[Yowakawaka]

Where’s the best place to weld the bung for the sensor? It’s going in a 83 S10 2.8. I was thinking after the Y but I’m not really sure. It’s only 1 sensor so is it better to pull from after the Y or just one side of the motor?

 

[Brawndo]

On yours to get an average reading I would and have put the o2 bung after the Y where the pipe is no longer deformed, providing of course you are using a heated o2 for your gauge / data collection.

 

[oldeerslayer]

What is the purpose of a wideband O2 sensor on a carbureted 2.8L?

 

[Yowakawaka]

@oldeerslayer I’m just using it to play with the carb and see how well I can get it dialed in.

@Brawndo I have this one. I was watching videos and I’m pretty sure it’s heated. What I read is it needs to be 12” away from the motor. I’d think that has to be the same from the cat because it gets hot.

 

[bk2life]

yes thats a heated WB. put it anywhere after the y and before the cat. if its going to be in long term put it up on top at 10pm or 2 pm postions so condensation doesnt collect in it. If it goes bad bosch 17025 is the replacement sensor.
some dyno shops put it inthe tail pipe, so, location doesnt really matter, but, i try to install in Y. On some vehicle i pull a left or right bank o2 and install it there. But, youre only getting half the reading on a v8..
hope this helps

 

[Yowakawaka]

@bk2life this definitely helps. I’ll let you know how it goes and send some pics.

 

[PeteD]

Where’s the best place to weld the bung for the sensor? It’s going in a 83 S10 2.8. I was thinking after the Y but I’m not really sure. It’s only 1 sensor so is it better to pull from after the Y or just one side of the motor?

View attachment 373678

Sensor tip should be parallel to ground or pointing at it to avoid condensation damage.

 

[bk2life]

 

[Mad Max]

The question is...
Are you running the stock Rochester?

If so, (unless you're a Rochester guru) good luck "tuning" that POS.
The only reason (IMO) to run a wide band is to dial in your engine to perfom it's best.
With a carb - as I'm sure you know - this involves mainly re-jetting, idle mixture and possibly adjusting the accelerator pump.
None of that is easy with the Rochester.
Example... the idle mixture screw has a block off plug in front of it to prevent any adjustment, unless it has been previously removed.
The Rochester doesn't even make a good boat anchor 😜
Yeah, I know there are those out there that think the Rochester is just fine... But

If you're running an Edelbrock intake with a Weber or Holley or a stock intake with a Weber conversion, that is a completely different situation...

 

[aitch]

The Rochester doesn't even make a good boat anchor 😜

Hey, actually it might, ........for a really small boat! (and, of course, after a thorough decontamination)

 

[PeteD]

Hey, actually it might, ........for a really small boat! (and, of course, after a thorough decontamination)

No carb is capable of maintaining air fuel ratio as close as a good EFI .(Engine Masters covers this in various episodes) You can spend your life trying. Demonizing a particular device that already has good long term service history is merely noting it's damaged beyond repair or that adequate parts/service aren't available. In that case a similar new unit makes sense for economics of time & $

 

[Mad Max]

^^^ PD
Well sort of... The stock unit is great for average driving, they were on millions of GM units.

There are several replacement (conversion) carbs that do a much better job than the Rochester. A rebuilt Rochester runs near $200, where for about double that you can have a superior carb to the Rochester that gives noticeably improved performance and in most cases, better fuel mileage.

And you are correct... EFI is much better than almost any carb, but the cost, time and resolving all of the issues that may develop can be prohibitive.

Ask I Have No Pants On.
He bought a Sniper set up IIRC, and has not been able to dial it in yet.
Seems like I remember Jimmykicker had similar problems converting from carb to EFI.

I m not trying to be argumentative, but am simply offering the least expensive and (I hope) the best way to resolve problems.

 

[PeteD]

Common issues with all EFI install is failing to heed instructions. ALL grounds , ALL powers must be separate circuit, direct to battery . Any other systems interference will cause glitches. OEs use shielding for this reason.
I've bought several systems for pennies on the dollar , thanks to today's 'close enuf - lack of detail attention' mindset. There was Nothing wrong with them .

 

[PeteD]

Common issues with all EFI install is failing to heed instructions. ALL grounds , ALL powers must be separate circuit, direct to battery . Any other systems interference will cause glitches. OEs use shielding for this reason.
I've bought several systems for pennies on the dollar , thanks to today's 'close enuf - lack of detail attention' mindset. There was Nothing wrong with them .

Many comments oft demonizing the Rochester Q-jet are also same cause as Vari-Jet enjoys. This venerable carb still holds more NHRA records than all others combined .

 

[Yowakawaka]

From my experience, the Rochester was a good, reliable carb. The main problem was the power and un-tuneability. Only time I hated it was driving over Colorado and Utah. To put that trip in a good light, it was slow. But other than that, I never had any problems with it.

@PeteD @Mad Max the weber replacement is a great carb. I’ve been playing with the jets and getting some good results. I want to see how close I actually am to getting the motor tuned. That’s why I’m installing this gauge. Plus, I need to know what direction I need to go as far as ordering more jets.

I like the originality of this truck but I wouldn’t mind an EFI setup on my other rig. Problem is I don’t know what the I’m doing. I was looking into some aftermarket systems and I couldn’t find anything. One guy I spoke to said the 2.8 doesn’t have enough airflow for the computer to do what it needs to do. Well, he said something like that. If you recommend any systems, I’m more than happy to look into them.

After owning this carb for a while and tuning it a little, I kinda see it like this. By the time you spend money on the carb, Wideband gauge, and tuning things (jets, etc), you’ll spend less than 1000 bucks. Plus, it’s simple to do anything to it. In the other hand, you can spend 1500+ for the sniper and probably still need more. It’s harder to diagnose and can potentially have more problems. Like I said tho, I wouldn’t mind trying an efi system out. It would be cool to get into that world a bit and see the difference first hand. Kinda Funny, this is pretty much a summary of what you guys said!!!

I got the bung welded in the pipes and there’re bolted back in the truck. I’ve ran the power wire through the fire wall and wrapped it with wire loom. That’s as far as I’ve gotten so far. I’m just reading and doing research now. The plan is to use a fuse tap in the “RADIO” fuse slot. It has a 15 amp fuse and the directions say to use a 10 amp slot. I’m not sure if this will be a problem. Also, the directions say to use a 12v source and I don’t know how many volts the “RADIO” slot is. I’m working on that stuff.

I keep forgetting to take photos but I’ll get some for you guys!!

Thanks for the replys!!!

 

[PeteD]

Ya, I put wideband O2 on a carb'd vehicle , but quickly found I'd need a data logger to make it useful.So
then I bought a FAST EFI sys for half price from original buyer who didn't get it to work & replaced the carb.Installed correctly in 2014, with its optional distributor, it's self tuning has worked well since My 4200lb Nova runs 12.8s thanks to that, a 352cid destroked 400sbc wAFR heads, 4L80 & 3.73
Still have working O.E. AC & PS.
The ECU shifts @ 6200. The limiter's @ 6500.

 

[Yowakawaka]

I finally got it all in. Just ended a fuse tap, grounded the black, and ran the wires for the gauge.

After getting the motor hot the gauge was reading in the 17s. Sometimes it would read higher and the gauge would read at all (over 18).


Before the drive

First red light around the corner from my house

I adjusted the idle stop screw from 1 to 1 1/2 turns in and took it for a drive. The first light I came to the reading was around 14-15, exactly where it’s supposed to be. On other stops, the reading was 15-16, and others 16-17 again. For some reason it was jumping around at each light. Vacuum leak maybe?

Where exactly are the reading supposed to be and at what speed/rpm? A higher number would be a rich mixture correct?

 

[PeteD]

I finally got it all in. Just ended a fuse tap, grounded the black, and ran the wires for the gauge. View attachment 374223

View attachment 374224

View attachment 374226

After getting the motor hot the gauge was reading in the 17s. Sometimes it would read higher and the gauge would read at all (over 18).


Before the drive View attachment 374222


First red light around the corner from my house
View attachment 374227

I adjusted the idle stop screw from 1 to 1 1/2 turns in and took it for a drive. The first light I came to the reading was around 14-15, exactly where it’s supposed to be. On other stops, the reading was 15-16, and others 16-17 again. For some reason it was jumping around at each light. Vacuum leak maybe?

Where exactly are the reading supposed to be and at what speed/rpm? A higher number would be a rich mixture correct?

ECU will try to hold 14.7 unless WOT demanded. Less is considered Rich . More is considered Lean. (If so equipped)
Carbs will be all over since they lack fast adjust ability. You change jets, etc inside the carb trying for 14.7 @ cruz. WOT shouldn't be richer than 12.5. It's a lifelong chase !
Exhaust leak before O2 nullifies its reading as do most unwanted engine vac leaks.