89 Cherokee failed emissions - HELP!

The original O2 sensor is under recall and I do not believe the aftermarked Bosch unit will work with the french renix computer you have.

I also spent money on my 88 then I finally I had spent enough to get an exemption when the damn $tealer's computer wouldn't give the exemption! Turns out the computer was smart enough to know there was a recall on the O2, unlike the techs that worked there.....

Put the 'free' O2 in and the readings have been low for the last two tests since.

I also got a bunch of my money back on the BS parts changing and called the pricks for charging a GST tax when it is exempt so got 2 or 3 test costs plus the extra tax on the final test back.

Stupid freaking 'mechanics'! I took it to a $tealer to avoid the BS from recalls and such, but they are worse than anyone!

Mike

Randy Perk>

First, lose the bosch O2 sensor. They're nothing but trouble. Put the factory one on.

Second, it's a heated O2 sensor. If the heater circuits aren't working correctly, you'll never see 'closed loop'. Needs the right thermostat too.

Third, expect to see those nice low NOx numbers rise as you lean out the mixture.

Fourth, slap the fool that put the new cat on a vehicle that's cranking out over

That's a start.

I am running a Bosch 02 sensor on my 88 XJ 4.0 for about 3 years with no problem. It just passed the Illinois emission test either late last year or early this year..........I forget.

Did that shop plug into your ECM to see what was happening?

Other things that may cause your problem are your:

1. CTS (Coolant Temperature Sensor). It may be faulty and not allowing the closed loop!
2. MAP may cause a rich mixture, so you need to check the vacuum to it also!
3. Are you sure those injectors are the right ones?

I stocked up on new 02s in case I need one or my parents' 88 XJ or another Jeeper needs one. :-) Oh and I should have a couple of used ECMs around here somewhere too!

later, dave AKA vwdoc1

Hey Dave, Thanks for the info. I have had two folks tell me that they had problems getting the Bosch O2 sensor to work. I am also going to check the CTS, MAP, MAT and ECM. I am going today and try and get a waiver to give me some more time to deal with the problem. I called the dealer in California about the injectors and they assure me that they are the correct ones. Possibly you or someone knows if these 19 pound pintle type are correct? Thanks, Randy

Have you considered converting to propane?

It would be less expensive if you found a shop, or person, that could plug into your 89 XJ to see what the ECM sees! A good shop might have one of the Snap-On Scanners that might have an adapter to hook up to yours.

good luck, dave AKA vwdoc1

Dave, the shop I took it to is an authorized emissions repair facility. They had it on the scanner/analyzer and what they tell me is it shows that the O2 sensor is not going into closed loop mode. Not sure if I have the correct terminology. Most of the feedback I get it seems that the ECM is what goes into closed or open loop..?? I am going to let the Jeep dealer put in the OEM O2 sensor (free on a recall) and then look at all the sensors input to the ECM. Could be that my ECM is bad...??Thanks for the info about the 19 LB fuel injectors. Any input is most appreciated. All the best, Randy

OK It is not going into closed loop (when the 02 sensor comes online) ............Now why is it not going into closed loop is the question! Yes it could be the 02 sensor. Also it could be a temperature sensor problem causing it not to go into closed loop. Yours was WAY too rich so I would suspect a temperature sensor problem. :-( And I will ASSuME that the fuel pressure was checked. I think you indicated that it was.

That shop should have been able to tell you what else was not right.

Let us know! later, dave AKA vwdoc1

Thanks to everyone for the input, it was all helpful. Mike Romain hit the nail on the head. The Bosch O2 sensor was the problem. Took the Jeep to dealer for free recall install of new Mopar O2 sensor. Immediatly took the Jeep to two different emissions test facilities. It now passes easily! Where the HC was in the 300+ range its now in the 20's. The CO is almost unmeasurable. Fantastic. Well you live and learn..Dont run down and buy any old O2 sensor..maybe you will get by with it but I sure didnt. Thanks again and all the best. Randy Perkins Fort Worth, Texas

WOW That IS good news! Did you keep the Bosch 02 to get your $$$ back?

Now I wonder if my XJ's or my parent's XJ's Bosch 02 sensors will go bad.

Way to go Randy!! :-)