Ah ha! Sorry for the ignorance, but what's a DRB? Not an OBD scanner I'd guess? Would that tell me where the leak is?

 

No....

 

Ok. Sorry to sound ignorant... just not familiar with what a DRB scanner is or used for. Better head to Google I suppose. Thanks.

 

Plug off the vacuum line to the cruise control servo.

 

Only scanner that work on Renix xj is either unobtainible or gastly expensive. The mt 2500 scanner works if you can find some one with the connector and cartriage but they just give you values .You cannot access codes from 90 nd down Jeeps.....

 

No. It's the factory scan tool. I have the adapters for Renix.

 

Ok. Replaced all of the soft lines from the charcoal canister. Replaced the EGR (gasket was terrible). Found two MISSING manifold bolts... one was gone, and the other (very front of the manifold) is broken off inside. Replaced the one I could, filled up with premium (I was told this lowered emissions?), and tested it again. Pressure test now passes. However, NOx and carbon monoxide are now quite a bit over. Could the premium gas and octane booster I put in cause HIGHER emissions? The NOx that was .02 over originally is now .72 over and the CO that was almost 5 under the 25 max is now nearly 33...

 

Glad you found/fixed the evap leak. Just NOx and CO. (thankfully not HC). Premium I don't see as a problem. No comment on "whatever product" though.

Which manifold bolt, and, if you check for vacuum leaks with starting fluid maybe you will find something.
I have yet to try it, but I've heard a guy can even use just water to check for vacuum leaks. How is the idle?

Arrrr! (just lost all my text,)Restated in short, if you don't know the history of your 02 sensor you might want to change it. Would expect high HC as opposed to High Nox, but an 89 from a no smog county with 250K + miles, it may well have allot of miles on it. It's crucial for MPG, so you may recoup the $70 before too long.

(maybe an issue with one high at idle, the other high at RPM. The TPS could be checked. The ECT, (engine coolant temp) sensor could tell it to be either rich or lean.

Sorry btw...Silver lining, you can lick this. Might be that high HC would be the one you might not beat.

Vac. leaks, 02 sensor, then the temp sensor might be what I'd be getting after. (and no "mystery product!")

 

I have a feeling it was the "mystery product" (STP octane booster) that shot me on the foot the more I think about it. Higher octane should be running richer. Opposite of what I want, and a stupid mistake. I think I have ant vacuum leaks worked out now. I did change the temp sensor as the gauge was jumping around way more than the actual reading could have been. 02 sensor is probably a good idea, but I think the failed emissions this time was my own doing with the premium gas and STP octane booster. Wellbeing through this tank and try again I think woth regular unleaded.

 

The gauge(or light), sender is top/left/rear on the head. The temp sensor is down under the manifolds on the left side of the block. There is a chart with resistance values for it in my signature. Kind of a booger. With the Jeep jacked up and the front axle hanging, and the left front wheel off both that and the 02 sensor can be reached.

Octane is not really "stuff", it's a rating. It has to do with the oxygen and the hydrocarbon burning smoothly. It's as if there were "stuff" between them preventing them from reacting too fast. That could cause "pinging", predetonation resulting in high combustion pressure and temps that could cause more NOx.

I'm at a loss. That 02 sensor is a thought, that and checking the other sensors. Btw removing and cleaning the IAT, (Incoming Air Temperature), sensor is something most of us could do at any time. It's on-top of the manifold rear of the TB. When you pull it you will likely find it all gunked up. Easy to remove and clean with a toothbrush and some solvent.

Vac. leaks, 02 sensor, then the temp sensor might be what I'd be getting after......Let us know what is up!

 

I'm at a loss too. Used up the rest of the tank with the premium and STP junk in it. Filled halfway up with regular unleaded, and dumped in 2 bottles of 91% rubbing alcohol. Went and had them run it through again, and it failed hydrocarbons, carbon monoxide, and NOx now. I'm going to order an o2 sensor right now. I did replace the coolant temp sensor for the gauge (on the top rear driver side of the block). The gauge reads somewhere down just about 1/4th of the gauge (150ish?), but it seems to be running much hotter than that. I might as well order the other coolant temp sensor and do that as well. Is this the one I am looking for? http://www.rockauto.com/catalog/more...596&cc=1179929

 

Please run it way down, then just put Shell regular in the tank, OK? Yea, an 02 sensor is never a bad idea since it is so crucial for your mileage. (and Hc's)

BOSCH # 12009, NTK #23553, Denso #2343116 I went with NTK. At the start of this thread is a link to 02 info > https://www.cherokeeforum.com/f2/ren...ce-rms-133153/ We have an 02 heater relay (and wire) that can be tested. Nothing "automatic" here. You test things, or hope your shop "gets" 87-90 Renix. 91> OBD might "throw a code for that) A new sensor will not help of it's 5v feed or ground is not there to it.

Idk about CTS's. I usually assume the stock is better than after-market, and test what I have.

In your shoes with high HC and questions about the temp I wouldn't hesitate to put in a Mopar (dealer) 195* T-stat. I don't say that lightly, I very rarely suggest anyone buy anything. In a nut shell, it won't work right if the temp doesn't come up where it belongs, and I've seen "quality" replacements not seat completely. (be sure to put the "weep hole" up, at 12:00)

The Renix ECU will run on default settings until it's up to operating temp. Might think of 160* as a minim. (on default the HC will likely be high).

I have one of those aim and shoot temp guns. I saw my CAT is about the same temp as the pipe going into it. No love googleing there. Been meaning to pull a plug wire while it's hot and see if the catilist does it's thing and burns those HC's, (and makes the converter heat up).

Sorry the HC's came up....No idea if the alcohol mattered. In any case a fresh catilitic converter has been known to get people through. One smog guy said he'd have them just drive across the street from the muffler shop, to his.

 

52028186 factory stat for sure.

Only NTK sensors for me.

 

Deal. I'll get an an NTK o2 sensor and factory tstat in then. May call a muffler shop as well and at least price a new cat.

 

I'm lazy and need to get to work. Which spark plugs are you using?