1990 Renix SMOG, CA problem with running Rich/Lean

[90XJ_Seth]

This is my first post and I'm at a total loss. Please Jeep guys, help.
I've become a mechanic over the past year...

1990 Jeep Cherokee, 4.0L Renix
Bosch 746 Reman Spark plugs
NGK 23553 O2 sensor
New TPS - checked by mechanic to be on spec
New IAC - checked by mechanic to be on spec
Was running high idle at warm 1500-2000
Mechanic said IAC was stuck and should be ok after new IAC.

HC around 160-170
CO over 3.00
NOX well within range

Problem, Can't pass smog because my jeep is dumping gas through the injectors and the O2 sensor is not oscillating it's just reporting a rich condition. O2 sensor is BOSCH but I just purchased and NGK to see if it's different. The sensors were stamped with the same numbers and look identical. There are four wires, red, white, black, and a random yellow at the end of the sensor that connects to another wire halfway up the to the connector. I'm finally at the CA BAR mechanic and this guy is really awesome but he is at a loss as well. I'm seeking some advice. Mechanic says grounds appear ok but he will check O2 sensor grounding again.

Mechanic said at cool start, engine runs to spec according to SNAP-ON reader and at hot it reports normal but is dumping fuel like it's cold. Mechanic also says engine is reporting 230 degrees from the coolant temp sensor when hot around the time the E-fan activates.

Parts list is below that I've already replaced.
***Emissions related fixes and parts installed before today, most done by myself
New Catalytic Converter and exhaust to manifold donut (not by me) 4/2018
New 02 Sensor NGK 2353 4/2018
New vacuum harness (front and rear) 3/2017
*New Map sensor 3/2017
*New TPS sensor Mechanic verified proper Ohms 3/2017
New Spark Plugs - NGK V-POWER OEM SPEC gapped to .035 4/2018
New Spark Wires 3/2017
New Distributor Cap & rotor 3/2017
New Air Filter 11/2017
Oil Change - High Mileage Pennzoil, 10W-40 /STP filter 4-2018
New Coolant Temperature Sensor (Lower block) - 4/2018
Cleaned Throttle Body & replaced TB gasket to manifold 2/2018
Cleaned all ground contacts on block and redid some of them 2/2018
Reman Bosch 4-port injectors with new O-rings 6/2017
New Gas Cap (STANT OEM) 3/2018
New Vacuum CAD lines to transmission / 4wd to reduce vacuum leakage from old hard lines 10/2017
New Vacuum line from intake manifold to 4wd t-connector 10/2017
Cleaned COIL contacts 4/2018
New Accessory Belt 3/2017
NEW IAC 4/2018
New Radiator, Thermostat w/housing, water pump, tranny cooler 8/2017
Refreshed all possible grounds I could locate (May have an issue at dipstick still?)
Mechanic checked vacuum and all was good at all locations
Mechanic said fuel pump and lines hold pressure well and are 31 with key on before start
Tiny intake leak at rear of intake manifold but takes a lot of brakeclean to find
Distributor and coil appear to be giving good blue spark and running proper

***What I have not replaced/repaired
I have not replaced the EGR Valve
I have not replaced the front right bumper vacuum Bubble or the vacuum lines that connect to them. I did close off the side closer to the radiator.
I have not compression checked cylinders

 

[90XJ_Seth]

It's reporting a lean condition not rich condition as stated above.

 

[90XJ_Seth]

Also,
at this point I've nearly memorized most of Cruiser54 mostly RENIX tips.
That's how I learned to be a mechanic.

 

[90XJ_Seth]

Just got the beast back. Mechanic chose not to install new O2 sensor because injectors reading 18.9 ohms. Thinks it is grounding or injectors themselves.

 

[lawsoncl]

Just got the beast back. Mechanic chose not to install new O2 sensor because injectors reading 18.9 ohms. Thinks it is grounding or injectors themselves.

Spec on the 746 injectors is 17.3 ohms, so that seems reasonable.
https://www.injectorrx.com/bosch-fuel-injectors/

 

[90XJ_Seth]

A few additions to my info above:
Automatic transmission
Had to put in a push button starter when the wiring in the steering column failed.
I am wondering if any grounds may have been improperly refreshed when I did the dipstick refresh for grounds.
Could grounding make the O2 sensor not oscillate rich-lean?

 

[90XJ_Seth]

One more thing, new 23553 Ntk sensor is all metal with 4 wires not the three wires with ceramic and boot.

 

[cruiser54]

It should be a 3 wire O2 sensor.

I don't know if NTK screwed up or what, but you're not the first one to have this issue.

 

[90XJ_Seth]

It should be a 3 wire O2 sensor.

I don't know if NTK screwed up or what, but you're not the first one to have this issue.

The mechanic and I both look at the Bosch and the ntk sensor and they are identical. The only difference was at the connector to the actual wire harness it was a slightly different part number. But the sensor itself had all the same markings all the same stamps and was fully metal just like the bosch 12009. They both had four wires, red white black and yellow. The yellow connector wire somehow ended before it ever reach the wire harness though. It was really confusing me. I expected to get three wires but I got more.

 

[cruiser54]

something is not right. There was a guy on Cherokee Forum or Jeep Forum having issues like yours.

 

[90XJ_Seth]

something is not right. There was a guy on Cherokee Forum or Jeep Forum having issues like yours.

I saw that yesterday but forgot my login so couldn't reply.
I'll try to call ngk/ntk directly and see if they can help. I got the part at pep boys and they said they have no say over what's in the box.

 

[90XJ_Seth]

Great news! Finally found an O2 sensor of the correct variety. Ceramic with three wires. Ordering an AC Delco part from car quest. This is my fourth O2 sensor in three months... They verified it was correct before ordering. Hoping my car runs normal on Monday! I wanted ntk but I can't get anyone to guarantee the part is the match before sending. I'll keep you guys posted.

 

[cruiser54]

Great news! Finally found an O2 sensor of the correct variety. Ceramic with three wires. Ordering an AC Delco part from car quest. This is my fourth O2 sensor in three months... They verified it was correct before ordering. Hoping my car runs normal on Monday! I wanted ntk but I can't get anyone to guarantee the part is the match before sending. I'll keep you guys posted.

Thanks!!

 

[Ecomike]

Sounds like NTK is trying to pawn off the 4 wire, HO O2 sensors for 91-01 as usable on the 87-90 which it is not. Second or third one of these I have heard in about 4 weeks. They are totally different O2 sensor guts between 90 and 91. Titania versus zirconia. The Renix is a resistor, the HO produces its own voltage.

Great news! Finally found an O2 sensor of the correct variety. Ceramic with three wires. Ordering an AC Delco part from car quest. This is my fourth O2 sensor in three months... They verified it was correct before ordering. Hoping my car runs normal on Monday! I wanted ntk but I can't get anyone to guarantee the part is the match before sending. I'll keep you guys posted.

 

[cruiser54]

Sounds like NTK is trying to pawn off the 4 wire, HO O2 sensors for 91-01 as usable on the 87-90 which it is not. Second or third one of these I have heard in about 4 weeks. They are totally different O2 sensor guts between 90 and 91. Titania versus zirconia. The Renix is a resistor, the HO produces its own voltage.

I have seen this also. Mis-boxed?

 

[Ecomike]

I have seen this also. Mis-boxed?

I have seen everyone out there showing 97-01 front turn light lenses as being the part they sell for Renic era XJ Wagoneers and 91-96 lenses for the 84-90 Cherokees, and the HO MAT/IAT temp sensors being sold as right for the 87-90 Renix. I think it is just getting worse. I think a key part data base is getting screwed up, maybe out of China....

 

[cruiser54]

Tomco 12134 IAT sensor.

 

[90XJ_Seth]

So Long story longer, I get the AC-DELCO part and it is the exact same part as the others stamped with 1274. I am frustrated. Here is what it has come to, I have ordered a New Old Stock original Chrysler part from Texas on EBAY, it's a verified Jeep guy who had an actual picture of the part so I am hoping for the best. The CarQuest guy in my town is awesome and is ordering another part trying to see if he can get the right one shipped to him this time as well. I now understand more about O2 sensors than anyone who did not engineer them ever should. I hope that I finally get the right part between the two of them. I just wanna smog it and get some better MPG since it is killing the mpg by dumping fuel.

 

[Ecomike]

Did you look at Rock auto to see what they had? That is where I got my last ones, Bosch.

 

[90XJ_Seth]

Did you look at Rock auto to see what they had? That is where I got my last ones, Bosch.

I did, they had all the same part numbers. I have become very Wary of whether or not they will send the correct part. I guess I could have called them but I found an exact part and ordered it to get it ASAP. Still waiting on the Car Quest guy. Never thought it would be so difficult to get a standard part. But then again I am not rebuilding a classic so hats off to those guys who look for months and even years for parts. :badpc: