Carb tuning advice - Oregon

[Dclowd9901]

Hey team,

I’m currently in a sisyphean hell trying to get my 2F to pass emissions in Oregon. Here’s where I’m at:
Passing values:
HC 220 (ppm hydrocarbons)
CO 1 (represents percent of unburned fuel in emissions)

EGR disconnected:
Idle:
HC 239
CO 4.7885

2.5k rpms
HC 239
CO 4.4625

EGR Connected:
Idle:
269
4.4218

2.5k rpms:
301
3.823

Carb tuned per FSM (EGR disc)
Idle:
343
3.5633

2.5k rpm:
372
3.1838

So, the EGR seems to have little effect on the overall numbers. Or maybe leaving it disconnected so long then suddenly connecting it gives a false reading.

At any rate, does anyone have any good tuning suggestions for meeting Cali-style emissions restrictions? The engine runs really well, but I do have some new spark wires on order (found a tear in the current ones that I patched with electrical tape for now). I would just take it to a shop, but they’re always busy up here for months out and I need to get this done.

 

[OSS]

This was my last test. All stock '86 FJ60 with nothing unusual in the gas tank.
Check the function of your air injection system. You should see some O2 coming out the tailpipe.
The EGR system is there to reduce NOX caused from high combustion temps. It isn't active at idle.
If the catalytic converter is worn out, smog will come out of the tailpipe no matter what.

 

[jestlurnin]

Increase your idle speed to about 950/1000. That’s how I always used to pass and both my 60 and 40 ran very well and were tuned with the lean drop method but would never pass.

 

[Dclowd9901]

Increase your idle speed to about 950/1000. That’s how I always used to pass and both my 60 and 40 ran very well and were tuned with the lean drop method but would never pass.

The idle was tuned this high on my first run through; I brought it back down to 690 thinking it might help with the idle check (it looks like my CO emissions did drop pretty substantially, but both HC and CO are still pretty high).

this truck, for what it’s worth, did pass emissions 2 years ago, so I’d be very surprised if something as sturdy as the cat became too smoggy in the interim.

 

[Dclowd9901]

Check the function of your air injection system.

I take this to mean the air pump and PCV; how can I check this system?

 

[OSS]

All the test procedures for the smog equipment are in the Emissions Manual. If you want to keep your cruiser and you've got to pass smog tests, memorize this manual... Or at least become very familiar with it.
See attached

 

[cps432]

Try pouring distilled water in the carb. Just buy a bottle of water and fill a cap and dump it in while you’re reving the engine via the carb linkage. You’ll hear it steam and stumble. Then it’ll kick right back to life. Do this a few times and then to run the test. This will burn off any carbon deposits on the piston heads and help the combustion chamber burn more evenly. I’ve chased things around for months before trying that and it worked. However, I’m failing emissions again and it’s not working for me this time. But try it. It won’t hurt.

 

[Godwin]

Try pouring distilled water in the carb. Just buy a bottle of water and fill a cap and dump it in while you’re reving the engine via the carb linkage. You’ll hear it steam and stumble. Then it’ll kick right back to life. Do this a few times and then to run the test. This will burn off any carbon deposits on the piston heads and help the combustion chamber burn more evenly. I’ve chased things around for months before trying that and it worked. However, I’m failing emissions again and it’s not working for me this time. But try it. It won’t hurt.

It won't hurt unless you dump too much water at once and hydrolock a cylinder leading to the bending of a rod.

 

[DFXR]

Try pouring distilled water in the carb. Just buy a bottle of water and fill a cap and dump it in while you’re reving the engine via the carb linkage. You’ll hear it steam and stumble. Then it’ll kick right back to life. Do this a few times and then to run the test. This will burn off any carbon deposits on the piston heads and help the combustion chamber burn more evenly. I’ve chased things around for months before trying that and it worked. However, I’m failing emissions again and it’s not working for me this time. But try it. It won’t hurt.

I’ve done it. Used a keg cup and poured really slow, like a trickle, while working the throttle. It’s kind of fun in an old school hot rod way but all the slimy black sludge and crap I was hoping would flush out never materialized.

 

[OSS]

The best/safest way to get water into the carb/intake while the engine is running is with a spray bottle.

 

[Dclowd9901]

All the test procedures for the smog equipment are in the Emissions Manual. If you want to keep your cruiser and you've got to pass smog tests, memorize this manual... Or at least become very familiar with it.

So, to extrapolate on this: you're saying that if the emissions system is in full working order, I should be able to pass emissions with the normal carb tune?

 

[OSS]

Absolutely.
The carburetor from the factory had the idle fuel mixture screw capped off with a plug to prevent tampering.
If that plug has been removed and the mixture screw messed with - there's no telling how far out of whack the fuel mixture is. Engine might run good but it also might be polluting.
On the next generation carbureted 3F engine (non USA), the manual has no mention of attempting a lean drop tune up though it could just as easily be attempted on that engine too. The new recommended method (they learned) was to hook an exhaust analyzer to the tailpipe and set the fuel mixture according to what was belching out the pipe.
The point is --- attempting a tune up using only the lean drop method by itself provides no guarantee that the end result will be emissions compliant.

 

[Dclowd9901]

Absolutely.
The carburetor from the factory had the idle fuel mixture screw capped off with a plug to prevent tampering.
If that plug has been removed and the mixture screw messed with - there's no telling how far out of whack the fuel mixture is. Engine might run good but it also might be polluting.
On the next generation carbureted 3F engine (non USA), the manual has no mention of attempting a lean drop tune up though it could just as easily be attempted on that engine too. The new recommended method (they learned) was to hook an exhaust analyzer to the tailpipe and set the fuel mixture according to what was belching out the pipe.
The point is --- attempting a tune up using only the lean drop method by itself provides no guarantee that the end result will be emissions compliant.

Well, it was definitely messed with long before I ever got to it, so unfortunately going back isn't an option, but it does sound like what you're saying is a bit contradictory. On the one hand, the factory tune should be good, but the lean drop method (as described in the factory service manual) may not be sufficient to tune.

I bet I could tune my carb to the extent that it passes emissions, but then my concern is tuning it too lean and hurting the engine because of it. At the end of the day, all of this stuff is difficult because I don't have a good way to test if my changes made any difference (nearest DEQ is about a 25 minute drive).

I was hoping there was maybe some way to easily tune for a "safe lean" mixture, or to have a short iteration cycle so I could try a lot of different things. I've actually been thoroughly through my emissions system trying to find issues around the classic "stumbling/hesitation" issues, and hadn't found a single thing wrong with it, but I guess I can do another pass.

 

[OSS]

The only practical way for a home mechanic to dial in the fuel mixture to prepare for a smog test is install a wideband O2 sensor and gauge. It'll tell you right away how lean things are.
@Spike Strip has one installed on his 60 and knows all the tricks to prep the engine for a smog test. His last test results looked like they were from a Prius.

 

[Spike Strip]

I haven't read they whole thread (on phone) just the OP post, but high HC *and* high CO together are usually because the mix is too rich. So is it too rich because of carb or not enough Air Injection ... I don't see % O2 listed on your test results, so they may not test for it but it's the key indicator how the AI sys is working and AI is probably the single most important sub-system for passing smog, outside the carburetor itself.

I'm in Los Angeles and I found out the hard way that it def makes a difference if you use Oxy gas vs non oxy gas, summer blend vs winter (I don't know what's avail to you in OR), and using the A/F meter to get the mix around 14.5 to 1 for the test. (too lean raises NOx).

You could always try the alcohol add. I've heard that works, too...

I use to only pass smog with the slimmest of margins until I figured out the gas blend thing, and I only figured that out serendipitously, because I had to delay the testing because of Covid lockdowns... My O2 number jumped 60% by just using gas that is more oxygenated (Los Angeles smog basin winter blend), and that leads to cleaner combustion (assuming all your smog controls are functioning properly).

You may need to go through (if you haven't already) the emissions FSM to test the sub-systems. And I would highly recommend an A/F digital meter.

Good luck!

Passed Smog Test

Kalifornia Timing @ 5* BTDC (Kalif only allows +/- 2* or test fail). I watched the Tech check the timing (after I showed him where the marks were ;) ) about 40% E-85 Flex Fuel mixed with 91 Octane (or higher if available) Normal AQMD Summer Blend (oxygenated) gas. Fresh Engine Oil Carb...

forum.ih8mud.com

 

[Dclowd9901]

The only practical way for a home mechanic to dial in the fuel mixture to prepare for a smog test is install a wideband O2 sensor and gauge. It'll tell you right away how lean things are.
@Spike Strip has one installed on his 60 and knows all the tricks to prep the engine for a smog test. His last test results looked like they were from a Prius.

This is awesome; I didn't even know it was an option.

I haven't read they whole thread (on phone) just the OP post, but high HC *and* high CO together are usually because the mix is too rich. So is it too rich because of carb or not enough Air Injection ... I don't see % O2 listed on your test results, so they may not test for it but it's the key indicator how the AI sys is working and AI is probably the single most important sub-system for passing smog, outside the carburetor itself.

I'm in Los Angeles and I found out the hard way that it def makes a difference if you use Oxy gas vs non oxy gas, summer blend vs winter (I don't know what's avail to you in OR), and using the A/F meter to get the mix around 14.5 to 1 for the test. (too lean raises NOx).

You could always try the alcohol add. I've heard that works, too...

I use to only pass smog with the slimmest of margins until I figured out the gas blend thing, and I only figured that out serendipitously, because I had to delay the testing because of Covid lockdowns... My O2 number jumped 60% by just using gas that is more oxygenated (Los Angeles smog basin winter blend), and that leads to cleaner combustion (assuming all your smog controls are functioning properly).

You may need to go through (if you haven't already) the emissions FSM to test the sub-systems. And I would highly recommend an A/F digital meter.

Good luck!

Passed Smog Test

Kalifornia Timing @ 5* BTDC (Kalif only allows +/- 2* or test fail). I watched the Tech check the timing (after I showed him where the marks were ;) ) about 40% E-85 Flex Fuel mixed with 91 Octane (or higher if available) Normal AQMD Summer Blend (oxygenated) gas. Fresh Engine Oil Carb...

forum.ih8mud.com

View attachment 2762806

thanks for weighing in; any recommendations for a wideband O2 + meter?

 

[Spike Strip]

I use an Autometer, but there are many brands. Whatever you buy, just make sure it comes with a genuine Bosch O2 sensor, and not some Chi-Comm knockoff.

Also, be aware the sensor must be mounted as close to 12 o'clock on the pipe as you can get it, and before the CAT. A bit tricky when the pipe is in the car. That downpipe is SS, btw.

 

[2mbb]

The idle was tuned this high on my first run through; I brought it back down to 690 thinking it might help with the idle check (it looks like my CO emissions did drop pretty substantially, but both HC and CO are still pretty high).

this truck, for what it’s worth, did pass emissions 2 years ago, so I’d be very surprised if something as sturdy as the cat became too smoggy in the interim.

The CAT won't work without a properly working Air Injection system (This is not the PCV system by the way). The CAT requires oxygen to reduce the concentration of smog gases. The CA smog report does also show residual oxygen measured at the tail pipe. Not sure what the Oregon report has on it. But you can test if the system is working via the emissions manual.

 

[Dclowd9901]

The CAT won't work without a properly working Air Injection system (This is not the PCV system by the way). The CAT requires oxygen to reduce the concentration of smog gases. The CA smog report does also show residual oxygen measured at the tail pipe. Not sure what the Oregon report has on it. But you can test if the system is working via the emissions manual.

Yeah, unfortunately the Oregon report doesn’t have o2 numbers.
I can’t fly blind here so I’m def going to pick up the o2 sensor and gauge. Then I’ll start throwing money at parts if I need to. Thanks all for weighing in.

 

[cps432]

Yeah, unfortunately the Oregon report doesn’t have o2 numbers.
I can’t fly blind here so I’m def going to pick up the o2 sensor and gauge. Then I’ll start throwing money at parts if I need to. Thanks all for weighing in.

I got sick of trying to pass emissions. So I’m buying all the parts for a desmog and I’m using that to justify moving to an other state