I'm swapping manifolds on an 84 D100 w/lean burn. The manifold coming off the truck has a sensor on the side of the manifold facing the firewall and there is a wire going to it. The manifold I'm putting on doesn't have this sensor.

Anyone know what this sensor is for and if it'll hurt anything to leave it off? I'm going to try and pass smog with this truck so I'd hate for that to have anything to do with it.

That is the oxygen sensor used by some lean burn systems. If you are interested n selling that manifold, I would be interested. I might even have a good stock manifold to trade. Let me know.

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Casually looking for a Clifford hyperpak intake for cheap.

Thanks for the quick response Reed. Oxygen sensor is definitely not what I wanted that to be.

The manifold is cracked, otherwise I wouldn't even be messing with the swap at all.

Is it possible to drill and tap to get that sensor into the manifold I'm swapping into the truck? I've never had to drill into an exhaust manifold so I don't want to risk cracking it or anything.

One way to avoid damaging the new one: Install a sensor bung in the steel head pipe. As close to the manifold flange as possible without being in the way. About every muffler shop I've been to can install one in short order.

CJ

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Part of Tyrde-Browne Racing

Yup.

However, where is the crack in the exhaust manifold? If it is in the front half of the manifold ahead of the "tower" I might still be interested. I am collecting parts for a dual exhaust and fuel injected slant I am building for my brother's 74 Duster and I would love to use a factory O2 sensor manifold for the rear dual exhaust manifold.

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Casually looking for a Clifford hyperpak intake for cheap.

Thanks Ceej....thats good info there as well.

Reed, the crack is on the side of the manifold that faces the driver side fender. I'm guessing someone torqued the two outer bolts down way too tight and caused a stress crack there. There is also a small one under the 1st cyl runner where it meets the manifold tower. The two bolts that were torqued too tight were also already broken off so the bottom halves of them are seized up in the threaded part of the manifold. I've yet to even be able to loosen one of them.

I cleaned the cracks up and put some JB weld on there. What I'm going to do is try going with the original manifold because it has the o2 sensor. If I can't get it to work or it still leaks, I'll go with the older manifold and see about moving the sensor as Ceej desribes. I'm trying to avoid any kind of extra work or money since I gotta have this thing smogged by the 20th. If I can't get the original manifold to work, I'll message you and I'll probably just send it to you for the price of shipping.

OK. Try this- drill a little hole at each end of the crack and then find a shop to braze the crack. The holes stop the crack and the brazing seals the crack. Good luck!

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Casually looking for a Clifford hyperpak intake for cheap.

----- if you r gonna replace lean burn then -----------------------

i would check the emissions map on the fender wall. If it does not show the
sensor than i wouldn't worry about removing it. See note:
I am removing all clean burn from my d150 83 and first thing i did was talk to the emissions testing people who told me they consulted the emissions map on the firewall to see if all major components were there.
Items required on my 83 d150 (Texas) was catalyst converter , charcoal canister & plumbing, pvc valve and smog pump and plumbing. The map did not show other items so they cannot require it. I am in process of removing all clean burn hardware and wiring from truck and will post pics soon.

Note: get the shop manual for your truck, it will show inputs to clean burn system. So if you r keeping clean burn then the truck will run better with all inputs operational. If it does not have all its inputs it defaults to a "get you home timing setting" which is not efficient at all. If you r removing the clean burn system then you might read the hei conversion posts. I replaced the clean burn carb with a bbd mechanical, also the distributor with a mechanical advance model and fabricated the hei conversion module per posts here, in essence replacing all clean burn hardware and wiring. When you get your shop manual you can unwrap your wiring harness at the firewall which will show you all the connections to the clean burn computer/carburetor/distributor connected to the computer.



jeff

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FRCC
(9) slant six engines / + misc parts for same.
1969 D100 318 4 spd

Jeff-

(1) it's "lean-burn." The system was designed to improve MPGs more than clean up the exhaust. The name "Lean Burn" was actually used for a time by Chrysler, but the same (or other versions of) the same system were also labeled "Electronic Spark Control", "Spark Control Computer", and "Electronic Lean Burn". See HERE

(2) Emissions laws and inspection standards vary from State to State and even county to county. Just because that works for you in Texas doesn't mean it will work anywhere else. It might, but who knows. The best bet is top check the laws in your jurisdiction.

(3) There were several variations of what is referred to collectively as "lean burn" systems. There carb only systems, ignition system only systems, ignition and carb systems, and systems that used and didn't use an O2 sensor. Heck, we even had one guy on here claiming that his 1987 Dodge truck with a slant six had an OBDI connector in it. That wasn't confirmed though. No matter what something has to fill the hole in the exhaust manifold if it is one with an O2 sensor port, and it might as well be a functioning O2 sensor. An O2 sensor is a valuable tuning tool, especially a wideband O2 sensor. In any case the O2 sensor would best be left intact and in the manifold.

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Casually looking for a Clifford hyperpak intake for cheap.

yep, corrected from clean to "lean", mine was "Electronic Spark Control" module mounted just outside air cleaner.....Thats also why its important to get the service manual for your particular vehicle as it will show you most of the options of your particular ignition, emission, fuel, vacuum systems etc. Also will list all the maps for those systems.

Yep, goes without saying check "YOUR" state regs before modification.
Her in this county in Texas they go by the emissions map. These are the most restrictive in "this" county, other counties check actual emissions, others check nothing because of the age of the car or truck.

As far as cracked cast iron manifold is concerned depends on the crack and location etc etc etc. You can try drilling at the crack at the extremities mentioned previously, and then braze the crack with a torch and flux rod.
Some may be able to gas weld it with a cast rod. One thing I did in the past when brazing is to heat up and cool down the piece slowly. Some other techniques involve "V" notching (grinding) the piece prior to brazing. Some people who do it often keep firebrick around to facilitate the slow heat and cool process. Low tech repair of cast iron generally leaves you as the bug or the windshield. Again, your shop manual will have torque setting and installation instructions that show which and what type washers go where and in what order, should you decide to repair the manifold off the vehicle. If you think you will braze or weld the crack i would remove the manifold from the engine.

And then again sometimes over the counter metal repair kits will do the
trick until "LATER".........................
jeff

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FRCC
(9) slant six engines / + misc parts for same.
1969 D100 318 4 spd

Jeff, I'm in CA which pretty much means everything on the truck has to be there and in working order...and burning "clean" . I'm kind of challenging myself with the project to get it past smog as cheaply as possible for now. Normally I would just be patient and find another manifold with the sensor but I have to get this thing past smog and registered by the 20th. I only need the cracks to seal for that one test and then they can leak after that for all I care. I'll have 2 years to find and replace this manifold with a good one. Plus I have a bunch of spare gaskets to use so I wont have to spend a lot of cash to work on it.

I understand.
My system didn't have an 02 sensor, but i have other "Electronic Spark Control" parts if you need them later. I have the air cleaner computer and a couple of distributors/coil and portions of the wiring harness that was removed. So if you need them let me know.
Have you had luck in finding sensors and computer parts to keep your truck running in the past, or, has that lean burn system been a pain to maintain in CA? Most parts suppliers here don't have them. One would have to goto junk yards here to get them. And, most yards now are crushing and selling vehicles as soon as they get them including classics that ten years ago they wouldn't. Recently I had a friend in our local junk yard torch/remove/deliver the entire running gear from an 84 van because the next day they were crushing it. The chassis hadn't been there a week. Yep, sounds like some kind of metal epoxy combo would be the ticket for your situation.
Good luck
jeff

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FRCC
(9) slant six engines / + misc parts for same.
1969 D100 318 4 spd

JB Weld doesn't last on exhaust manifolds. I have tried it.

Lean Burn computers are available remanufactured online, but they are expensive. Most of the other parts are available over the counter or online as well. One thing that is absolutely critical to have working is the vacuum transducer. It needs to be hooked to a source of manifold vacuum and the transducer mist be checked and confirmed that it still holds a vacuum. They can fail just like a vacuum advance pod in a distributor.

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Casually looking for a Clifford hyperpak intake for cheap.

Just a little input from experience. I did leanburn to hei on my 82 last month. I thought it was going to be way harder than it really was. After it was all said and done I replace 12 wires with I think five and replaced 50+ft of wiring for just over 10ft. It was actually very simple and really cleaned up my engine bay. If you want I can give you a diagram I made. I used slantsixdans diagram but changed some things for specifically leanburn to hei. Mine kept surging so that's why I did the swap. And reed is very helpful in this category. He knows his leanburn
$.02

Cody

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Old truck: 82 D150 225, 2bbl, dutra duals, 2.5" straight pipe to dual 2.5" tail pipes. Mud tires, 4spd, old forest service truck.
Current truck: 98.5 Ram 2500 ccsb, sport, 24v cummins, 5spd, 4.5" lift, 35's, 5" straight pipe.

Thanks for your input Reed, I'll definitely be going to you for any Lean Burn specific questions.

Ross, you gotta read the thread man...I can't do an HEI conversion lol

I'll keep you guys updated on what happens. Had to drill out the manifold bolts and am going to rethread them today. They were pretty much just welded in there. Actually everything that is threaded into this manifold is seized up, including the O2 sensor.