Help! Can't pass PDX DEQ...

Third time was not the charm for me... Do any of you guys have any ideas or tricks to get it through DEQ and tagged?

It's a '90 4.0/AX-15, roughly 180k. Runs great and idles smoothly, but has a bunch of blowby (blowing oil out the filler plug). All the emissions harness, etc. are there and not plugged up that I can tell, but don't seal well as the oily fumes seem to have dissolved the cement holding the joints together. The O2 sensor has about 30k on it, and the cat has about 70k-80k; it's not rattling as far as I can tell.

I just gave it a tuneup (Bosch plat plugs, wires, new cap/rotor, air filter, oil change), but no noticeable change in the emissions numbers


The results were:

HC std: 220
idle: 222
2nd idle: 228

CO std: 1
idle: 3.2621
2nd idle: 3.5963

CO+CO2 std: 6
idle: 12.2
2nd idle: 12

I don't know what needs to be tweaked, as the CO numbers are way off. Any suggestions? I'm curious if there is a way to test the cat, O2 sensor, and EGR, rather than swap and hope for the best. I'm also thinking to just replace the vac harness in case thwe leaks are causing it not to run right, but $80 for some crappy tubing just seems wrong. Hoping you guys have some ideas.

When was the last time you had the Injectors Cleaned and tested ?

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How hot did you get the cat. before you dorve to deq ? All I did to get my 1990 xj to pass on the 3rd try was drive up to goverment camp and back to the deq on 33rd ave.

When my 89 failed, I removed the EGR valve, did new plugs & cap took it back and it passed. Something with the EGR vavle. My buddy build a plate to cover where it mounts and it passed twice. I also removed my cat the second time it was tested and it passed.

I've never had the injectors serviced or cleaned, although I run a bottle of Techron every 3-4 months (I've had this XJ since new), and I just did the 3M topend/injector cleaner. Is there a way to check/test them at home, or a good place to do them cheaply locally? I'm building a stroker with my son, so want to avoid getting a new set of injectors unless they will work in the stroker as well (I think I need 24-27lb injectors for the stroker).
I only drove it about 15 minutes before DEQ. I ran it in 3rd down the highway (it was running 3k rpm), so the temp gauge was hot (at 210), but I didn't think about the cat warming up. The lady there said warming it up more would help it get by the HC check since the numbers are close, but said it probably wouldn't help the CO numbers. It looks like I can do a basic cat test by checking the inlet/outlet temps, and I know someone with a tire pryometer that I can use to cehck the temps, so hopefully I can eliminate that.
I didn't think to check/test the EGR. I'm surprised pulling it helped to pass. I thought the recirc would help burn off the excess HC. I'll try testing/pulling that as well. You just blocked it off and disconnected the lines? I can make a simple cover to block it off, and maybe just leave it hanging in place until I go through the test. I'm also going to try cleaning off and sealing the vacuum harness lines with RTV also; it does smell pretty bad under the hood when running....
Thanks for the suggestions; if you have any more, let me know.

Yep, all we did was fab up a cover, a little hi temp sealant & plug off the tubes. I don't even pretend to understand how all that DEQ stuff works. When I finished a new renix motor it went through DEQ with nothing smog on it. I mean nothing smog, and it passed no problem. So it might be something really simple on your XJ. If you search around you will see a few post of guys that reomve the EGR and say their jeeps run a lot better with out it. I know mine did.

1. Ditch the Bosch Platinum plugs. They're not causing your problem (YET), but the RENIX ignition system does NOT work well with Bosch Platinum's (or any fancy plug), stick with OEM basic Champions.

2. It is running rich, that is your high CO numbers. EGR is NOT causing your problems. Dirty injectors are not causing it. Most LIKELY causes typically are bad oxygen sensor, bad engine thermostat, or bad coolant temperature sensor. You said you've done O2 sensor semi-recently, so that's most likely not the cause. Even if the cat. conv. isn't working, those rigs should fly through emissions/DEQ if the rest of the system is functioning properly. Do you have any vacuum leaks or high-idle issues? Any chance you know anybody who has the ability to scan a Renix-era Jeep? (the auto parts stores will be of no help here).

I'm happy to help you out if you can provide a little more background. I'm in WA, but the laws/limits are similar. For a little background, I own a WA State emissions certified repair facility, and even though I'm technically not a licensed specialist any more, I know the systems and employ certified tech's.

John

Very true on the Bosch plugs. I tried them on my renix and they did not work. Worst plugs for a renix.

Wow; seems like I'm suspecting the completely wrong things.... I'd appreciate your help; please tell me what info you need.

I don't think I have vac leaks, but I'll test the harness. The leaks I know of are from the two vent line off the top of the valve cover, but I think they are under positive pressure?
The idle is rock solid at ~600 rpm. The temps seem fine according to the dash gauge, with the aux fan kicking in around 220(?).
I don't know anyone with a Renix scanner. I didn't even know that era could be scanned at all. I thought they just have the ignition key/flashing light sequence, and even that doesn't work on my car.
I did check the cat with temp gun last night. It looks like the before-cat pipe temp is around 430 degrees, and the post-cat pipe temp is around 460. The cat itself gets to 550, but I think there is something not right with this; is it possible for the temp to drop that fast?
I will change back to the Champion plugs, and try to test the hose harness and EGR with a mity-vac bleeder.

Your new o2 sensor was it the plug and play one or the cut the wires and do yourself?
Also make sure you reset your computer after any changes to the emission system.

The sensor is (was?) a Bosch plug 'n play; I didn't want to futz with wiring.
I don't think mine ('90 Renix) has a resetable computer like the OBD ones.

If you have another car in your name with good tags, take the plates into the dmv and say you want them transferred to your xj. Then buy new plates for your other car.

xj's dont flash cel codes with the key thing, and resetting the computer should just mean unplugging the battery for 5 minutes

streetpirate said:

xj's dont flash cel codes with the key thing, and resetting the computer should just mean unplugging the battery for 5 minutes

Click to expand...

Correct, Renix era XJ's (87-90) don't store codes at all, but there IS data available with the correct scanner.

I don't know of anyone with the drb scanner. I tested the harness yesterday, and it was all good. (pulled vacuum on each line with other end capped off. I did notice the the front breather was not blowing as much oil into the airbox as it used to after I cleaned out the valve cover ( the filter is pretty dry), but it it is still blowing oil out the filler. Does that mean anything?

This might be one of those cases where spending $100 at a shop to diagnose may be your best bet. You can waste an awful lot of money throwing parts at it. If you were closer, I'd be happy to dig into it a little deeper for you.

I'd put my money on a cracked exhaust manifold, Letting air in, o2 sensor then reads a lean mixture, and the computer Compensates with more fuel.

There are more cracked exhaust manifolds on XJ's nowadays then non cracked.. To say it's a common issue, is putting it lightly.

I'd be happy to take it to a shop, if I could find one on the west side of PDX that I could trust. I'm leery of Dick's Jeep after they lost a set of ARP header bolts on my Dodge, and then claimed it never had them, and NW Jeep sent my XJ off with no oil in it after an oil change... If you guys know of a good shop or independent, I'd like to find someone who can diagnose it. Thanks for your offer on digging into it; if I were closer...
I think the exhaust manifold is good, though I'll double check it. It's a Borla SS header, though it is about 12 years old now.

I'm in Vancouver and can give you a hand if your still fighting it.