Official Gramps' Memorial Eternal OT Thread

#34,129
#34,129
1972 Grad said:
Isn't the O2 sensor usually located in the head pipe just past the exhaust manifold? If so, the sensor reads the fuel mixture before the exhaust goes through the catalytic converter. In that case, it doesn't look like it would try to run rich. I'm just guessing here because I know much more about carbureted cars without oxygen sensors.
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Most vehicles these days have 2 sets of O2 sensors (V6 and V8 cars) upstream (before cats) and downstream (after the cats). The first ones check for air/fuel ratio primarily, the second ones are primarily for cat/emissions reading. @marcusluvsvols you have some options. Check rockauto for pricing, they are very reasonable and their inventory is usually in stock. Also, check Amazon. They won't be OEM but they'll work just fine. The light is probably throwing a P0420 code (emissions related).

Or just straight pipe it after the first sensor. Sometimes the ECM will reset after driving or you may have to take it to a tuner shop, they can bypass the cats for you and eliminate it.

And everything ND40 said. If you post the codes, he can tell you if its a particular o2 sensor or something else.
 
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#34,130
#34,130
marcusluvsvols said:
So I spent 7 hours yesterday on I85 troubleshooting my truck that cut off and wouldn't crank...tested everything electrical, fuel pump and relays etc...no luck. Finally called a tow truck and hauled it to the mechanic. They checked it out today, it was mud packed into the cam sensor. They cleaned it all out, she told me it would be $100 for the diagnostic and clean out. Got there to pick it up...she hands me my keys and says have a blessed night. Prayer answered...it was free. Walk to my truck and crank it...its dirt track racing loud. Oh no...look underneath...somebody stole both my catalytic converters. Sawed them off with a cordless sawzall . So they can sell em to a junkyard for prob $20 or $30, each.

What kind of piece of sheit sees an older Toyota thats obviously not a rich person's truck, broke down on the shoulder of the interstate...so down on their luck...and thinks to themselves "hey!!! I'll go steal this poor bastards stuff and cost him another $500 minimum so I can get $50" ??? What a piece of sheit human being. Good grief. I am still thankful...the Lord did answer my prayer about my truck. Unfortunately a couple of failed abortions decided to stop by and kick me in the balls. ..
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Sorry, Marcus. Wouldn't it be nice if just once somebody got caught with a load of stuff they'd stolen.
 
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#34,132
#34,132
ETV said:
Most vehicles these days have 2 sets of O2 sensors (V6 and V8 cars) upstream (before cats) and downstream (after the cats). The first ones check for air/fuel ratio primarily, the second ones are primarily for cat/emissions reading. @marcusluvsvols you have some options. Check rockauto for pricing, they are very reasonable and their inventory is usually in stock. Also, check Amazon. They won't be OEM but they'll work just fine. The light is probably throwing a P0420 code (emissions related).

Or just straight pipe it after the first sensor. Sometimes the ECM will reset after driving or you may have to take it to a tuner shop, they can bypass the cats for you and eliminate it.

And everything ND40 said. If you post the codes, he can tell you if its a particular o2 sensor or something else.
Click to expand...

Any idea how the computer reads the O2 monitor? Is it dynamic - or would a simple resistive load work? My guess it it can't be that simple, but sometimes ...
 
#34,134
#34,134
ETV said:
I know just some of the basics of the system. This link can explain it in greater detail than I can.

What the Home Mechanic Needs to Know about O2 Sensors
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I'd forgotten they generated a voltage, but the ones downstream of the catalytic converters should only be there to check cat operation and not used in the changing fuel mixture. I could see maybe faking a sensor downstream of the converters but not the O2 sensor in the exhaust manifold. I always wished when I had car manuals - the real ones - that they included better theory of operation sections.
 
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#34,135
#34,135
AM64 said:
I'd forgotten they generated a voltage, but the ones downstream of the catalytic converters should only be there to check cat operation and not used in the changing fuel mixture. I could see maybe faking a sensor downstream of the converters but not the O2 sensor in the exhaust manifold. I always wished when I had car manuals - the real ones - that they included better theory of operation sections.
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The manuals are out there, not the haynes ones. The OEM manuals I've located are for sale on FB marketplace or eBay, usually by current or former dealer techs. Prices vary, mostly on condition and demand. I was able to locate the OEM parts manual and a shop/service manual with the electrical supplement for the Z28
 
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#34,138
#34,138
ETV said:
The manuals are out there, not the haynes ones. The OEM manuals I've located are for sale on FB marketplace or eBay, usually by current or former dealer techs. Prices vary, mostly on condition and demand.
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Those are the ones I used to buy. They generally were pretty in depth on how to test, more limited in how systems work, and pretty sparse in the theory of operation - the difference in determining by yourself how to troubleshoot vs just being able to follow the steps they provide.

I've been trying to track down how the OBD-II system handles the tire pressure monitors and found a bit of info online. If things work as they should, you can interrogate the system and read tire pressures as you drive, the Maestro monitoring system I installed with my new stereo gives me the option of all kinds of engine info I can display as gauges, but the tire pressures aren't coming up. It's frustrating because my car has low profile Z rated tires stock - expensive if you screw up and sensitive to temperature change in the spring and fall. I may buy another OBD-II code reader that connects to an iPad and see if it does anything with the tire sensors. BTW - apparently the tire pressure sensors are battery operated and expected to last 5-6 years, so if the system starts acting funky ... I hate being captive of someone else to do monitoring and diagnostics for me.
 
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#34,139
#34,139
RavinDave said:
What became of your catalytic converters? You know they're worth some money, right? For the precious metals.
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Yep...stolen.


The 1st set of 02 sensors are RIGHT in front of the cats....so they stole those too when they cut the pipes out. The rear ones are still there. I'm gonna straight pipe it and hope it enjoys running with better airflow, I have heard that lack of backpressure can reduce torque....hope that isn't an issue. The engine on this thing...i swear it is lowballed when they listed at 240hp. It weighs like 6k, its a big SUV that had 3 rows of seats, but it gets up and goes much quicker than my trucks have, or our Honda Pilot with a VTEC V6 also listed at 240HP. I love this engine so far. Gas mileage sucks and the brakes aren't great either...gonna put new pads on it...but it has power anywhere in the RPM range, especially for only 4.7 liters. I only get 15mpg, but I am pretty heavy footed so I understand. Hopefully i can get these straight pipes welded on tomorrow and be good guys.

I REALLY appreciate that several of yall offered both advice, and help. Thats what I was posting about the other day. You guys are good to me and eachother, we always try to help one another. The VN brotherhood needs to get together and have a tailgate/game next season. If yall get me full of whiskey, I will beat up one of the libs for your entertainment (just kidding, kinda) would love to meet yall and hang out for a bit . We need to make it happen. I am 4 hours away, but have lots of family still in Knoxville including my Mom. Later

Edit...wasn't so much kidding about a couple of lib posters...would love to backhand a couple of them. The mouthy ones never show up when its time to get down to business though. I have always had to go find them in their habitats. Been seeing some weird texts lately about a crazy woman..then i remembered I put EL on ignore a while back. 1st person ever. Lol...BTW, I believe I am the 1st one to ever call her out for being a woman. I could tell by her catty, snarky tone she was a chick from day 1. Bet she's a real sloppy jo...
 
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#34,140
#34,140
marcusluvsvols said:
Yep...stolen.


The 1st set of 02 sensors are RIGHT in front of the cats....so they stole those too when they cut the pipes out. The rear ones are still there. I'm gonna straight pipe it and hope it enjoys running with better airflow, I have heard that lack of backpressure can reduce torque....hope that isn't an issue. The engine on this thing...i swear it is lowballed when they listed at 240hp. It weighs like 6k, its a big SUV that had 3 rows of seats, but it gets up and goes much quicker than my trucks have, or our Honda Pilot with a VTEC V6 also listed at 240HP. I love this engine so far. Gas mileage sucks and the brakes aren't great either...gonna put new pads on it...but it has power anywhere in the RPM range, especially for only 4.7 liters. I only get 15mpg, but I am pretty heavy footed so I understand. Hopefully i can get these straight pipes welded on tomorrow and be good guys.

I REALLY appreciate that several of yall offered both advice, and help. Thats what I was posting about the other day. You guys are good to me and eachother, we always try to help one another. The VN brotherhood needs to get together and have a tailgate/game next season. If yall get me full of whiskey, I will beat up one of the libs for your entertainment (just kidding, kinda) would love to meet yall and hang out for a bit . We need to make it happen. I am 4 hours away, but have lots of family still in Knoxville including my Mom. Later
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Well, I think we know who the culprit is.

Right @McDad ?
 
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#34,149
#34,149
1972 Grad said:
It is a Summit carburetor which is a remake of an old Holley 4010, which was Holley's version of an Autolite 4100.
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I've had a couple of quadrajets and a couple of Autolites. My dad was a big British car guy. Take 2 screws out of any carb and they remind me of spaghetti. Two things I never learned how to fix, transmissions and carburetors, I left them to drug addicts and weird people.
 
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#34,150
#34,150
VolStrom said:
I've had a couple of quadrajets and a couple of Autolites. My dad was a big British car guy. Take 2 screws out of any carb and they remind me of spaghetti. Two things I never learned how to fix, transmissions and carburetors, I left them to drug addicts and weird people.
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I have never been inside a transmission. Looks complicated.
 
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