Hello all,

I recently bought a 1981 D150 the motor has 140k 3sp w/OD
The truck ran fine on the drive home but now it will not idle. The electrical system is touch and go the carb has random wires hanging from it I assume the emission equipment is not even in use lol.. The truck was used on a farm the engine was just rebuilt. I want to clean it up and just have a reliable clean looking motor. I am mechanically inclined and have the tools to do any maintenance. Does anyone have words of wisdom or could anyone point me in a direction to start.

Thank you in advance

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• A Factory Service Manual for your year and model. You can get it on eBay or from any of many automotive literature vendors. I've had excellent and economical success for 15 years buying auto literature from Paul Politis, e-mail politpaul "at" yahoo "dot" com. There are lots of vendors of manuals on CD. Quality is all over the map; the officially-licenced ones come from moparmanuals.com .

It makes little difference whether you get the Dodge or Plymouth version. That is, if you're working on a '75 Dart, the 1975 Plymouth and Valiant manual will serve you just as well as the 1975 Dodge and Dart manual, for instance. What matters is that you get the genuine factory book—sometimes a 2-book set—rather than an aftermarket book (Chilton, Haynes, etc.). The aftermarket books contain a great deal of incorrect information, and leave out important info and steps. That's how they cram ten years and five models into a book 1" thick, while the factory books cover only a few models and are several inches thick! See Here for instructions on how to make the most effective use of an aftermarket service manual.

• Stockel and Stockel, "Auto Mechanics Fundamentals". These are always plentiful and cheap, since they were the standard textbook for just about every auto shop class ever taught in North America. Numerous printings; most any will do, but it's best to find one printed a couple years after your car was built.
See Here.

• Petersen's Automotive Troubleshooting & Repair Manual, 1975 (or thereabouts; there were a few print runs of this book. 1974, 1975, 1977 at least.)
See Here.

These three books are very, very highly recommended for anyone just starting out working on a slant-6 car. The Stockel book explains how everything works. The Petersen book has lots of pictures and explains how to fix everything. The factory service manual contains all the data and settings for your particular car.

Buy. Read. Assimilate!

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Dave

1977 d-200 crew cab ex-army pickup wants it's /6 back
1962 Valiant 2 door, 170, three on the tree
1972 d-100 parts truck
80 volare wagon now a parts car

Definitely get those book. Any chance you could take some pictures of the carb and the disconnected wires around the carb? Other pictures of the engine bay? The early 80s were a time when trucks could have no computer controlled carbs and/or ignition or both the carb and ignition could be computer controlled or one or the other culd be computer controlled. Plus, the Chrysler "lean-burn" computer is notoriously failure prone, and often didn't work right when new.

We need more info to help you out, especially about what emissions equipment the truck has and what sort (if any) of lean-burn system is there (and how much of it is left).

I will take pictures as soon as i get a chance and post them....
Thanks for your help... Also i was hoping to put an auto trans in is that a feasible thing to do?

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1981 D150 2wd slant 6 3sp/wOD

A 904 auto is an easy change. Just need to insure it is a slant six version. You will also need the trans to be 1968 and up.
Frank

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Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

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1981 D150 2wd slant 6 3sp/wOD

Here you go everyone pics of the engine bay... I would appreciate any and all help!!!! Thanks again

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1981 D150 2wd slant 6 3sp/wOD

I think the truck looks nice, but that engine bay needs someone with experience removing the computer controls to advise you on what to do.

Richard

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Part of Tyrde-Browne Racing

nice truck!
before you yank out the a 833, give it a try,, the slant six and manual tranny with OD is a nice combo.
I removed the lean burn from my 83, put in an old points distributor that I got for free,, cured a miss at idle and made the truck a bit peppier.

Oy vey. Give me some time and I will label those pictures with arrows and descriptions of what everything is and tell you what problems I see. And I do see some.

I already see that choke choke is missing major parts and is misadjusted and someone has ripped out some of the A/C system that the truck used to have. You are also missing a VERY important hose that hooks to the computer mounted on the air cleaner.

OK, sorry it took so long. I had court this morning and I had to prepare last night and argue this morning. But, here we go.

Good news first, since there is less of it:

(1) Your carburetor looks like it is actually in decent shape, or at least salvageable. Barring something I can't see like internal cracks or worn throttle shaft bushings, I think you can keep your current carb.

(2) The carb isn't computer controlled. This is a big plus.

Bad news (pull up a chair)

(1) You are definitely missing the choke linkage that runs from the pulloff spring in the exhaust manifold to the choke linkage on the carb. You must have this if you want thew automatic choke to work. This is probably a large part of why the truck won't start up right now.

(2) The automatic choke pulloff linkage is grossly misadjusted. it is there, so you can fix it, but it is way out of whack.

(3) You do, indeed, have a computer controlled ignition system. FUrther, I can see that one of the most critical parts, the hose to the vacuum transducer, appears to be missing. THis will severely affect how the truck runs.

There are lots of other little things I see, so here are the labelled pictures with some pointers on what to fix and how:



That wire flopped on the inner fender support is either an alternator field wire or the wire that runs across the front of the motor over to the A/C compressor clutch. It is most likely the clutch wire. You can let it dangle until the time comes to get the A/C working again. As a quick test, turn the ignition switch to "On" and depress the A/C button on the dash. Connect a test light to that wire and see if it lights up.

In the bottom left is the area where the cold air intake tube inlet should be. THis will be a round plastic fitting somewhere on the radiator support wall. Cold air intake is a nice option to have functioning. It helps with fuel economy and performance, and doesn't hurt anything at all.

The charcoal canisters on the fenderwell are emissions devices that are largely innocuous in terms of how the motor runs. They collect the gasoline that evaporates from the carb when the motor is shut off and store them to make starting the truck easier. I recommend you leave them in place, replace the filters in them, and keep them hooked up.



The cut vacuum supply hose is a bummer. THis is supposed to go to the vacuum tap tree on the #6 intake manifold runner. If this is disconnect, you will (a) have a vacuum leak at the intake manifold (unless the hole is plugged) and (b) have inoperative doors in the heating and ventilation system. You might be able to change the temperature (hot to cold and vice versa) but you won't be able to direct the air to floor, defrost, dash vents, etc...

The crankcase breather is another emissions device that does not harm to the motor and actually does lots of good. You should replace this item and run the hose to the big nipple on the outer rim of the air cleaner.



The upper circle is where the cold air intake hose connects to the air cleaner. All you need to do is find a hose of the right diameter and length to get this system functioning again. Find another truck or van in the junkyard and grab the hose, or get some dryer hose from your local home improvement store that is the right diameter.

The lower circle is very important. You truck has a computer controlled ignition system but not a computer controlled carb. I have circled what is called the "vacuum transducer" on the spark control computer. The computer MUST have a reliable manifold vacuum signal to the transducer to set the timing in the right place. The engine vacuum is one of the main variables the computer looks at in determining where the timing should be at any given time during operation. Without a vacuum signal to the transducer, the computer defaults to a limp-in setting ad will run like poo and get bad gas mileage.

Short term, I would first check that the vacuum transducer still holds a vacuum. These can fail internally and not hold a vacuum. I don't know if you can still get just the transducer new or if you have to order the whole computer. I do know that if you find one of these computers on a junked Chrysler/Dodge/Plymouth truck, car, or van form the 80s you can open up the computers and swap just the transducer by resoldering a couple wires. Try and keep the original computer for your truck since different vehicles used different computer programs. Hook the hose up to one of the ports around the base of the carb that has full vacuum at idle.

Long term, I highly recommend you abandon the spark control computer ignition system and convert to HEI. See THIS THREAD for instructions on how to do the conversion. You can use the (+) battery feed to the spark control computer as the power source for the HEI unit.



Fram filters are junk. Use Napa Gold, Wix, or Purolator.

Here is where is starts to get a bit messy:



The hose that is supposed to go to your EGR valve already apears to be disconnected. Leave it that way.







First, I have labelled two items bolted to the cylinder head- the EGR vacuum amplifier and the emissions vacuum switch. Both of these can be removed along with all the hoses that attach to them. Be sure to cap any vacuum fittings on the carb or intake manifold that no longer have a hose going to them.

Your carb has electronic devices bolted to it, but it is not computer controlled. The idle stop solenoid is a good thing to have since you have A/C. This solenoid acts as the curb idle screw. When you engage the A/C, the solenoid plunger extends and increases the curb idle. This is good because it raises the idle to compensate for the increased load the A/C compressor puts on the engine. Leave it in place and get a factory service manual to learn how to set your idle sped using the idle stop solenoid.

Your carb also has an electronically operated bowl vent valve attached to it. This is likely controlled by the computer, but maybe not. I can't say for sure. What I do know is that it won't hurt anything and you can just leave it alone and plugged in.

The worst things I see are that you are missing the thermostatically assisted choke pulloff coil and linkage assembly that bolts into the exhaust manifold and clips onto the choke linkage on the carb, and your vacuum choke pulloff linkage is grossly maladjusted.That little rod is supposed to have a pronounced "u" bend in the middle. When the motor is cold, the rod coming from the part on the exhaust manifold is supposed to hold the choke flapper closed. As soon as the motor starts, the vacuum operated choke pulloff is supposed to pull the choke open ROUGHLY 1/4 inch (this is a ballpark figure. The exact setting varies year to year and based on the emissions package. The factory service manual will tell you for sure). You are missing the rod that is supposed to hold the choke closed, and the rod that is supposed to pull the choke open is bent completely wrong, and I suspect that the choke doesn't even move anymore. I would track down the correct choke pulloff coil assembly and replace the vacuum operated choke pulloff assembly.I would then carefully go through the carb and check all settings- float level, idle speed, idle mixture, etc....


To summarize:

Short term:

(1) Check that the vacuum transducer holds a vacuum and reconnect a hose to it that provides a manifold vacuum signal.

(2) Get your choke linkages sorted out.

(3) Do a thorough tuneup. Replace cap rotor, plugs, oil filter, air filter, and carefully check all the settings on the carb. Get a factory service manual and set the timing, curb idle speed, fast idle speed, and curb idle mixture according to the steps in the manual.

(4) Get the cold air intake hooked up

(5) Get the vacuum hose for the HVAC repaired

Long term:

Dump the computer controlled timing and go with HEI. It is a much better system that will improve emissions, economy, and performance. i would also make sure that the catalytic converter(s) are not clogged. If possible, I say remove them, but if you must pass inspection just hollow them out and reinstall.

Hopefully this will at least get the truck running good, if not perfectly. If you decide to go to an HEI ignition system, you can keep your current carb (so long as it has a ported vacuum source, i.e. no vacuum at idle when the throttle is closed) and aluminum intake manifold, but you will need an electronic ignition distributor for a standard electronic ignition system with a vacuum advance.

Good luck! Let me know if something is unclear or you need more help.

Circled red, you have missing piece, this should have diaphragm and a cover with three screws. Could be the power valve?

Circled yellow. Do not use this for any manifold vacuum even PCV, try to make connections at the carb's unported if carb does have large nipple for PCV or take off a EGR port on the intake using one port that leads to the intake make a plate with nipple installed.

This allows more even distribution of fuel and air without introducing extra air in one runner.



Cheers, Wizard

THe #6 intake runner tap is fine for the power brake booster and other menial items such as the HVAC vacuum tap. The PCV should be hooked to the base of the carb.

The area circled in red may not actually be anything missing. Some carbs had that hole cast but didn't have anything that actually went there. Looks to me like this carb doesn't use that hole for anything.

I would never get rid of the 4-speed unless you want an under powered engine to feel like it has less power and get less gas mileage. Mine is a 85 but with the same power train and it routinely get 19-20 MPG running local in mixed driving. It no doubt would get 21-22 on an all highway trip.

My lean burn is still hooked up but is soon to go. Some people have run them forever with no problems, but most have had multiple problems. Idle quality with the lean burn is one of its usual issues.

Just my opinion,

Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

If I had a vehicle where the computer only controlled the timing, I would be more open to leaving it intact. However, the carburetor controlled systems are terrible. But I would still probably get rid of computer controlled timing...

Rick, I think you will see a big different in performance and economy when you swap out to HEI.