O2 sensor

[CopperNick]

Hmmm, just reread my post and oddly enough failed to find any sugggestion that he get rid of the CCC system as you describe it. In fact one of my primary comments was that, if the system is still working properly, that he keep it.

As for my contention that the OBD 1 unit is essentially an idiot, consider, that yes it can be read but only to a limited degree. There is no way to visit it and adjust or alter its configuration. yes it does govern the activities of the carburetor and distributor but within such a limited range of adjustability that for all practical purposes what the factory set as defaults pretty much have to be retained.

Further, I do agree that simply ditching the ECM without also replacing the carb and timer with independently functioning units is absolutely going to cause issues.

Where I was headed was in the direction of the O-2 sensor and whether or not the vehicle actually came with one as delivered from the factory. I am not about to say that it didn't come with one as first assembled but I would point out that there are all too many case of owners opting to delete components when they broke or became unavailable for replacement as a cheap option to shelling out big $$$ to find a replacement that is no longer made or has been withdrawn from dealer shelves for disposal.

Also not here to criticize GM but if you buy a new version of anything they make, better determine rather quickly what wear parts have short life spans and stock up as five years or so later, you may visit your dealer only to find out they no longer carry that item and the aftermarket has not yet picked it up.

For this owner to consider re -creating the O-2 circuit he, at least, has to determine if his ECM has a provision, i.e. plug in, for the necessary wiring, and if his present exhaust head pipe has a bung for the sensor itself. As you point out the sensor is available in many versions with various harness configurations. It is entirely possible that some remnants of the original circuit are still present but how much labor and repair is it going to take to rehabiliate them? This is 37 year old technology he is having to work with. Replicating the stock OEM configuration is a definite goal but is it practical?



Nick

 

[SSmooth84]

I think I found the o2 sensor connection I got to call the muffler shop to see what they charge to install a bung on the exhaust. Is there any o2 sensor recommended ill be going ac Delco 3 wires. How about the other connections like ground and power Any ideas were to connect them. Looks like the o2 sensor should be welded after the collector is this correct?

 

[Clone TIE Pilot]

The O2 sensor is a purple wire with a round weather tight connector. Ebay sells pre made 1 wire to 3 wire adaptors, you plug the purple wire to the adaptor, run the neg wire to any ground, and connect the red wire to any hot only in run circuit. All CCC systems came with O2 sensors which ard one of the most important sensors in any computer engine management system.

CCC ECMs can be reprogramed by burning new PROM chips and swapping them in the ECM.

 

[olds307 and 403]

There is a spot in the fuse box for a 12 volt ignition add on, use it. The heated O2 upgrade should be done to all these cars. There was no comparison between running open and closed loop on my 94 Z71 with an Olds 350 and larger cam. Open loop ran crappy and even crappier as the temp dropped. A tunable ECM was next on the list before it burned.

 

[69hurstolds]

Hmmm, just reread my post and oddly enough failed to find any sugggestion that he get rid of the CCC system as you describe it. In fact one of my primary comments was that, if the system is still working properly, that he keep it.

As for my contention that the OBD 1 unit is essentially an idiot, consider, that yes it can be read but only to a limited degree. There is no way to visit it and adjust or alter its configuration. yes it does govern the activities of the carburetor and distributor but within such a limited range of adjustability that for all practical purposes what the factory set as defaults pretty much have to be retained.

Further, I do agree that simply ditching the ECM without also replacing the carb and timer with independently functioning units is absolutely going to cause issues.

Where I was headed was in the direction of the O-2 sensor and whether or not the vehicle actually came with one as delivered from the factory. I am not about to say that it didn't come with one as first assembled but I would point out that there are all too many case of owners opting to delete components when they broke or became unavailable for replacement as a cheap option to shelling out big $$$ to find a replacement that is no longer made or has been withdrawn from dealer shelves for disposal.

Also not here to criticize GM but if you buy a new version of anything they make, better determine rather quickly what wear parts have short life spans and stock up as five years or so later, you may visit your dealer only to find out they no longer carry that item and the aftermarket has not yet picked it up.

For this owner to consider re -creating the O-2 circuit he, at least, has to determine if his ECM has a provision, i.e. plug in, for the necessary wiring, and if his present exhaust head pipe has a bung for the sensor itself. As you point out the sensor is available in many versions with various harness configurations. It is entirely possible that some remnants of the original circuit are still present but how much labor and repair is it going to take to rehabiliate them? This is 37 year old technology he is having to work with. Replicating the stock OEM configuration is a definite goal but is it practical?



Nick

I think there may be some miscommunications here on both sides of the fence.

Nobody said you said he needs to rid himself of the CCC system. I simply stated a CCC system is ALL or nothing. You can't just launch the O2 sensor and think your CCC system is going to function normally. Because it WON'T. But he's already stated that he DOES have the CCC system and a CCC carb and distributor with EST, AND- he no longer uses the O2 sensor in the system because he has headers. See the problem I'm seeing with that, now? His mechanic even picked up on that part.

Without the O2 sensor, changing plugs is a temporary fix band-aid. The wound will not heal itself. This is why if everything else is stock and working right, he's going to need an O2 sensor. Or, there will be more fouling of those new plugs. The coolant temperature control thermistor input varying the 5V signal to the ECM, and the MAP/VAC sensor may be the ONLY things saving him from a full rich condition 100% of the time because the car always will act like it's in the warm up mode. It will never go into closed loop even when it's supposed to but it also is just guessing on duty cycles for the m/c solenoid at this point because it's getting no feedback from the O2 sensor (proper operation of the CCC system should be around 30 degree dwell and varying a bit on 6 cyl mode or 50% duty cycle for the m/c solenoid when in closed loop). Usually, 5 minutes or so is about all it takes with summer weather atmospheric conditions to get the coolant temps up to 150-170 or wherever the temperature probe says it's ready to go to closed loop. So in current condition, it's likely going to at least give a failure code for a failed O2 sensor.

If a heated O2 sensor is put in the system somewhere, and with the shorty headers it can be put into the head pipe right behind the collector if that gives a bit more room to work with, the heating element will keep it above 600 degrees so it will work properly and give voltage signal feedback to the ECM during closed loop. The original OEM 1-wire self-grounding O2 sensor would need to be very close to the exhaust ports (closer the better) to get to 600 degrees faster. But with the heated type, it can be further away. So with headers, it's ALWAYS a good idea to use a heated style O2 sensor in the collector or right after the collector in the exhaust pipe. If you use it after the collector, ensure you have no leaks at the collector gasket.

If you keep the CCC system, get all the main players to work together properly or you're not going to be happy. If you remove it, make sure to at least change the distributor and carburetor to non-CCC control. It's going to cost you $$ either way.

 

[CopperNick]

Fair enough. I was not aware that he had hedders as part of his existing exhaust system and that, at some point during the header install, the factory head pipe with the O-2 bung from the original set up got trashed in order to run the collector/reducer. That little byte of information makes things much easier to sort out. As has been stated, a bung will have to be sourced and welded into position according to the instructions for that operation. When I went FI on my G-10 an O-2 sensor was part of the install package and being 3 wire, probably has the provision for heating included in it. I never did get into the intricacies of it, just did the weld in as opposed to clamping it on and moved on. My S-10 has Three of them and I have had to replace all of them due to problems/codes repeatedly coming up on the dash. In retrospect, my 85 probably did have an O-2 bung in it's original exhaust and probably an air line to the cat as well. All that was long gone when the car came into my possession, and one of the things that i did have to do with the motor was to lose the e-carb that remained as it was totally dependent on sensor input that was no longer there; think I did it as a package and lost the e-distributor as well in favor of a large cap HEI that I had on the bench that I knew i could tune. The carb got tossed in favor of a spread bore configuration Holley that would bolt right on to the stock manifold.

AS a question prompted by a comment up above, is it worth the work and hassle to crack open that OBD I CCC/ECM and rechip it?



Nick

 

[Clone TIE Pilot]

Fair enough. I was not aware that he had hedders as part of his existing exhaust system and that, at some point during the header install, the factory head pipe with the O-2 bung from the original set up got trashed in order to run the collector/reducer. That little byte of information makes things much easier to sort out. As has been stated, a bung will have to be sourced and welded into position according to the instructions for that operation. When I went FI on my G-10 an O-2 sensor was part of the install package and being 3 wire, probably has the provision for heating included in it. I never did get into the intricacies of it, just did the weld in as opposed to clamping it on and moved on. My S-10 has Three of them and I have had to replace all of them due to problems/codes repeatedly coming up on the dash. In retrospect, my 85 probably did have an O-2 bung in it's original exhaust and probably an air line to the cat as well. All that was long gone when the car came into my possession, and one of the things that i did have to do with the motor was to lose the e-carb that remained as it was totally dependent on sensor input that was no longer there; think I did it as a package and lost the e-distributor as well in favor of a large cap HEI that I had on the bench that I knew i could tune. The carb got tossed in favor of a spread bore configuration Holley that would bolt right on to the stock manifold.

AS a question prompted by a comment up above, is it worth the work and hassle to crack open that OBD I CCC/ECM and rechip it?



Nick

Depends on what the orignal chip was and what the replacement is. The ZZ4 chip is a good upgrade for a CCC SBC but requires a 87 or 88 ECM.

 

[69hurstolds]

Pre-87 ECM's usually only had an aftermarket chip available (or they used to) from Superchips or places like that. But those Superchip PROMS were limited in what they did. There were attempts by some to dig into the PROMS to see if special PROMS could be built to order so all you had to do was switch PROMS to do what you wanted to do, but that effort didn't get very far. And today, OBD1 just isn't worth the trouble/expense any longer. The tuneability just isn't there for the OBD1 like it was later on, but then again, today's PCM's, etc., are pretty much locked down by all the manufacturers now. In the 1990s-2010s there were many companies making tunes and tuning equipment to tweak the OEM units to do what they wanted. A hot rodder's paradise. Now that's gone too for the most part.

 

[CopperNick]

And patents and copyrights still exist and get enforced on stuff so old it makes fossils look contemporary. I'd surmise a whole lot of lawyers got rich by picking the financial bones of the aftermarket companies that had been involved in chip work.

 

[ELCAM]

I think I found the o2 sensor connection I got to call the muffler shop to see what they charge to install a bung on the exhaust. Is there any o2 sensor recommended ill be going ac Delco 3 wires. How about the other connections like ground and power Any ideas were to connect them. Looks like the o2 sensor should be welded after the collector is this correct?

Take a wider picture showing the source of that wire.

I don't think the O2 sensor wire would come from the top of the engine, it would have to cross the manifold and eventually get cooked. I would look for the wire coming from a loom on the firewall or the inner fender.