The process of elimination - post lean burn conversion troubleshooting

[Intrepolicious]

After getting my fuel delivery issues seemingly resolved, (I ended up finding a vacuum port not properly plugged in my "318 down" thread, and the car has been running great all week, with me driving it all over town, to work and back etc etc), she started giving me issues again on Saturday. I was doing some cleaning in the engine bay and decided that since I had just replaced the plugs, I should get new wires and a cap & rotor. Keep in mind that I was driving the car around like normal Saturday morning, even took the car up to get the new wires, cap & rotor.

Well, I get back and get everything installed. Yes, I have the FSM and carefully installed the wires in the correct 1-8-4-3-6-5-7-2 firing order etc etc. Started her up and she was running great! I let her idle for a good 10-15 minutes and she suddenly stumbles and stalls. Tried to start her back up and nothing... this is when I decided to check for spark. None!

So I decided to replace the coil... figuring this car is 37 years old, and I'm most likely having multiple issues... the fuel issue seemed to be resolved, as she's been running great with me driving the car all around town all week. Now it could be something else. The "no spark" condition I observed led me to the coil conclusion, so I installed said new coil and still nothing. "Seemed like" I was still not getting any spark. (for the record, a couple weeks ago when I was having issues, I checked for spark and had plenty of spark/arc between the cable and the block when using the old school method)) So maybe the coil is getting hot - easy: replaced the coil.

For good measure, and because the coil clearly reads "use with external resistor" on it's label, I also replaced the resistor since it was only $5 and they had it in stock when I bought the new coil. Still nothing.. crank crank and crank, but no fire. It was at that point that I gave up for the day and went to bed... Took the GF's Honda to work Sunday for my double shift.

-Monday a.m.-

This morning I get in and turn the key and she starts right up! Again... like nothing ever happened. WTF Charlene!

So is heat playing a role here in my intermittent problem? Maybe the control unit (the TP51 ECU) is getting hot and malfunctioning? It can't be the coil because it did the same thing with a brand new one. I don't see how the ECU could be getting all that "hot" way over there on the fender. Perhaps this weird changing in weather/temp lately is playing a role? (it's been real warm during the days up into the 80's (F) then dropping to the 40's (F) at night)

I'm going to buy one of those spark tester lights to eliminate the "no spark" from being a figment of my imagination for the next time she decides to not "put out" lol

So let me make a little list here of the things I've done/fixed/replaced on Charlene during the first two months of our relationship:

Purchased: 2/15/17 (the day after Valentine's Day - I'll always remember this day because it was the day the GF pointed out that instead of buying her something nice for V-day, I went and bought myself a Córdoba.......

(...and thus began the curse)


2/16/17 ~ 3/1/17

• New oil and filter - I plan on running conventional in her, but for the time being, I had a 5Qt jug of Mobil1 already in the garage, so I went with that for now. Bought a new Mobil1 filter.

• Replaced various bulbs

3/6/17

• Transmission rebuilt 2 yr/24k mile warranty

3/1/17 - 4/10/17

• Fuel Filter

• New Battery (the car had the wrong battery in it. Bought the correct one and upgraded to HD #27 version)

• Spark plugs (Champion copper plus)

• Wires

• Distributor cap & rotor

• Fixed speedometer (cable was loose behind cluster)

• New AC/Delco idler arm (tie rod ends are next, then wheel bearings, ball joints etc - all the fun stuff I know how to do!)

• Started using Non-ethanol fuel.


I guess the strategy here is to continue throwing parts at her. Next on the list is the ECU... (great price on those at NAPA - might just go ahead and get one to have just in case!) and then the pickup coil in the distro? I hear these are prone to failure as well.

What else is there? Thoughts?

 

[Intrepolicious]

Oh, the "process of elimination" title was geared toward my current no start/no spark situation. Which leads me to the ECU/ignition system. I've replaced the battery, the plugs, the wires, the cap and rotor, and the resistor. The only thing left in the ignition system is the ECU and the coil pickup in the distributor, right?

I feel like it may be this control module acting up because of the temperature changes.

 

[Intrepolicious]

So I replaced the next thing on the list; the ECU! The local Napa had the TP51 control unit in stock, went and picked one up, installed it, and the car is back to running great again!

 

[BudW]

Status report?

The ICU (Ignition Control Unit), voltage regulator, ballast resistor and a few simple hand tools (to change the before mentioned parts) are good to have a spare in the trunk – for these items are known to fail at a snap of a finger.

Lean Burn/ECS is a different story and when it dies, there is no simple side of the road fix for them.
BudW

 

[Intrepolicious]

Status report?

The ICU (Ignition Control Unit), voltage regulator, ballast resistor and a few simple hand tools (to change the before mentioned parts) are good to have a spare in the trunk – for these items are known to fail at a snap of a finger.

Lean Burn/ECS is a different story and when it dies, there is no simple side of the road fix for them.
BudW

Still running great! I got up this morning and she started right up (after a couple turns which I consider normal), took her up to the grocery

Installed all new:

• Battery
• Plugs
• Wires
• Cap
• Rotor
• Coil
• ECU
• Ballast Resistor

Ah yes... the voltage regulator! That and the pickup coil in the distributor are the only two things left I haven't replaced. But you're right, as cheap as these parts are, it's probably a good idea to keep a couple extras on hand just in case.

 

[BudW]

The distributor pickup coil is also not a side of the road fix.
Good to have a spare, but I would keep it in garage (or carry a spare small block distributor in the car).


A tip on distributor pickup coils.
The ones with orange and black wires are made in USA and are far better quality than the ones with white and black wires (which are made in Asia).

The white/black wire variety will work in a pinch, but are a lot more troublesome than the orange/black variety ones are.

In the mid/late ‘80’s Chrysler quit making these distributors in USA and started to get them overseas. When they did, the wire colors changed. At same time, all distributor part quality went downhill (including the Mopar Performance versions, as well).

I “think” there is only one outlet making these pickup coils in last 30 years, and they are Asia based.
If I had a choice, I would rather use a 40 year old used orange wire one, than a white wire one – because of all of the problems I’ve seen with them.

Note: the pickup coils either work fine, are dead, or work for about 5 to 10 minutes, then dies (which the ICU can do the same exact thing).


The only way to can tell a Lean Burn/ECS distributor was made USA or Asia is by wire color.
The Mopar Performance distributors also you can tell by wire color but also the mechanical advance weights are way thinner (as if they used Cheby thin weights vs. the Chrysler thick ones). The thin weights, um, well, can work but causes a lot of timing issues (very inconsistent).

Here is a Lean Burn/ESC version (which doesn’t move). This one is an older version (orange wire).

All pics taken (swiped) from eBay.
BudW

 

[AJ/FormS]

I used to carry a spare dizzy in the car. When the engine would quit I just plugged my spare in and gave the driveshaft a spin. If I had spark, I could hear the buzzing in the cap. If none, I would pull the coilwire out of the cap and near-ground it, and spin the shaft again. If no welders arc, I would do the one spark test, by cycling the key to off/run. If that failed I would replace the ECU, put it all together and drive away. If it passed the one spark test, I would replace the pick-up, put it all together and drive away. Diagnostic time less than 5 minutes. Repair time about 2 for the ECU and 10 for the pick-up. Oh yeah, I carried a 20 ft jumper wire. I could put battery volts anywhere, even to the Ballast resistor

 

[BudW]

Putting some jumper wires in the trunk, is a very good idea.

BudW

 

[volare 77]

I had a white one that was bad right out of the mopar box.

 

[BudW]

Those white wire pickup coils were garbage, when brand new.

I was looking for something else, and I found a grey wire pickup coil in my stash of spare parts (both wires were grey), this weekend.
It was made in Mexico and a Mopar part. I don’t recall seeing a grey wire pickup coil before (but I do have one) – so I can’t comment about them, yet (new part, not yet bolted to anything).
BudW

 

[Intrepolicious]

Charlene wouldn’t start tonight. Just cranked and cranked but no fire. First time since I started this thread.

Tomorrow I’ll do some spark checks and see what’s up. I’m too tired to play with her tonight.

 

[AJ/FormS]

I ran across a gray plus black out of a lean-burn D100 360

 

[Poly]

Charlene wouldn’t start tonight. Just cranked and cranked but no fire. First time since I started this thread.

Tomorrow I’ll do some spark checks and see what’s up. I’m too tired to play with her tonight.

Geeez, after all that work I hope it was something easy peasey like a loose ground wire. I wish I could be of some sort of help but have no idea what this lean burn conversion is, or involves. Our '83 318 looks like a '69 cop motor.

 

[BudW]

“Lean Burn”, “Computerized Spark Control”, and about another half-dozen other names are used for the computerized ignition and/or fuel system. The computer attaches to outside of engine air cleaner and looks like this:

You can even see where the name “Lean Burn” mentioned on air cleaner.
As far as FMJ-body cars are concerned, if there is a computer hanging off the air cleaner, the common term to describe the “computer system” is Lean Burn – even if there is no mention of the words “Lean Burn” anywhere.

The police versions (AHB optioned) has the computer mounted inside of the cabin. The police computer version is not worth seeking out (unless you need to replace a defective unit) – for I can’t find any differences between the two versions (in my opinion), other than mounting location.

The conventional ignition change-over system looks like this kit:

The controller can be in different colors.

This one is Orange.

This shows the ignition module on my ’77 wagon (which Lean Burn was an option).

This module is black.


There is nothing inherently wrong with the Lean Burn or computerized ignition/fuel system – other than most people either do not understand how it works and/or don’t have tools to diagnose problems with it. Because of that, many upon many “conventional” system problems caused the finger to get pointed to the Lean Burn system (like defective ignition coil (which is the same on either system), bad fuel pump, loose timing chain, and the list goes on and on.

If a person has a working Lean Burn system – I recommend leaving it alone.
If a person has a car with Lean Burn problems – or is performing modifications to car – then I might recommend a changeover to a conventional electronic ignition system (see above kit picture).

My ’86 Fifth Ave has the computer-controlled carburetor and ignition system.
When I convert the car to big block and to fuel injection, I will no longer need that computer system – so a changeover will be needed.

Hopefully this helps,
BudW

 

[Poly]

There's "Electronic Feedback Carburetor" in the '83 shop manual. That must be it.

The conversion kit... I don't recognize some of the pieces. The one I've got used a 4-pin hei ignition module. But the two terminal distributor is the same.

Crappy distributor caps are a known issue with some of this aftermarket stuff. And some won't seat properly to the distributor housing...and eat up the rotor in short order.

That could be another item on the checklist for no-start.

 

[lowbudget]

The ECU grounds through the fender well where it is attached. Make sure you are getting ground. I've always run a separate ground wire to the hold down screw. Don't ask me how much time was spent learning this the hard way.

 

[BudW]

Need pictures, lots of pictures of underhood area, including a few under air cleaner – for I think there might be a lot more to the story.
Also, can you tell me in detail what car is doing (or not doing).
Also mention what you have done to date, to the car?

The picture of the conversion kit I posted (post # 14) is the most common change-over kit out there – which there is several venders selling something close to it.
Basically, it is replacing the Lean Burn computer (or whatever name your system is using) with an older and simpler electronic ignition system. You mentioned (General Motors) HEI – which is also a system that can be used for changeover, but I have a gut feeling something else is amiss.

The changeover kit I had pictured (above) contains a Chrysler design ignition module, ballast resistor and a wiring harness pigtail (some splicing, and soldering is required). It also comes with a distributer that has both mechanical advance and vacuum advance – to replace the computerized distributer which uses neither version of spark timing advances (which is what the computer does when working correctly).

If your system also controls the computer controlled carburetor – then (it sounds like) someone tossed a wrench into the works . . . possibly.
BudW

 

[Poly]

Charlene wouldn’t start tonight. Just cranked and cranked but no fire. First time since I started this thread.

Tomorrow I’ll do some spark checks and see what’s up. I’m too tired to play with her tonight.

So where ya been ? How's Charlene doing ?