4.0 Jeep Emission test results HQ!

[kidarkitect]

Cool post idea! Heres my 89 w/140ish in slc, ut on the clock at the time- since this test i've done a few things and just been waiting to test it again. They weren't great, but it was a major improvement compared to last years numbers(barely passed). I get 18-21 day to day driving and 24-26 highway no kidding (i thank the skids and vac disco d30 for that)

emission co2 | o2 | HC | CO | NOx
test | meas | meas | meas | max | meas | max | meas | max
15mph | 13.9 | 0.0 | 66 | 240 | 1.01 | 1.26 | 634 | 2000
25mph | 13.8 | 0.1 | 94 | 230 | .91 | 1.20 | 1301 | 1800

 

[kidarkitect]

oh yeah mine was dyno test (load) 4.0, 4x4, manual, 231, 3.5" lift, 30's and 3.55 gears and we run 4wd's all day at my work (i'm an emissions safety tech.

 

[1990JEEPXJ]

my 90 with 165000

.............RPM... CO2 ......O2 ....HC (max)... (avg)... (meas)... CO (max)... (avg)... (meas)... NO (max)... (avg)... (meas)
15mph ..1652 ....14.70 .. 0.15..........123 ........34.... ....53 ...........0.73 ...... 0.11 ....0.22........1015........260.......52
25mph ..1631.....14.70....0.08..........103.........23........42............0.93........0.10.....0.21.........875.........217.......35

 

[T3hk1w1]

I've been having some inexplicable gas mileage trouble, and as a last resort my mechanic took my XJ in to get an emissions test yesterday.
'00 XJ, ATK rebuilt long block with 4400 miles on it. (getting about 11-12 MPG)
235/75/R15s, 3.55s, AW4
2 speed idle test

standard @ high speed (1874RPM).............low speed (1077RPM)...........
HC (ppm)220......... ....mine 6 .................220................mine 6
CO% 1.20..................mine 0.00 .............1.20...............mine .00
CO2 % N/A................mine 14.3 ............. N/A...............mine 14.0
O2 % N/A..................mine was 20.6 ..... ..N/A...............mine 20.6
Dilution >6.0..............Mine 14.3...............>6.0..............mine 14.0

No data on NOx for some reason...

 

[Ecomike]

I've been having some inexplicable gas mileage trouble, and as a last resort my mechanic took my XJ in to get an emissions test yesterday.
'00 XJ, ATK rebuilt long block with 4400 miles on it. (getting about 11-12 MPG)
235/75/R15s, 3.55s, AW4
2 speed idle test

standard @ high speed (1874RPM).............low speed (1077RPM)...........
HC (ppm)220......... ....mine 6 .................220................mine 6
CO% 1.20..................mine 0.00 .............1.20...............mine .00
CO2 % N/A................mine 14.3 ............. N/A...............mine 14.0
O2 % N/A..................mine was 20.6 ..... ..N/A...............mine 20.6
Dilution >6.0..............Mine 14.3...............>6.0..............mine 14.0

No data on NOx for some reason...

Take it to auto zone for a free scan to check for pending codes. My guess is the CTS or O2 sensor is bad.

 

[T3hk1w1]

My mechanic just spent a week looking it over, it's not throwing codes. I just replaced the O2 sensors about 300 miles ago. I'm thinking about replacing both the MAP and CTS.

 

[1990JEEPXJ]

when mine failed horribly and got poor mileage, i replaced the MAP and o2 sensors. it then passed with flying colors. id try the MAP. its cheap and easy

 

[Ecomike]

My mechanic just spent a week looking it over, it's not throwing codes. I just replaced the O2 sensors about 300 miles ago. I'm thinking about replacing both the MAP and CTS.

Have you actually tested the running O2 sensors? Or the running MAP, CTS? Why replace parts until you know what is bad?

All it takes is an analog volt-ohm multimeter, $20 to test all the parts, running, and not running.

Engine might need a little break in time. What oil are you running?

Don't you live or work on my side of town, near Pasadena?

 

[Ecomike]

My mechanic just spent a week looking it over, it's not throwing codes. I just replaced the O2 sensors about 300 miles ago. I'm thinking about replacing both the MAP and CTS.

Well T3hk1w1 came by today, and we located his problem. Seems the 12 volts to the upstream HEGO (Heated Exhaust Oxygen Sensor) internal heater was only getting 3.5 volts. The OBD-II year 2000 computer is not detecting the problem, as the O2 sensor does work, but only at 2000 rpm when the exhaust is hot enough to get the O2 sensor in to its proper operating temperature range.

He is going to try and find the problem hiding in his wiring harness now, as the 12 volts is getting to the relay and 15 amp, good fuse, but not the last leg to the O2 sensor.

Now pay attention every one as there is going to be a test at the end here!

He has a good, new O2 sensor. The OBD-II, year 2000 computer was not throwing codes. He was still seeing a 40% drop in gas mileage. WE got under the jeep and tested the O2 sensor with an old style analog volt meter. O2 sensor was pegged at 0.05 volts at idle, and 0.45 volts at 2000 rpm!

The voltage on the black heater wire was 3.5 volts, not 12-14 volts. The rear O2 sensor was worse, it was only getting .5 volts instead of 12-14 volts to the internal heater.

These O2 sensors will work under engine load, and elevated RPMs, fooling the OBD-II computer onto not throwing a code, but at low rpms, and idle, slow traffic, the O2 sensor is no longer hot enough, and the heater does not work as it does not have enough voltage, so the O2 sensors lies to the PCM says I am lean, so the computer continuously calls for more fuel to make it rich, thus poor mileage.

 

[Hellbent]

just got mine done today-two speed idle in my area of the sticks. '96 xj 4.0 man trans 223,730. last tune up was about 10 months ago. have k&n fipk, '99-up intake, 62mm tb, apn header, 2.5" ex w/flowmaster, relocated mat(to the k&n tube), and lt1 injectors.
pretty damn good, considering it's been 10 months since a tune up, and i had seafoamed it at that point as well. nothing down since. just drove across town 10 min, and he immediately pulled it up to test.
hopefully this comes out legible, took it with my phone.

 

[Ecomike]

87 Renix, 4x4, latest test results. Note the ambient temp for the test was about 40 F. Engine was barely warmed up due to the new H.E. cooling system upgrades made this summer. It passed emissions. Results:

standard: Limit @high speed (2477RPM)......Limit.......@low speed (0666RPM)...........
HC (ppm) 220......... ....mine 16 .................220................mine 47
CO% 1.20..................mine 0.19 .............1.20...............mine .34
CO2 % N/A................mine 14.9 ............. N/A...............mine 14.8
O2 % N/A..................mine was 0.1 ..... ..N/A...............mine 0.1
Dilution >6.0..............Mine 15.1...............>6.0..............mine 15.1

Once again, No data on NOx. Must have something to do with testing not being done on the dyno load due it being a 4x4.

These were the prior year results:

standard @ high speed ...................................low speed
HC (ppm)220...............mine was 8 .................220..............mine 28
CO% 1.2...................mine was .04 ................1.20...............mine .13
CO2 % N/A.................mine was 14.9 .................N/A...............mine 14.7
O2 % N/A...................mine was 5.1 ...............N/A..............mine 5.4
Dilution......<6...............Mine 14.9....................>6..............mine 14.8

The O2 numbers do not jive at all. I had speculated previously in an overheating thread discussion that mine might be running a lot leaner now, and this data supports that theory, but the numbers are so far apart on the O2 year to year test, that I question the data as well. I did have a much noisier valve train noise, that has gone away between the 2 tests, possibly a sticking valve that was causing lower mileage, and higher O2 numbers in the prior test, and a hotter engine and better mileage since the valve(s) unstuck themselves? But this is all speculation at this point.

MMO, frequent oil changes, and then finally following 5-90's suggestion of running the engine RPM up to 3500 RPM unstuck the valve(s).

Current Mileage is 266,000 miles.

Looking at reported O2 numbers in this thread made by others, also makes me question the reliabilty of all the O2 numbers, and units used for O2, reported here so far.

 

[Rammin97]

I can get this Jeep Free if i can get it to Pass. I figured I would post this up and see if anyone has suggestions. I will hopefully be posting Passing scores too. Thanks

.............RPM... CO2 ......O2 ....HC (max)... (avg)... (meas)... CO (max)... (avg)... (meas)... NO (max)... (avg)... (meas)
15mph ..1670 ....15.40 .. 0.00...........63 ........26.... ....08 ...........0.46 ...... 0.04 ....0.02........0460........175.......343(Pass)
25mph ..1894.....15.40....0.00..........038.........16.. ......08............0.56........0.05.....0.01.........539.........188.......577(Fail)

 

[1990JEEPXJ]

what have you done in terms of a tune up? and what year jeep?

 

[Ecomike]

Run some Gumout (or equal) through the throttle body (follow directions), or use some carburator cleaner and run it through the throttle body, and run some fuel injector cleaner in the fuel tank to clean the injectors and the valves and you should be good to go. It barely failed on NOx emissions at higher speeds, probably due to carbon fouling in the head/valves.

All the other numbers were very low!!!!

 

[Rammin97]

Thanks guys, its a 95 and according to my sister, the mechanic did a full tuneup and even replaced the CAT. ya, the numbers were all good accept the NOs. Once I get the jeep up to my place, I will go through everything and do the Gumout/fuel injector cleaner and see what happens. What do you think about Garanteed to Pass stuff? what the heck is it anyway? I will post the numbers up when I take in to my smog guy.. Note: My smog guy's wife is frickin HOT!!! mmm, I wonder if that's why i take all my vehicles there:gag:

 

[1990JEEPXJ]

.............RPM... CO2 ......O2 ....HC (max)... (avg)... (meas)... CO (max)... (avg)... (meas)... NO (max)... (avg)... (meas)
15mph ..1670 ....14.7 .. 0.02...........123 ........41.... ....23...........0.73 ......0.14 ......0.08..........711........332.......6
25mph ..1894.....14.7....0.02...........103.........33.. ......26...........0.93.......0.15.......0.08..........613........258......27

here are my results from today

 

[Ecomike]

here are my results from today

Was it A JEEP? LOL. Just a reminder that it helps to verify the actual jeep year with the data (Some of us have more than one), and thanks for sharing the data! Mod data, gearing etc, might also be usefull?

Very nice numbers!! A green Jeep! LOL

 

[1990JEEPXJ]

brain fart! you are absolutely right mike. info is very useful. i was surprised at how clean it runs as well. especially the NO at 15mph.

its a 1990 XJ, 4.0, AW4, 200k miles, 5" lift, 33's, stock 3.55 gearing, magnaflow exhaust, new magnaflow cat installed last year.

 

[slikxj]

Should have posted here first! 1990 AX-15 4.0. First failed test was run with a bad TPS. Second failed test new TPS, adjusted to 0.8 volts, new O2 Bosch, new magnaflow carb legal cat. Passed the 15 mph with no problem. The 25 mph test failed miserably. During the test it had a foul smell, kinda like rotten eggs LOL. Other than the CTS, MAP and egr, could dirty oil affect the test but only at the 25 mph test? A million thanks!

First test

Second test

 

[Ecomike]

I don't see how they could possibly get those bad numbers on the second test. I would have another shop rerun the test, and verify the higher speed, 25 mph, data. Did they have it in the wrong gear at 25 mph??? I ask that since it is a manual tranny, but even then those numbers look like a decimal place lab data, 10X error to me.

The 15 mph data shows a 95% drop in emissions after all the new parts went in, but the 25 mph data shows huge numbers, like over 9% CO???? and no NOX at all. It just makes no sense, compared to the first data run and the 15 mph data.