19963.4lsr5
New member
And how soon after startup does it go closed loop?
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Down on power after car wash (P0172) ?
- Thread starter thegipper
- Start date
And how soon after startup does it go closed loop?
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Boognish_Forever
Member
Did you have the undercarriage sprayed when going through the car wash? If so, the o2 sensor or wiring might of got damaged if it’s old and brittle.
thegipper
New member
O2 wiring is fine, just checked it. Unfortunately I doubt I'm going to be able able to get the Upstream O2 sensor off. The nuts are literally almost non existent. One almost looks entirely gone and the other is a round rusty mess the size of a pea.
I tried swapping the MAF but its still running rough. Haven't had time to take it for a spin since I got the kids and the wife's working. Not sure what I'm going to do about the O2 sensor.
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I tried swapping the MAF but its still running rough. Haven't had time to take it for a spin since I got the kids and the wife's working. Not sure what I'm going to do about the O2 sensor.
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thegipper
New member
I had to remove the down pipe to get the O2 sensor off. Once the downpipe was off, removing the O2 sensor was easy. Unfortunately, one of the studs broke off on the down pipe flange. Not sure how I'm going to fix that, it's the one closest to the engine.
Also, I found this. There was a crack near the O2 sensor flange. The metal is super thin and rusty so I busted out the welder I just got (I'm not a welder BTW). I did my best to plug it up and I was successful. I basically had to make blobs of weld and slowly connect them to keep it from blowing through (machine was turned all the way down). It's ugly but solid.
Tomorrow I'm going to get the downstream sensor off. I'll need to figure out what I'm going to do with the broken stud on the exhaust flange.
If the O2 sensors don't fix the issue, I'm going to swap the injectors next.
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Also, I found this. There was a crack near the O2 sensor flange. The metal is super thin and rusty so I busted out the welder I just got (I'm not a welder BTW). I did my best to plug it up and I was successful. I basically had to make blobs of weld and slowly connect them to keep it from blowing through (machine was turned all the way down). It's ugly but solid.
Tomorrow I'm going to get the downstream sensor off. I'll need to figure out what I'm going to do with the broken stud on the exhaust flange.
If the O2 sensors don't fix the issue, I'm going to swap the injectors next.
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19963.4lsr5
New member
Drilll out the broken stud and re tap it and use a hardened bolt.
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thegipper
New member
I don't see how you could ever get a drill in there. I'd have to remove the next peice that goes to the manifolds which would probably lead to more broken studs.
Not sure what to do.
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19963.4lsr5
New member
Ok so you never pulled the CAT.....on my 96 and 97 the front sensor is in the pipe with cat and the rear sensor is with the muffler section.
sadly you will need to pull it to fix it.
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thegipper
New member
I have a modified setup due to my cat being stolen when my truck was my brother's. So my downpipe is actually part of the old cat. He had an exhaust place weld on a universal cat. I'll see if there is anyway to get the stud out with it in, if not, I'll have to pull that peice of exhaust off the headers.
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rideexileex
Senior Member
Looks like you're in the right direction - I had similar symptoms on an old O2 sensor after getting it wet / through puddles and streams. O2 sensor wiring looks fine, but engine would stutter and die after more water exposure. New O2 sensor was the easy cure.
Depending upon how much of the stud is left, you can try to weld on a new nut to the stud. Soak with oil for a good long while, multiple times, then blast the surrounding area with MAP gas just before trying to remove. Say a prayer it doesn't break again.
Depending upon how much of the stud is left, you can try to weld on a new nut to the stud. Soak with oil for a good long while, multiple times, then blast the surrounding area with MAP gas just before trying to remove. Say a prayer it doesn't break again.
19963.4lsr5
New member
A friend of mine worked at the local Toyota dealer and said they always removed the studs and used bolts.
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I have a 2005 SR5 with 150,000 miles and she never ever failed to start and run properly. The only part that failed in 15 years on mine was the starters, and I replaced three of them with AM from Amazon. Dealer here in the Bahamas once told me they would order a new starter from Japan for over $900. I found an AM at Amazon for $100. I keep a "new" rebuilt Amazon bought AM spare in the garage and my mechanic can install it anywhere for $60.
Water and engines don't mix. Did you wash the engine off? Getting something electrical (wires?) wet will cause your issues. Hopefully, that part will dry off and she will run right again. Had that happen once.
I would never recommend washing the engine or engine bay of any car - no matter how dirty/greasy it got. :bolt:
Water and engines don't mix. Did you wash the engine off? Getting something electrical (wires?) wet will cause your issues. Hopefully, that part will dry off and she will run right again. Had that happen once.
I would never recommend washing the engine or engine bay of any car - no matter how dirty/greasy it got. :bolt:
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cblock406
Member
What do you think happens when you drive in the rain or drive through puddles!? That’s an absolutely ridiculous statement.
thegipper
New member
Did not wash the engine bay, just ran it through your run of the mill, gas station car wash. Plus, it's been several days now and pretty hot here. Any moisture that did get on anything would be gone now.
I've also driven this truck through 24+" deep water on my hunting land with zero issues.
The problem is elsewhere. I know it's not the MAF and a few other basic things. O2 sensors are next once I figure out what I'm going to do with the broken stud in the exhaust. If that doesn't fix it, I'm swapping injectors next.
96RedRunner
Senior Member
Maybe not where you live, happens all the time in the snow belt.
During winter gas stations that have drive-thru carwashes offer free wash with fillup.
21 yrs of washing every fillup if roads had been salted/cindered along with 3-400k other drivers, do the math nation wide.
Sheitte happens not that often.
If it were me I'd call in a GREAT auto mechanic (and stop throwing parts at it). A good mechanic that works on cars every day can troubleshoot and fix any engine IMO. I am not an any kind of (good mechanic) mechanic, myself.
It could be a simple as a dirty fuel injector. Faulty coil? Really good "street mechanics" are out there, you just have to be lucky enough to find one that will come to the house.
Some people will run a hose over the engine to clean off the dirt/dust, and that is a no-no, big mistake IMO.
Just wondered if you ran water directly on engine (to clean).. Been there done that... My sorrow!
BTW. Owned a 1995 GMC Jimmy from new. A 2005 4runner from new. Still runs like new. Had a 1996 Caddi Northstar. The GM V8 engine is tough, but car itself is junk compared to Toyota or Hondas IMO.
Also had three F225 Yamahas on the back of a 42 foot Performance (50 MPH at 5000 rpms - all day long!) that I ran across the oceans here (usually alone) for 12 years until I finally blew a PH.
Still say a really good mechanic can get it running right.
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thegipper
New member
I have spares of basically every part on these trucks minus the o2 sensors which is why I'm replacing them (mine are most likely original, so 220k+ miles).
I already swapped the MAF with the spare I had, no change. I have injectors to swap next if the o2 sensors don't fix it.
So far I've managed to complete this work on 3rd gen 4Rs:
Pull two engines, install one
Pull two transmissions, install one
Two timing belt jobs
replaced starter
rebuild alternator
LBJ's, sway bar links,sway bar bushings, front/rear suspension (twice)
replaced every fluid
steering rack guide replaced
Bled brakes
countless transmission fluid changes
replaced tranny solenoids
fixed broken wires throughout the truck
fixed rear window defrost
fixed the AC system
replaced the exhaust twice
swapped the entire engine harness
And probably another dozen or so things
I have zero intent on taking this to a mechanic.
So far I've spent $100 on replacing things that may solve my problem and if they don't, they needed to replaced anyway. I've also spent maybe 1.5 hours working on this.
Thanks
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96RedRunner
Senior Member
I'll pay myself what that GREAT mechanic is going to charge me, the process is the same. Paying someone else robs you of two things, your money and the knowledge.
gamefreakgc
Elite Member
That crack was most likely the problem! Here's the rationale as of why. That crack in the pipe is allowing unmetered fresh air to contact the oxygen sensor under some circumstances like idling. The oxygen sensor picks up that unmetered air and sensor a high amount of oxygen in the 'exhaust'. That tells the sensor that the engine is not burning off all the air and is running lean, even though it is not. The ECU adds fuel like you are seeing but under some circumstances that crack isn't pulling in much air, like when the engine is under load and exhaust is coming out of the crack instead of fresh air being pulled in. It then throws a rich code since oxygen sensor is out of normal range on the rich end.
If you pull the EFI fuse after that O2 flange weld and drive it around, I'm very confident that the fuel trims will be back to normal.
