Oxygen sensor

[Rc 415]

Hey all, I just replaced my oxygen sensor, and I would like to know if it is supposed to get power? because I tested the lead and it has no power going to it, If it is supposed to get power can someone tell me where the wire goes after it goes behind the engine?

[rfmaster]

Rc 415

O2 Sensor (NBO) should get 450 mV DC bias with ign on - engine off. Once engine is running O2 voltage should flactuate between 50 to 950 mV as ECM adjustes mixture from lean to rich and back.

GM used purple wire for a single wire NBO in TBI systems. I believe that CCC uses the same color for O2 sensor.

//RF

[Rc 415]

my truck is carbed... so I should look for a purple wire?

[rfmaster]

RC 415

Your '82 should have a computer controlled Carburetor - (CCC) Q-Jet. It uses O2 to provide mixture feedback information to computer (ECM) which in turn controls mixture control rod in the Q-Jet. ECM is hidden behind the glove box.
Personally I have avoided CCC systems like a bad decease. GM put this abortion while they were trying to iron out ECM speed issues as early ECM's were too slow to provide real time response in true EFI systems. Plus, Q-Jet tooling was still available and it was 'adapted' to CCC system. Back in those days, early 80's micro processor chips were just becoming fast enough to handle real time data so as to provide control outputs in EFI - such as TBI and TPI.
As GM cars transitioned from CCC to TBI or TPI wiring harnesses retained previously designed circuits.

Yes, look for purple color wire going to O2 Sensor.
//RF

[Rc 415]

So if I bought a non computer controlled carb how much work would it be to have it run right? also i'd probably need a new computer right?
basically, I'm buying a new carb anyway, a reman Rochester E4ME, exact replacement for my current carb, but I would like to know if you think I should get a diffrent model Rochester, one not computer controlled like the M4MED?

[rfmaster]

Rc 415

Since both of us live in the Eco-nazi state of California there are very few choices available. Remember, that your 83 is still subject to bi-anual smog check that is not going away.
With respect to your induction system - you must restore it to original configuration - ECM, sensors, carb, etc. CCC systems have been notoriously difficult to maintain due to half baked nature of it. The other option is to install 87 and later TBI EFI which is easier to maintain and allows for engine modifications. For more information look at thirdgen. For emission certification you may have to go through smog referee, but once it is done you'll be in better shape (fuel economy and emissions)

From personal experience - I've had it with carburetor maintenance and constant adjustments - and switched to EFI - never regretting the effort and money spent. BTW, I now get 18 MPG in 3/4 ton truck vs. 11 MPG I used to get.

//RF

[Malo83]

rfmaster i'm in the same boat as Rc415 with an 83 an the CCC E4ME Qjet you have any more info on your EFI conversion??? sounds like something I would look into down the road.

[Mickey_D]

The hardest part of doing a TBI conversion is if you're not fluent in electronics. There's a lot of custom wiring to do (unless you've got more money than common sense) and a little fabricating of brackets to do.

To sum it up, you're going to need the following:

TBI intake manifold
TBI unit
TBI distributor
TBI ECM
TBI ignition computer module
TBI fuel pump
custom fuel return line
custom wiring harness for first 6 items

Once you get the manifold and TBI unit installed, then put the distributor in, it's a matter of running the fuel return line and fabricating brackets for the throttle cable and the transmission shiftdown cable (if you've got an automatic).

Then fabricating the mounts for the ECM and ignition computer (I prefer the idea of putting them in the engine compartment instead of trying to custom make a firewall throughput, but that's just me), then comes the most time consuming and possibly frustrating task - wiring everything up. You're going to have probably 3 or 4 different wiring diagrams that you'll have to follow so you get the right connections for everything.

For anyone who's ever wired up a custom stereo system in a car, this won't prove to be much more daunting. But if you've never had experience with a pair of terminal crimpers, you're in for a learning experience.

It's well worth the effort, though. I'm going to be doing it to my 81 very soon.

And both of those considering it in this thread are a couple steps ahead of me. I don't have a hole in my exhaust manifold for the O2 sensor.......

[rfmaster]

I have to disagree with Mickey-D on couple of minor points, but overall you are right on.

To do a TBI conversion, ideally, you should have a complete donor vehicle. This reduces the need for putting TBI system piecemeal, which can turn very expensive after while. To avoid this, before starting conversion, I've compiled a comprehensive spreadsheet outlining every component and module. Not being shy - Junk Yards (JY) are your best cost effective source for most of these parts.

Basic electrical skills is a must. Understanding Ohms law, using a DVM. Ability to make brackets, punch holes - i.e a well stocked tool box and shop skills are required. If you are uncomfortable around a drill press or do not know how 1/4-20 bolt looks like this is not for you.

Designing and implementing fuel system took majority of my time. I have a dual tank system which allows for individuall tank selection. I also built a surge fuel tank which prevents fuel starvation during turns, etc. Plumbing fuel lines was not that difficult - I used braided fuel lines from summit with appropriate fittings.

I used several sources (among others) to guide me along:
http://www.bustedjeep.com/projects/junkyardtbi.asp
http://www.jagsthatrun.com/
http://grimers.com/vehicles/68wagon/efi/moparefi.php
http://www.binderbulletin.org/forums...ad.php?t=47254

and perhaps I should write my own as well.

//RF

[Mickey_D]

Horses for courses, rfmaster. Your way is probably a lot better than mine, it's just that's how I learned it all.

The first time I did something like this, the internet wasn't available. Mind you, that was putting the Bosch CSI system out of a 1980 Saab 900 into a 1979 Chevy Luv 4X4 in 1991....

But of course, things have come a long way since then and the ways of doing it have improved greatly since I first muddled through it. I agree with rfmaster in that a complete donor vehicle is your best bet.

[rfmaster]

LOL - I learn something new everyday!!
I'll try to compile write-up about my conversion experience and get a critique going.
After completing this conversion I can tell you that 'aurora' of black magic surrounding EFI has been lifted. GM EFI - TBI comparatively speaking is rather straight forward. 'General' learned from it's mistakes in CCC and designed a system that was maintainable and adaptable to various applications. It is not ideal (there is no such thing), as it was designed for low end torque, but parts are readily available and diagnostic flow trees are reasonable.

//RF