I have a 1987 D-100, a U.S. Air Force Vet. I got it from a gov web site about 15 years ago, in Peru Indiana, (Hometown of Cole Porter I learned while I was there) It's been a great truck, with the usual problems over the years. About two weeks ago I treated it to a good old fashioned shade of my garage oil and filter change, and decided to throw in a set of plugs, cap and rotor for the heck of it. (they were due). Finishing up, the coil wire broke while swapping from one cap to the other, so I put a new set of wires in as well. When I went to start it, I had "negative starting" condition. So...

* I replaced the coil with new
* I've broken and cleaned all connections related to the ECU (computer in the fender well) and throughout the ignition system.
* Removed the Distributor, checked for continuity in the pickups. Shaft binds slightly but I'm sure I could polish that up. I cracked the drive gear while removing it, it'll be two days till I can get one.
* This thing is aging I really should re-do the engine but right now I need it running.
* Over the years many things on this wonderful engine have been "cut out" of it's operations... electric choke, vacuum lines plugged, etc.

But it has always started and run like a good /6 is supposed to. Obviously I bumped, dinged or otherwise disabled something simply important.

Any advice would be appreciated. I have the Haynes Repair Manual but Zen and the Art of Motorcycle Maintenance it's not, they hop from topic to topic and I'm at that point I don't know where to start.

Well that's not entirely true, am headed to the junk yard to see if I can get the drive gear I need, and perhaps an ECU.

Thanks in advance... (no pun intended).

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No matter where you go, there you are.

It sounds like your 1987 truck is still running the stock ignition system and carburetor. That means that you have a "lean burn" computer controlled carb and ignition system. The lean burn systems are notorious for not working well when new and for deteriorating over time. Additionally, to function properly, the lean burn computer needs an accurate manifold vacuum signal as well as all the inputs from the various sensors on the engine. If someone has gone around cutting wires and capping vacuum lines it is very probable that something critical to the proper functioning of the lean burn system has been disconnected or removed. This is not a good thing if you want a properly functioning lean burn system.
The Haynes manual is good for two things- VERY basic and generic things like changing a tire and to be used a door stop. Especially if you intend to keep the lean burn system, you should purchase a factory service manual for your truck. Nothing is better than the factory service manual for your truck in regards to parts diagrams, clean instructions, and troubleshooting techniques.

HERE'S one now for $30. A good investment.


Why? You can still buy the drive gears new. However, the ECU is a one year only part that will be incredibly difficult to find used or NOS.

Most people who own a lean burn equipped Chrysler vehicle remove the system and replace the carburetor and the ignition system with standard non-computer controlled units. This usually gives improved economy and performance, but will violate Federal law regarding the tampering with or removing of emissions devices. Chances are slim that you will be caught, but if you are caught the penalties are stiff. You might also find that wise repair shops will not work on your truck since they can be fined for doing so.

That being said, I still recommend you install a non-computer controlled carburetor and the HEI ignition system. The HEI swap is covered elsewhere on this site.

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Casually looking for a Clifford hyperpak intake for cheap.

Agree 100% with buying that FSM,, 30.00 is a nice price,, while waiting for that to arrive
1) verify that the carb is delivering fuel, with the air cleaner lid off, peer into the carb while some one fully depresses the gas pedal, you should see fuel squirt in the carb throat.
2) to verify there is spark, attach a timing light to any plug - plug wire, have someone turn the key to crank motor.
3) if you have spark and fuel, verify the spark plug wires are installed in the correct order if they are, then verify that the distributor is indexed correctly,
Basically with # 1 cylinder at TDC, and in the firing position with both the intake and exhaust valves closed, the distributor rotor should point forward at about the 3:00 position. Remember #1 clyinder is at TDC twice during the 4 cycle progression. Spark needs to occur at the end of the intake cycle, not at the end of the exhaust cycle.

Reed said: "Additionally, to function properly, the lean burn computer needs an accurate manifold vacuum signal as well as all the inputs from the various sensors on the engine."

Thanks guys, is there a list of sensors that can cause my dead "Short" condition? I dinged something in the vicinity of the Distributor/Alternator when I swapped out the cap/rotor and plugs?

The truck was running fine prior to the oil change/tune up.

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No matter where you go, there you are.

Reed says: What makes you say that?
But OP said it was running well before he worked on it. That suggests the problem is something he did. I don't know anything about the lean burn system, but logically it seems unlikely to be the main problem.

Several things. Mainly: Multiple pickups in the distributor is an almost positive identification of the ignition system being a lean burn system. While a very few vehicles were built with a standard ignition and dual distributor pickups, they were built only in the late 70s and early 80s. By 1987 any slant six truck or van built would be equipped with a lean burn system controlling both the carburetor and distributor.
Gildo X actually said,
I don't know Gildo X and I do not know his familiarity with how a slant six is supposed to run. It is entirely possible for a slant six with a failed or faulty lean burn system to start and run, but it will do so with a limited amount of power and with decreased efficiency. He stated While intending no disrespect, saying that a lean burn controlled engine "runs like a good /6 is supposed to" with a non-operational electric choke, disconnected and plugged vacuum lines, and other things disconnected suggests that Gildo X is not familiar with how a slant 6 is supposed to perform. A lean burn system absolutely will not function correctly or well if sensors and vacuum lines are disconnected.

As far as the no-start condition, I would start by verifying that the distributor is timed properly. If you are sure the distributor is timed properly, I would then verify that both the pickups on the distributor are connected properly. When you reinstall the distributor gear it is a good idea to spend the time to set the gear depth and drill a new hole for the retaining pin.

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Casually looking for a Clifford hyperpak intake for cheap.

My family had 3 slant six powered vehicles when I was in high school, all with Lean Burn. Two ran perfectly and delivered good fuel economy. One sucked gas like a jet and idled horribly, and would stall for no particular reason. So "running like a slant" doesn't tell us much because like Reed said, it could have been down on power the whole time, but it still ran.

Ditching the Lean Burn was the simplest, best modification I have done on any vehicle I've owned. I am shocked any Lean Burn vehicle could run at all 20 years later. Such a failure prone piece of crap it was! I replaced mine with the HEI conversion and a Holley 1920 and was knocking down 21 MPG consistently, and it started first flick of the switch.

My advice: ditch the Lean Burn. A no-start can be as simple as a blown ballast, or a distributor off a tooth (or 180 degrees), or a loose wire somewhere.

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If it was easy, everybody would be doing it.

When I said it ran fine prior to the work... I meant that I could merge onto I-94, uphill, within 1 miles of the intersection of it and I-275, dodge (no pun intended) the semi's, and anal assholes that insist on jumping three lanes at the last second, to exit. and by the time I made the intersection of 94 and 275 be up to the flow of traffic (70 to 80 mph) in the middle lane. So I think it was running pretty damn good for a 30 y/o truck.

Via my lurking I realized I have the DREADED lean burn system, and am well aware of the problems, and somewhat aware of solutions to work around/replace it. (i'm not interested in that at this point, sorry but thanks).

It quit running fine (ref paragraph 1 this post) prior to a oil and filter change, shade tree tune up, plugs, rotor, & cap.

Disp. drive gear is on order. (I was only looking for a used one the other day so I could reinstall the Dist. and check and see if the cleaning of everything made a difference)

I sure wish there as a trouble shooting flow chart for checking things that I may have affected during my repairs.

Guess I'll just keep throwing money at him till I hit the mark (the good old shotgun method).

Thanks for all the advice on rebuilding the engine ignition system, when I get to that point I'm sure it will come in handy.

[/u][/i]

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No matter where you go, there you are.

What kind of coil did you buy? Did you get one specified for your year truck? Lean burn coils don't use ballast resistors and have different ratings than coils for standard electronic ignition Mopars.

Here is the lean burn troubleshooting section from a 1983 Dodge van service manual. THis will be similar to yours, but not 100% identical. It will give basic roubleshooting steps for a lean burn system but you should really get a factory service manual for your truck.







































I would verify that the spark plugs wires were plugged in in the correct order, the plugs were gapped corectly, the coil is the correct rating for a lean burn ignition, and all the wires are hooked back up correctly to the coil. But you really need the factory service manual for YOUR truck with the correct troubleshooting section for YOUR system to diagnose this properly. Hopefully you can tell from the diagrams above that the lean burn system will not function properly with disconnected vacuum fittings and electrical sensors removed. Also, verify the distributor is timed correctly. It can be tricky to get the distributor rotor pointed in the right place if the distributor is removed.

Just throwing parts at the problems will not solve anything.

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Casually looking for a Clifford hyperpak intake for cheap.

Reed, thank you so much for the scans! You're a gentleman and a scholar!

The coil came from my local NAPA so I can only assume it's the one to specs. I'll dbl/ck thanks for the heads up.

The drive gear that was supposed to be here this morning, wasn't... should have one by tomorrow.

Plugs are wired in correct order. And I'll insure I'm TDC to #1 when I reinstall the distributor. On the intake stroke. (Kind of sounds like an old P-funk song).

Any ways, the best thing to happen on this project is your help Mano! Thanks Again.

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No matter where you go, there you are.

I am happy to help, but remember those are scans for a 1983 vehicle. A 1987 vehicle may very well have slightly different wiring and troubleshooting steps. I still strongly encourage you to get a 1987 factory service manual for your truck.

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Casually looking for a Clifford hyperpak intake for cheap.

Im with Reed and his earlier post, Id scrap the lean burn now and be done. Give that retiree some new wings and you less headaches down the road. I have an 84' and followed the same advice, ditched the lean burn and ran great. Like a singer sewing machine. Still use the same hei setup now that I run a turbo too.

If by chance you still keep the lean burn, Id chip away at the parts to make the swap, check the boards for them and elsewhere. Make it a shade tree day adventure. Heck, no further than you are, drive down for a day and we will do it, who knows, you may find a two barrel intake here too

Either way, good luck and keep us posted.

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As someone who dabbles in electronics periodically, I can tell you the Lean Bum system will suffer failure due to exposure and age. The electrolytic capacitors dry out. The resistors get out of range. And worst of all, corrosion eats at the solder joints and the copper traces. If a Lean Bum works at all, it's a miracle. It's not because of being a bad design, it's just the components inside have lived a hard life. You could trace down each circuit and test each resistor and capacitor, and replace as necessary. But it's much simpler to swap to HEI.

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If it was easy, everybody would be doing it.

OK, OK, OK, Already...

I've just been challenged by the mystery of it all... (How the simple work I'd done had caused all this problem). But admit I'm getting tired of it.

Thanks SSG Pohlman, and Coconuteater... if this dist overhaul does not work, I'll do it!!!

Which of the links for the conversion gives the best (simple) directions for the HEI upgrade?

As always, thanks in advance.

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No matter where you go, there you are.

HEI INSTRUCTIONS

There are no instructions specifically for converting a lean burn vehicle to HEI. However, it is extremely easy. Hook the distributor up to the distributor side of the HEI module, hook the + and - feed for the HEI module to the + and - feed of the coil. Better yet, use the + feed for the coil to trigger a relay that will power the coil. That is it. Going from lean burn to HEI is even easier than going from points to HEI or standard electronic ignition to HEI. Be use to use a modern E core coil for the most benefit.

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Casually looking for a Clifford hyperpak intake for cheap.