Jump to content

Recommended Posts

Hey y'all, 

 

I've got a 1977 Toyota Chinook that needs to pass emissions and am curious to hear y'alls .02 cents. I live in Denver, Colorado. It failed the emissions test today. The results are as follows..

 

HC PPM ...  1135.8 with a limit of 400

CO % ...  11.31 with a limit of 1.50

 

Sooooo not great. Fortunately, the vehicle just needs to pass at idle.

 

Since Denver exists at altitude (5280 ft), I am going to check on the carburetor. It is likely running rich, especially if it has not been re-jetted. 

 

Past that, I will take a look at timing and the cat converter (which it may or may not have I plan on looking tomorrow) ... I am hoping it is the carbs!

 

Do you all have any thoughts, reactions, etc? 

Link to post
Share on other sites

Good luck, we are fortunate here in Washington they did away with them a years ago. When I was getting them the only thing I made sure was running the engine for a good stretch on the highway before taking it in, blows out any excess emission deposits in the system.

 

Cheers!

Gary

Link to post
Share on other sites

That's a hard one first, the failure rate even in its day was 37% there are mechanics out there that have never seen a carburetor and Denver is very high so vehicles with some age on them will test high in HC. Without a machine any adjustment is flat guessing. Need to find an old guy that has been there before. On the plus side they only have to pass emissions applicable to the date of manufacture so there is a threat someone can tweak it for you. If there is an emission sticker you maybe able to argue that it only has to pass for the date of manufacture.   

Link to post
Share on other sites

Now that Maineah mentions it there might be a grandfather clause in Colorado. Washington's clause was any vehicle 25 years or over was exempt from testing, check with your DMV.

 

Just saying testing was contracted out in my state for emission testing and they didn't even tell you if the vehicle needed it or not. I found that out the hard way. Heck they'd probably test my 2-cycle lawn mower if I took it in, they're just after the money.

 

Gary

Edited by Gary_M
Add additional information
Link to post
Share on other sites

Unfortunately Colorado started using California standards a couple of years ago. Any Californian knows how strict that is. The allowed limits he posted are the correct ones for a 1977 vehicle. I looked it up. Only vehicles older than 1975 are exempt. 

I am sure you can find a local mechanic who is used to dealing with these older carbs. 

High altitude jet for your year 90999-41117

here's the page I found with EPA information

https://nepis.epa.gov/Exe/ZyNET.exe/94002P7O.txt?ZyActionD=ZyDocument&Client=EPA&Index=1981 Thru 1985&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&UseQField=&IntQFieldOp=0&ExtQFieldOp=0&XmlQuery=&File=D%3A\ZYFILES\INDEX DATA\81THRU85\TXT\00000029\94002P7O.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h|-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r75g8/r75g8/x150y150g16/i425&Display=hpfr&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results page&MaximumPages=1&ZyEntry=94

More info. Make sure to look at next page too

https://nepis.epa.gov/Exe/ZyNET.exe/94002P7O.txt?ZyActionD=ZyDocument&Client=EPA&Index=1981 Thru 1985&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&UseQField=&IntQFieldOp=0&ExtQFieldOp=0&XmlQuery=&File=D%3A\ZYFILES\INDEX DATA\81THRU85\TXT\00000029\94002P7O.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h|-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r75g8/r75g8/x150y150g16/i425&Display=hpfr&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results page&MaximumPages=1&ZyEntry=98

Discontinued by Toyota but part number might help you find a replacement. Don't know if Weber jets will work.

Do a complete service. Spark plugs ect and then run some seafoam through the engine. 

Good luck

Linda S

Link to post
Share on other sites

It's hard for me to believe that if you go to higher altitudes they (Linda's second link in her post) recommend that you need to change your "primary main jets to a larger diameter".  This is exactly what you don't want to do.  Smaller jets at high altitude is what I believe.  (I have no direct experience with this since I have been an east coastal dweller my whole life.  Am I all wet on this?)

Link to post
Share on other sites

no idea about Toyota carbs, but with Holley and Webers, I go 2 number sizes smaller on main jet and 3 smaller on secondary.

If retests are cheap the drive around and get below a 1/2 tank and add 2 gallons of E-85, after testing drain all the fuel out of the tank and burn it in a modern car. DO NOT leave E-85 in your Toyota

Link to post
Share on other sites

Less air = less fuel,  aircraft have been doing this for decades with adjustable carbs and AF/temp gauges. Question the measurement vers age you can not make a old vehicle meet today's standards it is impossible. Try this register the MH as an antique it may not have to pass emissions.

Link to post
Share on other sites

OK your's only has to pass a two speed idle test that is doable with a bit of twerking again you need to find someone that speaks carburetor and can retweek it after the fact. https://cdphe.colorado.gov/air-emissions/general-emissions-inspection-requirements-and-information

Link to post
Share on other sites

Hey I'm also in Denver area & have an '86 with the 22RE engine - here's a very useful tip for you (sorry, I'll tell a story to illustrate the point).   Got the RV from my old man & he licensed it in South Dakota where no emissions tests exist - so he removed the Catalytic converter.  When we bought it from him, we had just borrowed the rig for a several hundred mile trip to Ridgway (in Montrose), over Monarch & several other passes, so we'd driven it at max RPMs crawling over those mountains.   When I took it to the emissions station a few weeks later, not realizing there's no cat, we got a peculiar result that left the inspectors scratching their heads. 

 

"We don't understand it, but your numbers are just fine.  However you fail the test because we have to visually inspect the catalytic converter, and you don't have one."

 

So here's my advice - and I've done this with various old cars in Denver over the decades:  after you do some steps above, especially tuneup related, and you have that carb adjusted, and that timing reset is critical - run your rig up to Evergreen & back on I-70.  Depending on your transmission, you should find what speeds in what gear cause close to max RPMs - there are others here who know what that is.  In my '86 22RE with 3-speed transmission (don't use overdrive), I go with about 28 MPH in 1st, 55 in 2nd.  This will burn out & clean up those cylinders & valves & plugs amazingly well.  (Make sure your hoses are OK before you do - this will test any weak spots in the cooling system & maybe other systems in the mechanics.)

 

Then even if you retest a few days later, drive on the freeway for 20 minutes, so you hit the emissions station with the engine hot, and during a quiet time when you won't shut it off sitting in line for more than 20 or 30 minutes - this makes a big difference on older vehicles.

 

Luck!  Oh yeah, the rest of my story - Diane & I own a house on some land in the country, south of Strasburg - we plan to move there next summer from Parker, once the current renter's lease is up - so I register & license the rig out there.  It's far enough out in the agricultural country that emissions aren't yet required.  Eureka!  ...city's growing that way, I expect I'll add a cat in the next few years.

 

Edited by tstockma
added warning re weak hoses
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...