Zpersico

Hey just recently I put new plugs cap rotor fuel filter o2 sensor (denso) oil change sea foam and fuel additive in my 91 2wd yota pickup... The last thing I did ws the o2 sensor. It had a chk engine light for the o2 sensor and ran rough before I changed it. So after I put the new one in it ran great for a few days w no CEL.. Then just today after driving around stop n go all day it started running rough again. Really bad idle almost sounds like a miss and when you pull away in 1st n 2nd gear mostly it kinda jumps and surges power under moderate acceleration... Only if I slam It to the floor does it get up n go but mid throttle/ pushing the pedal half way it does nothing but run like crap... I've heard of a "cold start injector" and wanna know if that is something to look into because when it's cold it runs fine but once it's warmed up its garbage... If anyone can help that'd be much appreciated! Thank you

BamaYota1

Did you use the direct fit o2? Any codes? Some codes don't trigger CEL.

Co_94_PU

iTrader: (-1)

Not unheard of for new parts to be damaged out of the box.

Check the wiring for damage, and make sure the harness side of the o2 plug is clean and fully seated.

Zpersico

Well, the old o2 sensor was welded in, n when I say welded I mean they layed it on thick... So I got a new sensor n new piece of exhaust tubing. Drilled a hole put a little bead of high temp epoxy around the sensor clamped it in place and put two tack welds on each end... It was air tight after it all dried... The truck ran great for 2-3 days then today like crap but after about 50miles of stop n go(drove somewhere parked n shut off 10 mins later start n drive 5 miles then park n shut off) just before I was driving n it started rough idling real bad almost stalled n the chk eng light flashed for a sec that's it... Can anyone tell me exactly how the paper clip method works to scan for codes? Thanks

Zpersico

The quick connect on the engine side of the o2 sensor wiring was a ball of rust so I hard wired the new sensor to the trucks harness.. N it did run great for a few days. Thanks

HighLux

If the epoxy touched the sensor at all...it will ruin it. I dont even touch the business end of an 02 without a latex glove on so i dont get skin oil on it.

They are sensitive.

Your answer lies in the wiring or something to do with your 02 install.

Why would the 02 have been welded in? doesnt make sense. Also welding the new one one was a bad idea. You want to weld a bung to the exhaust and bolt the o2 to it.

Zpersico

Yea I didn't touch it for the same reason u stated n the epoxy was applied after it was welded so it shouldn't have touched the sensor at all. I knew to be carful. As for the Welding I'm a certified welder so I just did a 2 second tack followed buy a very cold rag to keep temps down... I think it was welded last time bc the old owner wasn't really mechanically inclined n didn't know any better then to lay beads on it like it was the Empire State Building ... I woulda used a bung but couldn't find any as I kinda live in the middle of no where.. No junk yards for 75+ miles ... Kinda the same for parts suppliers :/

HighLux

Well...checked the wiring you spliced? Its gotta be that 02 in some shape or form. Use the Bosch 02 or the denso?

BamaYota1

Stick a paper clip between e1 and t1 ports in the diagnostic connector next to the engine fuse block.

Our trucks don't like anything except Denso direct fits. I would start with pulling the codes, then check the splices you made. I don't think welding the o2 was a great idea, sorry. An exhaust shop would weld a bung on for you for about $25.

Zpersico

Maybe ill do it over again if I get an o2 code... Weld the bung n drop a new denso in there... Is there an ohm test for an o2 sensor?

BamaYota1

http://personal.utulsa.edu/~nathan-b...42oxygense.pdf

Zpersico

Well the o2 sensor has been installed for awhile now, at least 300 miles on it and it hasn't had a check engine light... Yet. I checked for codes and got a code 14. I had my brother look it up bc I ws not in town and he said it ws an ignition related code and most ppl found changing the coil and wires solved it. So that's what I did as soon as I got home and it ran good all last night and all day today ... Until it popped and stumbled today on my way home after driving all day. The CEL flashed for a moment then went off. Then it did it again about 1/2 mile down the road except this time it stalled and wouldn't restart.. So after sitting for an hr it started n ran fine all the way home... I got it home n it had code 14 again. Also after I did the new coil n wires I cleared the codes n checked it and the CEL just flashed really fast as long as I kept the key on... Is this normal?

BamaYota1

http://personal.utulsa.edu/~nathan-b...26diagnosi.pdf

Light flashes about two times per second when there are no codes.

Sounds like a loose connection at the igniter, or a broken wire between igniter and ecu. Check your ignitor per FSM, and if in specs, make sure your wire is good.
http://personal.utulsa.edu/~nathan-buchanan/93fsm/ignition/4onvehicl.pdf

Co_94_pu has a great write up in how to find broken wires in this thread.
https://www.yotatech.com/forums/f116/86-sr5-pickup-22-rec-bogging-out-sputtering-264691/

Co_94_PU

iTrader: (-1)

The first flash (while driving) is the same as the second. The ignition (or other) cut out the motor stalled and picked right back up.

Check all the wiring you redid, paying attention to the grounds and such.

Being a metal worker I assume you can figure out how to make a housing with a bit of scrap. Do so at your earliest convenience. And in case you don't hammer some tube flat bang it around into a tapered rectangle and weld up the seam and put a top on it.

The position of the oxygen sensor in the center of the pipe is kind of important. Also even the fumes from welding or epoxy and alter it's readings.

If you must build an expoxy housing use an old one next time well waxed and you can pull it out and put a new one in with screws. Still might have some fume issues no matter how fancy your epoxy work is however.

And finally, the o2 sensor reading only triggers when it has failed not when it is getting bad readings. The only error code for a badly reading sensor is if it hits the maxium fuel adjustments rich/lean.

tacodriver22

E1 and Te1