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Topic Review (Newest First)
05-23-2013 01:55 AM
CyndiB You're welcome, I hope he works out for you. There was another Jeep there when I was there, an 88 that needed a carb adjustment, and the guy told me that he works on a lot of Jeeps. After reading all the posts about failed smog tests and then having problems of my own, I was worried that I'd never get it to pass, so I'm very happy to have found this place. I live an hour away, but it was definitely worth the drive and time spent.
05-23-2013 01:10 AM
c5wagner
Quote:
Originally Posted by CyndiB View Post
It's called Arrowhead Auto Repair & Smog, 427 S. Arrowhead Ave., San Bernardino 909-888-6687. It's a busy place so it's best to make an appointment. They charge $75 for the diagnostic testing, and he's real upfront about the charges. I spent $210 total including the smog cert, but I had already spent $100 on a failed test and pre-test, so I would have saved that had I gone there first. They have the equipment to tune the carb to specs, and since they test there, they can tune it to pass smog. One stop shopping.
Thank you so much, I have heard of that place from a friend but it's good to here from someone else with a Jeep
05-23-2013 12:54 AM
CyndiB
Quote:
Originally Posted by c5wagner View Post

What's this place called, I'm trying to find someone nearby to tune my carb.
It's called Arrowhead Auto Repair & Smog, 427 S. Arrowhead Ave., San Bernardino 909-888-6687. It's a busy place so it's best to make an appointment. They charge $75 for the diagnostic testing, and he's real upfront about the charges. I spent $210 total including the smog cert, but I had already spent $100 on a failed test and pre-test, so I would have saved that had I gone there first. They have the equipment to tune the carb to specs, and since they test there, they can tune it to pass smog. One stop shopping.
05-22-2013 02:22 AM
c5wagner
Quote:
Originally Posted by CyndiB View Post
UPDATE: after changing the air filter, 02 sensor and PCV, it failed again, but the technician referred me to a place in San Bernardino that specializes in carburetor repair and also does smog testing. I took it there today and they adjusted the carb and it passed with flying colors. I highly recommend this place, they were honest and reasonably priced. I spent 4 hours there and they charged me $150 for the diagnostics and adjustment. They also use a tighter fitting for the evap test, so that passed too. So relieved to be done with that headache.
What's this place called, I'm trying to find someone nearby to tune my carb.
05-22-2013 01:40 AM
ChicoJeepy Good job man! It's hell to get an older rig to pass smog. My sisters 89 Cherokee was a GROSS polluter. I sure hope my Jeep isn't like that. It passed last July according to the previous owners smog certificate. I'm gunna be an ass and go to the same place it passed last year in Oroville. if it doesn't pass then well he better tell me how to fix it xD
05-22-2013 01:16 AM
CyndiB UPDATE: after changing the air filter, 02 sensor and PCV, it failed again, but the technician referred me to a place in San Bernardino that specializes in carburetor repair and also does smog testing. I took it there today and they adjusted the carb and it passed with flying colors. I highly recommend this place, they were honest and reasonably priced. I spent 4 hours there and they charged me $150 for the diagnostics and adjustment. They also use a tighter fitting for the evap test, so that passed too. So relieved to be done with that headache.
03-29-2013 11:03 AM
2xs
Quote:
Originally Posted by CyndiB View Post
Thanks 2Xs, this helps a lot. I had a bad feeling about that smog check place, but it was too late, the test had already started. Is it normal for them to charge by the age of the vehicle? They charged $71.25 for vehicles older than 1995. I was too dumb to notice that too since the sign out front advertised $39.95. They said they would do the retest for $40 cash, which sounds fishy to me.
The test on 1995 and older vehicles usually takes longer, involves more testing, I charge an extra 5$ for all non OBD2 vehicles, but I also offer one free retest. Sorry im WAY too far away to help you in person, its a bit of a drive to get here from there...
03-29-2013 03:25 AM
CyndiB Thanks 2Xs, this helps a lot. I had a bad feeling about that smog check place, but it was too late, the test had already started. Is it normal for them to charge by the age of the vehicle? They charged $71.25 for vehicles older than 1995. I was too dumb to notice that too since the sign out front advertised $39.95. They said they would do the retest for $40 cash, which sounds fishy to me.
03-29-2013 02:22 AM
2xs
Quote:
Originally Posted by CyndiB View Post
I'll try to post a pic of the report, but the CO2 was 12.96% at 15mph and 13.2% at 25mph. Only the HC and CO failed, the NO was well under Max. The HC was 156 & 117 when max was 87& 73 and CO was 3.26 & 3.03 with max 0.52 & 0.66. Thanks for the help.

Attachment 228763
Yea, dont worry about he HC, that will go down when you fix the CO issue, your CO2 tells me there defiantly is a Efficiency issue.

That inspector is horrible FYI:
STAR Inspector Page

Failed the EVAP functional test, so you will need to take it to a shop that can do a smoke test, but normally the YJs leak at the fittings on top of the tank, so check there before you take it in.

As far as the CO, you defiantly need to have a DVOM, check the O2 voltage to make sure it is seeing a rich condition and not a lean condition, the range is 0-1.1v, if the voltage is low its seeing lean, and that is BAD, if the voltage is hanging above .7, its seeing rich and thats expected with your readings.

Once oyu have the O2 verified/fixed, start looking at the computer output to the carb, This is where Jeep Adventures Under the Hood comes into play, but to do a base check, you need a 4 gas analyzer, adn your fingers....
While sniffing the tailpipe, grab the lead from the o2 connector, computer side, with one hand. With the other hand, touch the battery + terminal (dont worry there is enough resistance in your body that you wont screw up anything, and NO you will NOT get zapped). While touching the + terminal with one hand and the O2 lead to the computer in the other hand, watch the CO and HC readings, if the computer and related carb is working correctly, the mixture will lean out, if it does this correctly, replace the O2 sensor, if not, look more into Jeep Adventures Under the Hood

For a good explanation on an O2 (its in MR2, but the principles are the same).
http://www.mr2.com/TEXT/O2_Sensor.html

Good luck!
03-29-2013 01:58 AM
CyndiB I'll try to post a pic of the report, but the CO2 was 12.96% at 15mph and 13.2% at 25mph. Only the HC and CO failed, the NO was well under Max. The HC was 156 & 117 when max was 87& 73 and CO was 3.26 & 3.03 with max 0.52 & 0.66. Thanks for the help.

Attachment 228763
03-29-2013 01:16 AM
2xs
Quote:
Originally Posted by CyndiB View Post
Hi guys, I need some help trying to figure out what the results of my failed smog test mean. I have a 1990 YJ newly rebuilt 6 cyl engine with stock Carter carb. Cat is a year old. I took the jeep to a shop yesterday for a pre-smog tune-up and oil change. The smog test this morning showed double the limit for HC and way too high CO (3.26 and 3.03). The jeep runs fine and the exhaust doesn't smell like its running rich. The smog test guy says I should rebuild the carb, but I would think if the carb needed rebuilt, it would run badly. Any ideas on where I should start?
NonRubicon has some great points

Did you fail for anything else? A leaking exhaust is a fail too, they call it untreated exhaust, but not all techs will fail it for this.

CO is a direct result of too much fuel, the HC is raised, but the target gas is the CO.
Rebuilding the carb might fix it, but the carb is computer controlled, before just rebuilding the carb, you have to make sure the computer controls are telling it what to do correctly.

You could have a bad computer, or the O2 is stuck lean, telling the computer you are running lean, so the computer tells the carb to go full rich....

What is the Co2? that should be around 14.7%, if its low this verifies the reading as poor combustion efficiency, or a bad cat (Running too rich can kill a cat quickly).

Can you scan or take a pic of the whole test report and post it here?
03-29-2013 01:07 AM
NonRubicon Here's a link to a good site that explains the workings of the 4.2L with the Carter BBD: Adventures Under the Hood . I would start there to understand the system. It also has some tips for troubleshooting that are probably better explained than I could do for you.

Unfortunately, the Carter BBD can be a pain to diagnose. It is time consuming and laborious without a diagnostic tool. It's a computerized carb, but nobody makes a diagnostic reader for the system on the 4.2L - you have to build your own. Readers aren't too difficult to build if you know how to solder and can make simple circuits. Unfortunately I no longer have the ones I made to use when I had the Carter.

There are so many things that could go awry on the stock 4.2L with the Carter BBD setup to cause a rich exhaust.

Just what I can think of:

  • Computer not going into closed loop
  • --Thermal Electric Switch/wiring (needed to tell computer to go closed loop)
  • --Coolant Temperature Switch/wiring (also needed to tell computer to go closed loop)
  • Computer bad
  • Bad O2 sensor/wiring
  • Stepper motor malfunction/wiring
  • Crack in exhaust manifold upstream of O2 sensor
  • Dirty carb/fuel dripping from venturis
  • Choke out of adjustment
  • Bad catalytic converter (unlikely in your case, but still possible if you've been running rich)
03-28-2013 11:14 PM
CyndiB
Need help with CA smog results

Hi guys, I need some help trying to figure out what the results of my failed smog test mean. I have a 1990 YJ newly rebuilt 6 cyl engine with stock Carter carb. Cat is a year old. I took the jeep to a shop yesterday for a pre-smog tune-up and oil change. The smog test this morning showed double the limit for HC and way too high CO (3.26 and 3.03). The jeep runs fine and the exhaust doesn't smell like its running rich. The smog test guy says I should rebuild the carb, but I would think if the carb needed rebuilt, it would run badly. Any ideas on where I should start?

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