sensor? It seems like the Denso sensors were working (not giving you code 25/26) with the pin configuration from the factory. I agree that you shouldn't have to repin the Denso 4153s - just grind the tabs off and install.
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The original post here talks about swapping the pins over to the original connector and switching the location of the blue and white leads. I believe this is incorrect - see my earlier post in this thread (#38). On my 93, the Densos are still working fine and no codes for 1500+ miles.
I'm curious - which obd1 reader are you using? Would you recommend it?
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cc93cruiser
CRUZAHEAD
I switched back to the oem o2s.. My truck with the new o2s repinned or not, never ran right (this was done with the new ect sensor already installed). With it repinned (using old pin connector) I did get a code 26. With it pinned with the factory configuration (using old pin connector once again), the 80 struggled to get to highway speeds and maintain those speeds, an obvious performance loss. I would depress accelerator about 75% and engine hardly gained any speed/rpms and was still hesitant...
Interesting...since you have 2x 1993s, I wonder if the Denso o2 sensors would do the same thing on your other truck. If it does, then it's very likely an issue with the Densos. But if not, then you may be facing another issue. My truck has always struggled to get up to highway speeds so I assumed it was normal. Once I get to 70mph though it can maintain it without issues. Since you're just across the bay I'd be happy to meet up somewhere and hash this out.
^^ WE links fail, need update @NLXTACYUnfortunately this is going to be one of a my few threads that is NOT photo intensive and that is just because I ran out of time before leaving town and I wasn't thinking about photos at the time. So...sorry
Here is the deal: 93-94 oxygen sensors from Toyota are now NLA and I'm sure by now the last set have been snapped up. But 95-97 oxygen sensors are still aplenty. In fact I carry the Denso on the site:
80 Series Denso Oxygen Sensor- Front, Short Pigtail
80 Series Denso Oxygen Sensor- Front, Short Pigtail (DOS-2)wits-end.mybigcommerce.com
80 Series Denso Oxygen Sensor- Rear, Long Pigtail
80 Series Denso Oxygen Sensor- Rear, Long Pigtail (DOS-1)
After a lengthy conversation with a customer it was decided to have him make the attempt to convert the 95-97 sensors to be used on the 93-94 trucks. For those not familiar, the 95-97 (OBD2) setup is upstream and downstream (inline) whereas 93-94 (OBD1) are left and right banks.
After going thru the EWD for both the 97 and 94 trucks it seems there was a path forward to convert the sensors. Again, my apologies for not having photos. Maybe someone else will add photos after doing this themselves. But simply put the only thing different between the sensors is the wire colors and connector. The physical sensor is the same for up vs down and right vs left. So all that needed to be done was figure out the wiring and swap the connector.
So one by one you remove the old 93-94 sensor, use VERY skinny terminal pin tool to remove the pins from the connector. You will NEED the connector. If your connector is melted or broken...my condolences. Now remove the connector on the new 95-97 sensor (with the pigtail length that matches best) and ALSO remove its connector. Re-pin according to the drawing below and then BE SURE to use the OLD connector on the NEW sensor. Rinse and repeat with the remaining sensor. After more than a month now and a few hundred miles, the truck is running awesome, picked up some increased mpg (don't expect a lot) and no more CEL.
View attachment 2151884
mudgudgeon
Resident galah
Malleus
Far west of Siegen
Different length pigtails. Same connector housing.
But we (OBDI) still need one each for left & right? Or two of just one of them to work in both locations?
edit: asking because I'll prob move mine to the former PAIR ports on the ex manifold. Thinking 2 shorties will work best if possible.
mudgudgeon
Resident galah
Do we know which is long, which is short?
Malleus
Far west of Siegen
I used to. If I can find my notes before someone else posts the answer...
mudgudgeon
Resident galah
Denso 234-4135 ~18" wiring harness
Denso 234-4137 ~10" wiring harness
Denso 234-4137 ~10" wiring harness
I just did this on my '94.
- Got a check engine light code 21 (Heated oxygen sensor (H02S)- cylinders 1, 2 & 3 – circuit, per this site) which is the outer O2 sensor. Mine actually smoked a bit.
- I bought an O2 sensor for the 95-97 models (Denso 234-4153 Oxygen Sensor). Plenty of wire length. Was like $53.
- I shaved down the outer ribs as mentioned in prior post (turned on angle grinder and simply pressed connector onto flat side of blade to smooth down side ribs to flush). source: Post #38.
- Following that post, I didn't touch the "tabbed" side that actually clips into the harness.
- Installed into pipe, plugged into connector smoothly - I DID NOT retab or switch any wiring connections around - and fired her up.
- No CEL immediately. Didn't have to clear it. And still no CEL reemergence.
If things change, I'll be sure to share. Just happy I didn't blow my wad on a "true" O2 for these 93-94 models. And very glad I didn't mess with re-connector-tabbing anything.
