Greetings friends. Presently, my tail is in a vice as they say. I have a 1986 Dodge B-150 Van. It's running a 225 Slant and I am unsure of the carb configuration. (the carb type is another question as part of the bigger problem I am experiencing) I failed emissions miserably a couple weeks past. Now I can't get current registration. I desperately need my van for daily transportation. Right now I am riding one of my vintage Triumph motorcycles and this is not fun because it's freezing this week and the old Bonnevilles need constant attention. Most folks are aware that the old English bikes do not make the most reliable or regular form of transportation.

Here's my confusion: Before the emissions test I changed out the PCV valve, changed oil and did a complete tune-up (changed plugs and wires, etc.) in an effort to get through the test successfully. This is not to mention that the motor I am running is a fresh rebuild. It was rebuilt one year ago. The oil still has a goldish brown color when the dipstick is examined. Once the van was on the test machine, it immediately failed. I've known the mechanic for a long time and he's quite honest. (too honest in the case as he will not cheat the test for me) He told me there were a few things that could be the problem but he couldn't guarantee which one would completely fix the problem. Of these possible problems were a worn-out carb, bad catalytic converter or even bad blower.

THE EMISSIONS TEST SHOWED "EXTREMELY HIGH CARBON LEVELS." Or is it referred to as C.O. levels. I can't remember now.

Okay guys ... I am an adequate wrench. I keep two Triumph Bonnevilles running. But with being a good wrench, 75% of the success rating is based in diagnosis and previous knowledge. Let's face it, I am a complete idiot when it comes to figuring out automotive electrical systems and emissions systems. Well, other things too like transmissions and rear ends as well.

Can somone help me out? I am at the end of my rope.

Some History: As mentioned earlier I had the 225 rebuilt by a guy who speacializes in MOPAR rebuilds. He did a great job and used high-quality parts. Prior to the rebuild I would constantly clog PCV valves and experience high engine pressure resulting in a leaking valve cover (generally in the front end of the valve cover). I replaced three valve cover gaskets in one year. Finally I decided on the rebuild after the motor began to burn over 2 quarts of oil per week.

Well, guess what? I have a straight motor now and I have clogged PCV valves again, oil in my air cleaner and just sprung a valve cover leak in section of the motor. Certainly this must be connected to my emissions failures?

More history: The air blower over the manifold is actually dead. It failed a while back after cranking one morning. Engine performance was not effected and so I have been lazy to replace it. A new one is $100. And it bothers me that a blower costs $100. Would this be contributing entirely to the emissions problem I am currently experiencing? I always thought the air blower was mostly useless and simply blew excess air into the exhaust manifold. But possibly it blows other fumes downward to be burnt off? I aksed a couple mechanics in passing and they said they didn't think a bad blower would cause an enitre failure of an emissions test. In fact the mechanic at the test itslef was one of these guys. He said I should replace it but it would not guarantee that I'd pass the test afterwards.

More symptoms: Besides the PCV valves and valve cover leaks I am experiencing a lot of black carbon build-up on the tailpipe. There's so much of the stuff that two to three inches of the outside tailpipe is solid black. The catalytic converter and exhaust on the van is only a year old. These were both replaced with the the motor rebuild. Okay, there is a slight odor of gas coming from the doghouse when the motor has be running for a while. Like on a trip or after a period of driving around town. But also, the fumes from the exhaust are quite rich. So, I suspected I have a bad carb. The carb was supposed to be rebuilt with the motor. And the carb looks fresh upon inspection. But again, it is an old carb (no matter a rebuild kit) and I heard that the late 1980s slant-sixes have problems with intake manifolds and carbs separating causing weird leaks and problems.

So — after this long-winded post — in a nutshell I am trying to figure out the most cost efficient way to fix the emissions nightmare I am experiencing. I want to avoid un-needed repairs and replacements. But I am also interested in puttting a higher perfomrance carb on the motor. Possibly this would be the part of the solution to the emissions problem. But this takes me to even more questions. Stuff like can I use a 4-barell or what carbs can bolt on to the existing manifold, etc., etc.

Any help is highly appreciated. Cheers!

Jason

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"The first thing we do, let's kill all the lawyers ..." — William Shakespeare

The air pump adds air to the exhaust so unburned HC & CO can burn in the catalytic converter. Without the excess air the HC & CO won't burn............

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Three different pollutants are tested for. They are CO (Carbon Monoxide), HC (unburnt hydrocarbons) and NOx (Oxides of Nitrogen). So, your "Extremely high carbon" could be high CO, high HC, or both.
OK, that's very high oil consumption, and all that oil pumping through your van's catalytic converter almost certainly poisoned it so it doesn't work any more. So that's one very likely contributing cause to the emissions failure.
Ooh. It's certainly not good, and yes, there's a high likelihood whatever is causing this problem is also contributing to the emissions failure. This problem could be caused by something as simple and cheap as an old crankcase breather that's past due for replacement (this is the device at the rear of the valve cover, connected to the air cleaner by a 5/8" rubber hose -- that's how the oil is getting to your air cleaner!). However, this problem could also be caused by an internal engine problem (holed piston, bad rings, bum head gasket, etc.). Even with an excellent mechanic and quality parts, sometimes shìt happens.
Air pump or "smog pump"...
Oops, yes, this is another likely contributing cause to your emissions failure. The air pump doesn't just blow air into the exhaust stream to dilute the exhaust and "fool" the test. When the engine is cold or in open-loop mode (on a feedback system), it injects air into the exhaust ports, just downstream of the valves, to provide Oxygen so that fuel that didn't burn in the combustion chamber can burn in the exhaust stream. When the engine is warm or in closed-loop mode, the air injection point is changed to the catalytic converter, to provide oxygen for the oxidation of HC and CO. If this injected air isn't present, then several emissions-negative things will happen:

•The catalytic converter will not work efficiently.

•There will be higher-than-tolerable levels of raw fuel reaching the catalyst, causing it to overheat, stop working at all, and begin to melt down. This, in turn, severely restricts the exhaust flow, which in turn causes additional running and emissions problems.

The slant-6's combustion chamber was never updated after 1967, and it is a stone-age, crude chamber that does not facilitate complete combustion. As a result, the slant-6's exhaust is rather dirty, so the "post combustion" emission controls (air pump, catalyst) have a big cleanup job to do. If any part of the system is not in proper repair, a test failure is quite likely.
OK, that tells us the van is running very rich. Rich running does several things:

•Produces high CO emissions
•Produces high HC emissions
•Cooks catalytic converters
It is highly probable you will need to replace the catalyst again, due to its prolonged operation without air injection and with massive amounts of raw fuel in the exhaust.
Your 1986 may have a feedback or a non-feedback emission control system. If it is a feedback system, there will be an Oxygen sensor screwed into the exhaust manifold. Looks like a weird spark plug screwed into the rear "wall" of the exhaust manifold's central collector area, inboard of the rear pivot for the manifold heat control "heat riser" valve. One thin wire runs to the sensor.

If you have an Oxygen sensor ("O2 sensor"), then it opens up a great many more possibilities for factors in your emissions failure. The O2 sensor itself needs to be replaced every 30,000 miles...and that's on an engine that's running properly! Rich or oil-burning engines destroy O2 sensors quickly. The carburetor used in the slant-6 feedback emission system is of a problem-prone design. It contains a solenoid-activated mixture control system that frequently causes trouble.

See if you can find an emissions decal under the hood. It will state what kind of emissions system the vehicle was built with. Sometimes previous owners or well-meaning mechanics make thoughtless modifications and equipment deletions!

Even if you have no O2 sensor (and never did), the Holley 1945 carburetor was an unfortunate design when it was introduced in 1974, and the modifications made through the '80s to squeak through Federal emission certification tests made it considerably worse. They are notoriously resistant to even careful, competent rebuild efforts—the factory "remanufactured" units are utterly hopeless.

[quoteI heard that the late 1980s slant-sixes have problems with intake manifolds and carbs separating causing weird leaks and problems[/quote]

Some of the 1980s vehicles still used the ultralightweight 2-piece aluminum intake manifold. The one with a very visible weld bead/ridge running all along its top edge. These had a high failure rate when new in '81-'83 (cracks in the manifold floor and at the weld bead, warping, porous castings). Most of the junk-from-the-factory items have long since been melted down and turned into coke cans or Audis. But even the ones that weren't junk from the factory are less robust than the cast iron or 1-piece aluminum intakes. The most common long-duration service failure is cracks in the manifold floor, which allows exhaust into the intake tract constantly, which requires very rich fuel mixtures to get the engine to run acceptably.
You can certainly put a *different* carb on the engine, though your options are less numerous than on an older, emissions-uncontrolled application. First figure out if you have a feedback system or not; that'll bring heavy influence on your carb options.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dan.

Thanks a million for the informative post! I pull the doghouse off tomorrow in daylight and look for the sensor that you mention. Unfortunatelyt any emissions decals have long disappeared fom beneath the hood. I'll repost tomorrow with more info and questions.

In the meanwhile I do have some options. Of course I'll weigh these based on things like expense and convenience. Legality even.

I can cheat the system which I find "UNFAIR" in the first place. How can a 1986 vehicle with ancient engine technology be expected to pass modern emissions tests? As you mentioned (and I was somewhat aware) that the slant sixes run a bit dirty. Even the mechanic at the testing facility said the standards were extremely tough on the older vehicles like mine. Say if my vehicle were a 1981 or lower I'd be immune to all emissions tests yet there's not a lot of difference in the performance of a 1981 Dodge Van versus a 1986 Dodge Van. But I have to still attempt to pass strict test levels.

I can "CHEAT" the system by simply getting registration transferred to my mom's town where there are no emissions restrictions. But this is a bit of a hassle and illegal after all. Again though, this is a probable option if I cannot pass emissions because I cannot afford a new van and I quite like my old van anyway. I have always owned Dodges (previsouly had a '72 Challenger and a '70 Dart) and love slant sixes. Plus my van has great power but still gets fantastic gas mileage.

Say I did go the route of "changing registration," I wonder if I'd be able to yank every single piece of emissions garbage off of the motor? And this is when I'd have the option to tweak things a bit more. At least I'd think so. You know in areas of carb options and what not.

I'll repost tomorrow or so with my system type. Because if I go the route of legal emissions, I'd still like to consider other carb options.

Thanks so much again for your informative response!
Cheers!
Jason

_________________
"The first thing we do, let's kill all the lawyers ..." — William Shakespeare

How likely am I to find a working smog pump in a junk yard? I assume that a re-man would be as difficult or expensive. Mine and the pulley beside it both have their shafts bent to some degree. It's noticeable with the naked eye while not turning.

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The Old Goat '83 D150 225-2

AKA Ice Titan

No problem.
You're not expected to pass "modern" emission tests. The pass/fail threshold is much looser (dirtier) for a 1986 vehicle than it is for a 1996 or a 2006 (and in turn, the standards your 1986 is required to meet are tighter/cleaner than those for a 1976 or 1966 vehicle). This is the case even in the tightest, strictest vehicle emission testing programs in North America (California, Arizona, Denver area, etc.). The standards your 1986 vehicle must meet are at a level such that if you can't meet them, your vehicle really is an excessive polluter. Cheating the test gets you the sticker, but you're just cheating yourself, since your van in its current condition is burning a lot more fuel than it should, costing you money in gasoline and in increased engine wear.

What's more, as popular as it is to snicker and cheat past the test, keep in mind that a lot of people, including people who write laws, form their opinions on older vehicles from what they encounter on the street. Driving a gross polluter does all of us a disservice, because it gives ammunition to those who want to legislate all older vehicles off the road. Not just lawmakers, but also Todd and Margo Homeowner, driving along in their BMW behind your van in traffic. Stink up their fancy car, and they'll start writing letters to their lawmakers and newspapers, demanding that something be done. Of course, older vehicles can produce acceptably clean exhaust, but only if they're properly maintained and repaired. As drivers of older cars, I think we each have a responsibility to make as small a mess as possible.
Key phrase: "like yours". Older vehicles that need repairs have a hard time passing the test! If your vehicle were in proper repair, it'd have no problem passing.
Well, sure, but even if it were never tested, your van would still be burning a lot more gasoline than it should, and putting a lot more trash into the air than it should. Just like the trash we put on the curb every week doesn't go to a magical place called "away", neither does the trash that comes out of our cars' tailpipes. We all gotta breathe...
Actually, that's not so. The Federal emission certification tests (multiple-day, multiple-thousand-dollar, very involved tests) that Chrysler had to pass with each and every different body/engine/trans configuration were tightened significantly between 1981 and 1986.
Have you checked your mileage accurately...lately...? With gobs of black carbon all over the tailpipe and grossly high HC and/or CO levels, I don't think you're getting very good mileage right now.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Fairly likely. Use www.car-part.com (searchable used auto parts nationwide).
Can you afford thirty-six whole dollars? www.rockauto.com , probably similar pricing locally to you.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Sorry about that. I should have taken the time to at least look. Someone that I work with suggested that a smog pump would be a hard item to find. Of course they also thought a carb rebuild kit was $100+.

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The Old Goat '83 D150 225-2

AKA Ice Titan