http://tc.wagoneer.net/sblog/index.php ]]> Copyright 2010, Michael Shimniok Michael Shimniok en-US SPHPBLOG 0.5.1 http://tc.wagoneer.net/sblog/index.php?entry=entry100826-233811 Hunting http://tc.wagoneer.net/sblog/index.php?entry=entry100826-233811 Michael Shimniok Fri, 27 Aug 2010 04:38:11 GMT http://tc.wagoneer.net/sblog/index.php?entry=entry100814-014257
The military trigger on there now is pretty heavy and seems to have a lot of gritty creep even after taking up the initial slack.

It was after shooting a really nice Savage tactical rifle with a truly brilliant trigger and putting a group inside an inch, especially two holes touching, that convinced me to upgrade my rifle.

The Savage had zero creep that I could feel, a light pull, and such a crisp, instantaneous break with zero overtravel, that it was just a matter of thinking about firing and it suddenly happened without even feeling like I'd moved a muscle. Very cool.

I'm hoping my sad 3-6" groups at 100 yards will tighten up considerably once I get the firearm back.

The biggest upgrade will be to my confidence if I can put a string of bullets in an inch circle on the bench. I've always worried that if I shoot minute of pie plate at the range, I'll be shooting minute of barn door when I'm vibrating from buck fever in the field.]]> Outdoors http://tc.wagoneer.net/sblog/index.php?entry=entry100814-014257 Michael Shimniok Sat, 14 Aug 2010 06:42:57 GMT http://tc.wagoneer.net/sblog/index.php?entry=entry100809-071513 this article on theft of catalytic converters from NPR.

"Thieves are attracted to the platinum, palladium and rhodium found in the converters, which reduce auto emissions."

"There are recent episodes in Baltimore, Maryland, in Texas, in Colorado, and some in Illinois. So thats all the confirmed recent reports. However it's sporadic, but they continue over the last several years, for sure."

"The easiest thing for them to do is to find one that doesn't require jacking the vehicle up at all. So we find most of our victims are owners of SUVs or pickup trucks, vehicles that tend to have more of a ground clearance. ..."

Sounds like it's a fairly uncommon crime, but with a 4" lift, TC is in the higher risk group for being targeted. Maybe I'm jumpy because someone stole my stereo not that long ago.]]> http://tc.wagoneer.net/sblog/index.php?entry=entry100809-071513 Michael Shimniok Mon, 09 Aug 2010 12:15:13 GMT http://tc.wagoneer.net/sblog/index.php?entry=entry100806-000133
HC 3.4251 limit 4.000
CO 24.2467 limit 40.000
NOx 5.8338 limit 6.000

I'll be getting my tags tomorrow.]]> Tinkering http://tc.wagoneer.net/sblog/index.php?entry=entry100806-000133 Michael Shimniok Fri, 06 Aug 2010 05:01:33 GMT http://tc.wagoneer.net/sblog/index.php?entry=entry100805-104351
A rebuild kit arrived from Autozone via FedEx Wednesday and that night I rebuilt the carburetor, readjusted the aneroid, and installed an emissions vapor canister.

How It Works
Reading three IFSJA threads, I discovered the importance of the emissions vapor canister. Gas tank and carburetor bowl vapors are deposited in the canister's activated charcoal.

At idle, a tiny bit of those vapors are sucked back into the PCV (Positive Crankcase Ventilation) valve. At part throttle load, the purge valve is activated by ported vacuum, allowing even more vapors to be sucked in through the PCV.

All this sucking means that disconnecting and plugging the PCV purge inlet would enrichen the mixture at idle and part throttle load. Less air is drawn into the manifold. In fact, I'd disconnected and plugged my PCV purge inlet so maybe that explains my high part throttle emissions.

Replacements
The stock emissions canister is no longer available but a canister from a 1993 Jeep Grand Cherokee can be adapted, per a thread on IFSJA. Cross ref part numbers: Standard Motor Products CP3045, NAPA CRB 220052, Borg Warner (BWD) CP1061.

Simply drill out the right hand inlet and clamp the tank vent hose to that. Clamp the bowl vent hose to the left inlet. The purge outlet is just below the purge signal valve, top center.

Carburetor Bowl Vent
On the later FSJs, the bowl vent is closed by an electric valve when the engine is running. Probably typical of old FSJs, my valve is broken. This shouldn't affect tailpipe emissions. The purge system is what's key. But, if you need a replacement valve, look up a Carburetor Bowl Vent Solenoid for a 1978 Ford Bronco, 400cid engine at Napa online, Rock Auto, Auto Parts Giant, etc. Or look for Standard Motor Products BV1, Echlin CRB 22109, Motorcraft MICX239, Airtex 1G1007, BWD BVS1. Additional part number cross references here

Results
I now have the purge system working, and a new power valve, and the truck is finally running too lean at part throttle. That is a good sign. Now it is a matter of enriching the mixture just enough to make it drivable and I should, hopefully, be much closer to passing emissions.]]> Tinkering http://tc.wagoneer.net/sblog/index.php?entry=entry100805-104351 Michael Shimniok Thu, 05 Aug 2010 15:43:51 GMT http://tc.wagoneer.net/sblog/index.php?entry=entry100729-132431 last time, and had exactly the same fiasco as last time.

First test wasn't accepted. Hose fell off on the second test, and the "driver" miserably failed to maintain speed on the second test. Just... like... last time!!

How is that POSSIBLE?!

Only this time the second test was accepted by the manager. Despite how badly the "driver" blew it in the highway driving section, no doubt making my numbers much worse than they should have been.

To top it all off, despite leaner jets, the truck failed worse than before on CO and HC!

Last time: HC=3.8015, CO=62.2980, NOx=6.5254
This time: HC=4.7772, CO=82.9261, NOx=4.7884

I'm in a quandary about what to do next. I can go another two stages leaner on the jets, but I suspect the accelerator pump -- and the "driver's" gratuitous use of it -- is hurting the most. For that matter, the power valve might be the biggest source of trouble and may need replacing.

The hot temperatures probably aren't helping either. I could take it in during the early morning hours. To a different facility in hopes that I get a competent driver. Should I take it into the testing facility tech center for diagnosis? Or to a local carb specialist? Or just install the fuel injection system that's ready to go in the garage?

What boggles my mind is that last time TC passed two years ago, the truck posted outstanding numbers. This time around I'm on my fourth test failure. What gives?! I mean, besides the fact that NOx and HC limits got stricter...]]> Tinkering http://tc.wagoneer.net/sblog/index.php?entry=entry100729-132431 Michael Shimniok Thu, 29 Jul 2010 18:24:31 GMT http://tc.wagoneer.net/sblog/index.php?entry=entry100703-091649
And it is a long road trip and we've not really tried taking Violet on extended drives like that. So I think we'll end up throwing in the towel and trying for a four wheeling run a little later on.

Meanwhile, the set of #50 and #48 jets I ordered arrived from Carbs Unlimited while I was away on a business trip for the week. At some point I'll give those a try and see if I get any closer to getting through emissions.]]> http://tc.wagoneer.net/sblog/index.php?entry=entry100703-091649 Michael Shimniok Sat, 03 Jul 2010 14:16:49 GMT http://tc.wagoneer.net/sblog/index.php?entry=entry100618-120037
I did a few tweaks to make the truck run and idle leaner and advanced the timing a little.

The third try was decidedly not a charm. The inexperienced driver had to run the test three separate times before it was accepted. First try, the hose slipped off the exhaust... right at the end. The second time the guy still couldn't match the required speed so the test wasn't accepted. I guess driving a carbureted vehicle was a new thing for him. His third attempt was accepted but the truck was over the limits on CO and NOx.

I thought it'd be interesting to try and analyze the IM240 graphs to see what might be wrong with the truck that's causing the emissions test failure.



Oxides of Nitrogen (NOx) was just over the limit of 6.000 at 6.5254. When NOx is high that is usually a sign of high combustion temperatures, either due to a malfunctioning EGR, a device that lowers combustion temps, or because of too much spark advance for the mixture.

Because I increased the timing, I suspect I went too far. According to the printout, acceleration contributes 57% to the NOx readings, where cruise is contributing around 15-20%, suggesting the problem isn't isolated to part throttle acceleration (vacuum advance is controlled by ported vacuum on this truck). Base timing is probably too advanced. When vacuum advance is added under part throttle load (acceleration), even more NOx is generated. You can see from the chart that the driver was punching the gas way too frequently causing NOx spikes. It's possible that if the mixture is too rich, less advance is needed. So the mixture contributes to the problem.



The HC (hydrocarbons) chart shows spikes on acceleration indicating unburned fuel because of an overly rich mixture, undoubtedly. HC spikes on deceleration too; typical for a carb'd vehicle (computer controlled cars lean the mixture severely during deceleration). Maybe I can do something to improve that issue, I don't know. The numbers on the printout show a 58% contribution by acceleration to HC and 23% by deceleration.

It's also possible that the AIR system isn't diverting (enough) air to the catalytic converter to aid in converting the exhaust gases under acceleration. I might see about working on the ignition system, too, in case it helps more completely burn the air-fuel mixture.



Finally, Carbon Monoxide (CO) is pegging out on acceleration, contributing 80% of the overall CO output. The power valve clearly works only when it is supposed to, but is delivering way too much fuel. I'm not sure if a new power valve would fix this, or if I just need to adjust base jetting of the carburetor for thinner, hotter summer air.

Last time I passed it was pretty cold outside. I am leaning towards switching to #50 jets or smaller, then adjusting the aneroid again. I might need to replace the power valve after all, though. If there were a way to adjust the amount of fuel delivered in power enrichment mode, that'd make this easier to solve. On a Quadrajet, Edelbrock Performer, Motorcraft 4350, and others, the carb uses rods to meter fuel in power mode; one can select rods with wider diameters for power mode to deliver less fuel.

The 2150 is stuck with two-stage power valves. Supposedly 1-stage valves can be used but when I tried this last time, the valve wouldn't fit; not enough threads to engage properly. If it worked, one could select a power valve that engaged at a lower or higher vacuum to suit the application. This is the same concept as changing rod springs on an Edelbrock Performer.]]> Tinkering http://tc.wagoneer.net/sblog/index.php?entry=entry100618-120037 Michael Shimniok Fri, 18 Jun 2010 17:00:37 GMT