PDA

View Full Version : *Smog help!*



rm2406
04-13-2014, 12:00 AM
hello all!
so ive looked all over the web and cant get much help for the cherokee...
I just went for a smog check the other day and "FAILED".
EVERYTHING was good except "NOx".. max is 539 jeep measured 855 on 25mph run.
on 15mph run max is 460 jeep measured 451.
NO problems driving.runs great. any ideas anyone???

JeepFreak
04-13-2014, 12:09 AM
Exhaust Gas Recirculator (EGR) is bad. The whole point of the EGR is to bring the NOx down. Find the source of the EGR problem and you'll pass. Let me check my manual and get back to you in a few minutes.

rm2406
04-13-2014, 12:14 AM
Ok... I thought jeeps (obd1) didnt have EGR's and use just the CAT?

JeepFreak
04-13-2014, 12:16 AM
EGR valves on Jeeps fall into 3 categories:

2.5/2.8L: Ported Vacuum Controlled EGR valve with no backsensor

4.0L: External Backpressure Sensor EGR valve controlled with backpressure and Ported Vacuum

5.2L: An EGR Valve with an electric EGR transducer (EGR is controlled by TES based on air and water temp to disable it before Operating Temp is reached)

take your pick.

rm2406
04-13-2014, 12:22 AM
Its this:
4.0L: External Backpressure Sensor*EGR valve*controlled with backpressure and Ported Vacuum

But what exactly does it mean? Wheres is it located?

JeepFreak
04-13-2014, 12:42 AM
From the top of the throttle body, it looks like a spaceship saucer on the side of the block.

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/0a/9b/af//small/0900c152800a9baf.jpg

Here's how to test it:

EGR Solenoid:

1. Start the engine and bring it to OpTemp. ONLY IDLE during tests.
2. Attach a vacuum gauge to the solenoid vacuum. Test for 15 in. Hg. If it's low, check for leaks, loose fittings, or kinks in the line.
3.Check vacuum at solenoid port. Disconnect the line and attach the gauge.
4. If vacuum is ZERO, move to step 5. If vacuum is present, test with a DRB (Diagnostic Readout Box II) and repair.
5.Disengage electrical connector at solenoid. If vacuum is present, proceed to EGR valve test. If not, replace the solenoid.

EGR Valve test:

1. Leave solenoid connector disengaged. Bypass the vacuum transducer if equipped, and connect EGR valve solenoid output hose directly to the EGR valve nipple.
2. The engine should run roughly or stall. If this occurs, the valve is good. Proceed to transducer test, for 4.0L engines. If RPM's do NOT change, disconnect the hose from the EGR and attach a hand vacuum pump.
3. Apply 12 in. Hg. of vacuum. If engine roughs out or stalls, inspect EGR lines in the system for leaks and repair if necessary. If no leaks are found, go to transducer test.

Transducer Test:

1. Disconnect all transducer lines and remove transducer.
2. Plug the transducer output port and apply 1-2 pounds of air pressure to transducer backpressure port (used compressed air adjusted to correct pressure) Apply a minimum of 12 in. Hg. of vacuum to the input port.
3. Replace if it will not hold vacuum.

rm2406
04-13-2014, 12:52 AM
Hmm. That part of my engine has nothing there... there is nothing there to install one either.
is that for a 95 jeep Cherokee xj? Smog tech said could be cat going bad....

JeepFreak
04-13-2014, 12:58 AM
That's a 4.0L 1994 cherokee HOWEVER this works for 1984-2001 Cherokee/Comanche/Wagoneer models.

bigjim350
04-13-2014, 01:04 AM
91+ XJ's dont have a EGR valve. Anytime I have a high NOX level I put on a new cat. It might not fix the main problem, but it will get it clean enough to pass emissions.

JeepFreak
04-13-2014, 01:07 AM
Interesting. Mitchell, Haynes and Chilton say there's an EGR on all 1994 4.0L's. Ok now I have to go look cause I swear I have one.

SIDE NOTE: NON RENIX ENGINES DO NOT HAVE AN EGR!

bigjim350
04-13-2014, 01:09 AM
SIDE NOTE: NON RENIX ENGINES DO NOT HAVE AN EGR!

Correct, and they didnt make renix after 90

JeepFreak
04-13-2014, 01:14 AM
Ah that would make sense. Chrysler came out with the Multi Point Fuel Injection or MPI System. This is all PCV/CCV operation.

rm2406
04-13-2014, 01:19 AM
Engine runs cool consistantly. O2 sensor changed a few months back. Runs great.
only thing ive noticed was when revving in park there are a few small backfires from tail pipe. In drive It doesnt do it. .

rm2406
04-13-2014, 02:43 AM
Searching google.. im leaning towards faulty o2 sensor or failing cat.
Any other thoughts?

JeepFreak
04-13-2014, 03:14 AM
Searching google.. im leaning towards faulty o2 sensor or failing cat.
Any other thoughts?

If you had a failing cat...you would know. Bad smell, fiery red or orange heat buildup like a metal spoon left too long in a fire and EXTREMELY bad gas mileage and smoke. The O2 sensor only deals with fuel/air mixture. That wouldn't be an issue.

4.3LXJ
04-13-2014, 07:37 AM
A cat can just wear out and marginally fail. Just went through that on my pickup. But generally that is indicated by higher than normal hydrocarbons. How long since your O2 sensor was changed. A lean burn condition can cause higher than normal combustion chamber temps and give you higher NOX

JeepFreak
04-13-2014, 11:15 AM
The best thing to do before randomly replacing items you may not need to is to do some diagnostics. Check your cat with a simple gas ranging meter (like a carbon monoxide/dioxide meter but not quite for those) and see if they jump through the roof before it hits your CAT. Also, an O2 sensor is supposed to give off 0v-5.0v when it is working properly. Test it with a DVOM. Simple stuff. If it's in range it's fine.

rm2406
04-13-2014, 11:35 AM
O2 sensor was changed about a few months back with a bosch
and EVERYTHING passed clean just the NOx was almost double max. HC & CO were very good. That puzzled the smog tech.
Jeep runs 190 deg. Constant.never overheats. If combustion chamber was really reaching high temps wouldnt it be overheating?maybe dirty pcv? maybe faulty ECT sensor?I will test suggested and report back.thanks for helping guys..

JeepFreak
04-13-2014, 11:51 AM
No. The NOx (oxides of nitrogen) are only created when the combustion in the combustion chamber gets over 2,500 degrees F. Completely normal. You have to remember that combustion is literally a small contained explosion. Damn thing is gonna be hot lol. Somewhere along the line your vacuum system is not drawing the oxides back into the chambers to burn off. Check your vacuum lines and diagrams first and see if the vacuum is the culprit. Even a small hole can have major consequences especially if it's in a low pressure line. Whatever air may have been going through it is now equalized by the pressure outside the hole. Let me see if I can get a diagram of the vac lines for you.

JeepFreak
04-13-2014, 11:55 AM
This is for a 96 cherokee. Don't worry if the components aren't in the same place. They aren't for my 94 cherokee under "1994 cherokee vacuum diagram" either -_- just check these basic vacuum lines AND, I can't stress this enough, make sure they are connected and connected to the correct locations.

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/0a/9b/97/large/0900c152800a9b97.gif

rm2406
04-13-2014, 12:09 PM
Thanks! I will use this diagram to go check....

rm2406
04-13-2014, 02:33 PM
So far from visual inspection. The big hose on the charcoal canister is cracked and very deteriorated. Also how can I check pcv valve for working condition? Hose is a bit restrictive too.
I will continue to do some other checks........

JeepFreak
04-14-2014, 12:50 AM
So far from visual inspection. The big hose on the charcoal canister is cracked and very deteriorated. Also how can I check pcv valve for working condition? Hose is a bit restrictive too.
I will continue to do some other checks........

Big hose in the middle...goes to the TB? If so I'm not sure that that's the problem.

Also if the ignition timing is incorrect, that will also cause a high NOx level. You said the O2 sensor was replaced. I did some digging and a lean air/fuel mixture will cause high oxides. Overheating can cause higher than normal oxides as well considering it is only created in extremely high temps. Carbon buildup in the chambers themselves can cause high oxide readings. Most common cause in older vehicles is effed up ignition timing such as "I replaced the rotor and distributor and it's off by a few milliseconds". Honestly, from what other people have said check your timing for the ignition and check the spark plugs or coils, whichever you got.

rm2406
04-14-2014, 01:31 AM
Ignition timing is not adjustable on my jeep. Tomorrow I will check manifold bolts and any other possible intake/exhaust leaks. Pcv hose is kinda deteriorated also.
if I rev the engine in neutral and let off the gas the tail pipe makes small Iittle backfires.
Normal driving no problems...incase it might be related to something............

JeepFreak
04-14-2014, 02:45 AM
Ignition timing is not adjustable on my jeep. Tomorrow I will check manifold bolts and any other possible intake/exhaust leaks. Pcv hose is kinda deteriorated also.
if I rev the engine in neutral and let off the gas the tail pipe makes small Iittle backfires.
Normal driving no problems...incase it might be related to something............

I hate to say it but the ignition timing IS adjustable...just not by humans. The onboard computer retards or advances the timing of the injectors and plugs. So if all else is proving ok, the onboard may be suspect and they ain't cheap lol. Check your injector air flow sensors. If it isn't getting the correct reading, it may cause the backfire. Unfortunately, MOST backfires are caused by faulty O2 sensors. Rich mixtures cause incomplete burnoff of the fuel which travels through the exhaust and explodes in the HOT cat which is visible from the exhaust. Lean will do the same thing. Explodes too early and the unspent fuel travels to the exhaust, igniting unpredictably. It has nothing to do with the gear you're in. I know you said it was replaced, but it could have gone bad, had a defect, got a foreign contaminant on the O2 sensor itself, or maybe a faulty wiring to it. The problem is the longer it goes on, the more damage the cat will take. It can't (or rather isn't meant to) take explosions.

RECAP:

Problem areas possibly are:

Vacuum lines
O2 sensor
Intake leaks
CAT itself
Fuel System (clogged filters, fuel pump, etc can cause a rich or lean scenario)
Poor Ignition timing (controlled by the onboard comp)
Injectors
Air Flow sensors
Improper Ignition wiring

Good luck :D keep me and everyone else posted as you cross off the issues one at a time.

rm2406
04-14-2014, 08:36 AM
thanks jeepfreak for all the help... the o2 sensor is a bosch and i read they dont function so well in cherokees... also the wiring connector to the oxygen sensor is a bit cruded up from a little oil and road debri.. i will get that cleaned up as well. also i believe i put some kind of platinum plugs in a while back too.. could those be a problem in this matter? should i stick with "champion" only? a few of my vacuum hoses are deteriorating like both the pcv hoses on valve cover and one that goes from manifold to evap canister... im currently trying to find these hoses online with no luck.. is there a kit or something for vacuum hoses?? or can i buy some kind of universal hose and replace myself? once again thanks buddy!

rm2406
04-14-2014, 10:32 AM
another small update... my exhaust manifold also has a hairline crack on the part where they all join together... could this cause false readings from o2 sensor as well as cause jeep to run lean??

4.3LXJ
04-14-2014, 10:33 AM
Most likely it would make it run rich if it was a problem

JeepFreak
04-14-2014, 12:10 PM
A crack in the manifold is extremely common at the 'Y' joint where the two sides of the block come together to go down the exhaust. I have that same issue. You have a 95 so I'm gonna take a guess that you do not have more than one O2 sensor. I think before 96 all Jeeps had only upstream O2's. After 96, they had both upstream and downstream. So because the hole is before the sensor, yes it will cause false readings. Don't have the money to replace it? Go down to any auto store and buy VersaChem Exhaust System Joint and Crack Sealer. At AutoZone I think it was like $4-6. All it is is a putty that can withstand well more heat than your car will even get to (like temperatures that would melt your car) and you just paste it all over your crack in the manifold. Really simple. I had to do it to mine and I'll tell you what, the difference was IMMEDIATE. I mean I went from averaging 14MPG overall to averaging 16-17MPG overall. All you really need is a putty knife or something you can put it on then spread it and you are golden. Just let it dry overnight then drive it in the morning to cure it.

As for the plugs, I have heard that platinum plugs get pretty fudged up with buildup in our Jeeps although I am unclear as to why. I usually just stick with the gold ones from Bosch. If I had to take a guess, I would say it's because gold conducts electricity better than platinum.

Now the PCV/CCV does NOT have a specific replacement hose. You have to jury-rig it pretty much. Buy an equivalent sized hose, an equivalent sized grommet (mine is actually for a GM from Autozone LOL) and hook those bad boys up. It'll most likely crumble when you try to remove it but don't worry, it won't go down into your engine and kill your Jeep. Just make sure you have some sort of pliers or skinny grabbing device to remove ALL pieces that fell into it (it's only like an inch to an inch and a half to the bottom of the block since it only sucks in air).

rm2406
04-14-2014, 12:53 PM
you are correct.. i only have 1 oxygen sensor, and its right after the crack in exhaust more than likely reading false. i have some stuff for the crack seal called "THERMO STEEL".
ive used it on past jeep with good results... dang jeeps and there cracked pipes!
as far as the plugs. i will be installing champion plugs again just thought id try out platinum..(no obvious results from that).
i also found high temp silicone hoses to replace old ones..
thanks for the help! very much appreciated!

JeepFreak
04-14-2014, 07:37 PM
No problem. If you fix the leak and the Sensor and the plugs, you should test for the misfire. If it's misfiring a simple trick is to take a money bill (any denom) and hold one end up to the tailpipe. If it flaps around wildly, no misfire. If it SUCKS IN the bill like a lot and towards the pipe, then you have a misfire. Test it after the repairs and find out. If it's completely done misfiring, it probably solved your problem and you should have it retested. Even if you fail it gives you valuable insight. If the numbers changed at all and I mean by like more than 5 ppm, you know you're getting on the right track and something you did affected it.

xj4life2
04-16-2014, 12:03 PM
First of all my Renix had an egr on it . Secondly high NOX is caused by 3 things in this case 1. carbon build up on pistons due to bad o2 2.high temp, high pressure PVC orifice is clogged 3. bad cat. Your popping noise is more than likely caused by a lean misfire, bad o2 , tune up , ect ect . This will cause NOX and damage the cat. If you replaced the o2 did you use Jeep Parts? If not it is probably already bad as the Bosch and Denso do not work well in the Jeep at all. The quick fix and probably the best is to replace the o2 with factory part and replace the Cat. you can get them from NAPA cheap. Walker part number is a 80905 if you have a 1995. You should also replace the PCV orifice or at least be sure its not clogged.

rm2406
05-12-2014, 04:33 PM
ok.. did a retest and failed. it was even higher.. so before this 2nd attempt this is what i did to my jeep.. replaced map sensor, engine coolant temp sensor, oil change, new air filter, replaced badly cracked PCV hoses (both in and out), also charcoal cannister hose was replaced due to cracking, ran "guaranteed to pass" stuff, cleaned iat sensor. now with all this done i ran the jeep for 20-25 mins hit the test center and got the failure..
what really ticked me off was after i left the place using my free retest i went home opened hood took a look to see what i might be missing out on... jeez after all that i forgot to re-attach the air box to the throttle body during my maintenence. it was sitting on top of throttle body just not fully seated and clamped with plastic clamp. this only happened after my 1st failed attempt but now i dont know if EVERYTHING i did worked or not.. i guess i will have to pay again with the air box now attached and see what happens.. if NOx is still high than my last solution is O2 sensor and maybe CAT.. current o2 sensor is bosch installed about 6-8 months ago. (heard they are bad sensors?) also installed at that time was autolite platinum spark plugs. (does platinum burn hotter?) and CAT will be tested for efficiency. engine has 70k on it. now i wonder if my last failed smog shoud of been a PASS.

JeepFreak
05-12-2014, 05:26 PM
Platinum has better spark potential but it wears out quicker. Silver is the best because it is somewhere in the middle and has the highest conductivity of any metal, even more than copper. The only reason they don't use silver is because it is way more expensive than copper in auto applications. It's also not readily available for recycling to be used again. I know that because I worked at a scrapyard/recycling center for over 2 years. Check your MAP or MAF sensors. Typically, older model Jeeps use one or the other, and rarely both. I have a MAP. That's it. If your MAP is malfunctioning, it would cause ignition timing to go crazy. I know you said you replaced it but get it with the voltmeter and see what it reads at different times. It may not be the sensor but the computer, misinterpreting the voltage. Our MAP's are usually 2 wire configurations. 2 wire has a shared ground with a set 5v control voltage from the computer going through a resistor to the sensor which has another resistor then going through to ground. The way this changes is as the resistors change Ohm readings, the computer translates the voltage changes into set manufacturers values. The computer ALWAYS sends out a 5v reference voltage. If it doesn't, you got major problems lol check to see first that it even sends out voltages to your sensors. They should always be 5v controls with a variable rate between 0.5v-4.5v. If something isn't getting that reference voltage, it won't work. Check for those then see if they are wrong. If they are, clean all your grounds for the computer and the affected sensor.

xj4life2
05-12-2014, 06:09 PM
I can not give a reason , technical at least but fancy plugs suck in the 4.o change to regular Champion plugs they run the best and are the factory replacement for the vehicle. Again replace the o2 with a factory one. DO NOT run that Pass or Don't pay crap in it , that stuff actually drives up the HC and NOX , If you want to clean it out internally , one pint or ATF to a tank of gas is the best cleaner you can get. Be sure to run the entire tank empty before testing again . As for the hose not being attached that would not cause a failure other than it should have also been tagged as missing or modified ( a separate failure) as always good luck !!

rm2406
05-12-2014, 09:39 PM
But if the air filter in hose is disconnected that means the ccv is also not doing its job helping remove NOx due to it being attached to the same hose correct? Ok so im gonna replace plugs with champion plugs and o2 sensor with oem sensor. Replacing CAT is still my last option. If cat WAS bad wouldnt my other numbers be high? Also any other thoughts? Thanks all for helping out!

JeepFreak
05-13-2014, 04:53 AM
Not enough to cause a big jump. And always replace your parts with OEM replacements. Never go aftermarket as most of them are deeply non-universal and simply aesthetic. Most aftermarket parts do nothing for your car. Mufflers make lawnmower sounds, 'racing' air filters are cheaply made and choke the engine because they let less but cleaner air through while being overpriced, and most headlights that aren't stock supported or are add on lights are illegal in certain conditions. I can't even have my aftermarket running lights on anywhere in California if my high beams are on. Not to mention, aftermarket parts void manufacturer and mechanic warranties on your car. Anyone who says they will warranty an aftermarket part they didn't put on is full of it. It helps to have family and friends who are part of the automotive industry and auto insurance industries. Most insurance companies won't even cover you if they feel your aftermarket part caused your car to crash, break down, etc. Always put on OEM parts since they are universal 99% of the time and are almost the exact configuration as the original part with basically the same rate of wear. You'll be better off using OEM parts in the long run. Certain things are understandable as most 'lifts' are generally not stock, same with gauges but they make aesthetic OEM's of those too.

rm2406
05-17-2014, 10:38 AM
ok. so to report back a bit.. i pulled the double platinum plugs to check them also get a view inside combustion chambers to see for any buid up.. (part of high NOx, combustion chamber exceeding temps of 2500 deg. with a cause of heavy carbon build up)...
anyone have problems using CHAMPION 7034 DOUBLE PLAT plugs? im gonna be puttin in champion oem's any how.
couldnt get a picture of combustion chamber but it was pretty carboned up good.. on a scale of 1-10 of carbon build up i would say it is a 6 1/2.... with out removing anything whats the best thing i can use to clean out my chambers as well as entire fuel system?
http://i1069.photobucket.com/albums/u463/rm2406/20140517_072450.jpghttp://i1069.photobucket.com/albums/u463/rm2406/20140517_071848.jpghttp://i1069.photobucket.com/albums/u463/rm2406/20140517_071805.jpg

JeepFreak
05-17-2014, 01:59 PM
Honestly, the best fuel system cleaner you can get is Lucas FSC. Lucas uses a base formula that mimics gasoline so it burns better and isn't bad for your car. It is made thicker so it coats everything with its detergents to clean it out. Never had any problems and nobody has come into our shop with problems from it either. I, personally, use Lucas every time I fill up but the recommended is every 2-3 fill ups. You should try Lucas Heavy Duty Oil Stabilizer as well. The added friction from an underperforming oil can lead to excess heat thereby increasing NOx. Next time you do an oil change, put about 3/4 of the bottle in it. As you lose oil or it gets low due to breakdown, add the rest of it.

Now about those plugs, as I have said before, platinum plugs burn the hottest and generate the most spark due to the low ignition point for the metal. The issue with platinum plugs (ANY plat plugs) is that the tips wear out much easier from being so readily sparked and will not burn off the gas as well as it should leading to excess carbon buildup. Go with iridium plugs OEM. That's what I have and I have practically zero carbon buildup (I check it every 3,000 miles at the oil change). Iridium is a stronger metal, less prone to wearing out than platinum. Yes it has a smaller spark potential but it also doesn't wear out as quickly as plats. You have a sustained spark for the majority of the plug. Platinum plugs also have a problem with the tip literally being blown off by the spark and that is never good. Platinum is not a very strong metal when used in plugs. Reason being, the metal is stretched thin to make the tip which weakens the metal and once it gets really worn, the tip blows off and can do massive damage to the engine i.e scratching the cylinder walls/piston heads, imprinting in the walls/heads, damage to the valves, etc. Besides the obvious damage your vehicle will now run terribly and if one is at that point the others are soon to follow.

rm2406
06-05-2014, 09:00 AM
ok so a little update on my situation... things ive changed: o2 sensor,map sensor,engine coolant temp sensor,fuel pressure regulator,put oem spark plugs,ran berrymans b12 in tank,coolant flush. so after all this being done my NOx went from 855ppm to 454ppm.
i had a few vacuum hoses cracking and very brittle but i couldnt find them at any stores so i bought silicone universal hoses and replaced them.. good news! i passed the smog test.. kinda.. bad news they failed me because the universal silicone hoses are considered aftermaket and they put modified hoses=FAIL. also my IAT sensor was installed on the intake boot rather than intake manifold=tampered=FAIL... after 3 attempts i pass smog and fail because of hoses and IAT sensor.. thats B.S!!
so i have to replace hoses with factory hoses but cant find them.. anyone know where to get oem hoses? i will also have to put back IAT sensor in original location... last smog tech said nothing about all the hoses or sensor....

4.3LXJ
06-05-2014, 09:34 AM
Are you going to a regular smog station or a gold station? The gold are more strict. You should be able to find original hoses at a pick and pull for a 95

rm2406
06-05-2014, 10:11 AM
it was a test only smog station... i will check out the pick and pull yard but incase i dont find any or the ones i do find are cracked or old also, will the dealer carry these hoses?

4.3LXJ
06-05-2014, 10:14 AM
Dealers should. Also if you see any YJs with the 4.0, they will have the same engine parts. Check around for smog shops. I have gotten to know the guys in one that let a few things like hoses slide as long as it passes and they can show it on paper work

rm2406
06-05-2014, 10:44 AM
so far the dealerships around here said that those particular hoses are discontinued.. im gonna just check out the pick in pull for now. yea he could of definetely overlooked that especially that he is a friend of a friend..

4.3LXJ
06-05-2014, 10:48 AM
I would start checking around at various smog stations. For instance, I have friends at the local 4X4 shop. But they are a gold station and they will not let me get away with my non stock air cleaner box. Hey it is a conversion anyway. But I got to chatting with some gear heads across town from them and they don't care, as long as the rest passes. I even have a 3" inlet on my cat, which is not legal in CA and they let that go. But it always passes with flying colors

XJ Wheeler
06-05-2014, 03:03 PM
^^^ Just some of the reasons i couldn't live in cali. Shame such a beautiful place is so messed up!

Sent via messenger pigeon - i talk, he types.

rm2406
06-06-2014, 03:15 PM
question... when i was replacing a few parts for maintenence to my jeep and possibly help smog test i developed a new problem.... i think. ok ive replaced alot but these are the things i last replaced before this happened. o2 sensor (denso- same as previous one installed). fuel pressure regulator.changed spark plugs (champion oem's) gapped .035"
PROBLEM: when i start the jeep for the first time in the morning it idles perfect then if i give it light throttle the engine stumbles or kinda like chokes but NEVER dies or even start to die.immediately after letting off the pedal it idles like nothing is going on then i give it light throttle and it does it stumbles again. then i left off the pedal and it still idles good. this only lasts no more than 10secs then after that its GREAT ALL DAY til i park it for awhile or til morning. did i do something wrong maybe??

4.3LXJ
06-06-2014, 03:40 PM
Hard to say on that. TPS may be getting a little worn out

rm2406
06-06-2014, 03:44 PM
the only reason i havent looked at anything else is because it only happened after those changes.. but wouldnt the TPS remain like that for the whole drive? or interfere with shifting? which it shifts GREAT! and it ONLY happens if it sits for maybe 4hrs or mornings...

4.3LXJ
06-06-2014, 04:17 PM
I really don't know. That is the only thing I can think of. If it only happens for a few seconds, see if it works itself out. Might be the computer has to relearn.

rm2406
06-10-2014, 09:42 AM
did a computer relearn.. so far it still bogs down when i tap the throttle but it doesnt last as long anymore.. idle in morning is low though. not real low just low for a morning start up. normally morning start ups have a bit higher rpm to warm up engine. maybe relearn procedure needs more time to smooth out.

4.3LXJ
06-10-2014, 10:25 AM
It takes the computers awhile. They are slow learners. Give it a couple of weeks

rm2406
06-11-2014, 10:16 AM
if the computer doesnt smooth it out, what controls morning start ups? (high idle to warm engine on cold days)

4.3LXJ
06-11-2014, 10:19 AM
Have you tried running a tank of premium in it yet?

rm2406
06-12-2014, 08:24 AM
i have chevron in my tank now. before that i ran berrymans b12 with regular gas..everything else runs great except the morning or cold start up.. every cold start my engine idles as if its warmed up already only its not. i switched out my old ect sensor with new one and still the same problem.

rm2406
06-12-2014, 10:09 AM
i read also that a faulty heated o2 sensor can cause cold start problems. sensor itself can be in good range but heater on sensor can malfunction on its own causing my problem.. this is also something i just replaced RIGHT when my problem occured. (what was changed right before problem- MAP SENSOR,ENGINE COOLANT TEMP SENSOR,O2 SENSOR). before this idle at cold start was perfect.

4.3LXJ
06-12-2014, 10:24 AM
I suppose that could be it

JeepFreak
06-15-2014, 11:42 PM
The sensors may be slightly off on the voltages they give out. Between .5v-4.5v is normal but lets say the voltages coming from the sensors are slightly higher .7 or so. The computer is getting the voltage correctly but it's interpreting a slightly higher 'normal' voltage as not normal so it tries to counteract it but never can because the highs and lows of the voltages don't match. It can cause problems due to the resistances. Kinda like how I was saying with my coolant temp gauge lol it reads higher than it is but it's normal. The voltages are higher than the computer determines as 'normal' even though the sensor is functioning perfectly.

rm2406
06-18-2014, 08:48 AM
well so far idle at cold morning starts has seem to go back to normal as 4.3LXJ stated "It takes the computers awhile. They are slow learners. Give it a couple of weeks"
being that i did a ecu reset... so far its getting better every time i start it.. ok back to the original problem of failing NOx emissions.. as i said my last test NOx was reduced by enough to pass after changing multiple parts and using berrymans b12 in tank.. i continue to use fuel injection cleaner to clean up as much as i can before my 4th last free emissions test. im almost certain my high NOx is due to combustion chamber carboned up alot.. i do alot of short trips... emissions guy said change my CAT and it will pass but my CAT is good and i dont want to only mask whats causing high NOx, i want to fix it. and after MUCH parts being replaced just for regular maintenence i beleive i benifitted the most from "berrymans b12". i checked my combustion chamber after running 1 tank of that cleaner and it definetly cleaned alot out as well as giving me a slight boost in mpg's.. last test will be done tomorrow so i will report back my results and compare them to my first test and whats helped out.. thanks all!

rm2406
07-08-2014, 01:18 AM
FAILED NOX AGAIN @ 25MPH run. Ran numbers through lambda and got these results. Attached.
Can anyone tell me if anything looks wrong please?

rm2406
07-08-2014, 01:25 AM
Here are test results:

rm2406
07-08-2014, 09:25 AM
can anyone please review lambda numbers and let me know what they think please??
thanks for your time!

4.3LXJ
07-08-2014, 09:58 AM
I have to say that I don't know what to say. I am completely unfamiliar with lambda. And I am baffled as to why your NOX is still high

rm2406
07-08-2014, 11:09 AM
what ive replaced so far:
spark plugs (champion oem)-fuel pressure regulator-air filter-oil change-oxygen sensor-map sensor-engine coolant temp sensor-ran berryman b12 chemtool fuel system cleaner-checked ccv valve for clog (clear)-replaced ALL vacuum hoses.
according to test results CAT is doing its job. as for the jeep its runs GREAT, no overheating at all, has power and has NO problems...
while changing spark plugs i noticed the combustion chambers were RELLY carboned up bad. using the berrymans b12 helped clear alot but theres still some in there. (currently running another tank of treatment for carbon-could be the suspect??) im absolutely at loss now.. i hoping the fuel treatment will help with carbon in combustion chambers and that it will help bring nox down.

4.3LXJ
07-08-2014, 11:33 AM
Then I would say you probably have carbon still in the combustion chamber. One thing you can do to get rid of it is trickle water down the intake at about 200 rpm. As much as it will take and not die. The steam loosens it up

rm2406
09-08-2014, 10:07 AM
UPDATE: FINALLY PASSED SMOG!!- 5MONTHS LATER-6 SMOG TESTS FAILURES!!
ok so in my post i put down everything i did to help my NOX lower for smog test.. did alot of repairs and even though they didnt contribute to much to lower NOX i know i wont have to replace those parts for a while!! :) in the end, it ended up being my INJECTORS.. they were really dirty. i guess a bit clogged or carbon build up the mechanic said. after he cleaned my injectors my NOX went from 1100ppm to 102ppm passing!

bluedragon436
09-08-2014, 10:12 AM
Glad to hear you got her taken care of and through inspection... At least now you know you got good parts in there for the ones you did change out.. and now you should def get better gas mileage with the parts changed and the injectors being cleaned!!

4.3LXJ
09-08-2014, 11:47 AM
Well who would have thought of that. Congrats

rm2406
09-12-2014, 09:15 AM
yea definetly drives smoother and noticeably better! with only 70k im kinda suprised it was carboned up that bad but then again i only drive it to work which is only 7mins away from where i live and i believe short trips contributes to carbon build up. the best part is driving again without looking in my mirrors for police to pull me over for expired tags!!
thanks again fellas!!