Rebuild stock carb cost? Issues with passing CA smog (2 Viewers)
- Thread starter ro11dice
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
jumping on the bandwagon. just failed CA today (barely) carb rebuilt two years ago and passed easily. CAT is (aftermarket) 4-6 years old. time for another CAT? I understand the aftermarkets do not last for more than about four years or so. any ideas?
At first I looked at this pic and thought, WTF? but realized in 2WD you can have the different sized tires and just run to the test then remove.
Great f'kin idea! I'm gonna try that next year!
Yup. Prices of new CATs have skyrocketed (up from ~ $350 a year ago due to all the CAT theft and precious metal shortages). But notice how non-smog States the prices are only slightly up? Keep voting for you-know-who if you're ok with this shizzle.
A Diagram or Schematic of the vehicle being tested pops up on the Tech's screen, with location of various required smog control pieces .
Maybe lean drop mix adjust and try some E85 gas and the smaller rear tires (see above) and retest. You're very close except for the low speed running rich.
- Thread starter
- #24
Great point. I am running 33s and my previous smog pass was on 31s I believe. So you ran 31s in the back and 33s in the front for the test? I may need to run the 31s. Thanks for the tip.
Yep. I ony did the mismatched sizes for the morning that I took it in for the smog test, and since they only test in 2wd I only bought 2 old rims and used tires. The smog tech probably thought it looked strange, but it definitely works.
If you already have a set of 31s I would definitely give that a shot before spending any significant money or time trying to chase minor adjustments in the tune-up.
I am running 31s and still didn't make the cut. i am wondering if my engine simply wasn't hot enough
Last edited:
E85 is 15% Ethanol. The closer you can get to running straight E85 the better. And if you can wait until the switch over to summer blend gasoline, that's even better, too.
Just fill up with straight gas after you pass (hopefully).
Just fill up with straight gas after you pass (hopefully).
yeah, fingers crossed. can you run E85 all the time instead of normal gas?E85 is 15% Ethanol. The closer you can get to running straight E85 the better. And if you can wait until the switch over to summer blend gasoline, that's even better, too.
Just fill up with straight gas after you pass (hopefully).
two years ago i had zero CO on my test so I hope it is just a mater of getting it hot before the test. I had to wait about 30 minutes this last time. should have idled. wish I could wait for summer gas but smog is due this month.
@Spike Strip I Installed the Autometer A:F gauge with Bosch O2 sensor and would love to chat about the numbers I'm seeing. I have to pass Denver emissions in March, so I want to make sure I'm using my data from the A:F to tune the carb correctly before rolling into the testing center. I'll have a freshly rebuilt head by then so hopefully that will help, but I want to do everything I can to get it done on the first shot. My cat (oh wait, I don't have a cat right now - but I will by test day) has never had a temperature sensor for controlling the AI system. I really need to find one of those. Maybe a generic would work but I don't know if it would be calibrated the same as an OEM one was.
For anybody looking to rebuild a carb that needs an extra for rebuilding off the truck (maybe because you daily drive your 60 like I do) I have one. PM me and we can work out a deal. I had Jim C do mine a little over a year ago and it's still good. Yes the Slow Cut valve leaks on this one. It leaked on my old one and it leaks on my rebuilt one too. No problem passing smog two years ago and no drivability issues.
For anybody looking to rebuild a carb that needs an extra for rebuilding off the truck (maybe because you daily drive your 60 like I do) I have one. PM me and we can work out a deal. I had Jim C do mine a little over a year ago and it's still good. Yes the Slow Cut valve leaks on this one. It leaked on my old one and it leaks on my rebuilt one too. No problem passing smog two years ago and no drivability issues.
The temperature probe poking into the original cat is a safety feature, not an emissions requirement.
The thing that really heats up the cat (maybe to the point of too hot) is long duration fast idling on a really hot day with the car not moving at all. While driving, the airflow created by the movement of the vehicle will cool down the cat
The thing that really heats up the cat (maybe to the point of too hot) is long duration fast idling on a really hot day with the car not moving at all. While driving, the airflow created by the movement of the vehicle will cool down the cat
Part of wanting one is for the visual test. I was also under the impression that in addition to the AI system regulating cat temps, it can effect what's coming out the tailpipe. The latter piece is not in the Emissions FSM but has been mentioned here on Mud. I'm unsure of the veracity of that claim, though.
As far as I understood it, if the cat gets too hot, (as measured by the probe) that signal is sent to the emissions computer which then tells the air pump ABV to divert the air flowing into the exhaust and send it to the air filter instead.
Apparently if there isn’t any oxygen in the exhaust (as supplied by the air pump) the cat doesn’t run as hot (nor really work too well).
Apparently if there isn’t any oxygen in the exhaust (as supplied by the air pump) the cat doesn’t run as hot (nor really work too well).
Don't run the E85 - Not good for vehicles that aren't designed for it. Bad for Carburetors! Bad for rubber. Dilute as much as possible after testing.
You can pay your fees online and then wait for the test - NO penalty that way, but you will have expired tags for a couple months. They usually give a couple of months grace. Also, FYI - New law in Kalif as of 1/1/22 The SMOG station can issue you registration Tags ON THE SPOT.
Theoretical perfect stoichiometry for Air/Fuel is 14.7:1 (fixed) You'll find the analog meter you have is slow to react, taking about 30 sec or so for the needle to move as you adjust the carb, so you'll need to make small adjustments, wait, more adj, etc ...
For testing try to get the mix around 15:1 or so (slightly lean). When I add E85 for the test, it goes way lean, up around 17.
After testing, I richen mix to around 13.5 or so for best performance, but I'm at approx 700 ft above sea level. Since you're at high elevation, you're probably going to want to keep a lean-ish mix. It's going to require a bit of experimentation to find where it runs best, usually around 14.7:1 Also, you said you're running a Jim C. carburetor? He's probably tweaked the jetting for best performance, so again, it's gonna take a bit of fiddling to get the carb tuned (I believe Jim does this for performance at his shop) for smog test.
Last edited:
@OSS Thanksa for the info. I was imagining some of that diverted air not burning up in the cat and making it through to the tailpipe where it dilutes the whole mess. I'm probably overthinking it.
@Spike Strip Thanks for the input! The A:F gauge is a digital stepper motor controlled needle. I can see the accelerator pump hit the exhaust stream in less than a second. That being said, when I adjust the carb I give it some time before adjusting again. When I sent my carb to Mr. Chenoweth I was clear on being fully smogged and he said he would rebuild accordingly. I'm finding that at part-throttle cruise, maybe 70% throttle, I run VERY lean - around 16 or 17:1. This is typically on the highway going up a slight incline that requires a good amount of throttle input but NOT going wide open. I'm wondering if my secondary jet needs to go bigger. Right now I idle at ~12.5, cruise under light load at ~14.5-15, cruise under heavy load around ~16.5 (as mentioned above), and WOT gets me to ~14.5. I'm certainly not a carb expert but I'm thinking both the heavy load cruise and WOT being as lean as they are both points to the secondary jet. I'm going to adjust idle leaner for a while this week and see what happens. Maybe it's the balance between the mixture screw and the idle speed (air leak) screw as well.
Also, I thought stoich was 14.7 ... did you typo that one? By the way, my emissions test is a full driving test on rollers - not just a two speed or idle test.
@Spike Strip Thanks for the input! The A:F gauge is a digital stepper motor controlled needle. I can see the accelerator pump hit the exhaust stream in less than a second. That being said, when I adjust the carb I give it some time before adjusting again. When I sent my carb to Mr. Chenoweth I was clear on being fully smogged and he said he would rebuild accordingly. I'm finding that at part-throttle cruise, maybe 70% throttle, I run VERY lean - around 16 or 17:1. This is typically on the highway going up a slight incline that requires a good amount of throttle input but NOT going wide open. I'm wondering if my secondary jet needs to go bigger. Right now I idle at ~12.5, cruise under light load at ~14.5-15, cruise under heavy load around ~16.5 (as mentioned above), and WOT gets me to ~14.5. I'm certainly not a carb expert but I'm thinking both the heavy load cruise and WOT being as lean as they are both points to the secondary jet. I'm going to adjust idle leaner for a while this week and see what happens. Maybe it's the balance between the mixture screw and the idle speed (air leak) screw as well.
Also, I thought stoich was 14.7 ... did you typo that one? By the way, my emissions test is a full driving test on rollers - not just a two speed or idle test.
Yes, you're right: Ideal Air/Fuel ratio is 14.7:1 I meant for Performance, tuners try to get around 13:1 or lower, IOW, a rich mix. Watch out for those flames out the tailpipe! (kidding).
I think Jim normally opens up the 2ndry Jet a bit for performance, but if he built your carb for smog then I'm sure it's stock at 2.00mm. If you need to pass smog I wouldn't mess with the jetting, unless you're prepared to swap every couple years ...
Modern Gas (RFG) has less BTUs and runs leaner, but again, we're hampered by having to appease the smog police, so, those numbers you're getting seem good, at your elevation. Thin air mean you need MORE air for efficient combustion, or as efficient as these archaic pumps can get.
When I tune mine for smog test, I run about the same numbers as you and it seems fine. I've done it enough times now that I know it's just a simple 1/8-1/4 of a turn or so on the mix screw for test vs normal driving.
Also, that Thermosensor probe that goes into the CAT. For a long time it was routine at Muffler shops around here, when installing a new CAT, to simply clip the probe wires at the spot where they come out of the body and install a universal CAT without the probe. Since the Retroactive OBDII law went into effect (in CA), they don't do that any more because all the CARB approved CATs for an FJ60 must have that Thermosensor port.
But new CATs are way more efficient than the old thick brick that was on there. That thermosensor isn't needed and you won't fail visual if you don't have it. It's not on the Smog Techs diagram that tells them what they need to look for. I've watched when I have my tests done.
@Spike Strip I'm considering getting 5-year classic plates, that way I'm smog testing every 5 years instead of every 2. I'm even considering desmogging between tests if I do the 5-year deal. The only problem is Colorado limits you to 4000 miles per year with classic plates, under penalty of perjury (a felony). I really, really doubt the state is spending a single cent going after people with classic car plates ... but, on the outside chance they were to "come after" me there goes my job and ability to provide for my kids. Oops. So the jury's still out on that.
As far as altitude goes, the theory is that slightly leaner is better because there's not as much O2 in the same volume of air being pumped by the engine as at sea level? I thought the A:F sensor was an O2 sensor, so wouldn't that already be compensating for the difference? My worry about the lean condition is that I've had two people tell me now that running so lean can cause localized extremely hot temps that can damage pistons and valves ... but what do I know?
As far as altitude goes, the theory is that slightly leaner is better because there's not as much O2 in the same volume of air being pumped by the engine as at sea level? I thought the A:F sensor was an O2 sensor, so wouldn't that already be compensating for the difference? My worry about the lean condition is that I've had two people tell me now that running so lean can cause localized extremely hot temps that can damage pistons and valves ... but what do I know?
Well, fortunately for FJ60s the only way to tell how many miles you've driven is the Odometer ... So, either disconnect the speedo cable or buy a spare cluster you can swap out between tests to keep your original cluster unchanged or low. Swapping out a complete cluster takes about 15 mins once you've got the trick to releasing the speedo cable. I'm sure you would be the only 'enthusiast' who has done this.
It will also lower your insurance, I bet.O2 sensors work (I think) by generating their own voltage depending on the Delta of O2 between exhaust and outside air (there's a port on the section of the sensor that's outside the exhaust pipe. I have no idea how that works. So the voltage produced (and what you see on the meter) is going to be consistent with how efficient the burn is, whether at altitude or sea level. But yes, you don't want to run too lean; that does increase combustion temps. That's where the A/F meter shines as it will let you know if you're too lean, or if your deceleration circuit is not working. When you let off the gas at cruising, the ICS should momentarily shut off and you'll see the meter sweep lean for a second - This circuit is to prevent backfire as the engine vacuum momentarily jumps up to 21-25 when throttle closes and otherwise (without closed ICS) would suck in a bunch of gasoline.
Watch the A/F meter and the Vacuum gauge at the same time and you'll see the correlation.
Last edited:
@Spike Strip Well there's an idea. I happen to have a spare gauge cluster now that you mention it.... I have asked a bunch of local Cruiser heads about the classic plates and they have ALL said that at no point in the process does the DMV ask your mileage or log it anywhere. The only way mileage could be verified is at the emissions test - but they aren't tracking it for any reason or submitting to another agency to my knowledge. I'm 98% sure I'm safe, but like I said that 2% chance of a damn felony really scares me. I got mouths to feed over here.
Interesting about the decel fuel cut circuit. I tested it out yesterday at 30mph and 55mph and the A:F quickly goes a little rich, then slowly comes back to lean after maybe 1-1.5 seconds. Cruising at ~14, let off gas, A:F hits 12.5-13 immediately, then drifts back towards 15-15.5. Perhaps that super lean blip doesn't register because my A:F gauge isn't fast enough. It's fast enough to catch the accel pump in action though...
The vacuum does immediately go high when I let off the gas, so maybe the ICS circuit isn't shutting down fuel supply very quickly. The solenoid does click when I unplug and plug it back in, so there's that. Over ~40mph or so if I let off the gas completely vacuum is limited to slightly below idle vacuum. I believe those two circuits are related. And for what it's worth my vac gauge takes its reading from the "gas filter" on the intake manifold. I stuck a tee in one of the hoses immediately coming off one of the nipples. There are other places to read vacuum of course, but I want to see what the engine is seeing.
Interesting about the decel fuel cut circuit. I tested it out yesterday at 30mph and 55mph and the A:F quickly goes a little rich, then slowly comes back to lean after maybe 1-1.5 seconds. Cruising at ~14, let off gas, A:F hits 12.5-13 immediately, then drifts back towards 15-15.5. Perhaps that super lean blip doesn't register because my A:F gauge isn't fast enough. It's fast enough to catch the accel pump in action though...
The vacuum does immediately go high when I let off the gas, so maybe the ICS circuit isn't shutting down fuel supply very quickly. The solenoid does click when I unplug and plug it back in, so there's that. Over ~40mph or so if I let off the gas completely vacuum is limited to slightly below idle vacuum. I believe those two circuits are related. And for what it's worth my vac gauge takes its reading from the "gas filter" on the intake manifold. I stuck a tee in one of the hoses immediately coming off one of the nipples. There are other places to read vacuum of course, but I want to see what the engine is seeing.
ok! ran her in hot with some premium gas and got the winning ticket. stoked. two more years of care free wheelin.
