Overheat and smog fail

[Ecomike]

While the CAT may be bad, probably is bad, a red glowing CAT can also be a sign of raw unburned fuel getting past a burned leaking exhaust valve, a miss firing cylinder, leaking fuel injector, bad spark plug, lost compression on a cylinder or....etc.

That kind of excess fuel will ruin a new CAT very quickly, so do some tests and see if one injector is stuck open, any cylinders not working right. You can pull the plug wire or injectors, one cylinder at a time. A good cylinder will manifest itself with a rough idle when you kill fuel or spark to it. Might need a compression test if you find a weak power cylinder.

I use local muffler shops all the time, but they don't seem to want to mess with manifold swaps.

 

[88trailcrawler]

Hmmmm

So the red glowing cat could have just been from the misaligned plug wire and maybe isn't one of my underlying issues.

I trouble shoot the cylinders, make sure all my wires are clicked in then look at that CAT again tomorrow.

If the temps are staying down, idle and cylinder checks out and the CAT glow in the dark tomorrow, I may go for retest without new cat.

 

[88trailcrawler]

OK. Thanks for all the help to date. I think (hope) I am getting close.

I am focusing on the CAT right now:
- cylinder check was kinda inconclusive the jeep ran like crap and eventually died with any single plug wire pulled
- I pulled all the plugs and wires today and made sure all was clean and confirmed a solid "click" when plugging in wires.

Started it up:
- ran good in the driveway at idle and higher RPM.
- driving around the block under load, temps come up but NOT too high
- jeep can go down the street and get up to speed but significant loss of power
- feels kinda like mis-fire or exhaust leak (I am not a mechanic)
- back in driveway after trip around block it does NOT idle or rev up like it did before the test spin
- CAT is noticeably much hotter than muffler and down pipe from manifold and is likely glowing red (daylight out still)
- at tail pipe there is no smoke or fuel smell, some condensation and there is black carbon-ish deposits

QUESTION: Is this sounding more and more like a CAT issue?

I don't mind investing in a new CAT but would like some reassurance that it may be THE issue right now.

Any logic in butting the bullet and having exhaust manifold and all done at same time? Or does it good to just go CAT back and get this thing street able first?

 

[Ecomike]

Check and make sure you did not crisscross two of the spark plug wires at the plugs or the cap!!!!! Easy to do!!!! That would cause late or early spark and raw fuel making the CAT glow.....etc.

Pulling one plug wire should not kill the engine, unless two others are in the wrong place already.

A glowing Cat may mean the CAT is good and getting too much unburned fuel!!!!

But it may also be heat damaged, melted, and blocking free exhaust flow now as well, causing a drop in power under load....

The CAT should not really glow unless the catalyst is still somewhat good, and too much raw unburned fuel is reaching it!!!

I would do a compression test if the CAT keeps glowing, and all the cylinders are firing, to see if you have a burned exhaust valve!!!

See if the exhaust manifold is glowing tonight!!!

 

[88trailcrawler]

Doh! I had 5 and 6 reversed!

Power restored. CAT doesn't get super hot now. Seems about the same as the muffler.

Starter fluid found high idle. Front bolt that holds intake/exhaust manifold was loose and lower front exhaust manifold bolt is snapped off in block.

I gently spread the exhaust manifold gap open a bit, squeezed a bit of RTV tightened the loose bolt and high idle is GONE.

I think I'll go for a retest tomorrow, if it fails, I'll look at the NOX numbers and consider a new CAT then. Or start chasing sensors. I think (hope) I have found some obvious contributors.

Hopefully with corrected cooling, CCV, intake manifold leak, tune up, etc. she will get better test results........or at least narrow the problem down

One other note: the oil looks like oil and the coolant looks like coolant, I am hoping that is a basic sign of a 4.0 with some life left in her. I'd much eater be doing upgrades than repairs!!!

 

[Ecomike]

You might just squeeze by now. Good luck!

Save and post up the exact numbers if it fails.

Check the EGR and make sure it is not stuck before you get the retest!!!

There are some good photo threads and details on checking the EGR here. They are there to reduce the NOx. But your old numbers were not that bad for a poorly running jeep.

If the CO, HCs and NOx all fail by just a little bit, then it is time for a new Cat.

Congrats on finding all the real problems!!!!

 

[88trailcrawler]

Damn! Jeep is running REALLY good right now.

Smog tech wouldn't retest, showed me the canister thingy in the engine bay, passenger side the cap has three nipples, mine only has one hose coming out of it.

couldn't find any stray, unconnected lines laying near by.

Brought it home and started to research.

UPDATE:
- Read on here there is only 2 lines to connect (stupid smog guy)
- Crawled under the jeep and found a random hose laying between the engine and firewalls, looks to be about the right size. It goes up to a hardline connection at the firewall driverside.
- Clipped off the end for a clean connecctions and stuck it on the small nipple of the canister.
- Outside of hose looks a bit worn, but inside was good.

Back to the test station!!!!!!

 

[88trailcrawler]

Failed retest.
HC jumped from 63 to 148. Max is 124 @ 15MPH

CO at 15 mph went up from .94 to 1.11 max is .75
CO at 25 mph went down from 1.26 to .98 max is .95

NO at 15 mph went up from 1094 to 1305 max is 714
NO at 25 mph went up just a bit from 1107 to 1112. Max is 616.

Smog tech just says something is wrong.

Sitting in shop getting a new CAT put on now. Muffler guy says what's on there is a cheapie generic probably only good for a few years. I know it's 5-6 years old.

Thoughts/comments? Will new CAT address latest test numbers? What else to do/check?

EGR valve is opening and closing.

 

[mako my day]

Crazy. Thanks for the great thread. Good luck with the retest.... Today maybe? Also, what is the cost for your cat replacement?

 

[Vanimal]

i know when my van failed due to a bad cat, the numbers were all high. changed the cat and it passed like a friggin prius.

 

[Ecomike]

Failed retest.
HC jumped from 63 to 148. Max is 124 @ 15MPH

CO at 15 mph went up from .94 to 1.11 max is .75
CO at 25 mph went down from 1.26 to .98 max is .95

NO at 15 mph went up from 1094 to 1305 max is 714
NO at 25 mph went up just a bit from 1107 to 1112. Max is 616.

Smog tech just says something is wrong.

Sitting in shop getting a new CAT put on now. Muffler guy says what's on there is a cheapie generic probably only good for a few years. I know it's 5-6 years old.

Thoughts/comments? Will new CAT address latest test numbers? What else to do/check?

EGR valve is opening and closing.

New CAT will bring the HCs and CO way down, and should bring the NOx down, hopefully enough to pass. Are you in the hard case Ca inspection area, where you must buy the OEM approved CAT only?

If the NOx is too high still, we need to test the O2 sensor with an analog volt meter and test the electric heater in the O2 sensor (needs to be about 8 ohms).

IIRC you already ran seafoam?

Are the tires and gearing stock????

 

[88trailcrawler]

Mako:
- The CAT cost me $265. Cut off and weld on a new flowmaster. I wasn't really in a place to shop it. The Smog guy said to stay away from cheapie CAT's and the muffler guy had it done in like thirty minutes.

Mike:
- I don't know about OEM requirement on CAT. The muffler guy I went to actually also does smog tests and he knew why I was buying, plus he said I had a cheap generic CAT on there which had passed before AND the smog guy didn't even look at the CAT, so I am guessing I am OK with the Flowmaster (he says he installed)

- O2 sensor was next on my list, I did have it replaced a few years back in an effort to chase down my Renix sputter gremlins so it's not that old, but we will cross that bridge after the re-re-test. (BTW ground cable upgrades seemed to go a long way wit the sputter/hesitation gremlins)

- I did Seafoam treatment shortly after I purchased the XJ (5 years ago). Honestly never saw the smokey belching thingy that was described during that treatment, the optimist in me believed I must have had a clean internal engine.

- I have Seafoam a few times and fuel additives over the years as well trying to exorcise those Renix gremlins.

- CURRENTLY I have dumped in a bottle of "guarenteed to pass" fuel additive and put in a full tank of Premium. Since I was told to heat the CAT a few times before re-test, I figured it was cheap insurance.

- WILL RETEST in a few days.

- Today I drove the XJ around town, probably more miles than I have driven it in a long time. I was actually suprised at how good it was running, accelerating and especially ideling at red lights.

- I unleashed the kid (he hasn't driven the XJ in over a month) figured he could explain his way out of an expired registration with all the test and repair paper work in the glove box. I expect that tank of gas will be burnt up in the next couple of days and we go back to the test station.

- Tires are 33", Gears are 4:56. (Would much rather talk about this fun stuff than a damn smog test)

Thanks again for all the input! - Cross your fingers.

 

[Ecomike]

Sounds like a good plan. We use the cheap Cats here in Texas, about $65 on Ebay, but the smog tests in parts of Ca are tougher than here.

I am not an expert on tires and gearing here, but I have read where people had to change the tire size to get to the sweet spot on engine RPMs to pass the last little bit of NOx emissions in some places, CA and I think CO.

But if you past last year with those tires and gears, it should be able to pass again!!!

 

[Ecomike]

It sounds like you did enough seafoam like treatments, plus a gasoline wash down of two cylinders with off time spark to clean and remove any carbon off the valves.....which can cause high NOx.

You might want to check the engine oil for gasoline by the way!!!!!!

 

[88trailcrawler]

FAILED retest today.

15 MPH (1653 rpm)
25 MPH (1639 rpm)

- CO2: 13.9/13.6
- O2: 0.0/0.0
- HC: 134/152 Max: 124/104: HIGH
- CO: 1.27/1.68 Max: .75/.95: HIGH
- NO: 0/0 Max: 714/616 NONE measured

Smog guy says indicates a rich condition.

If the trip odometer is correct (my speedo is generally correct) I got somewhere near 13-14 MPG on that clean out tank, mostly running around town, no highway.

Are we looking at O2 sensor as likely candiate now?

I need direction (Idiots guide) on what to try next.

 

[blondejoncherokee]

i would replace the O2 sensor.

test MAP, TPS, CTS, etc as well as look for vacuum leaks, intake leaks, etc.

 

[88trailcrawler]

Here is what I did today after the fail:

- Did a seafoam treatment. Dribbled about 1/3 of a can into TB with the engine running, then increased flow until engine died. Let it sit, restarted and got a nice white cloud out the exhaust.

- Did my best to test O2. (Not sure I did this right) I tested the plug and had 12v at larger orange, 3-5 v at one black and no resistance to ground at other black (all with engine idling) NOTE: test was done at plug, with sensor unplugged....I think this might be wrong? And I only have a digital MM available to me so I don't think my test was very effective.

- I pulled the O2 sensor and compared it to an old replaced one I had in the garage. The recenly removed one had black deposits on it, where the older removed one seemed to be more grey-ish.

- I would love to just replace the O2 and get it retested if there is a consesus that is likely to correct the current readings, BUT I don't want to keep replacing one or two things at a time and keep paying for retests.

- One big concern I am starting to have is that I am chasing down typical suspects, but may ultimatley have an internal engine problem, I don't really know how to diagnose.

- I do know that we had significant overheating problem at the on-set of this and now that I have corrected that, realize that the XJ may have been running too hot for some time. (possible cause of internal damage?)

- also know that one evening my son told me there was a clicking/ticking noise in the engine, he drove home 25-30 miles and there was NO OIL on the dip stick (possible cause for internal engine problem)

- What kills me is that besides this SMOG test deal, I really think the jeep is running better than it ever has since we bought it.

Whats Next:
- Am I a fool for simply sticking in a new O2 sensor and trying again? How about a new MAP?
- At this point, even if it was a few hundred dollar overkill safety net approach, I would be willing to to it just to get this XJ back on the road.

 

[Ecomike]

How old is the O2?

Have you checked the fuel pressure regulator (FPR) vacuum line connection, to see if it is leaking gas? If it is, it is bad, and causing the rich fuel condition.

The MAP, and other sensors are not a likely issue, but a fuel injector(s) may be leaking a little!!!

So check the FPR, fuel injectors (pull the rail, turn on the ignition switch switch to run for a few seconds (get fuel pressure) and see if any leak, then if those 2 are OK, I would dig deeper into the O2 sensor, but it could be a cracked exhaust manifold confusing a good O2 sensor, so don't jump the gun yet!!!!

You need an analog volt meter to test the 3-5 Volt wire, with the connector attached and back probed, and the engine running. It should run about 2.5 volts at 2000 rpm, and swing quickly back and forth from 1-4 volts at idle. A digital meter won't do that test. The orange wire connection on the O2 sensor should read 8 ohms to ground, it is an internal electric heater, but is only there for smooth idles, not for the emissions load tests IMHO.

 

[desertjr]

Every time I test I run her down the freeway good and hard. romp the suck from the on ramp on up. Heat up the cat nice & good! I also let it idle before its tested..don't turn it off!
I also test with only 1/4 tank & a full bottle of Techron..black bottle of stuff can be bought at autozone for 8 bucks.

I run my gap on the plugs a little low. I guess factory calls for .035, mine are at .030. I have a full 0 guage power/ground wires, Accel wires & OEM coil. Also whats it failing? Everything? Just Nox? Just Co2? What?
You could relocated your IAT sensor from the intake manifold to your airbox..just extend 2 wire is all thats needed! Very easy & will read true air temps vs retartedly high temps of the manifold.

 

[88trailcrawler]

O2, MAP, TPS, CPS and IAC are all maybe 2 years old which is probably 10,000 mostly short trip miles around town

I am off to check FPR and fuel injector leaks.

Stay tuned. (Please)