Top C Posted September 26, 2021 Share Posted September 26, 2021 I need to replace 02 sensor on 87 4.0 Jeep Comanche engine. I see many replacement ones but what is the correct part for this engine & year? I know its made up of certain materials which if not correct would not work properly. The engine will not go into a close loop even when it reaches correct temperature. Although the engine seems to run okay but I'd like to make sure it's going in to Open & Close loop like its suppose too. I've also clean the grounds. Thanks for your input Mike Link to comment Share on other sites More sharing options...
Ωhm Posted September 26, 2021 Share Posted September 26, 2021 Make sure you got Battery Voltage on pin D2_9 (O2S Heater). Depending on which wiring (w/fuel pump ballast resistor or wo/fuel pump ballast resistor) you have will determine how to read this voltage. Meaning it either HOT with KEY ON or HOT when fuel pump relay is ON. Also with KEY OFF check for continuity between D2_9 and engine GROUND. Looking for ≈6 Ωhms. Link to comment Share on other sites More sharing options...
Top C Posted September 30, 2021 Author Share Posted September 30, 2021 I've check this and I found 12volts D2-9 key on and I found 4.2 ohms on D2-9. So I think the 02 sensor is bad as it calls for 5 and 7 ohms. I will check the ohm reading at the 02 sensor. Looking at the physical description of mine and comparing it to new ones, the new ones seem shorter and in some of the descriptions for new ones they call it an upstream 02 sensor. I think because mine is ahead of the catalytic converter it would be an upstream 02 sensor. Is there a one manufacturer better over another prices are all over the place. Should I look for one that says upstream? Thanks Mike Link to comment Share on other sites More sharing options...
dasbulliwagen Posted September 30, 2021 Share Posted September 30, 2021 Check MOPAR first for new ones. They still had new ones years ago when I got one for my 87, but thats been a while ago. I work at a GM dealer now, and we've been having problems with Bosch sensors lately and won't use them anymore. For the price, I would get a new one weather you find you need it or not. And I'm pretty sure the older models only had one O2 sensor. Link to comment Share on other sites More sharing options...
fiatslug87 Posted September 30, 2021 Share Posted September 30, 2021 If you have not come across this yet: Link to comment Share on other sites More sharing options...
BlackComanche89 Posted September 30, 2021 Share Posted September 30, 2021 6 hours ago, dasbulliwagen said: Check MOPAR first for new ones. They still had new ones years ago when I got one for my 87, but thats been a while ago. I work at a GM dealer now, and we've been having problems with Bosch sensors lately and won't use them anymore. For the price, I would get a new one weather you find you need it or not. And I'm pretty sure the older models only had one O2 sensor. Agree, Bosch is crap for the moment had to replace two of them after only a couple of months.. Trying a Walker for the moment hopefully it will work Link to comment Share on other sites More sharing options...
Ωhm Posted September 30, 2021 Share Posted September 30, 2021 8 hours ago, Top C said: I found 4.2 ohms on D2-9. So I think the 02 sensor is bad as it calls for 5 and 7 ohms. I will check the ohm reading at the 02 sensor. Most faults are OPEN circuit on the O2 Heater circuit. O2S is a maintenance item. Link to comment Share on other sites More sharing options...
Top C Posted September 30, 2021 Author Share Posted September 30, 2021 Okay thanks to everyone that responded. I went to the replace (junk) yard and found one from a 87 Cherokee check it with ohm meter and it appear good so for $10.00 not bad. I put it in and now it goes to close loop with in a few minutes. I will purchase a new and keep this as spare to use check if the new one goes bad. I'll check with Mopar for a new one first. I also have a RenixEngineMonitor form Nickintime and that's how I found my close & open loop wasn't working correctly. I wish he would make some up in clock face that would be the greatest. Thanks Mike Link to comment Share on other sites More sharing options...
JustEmptyEveryPocket Posted September 30, 2021 Share Posted September 30, 2021 1 hour ago, Top C said: I wish he would make some up in clock face that would be the greatest. You and me both. I'm waiting to buy till those come back. Link to comment Share on other sites More sharing options...
fiatslug87 Posted October 1, 2021 Share Posted October 1, 2021 Like this? Link to comment Share on other sites More sharing options...
JustEmptyEveryPocket Posted October 1, 2021 Share Posted October 1, 2021 @NickInTimeFilms Yea, like that one. Just like that one. Would pay $$ for one. Just like that. Link to comment Share on other sites More sharing options...
Top C Posted October 1, 2021 Author Share Posted October 1, 2021 Wow just like that one where in the world did you find that one? That's exactly what I was looking for. My original ones great but this would really dress the dash up. Link to comment Share on other sites More sharing options...
fiatslug87 Posted October 1, 2021 Share Posted October 1, 2021 I bought it from a member on here several years ago. Link to comment Share on other sites More sharing options...
Top C Posted October 5, 2021 Author Share Posted October 5, 2021 On 10/1/2021 at 11:41 AM, fiatslug87 said: I bought it from a member on here several years ago. On 9/30/2021 at 11:04 PM, JustEmptyEveryPocket said: @NickInTimeFilms Yea, like that one. Just like that one. Would pay $$ for one. Just like that. Link to comment Share on other sites More sharing options...
Top C Posted October 5, 2021 Author Share Posted October 5, 2021 Update to the 02 Sensor I went to the Jeep dealership today to see if they had a replacement 02 sensor which they didn't but I did get an updated Part number CH5014215-AA in case some one is interested. I check on line for this part but no results. I got a new one in from PartsGeek which is a NGK/NTK 23553. The physical shape of the sensor is shorter than the old one I wonder if that makes a difference? I found an old 02 sensor that appears physically the same as this new one. Before I install this new I'm going to put this old similar one in and see if it works. So as not confuse someone in an earlier post I made, I found the exact same one in a junk yard as the one I pull out that and its working now but who knows how it will work that's why I wanted a new replacement. Will update with my findings in a little while Mike Link to comment Share on other sites More sharing options...
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