Will Doe

Ok, my first CF post so I hope I don't screw it up!


I just bought a 90 xj limited 4.0 auto that was sitting for about 3 years ( thanks bendix 9). I learned after the fact that it failed its last smog test.... High NO, very high!
I'm going to try and attach a picture of the results for everybody's viewing enjoyment.

The jeep also had a bad fuel pump ( failed on the way back from the test station, so the story goes).

So far I've replace the pump, located a disconnected vacuum line going to the accumulator in the bumper, and a loose intake bolt causing a lake resulting in a high idle condition once warm.

Would you guys say I've corrected the problem or do we suspect the beginning of a wild goose chase?

Thanks for any advice/ opinions.

I wanna go jeepin' !!!

Will Doe

LEAK, not LAKE.. Effin autocorrect!

caged

looks like you need a new cat.

Will Doe

Crap! But thanks!

I'll follow up with a report this weekend, I found a shop that will test it for $20, so it worth a shot.

salad

Lowish HC but high NO leads me to suspect that combustion trmp is too high. EGR problems? You given the thing a tuneup? Some other things to think about aside from cat.

Will Doe

I was hoping that the two vacuum leaks I found were causing it to run lean/ hot.


And Caged, how did you score a 80k mile xj for $100!!! Did some poor dumb drunk bastard have to explain to his wife why her car never made it home from the bar?

5-90

HC and CO seem to be well WNL, so I'm going to suspect the EGR first. (Yes, we're stuck with the damned thing...)

However, expect both HC and CO to have an uptick when you replace the EGR - I've been through this before. If they jump enough, you may need to replace the catalytic converter after you replace the EGR.

A small vacuum leak isn't usually enough to "lean out" an engine, but it can screw with controls - and have that effect anyhow. NAPA carries replacement vacuum harnesses for RENIX under their house brand (Belkamp now?) - you can get all three part numbers for $50 or so, and it's an easy job.

F1Addict

Here are mine, for comparison...

caged

young lawyer that didn't want to fix it. it wouldn't start and left him stranded on yonge street in toronto. he didn't know it was just the nss. so i scored.

salad

Nice. Kijiji? Also Yonge St ain't so bad. He probably would've given it away for free to anyone who gave him a ride if he was stuck on Finch lol

caged

it was a friend of a co-worker, and it was up by finch. lol.
he showed up in a brand new lexus right off the lot when i met him there.

anyways, back to the op...
we have pretty much the exact same testing here, and with my experience, hi co is almost always due to a bad cat.
don't run the guaranteed to pass crap through it, it's almost a guarantee to fail.

lets just hope they don't change the testing procedure there as they just did here on the 1st.

now they plug right into the OBDII reader, so if you so much as have a check engine light on, or even disconnected the battery, you fail.
you have to wait for 4 days to test after you have done anything to your vehicle or it will show up.

Will Doe

Yup, same retard writing our emissions laws as well. The only think I'm dreading more than the smog test is the trip to the M......*#%^ DMV to pay the fees the last owner forgot to.

McCaffrey

Just replace the cat and stop hoping for a cheap fix. I had very similar results when I bought my 89. Did a full turn-up and parts in hopes that would fix it. Nope, failed again with almost the same results. Finally replaced the cat and passed with very good numbers.

Ca has been doing the OBDII check as part of the smog test for a long time. Thankfully the Renix doesn't have one.

Will Doe

Ok, so I took it down to roll the dice and see what happened, gave almost the same numbers as before, very high NO. I heard you guys tell me to just replace the cat, but it looks fairly new, as does the EGR Valve which I tested and it appears to be fine ( engine stalls when I apply vacuum). I entered the numbers into a fuel mixture calculator I found and it is right where it should be. I plan to test inlet and outlet temps on the cat whenever they let me go home at a decent hour from work. If it is the cat then I'll replace it, but I just hate throwing parts at something that hasn't been diagnosed as faulty, or I'm cheap? Call it what you want...

caged

your cat "could" be hollowed out.
so just because it looks new, doesn't mean it's doing it's job.

replace it with a stock replacement for best results.