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Lean Burn Conversion Question #928674
02/14/11 01:49 PM
02/14/11 01:49 PM
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Posts: 395
Knoxville, TN, USA
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mantonas Offline OP
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I got rid of my lean burn and installed a procomp one wire distributor, which has a built-in electronic control unit and no ballast resistor. I'm beginning to suspect it might be a piece of junk, so I want to throw in a conventional Chrysler electronic distributor that I've got laying around. My car appears to have an ECU and a ballast resistor. I know I can trace wires and figure this out, but since I'm lazy, I thought I'd ask people who have done this already and find out if it's easy to convert from lean burn to conventional electronic (something like, "just use one of the two plugs that connect to the lean burn distributor - the one with the green and brown wires").

Any war stories?

Thanks!


69 Chrysler 300 Convertible 77 Chrysler New Yorker Brougham 2-dr 03 Jeep Grand Cherokee Limited
Re: Lean Burn Conversion Question [Re: mantonas] #928675
02/14/11 02:07 PM
02/14/11 02:07 PM
Joined: Dec 2007
Posts: 18,157
Mass
DAYCLONA Offline
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Mass
Don't bother trying to convert it over to a Chrysler Electronic/ECU, not woth the hassle, I was going to go this route on a customers car, but decided otherwise, (the Chrysler Electronic/ECU is just as bad as the Lean Blow IMHO).......I've converted a lean burn 1987 318 over to a Petronix Ignitor II, using a Chrysler single point dist, if you retain the original carb, use a mechanical advance Chrysler single point dist as your conversion base, as there are no provisions for vac advance, the vac advance was on the lean burn module that gets tossed in the conversion,...get a Haynes/Chilton manual on the year and motor in question, as there's 2 Lean Burn series, LB1 & LB2,...plus makes re-wiring so much simpler, you can retain the ballast or lose it your choice, if you lose the ballast, you'll need the Petronix Flame Thrower II coil, as it's rated different than the factory coil in regards to OHM ratings, plus it has an internal ballast resistor built in to the coil,....the customers NOW daily driver that I converted has been running about 2 yrs straight without any problems,...where as before it sat in his garage or a repair shop because the Lean Blow ignition is just a piss poor design from day one, frought with to many problems

Mike

Re: Lean Burn Conversion Question [Re: mantonas] #928676
02/14/11 02:12 PM
02/14/11 02:12 PM
Joined: Dec 2006
Posts: 3,533
Indiana
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Fury Fan Offline
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Posts: 3,533
Indiana
Quote:

I know I can trace wires and figure this out, but since I'm lazy, I thought I'd ask people who have done this already





This took about 30 secs to type and hit 'enter'.
http://www.google.com/search?hl=en&s...mp;aql=&oq=

Re: Lean Burn Conversion Question [Re: DAYCLONA] #928677
02/14/11 03:43 PM
02/14/11 03:43 PM
Joined: Oct 2010
Posts: 606
Montana
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Yancy Derringer Offline
mopar
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Montana
Quote:

Don't.......... convert it over to a Chrysler Electronic/ECU, ...............the Chrysler Electronic/ECU is just as bad as the Lean Blow IMHO).......





Baloney. There were and still are MILLIONS of Mopars on the road with factory style ECU's. Pertronix may or may not be OK, but they use NON STANDARD PARTS, which means you have to buy about THREE complete kits just so you can have parts when it quits on the road.

Re: Lean Burn Conversion Question [Re: Yancy Derringer] #928678
02/14/11 04:44 PM
02/14/11 04:44 PM
Joined: Apr 2007
Posts: 2,918
Calgary, Alberta Canada
a12rag Offline
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Did the conversion on a couple cars . . . using Chrysler ECU . . .way easy to do.

Biggest hassle was changing the carb - lean burn carbs just won't work for non-lean burn applications.

Would make the switch to std. Mopar elec. ignition, but look at changing the carb up too . . .

Cheers

Mark

Re: Lean Burn Conversion Question [Re: Yancy Derringer] #928679
02/14/11 06:27 PM
02/14/11 06:27 PM
Joined: Dec 2007
Posts: 18,157
Mass
DAYCLONA Offline
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Baloney. There were and still are MILLIONS of Mopars on the road with factory style ECU's. Pertronix may or may not be OK, but they use NON STANDARD PARTS, which means you have to buy about THREE complete kits just so you can have parts when it quits on the road.







3 kits huh?, hmmmm?...you must know what your talking about?,...how many orange boxes does it take to start a Mopar AND keep it running? with Electronic Ignition

Re: Lean Burn Conversion Question [Re: Yancy Derringer] #928680
02/14/11 06:41 PM
02/14/11 06:41 PM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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RapidRobert Offline
Circle Track
RapidRobert  Offline
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
Quote:

Baloney. There were and still are MILLIONS of Mopars on the road with factory style ECU's. Pertronix may or may not be OK, but they use NON STANDARD PARTS, which means you have to buy about THREE complete kits just so you can have parts when it quits on the road.


You know Yancey for a newbie here you are one argumentative SOB but I will give you credit you do have some extensive knowledge


live every 24 hour block of time like it's your last day on earth
Re: Lean Burn Conversion Question [Re: RapidRobert] #928681
02/14/11 07:40 PM
02/14/11 07:40 PM
Joined: May 2003
Posts: 15,487
Florida
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scratchnfotraction Offline
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Florida
nope, you dont have to buy 3 of them or odd ball parts,i threw the points/cond in the glove box..just like the instructions from pertronix said to do

few mins and it will be running agian

with lean burn, swap carb also at that time

but to drop a points dist in,you just un-hook the negitive wire/side of the coil and hook the 1 wire from the points to negetive side of coil

how hard is that

thats the fastest way i know to ditch a lean burn system and on the cheap

to each his own,,but i like points and the pertronix conversions

never have used anything else

keep you ecu/pcm crap

Re: Lean Burn Conversion Question [Re: RapidRobert] #928682
02/14/11 07:41 PM
02/14/11 07:41 PM
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo Offline
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Posts: 21,318
Manitoba, Canada
I used one of the pro-comp style distributors off ebay. Works just fine for me, but like you say, if something craps out on the road it's all non-standard parts. Does really clean up the wiring tho, the pro-comp distributor is all in one unit so just one wire to 12v+ and one wire to the coil and you're in business.

Re: Lean Burn Conversion Question [Re: a12rag] #928683
02/14/11 09:54 PM
02/14/11 09:54 PM
Joined: Jan 2003
Posts: 4,145
Canada -- Posts: 4034 -Registe...
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5thAve Offline
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5thAve  Offline
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Quote:

Did the conversion on a couple cars . . . using Chrysler ECU . . .way easy to do.

Biggest hassle was changing the carb - lean burn carbs just won't work for non-lean burn applications.

Would make the switch to std. Mopar elec. ignition, but look at changing the carb up too . . .

Cheers

Mark






Leanburn was gone by the late 70s and you don't need the manual for the year/engine you're working on to figure out wiring. Just the simple ECU wiring diagram and a test light to figure out what 2 wires to connect to, and only one if you go right to the starter relay with the other one.

Re: Lean Burn Conversion Question [Re: 5thAve] #928684
02/14/11 10:19 PM
02/14/11 10:19 PM
Joined: Mar 2003
Posts: 1,806
Newfoundland Canada
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Mopar1 Offline
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Newfoundland Canada
Quote:

Quote:

Did the conversion on a couple cars . . . using Chrysler ECU . . .way easy to do.

Biggest hassle was changing the carb - lean burn carbs just won't work for non-lean burn applications.

Would make the switch to std. Mopar elec. ignition, but look at changing the carb up too . . .

Cheers

Mark






Leanburn was gone by the late 70s and you don't need the manual for the year/engine you're working on to figure out wiring. Just the simple ECU wiring diagram and a test light to figure out what 2 wires to connect to, and only one if you go right to the starter relay with the other one.






Leanburn was used well into the 80's. I had an '87 Caravelle and it had the leanburn ignition. My '84 Caravelle also had it.

Re: Lean Burn Conversion Question [Re: Mopar1] #928685
02/14/11 10:35 PM
02/14/11 10:35 PM
Joined: Jan 2003
Posts: 18,415
UPPER MICHIGAN, MARQUETTE COUN...
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NITROUSN Offline
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Quote:

Leanburn was used well into the 80's. I had an '87 Caravelle and it had the leanburn ignition. My '84 Caravelle also had it.






84 on up Caravelle, newyorker fwd, and dodge 600 were all throttle body injection except the models with a 2.6 which were mitsubushi carburated.

Re: Lean Burn Conversion Question [Re: Mopar1] #928686
02/14/11 10:39 PM
02/14/11 10:39 PM
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo Offline
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Quote:

Leanburn was used well into the 80's. I had an '87 Caravelle and it had the leanburn ignition. My '84 Caravelle also had it.




Lean Burn ended in the late 70's because it was a flop. Chrysler ditched the lean burn carbs but retained the Electronic Spark Control feature which is what the 80's cars had. Somehow so many owners of these systems confuse them for lean burn even tho they don't say lean burn anywhere on them. Electronic Spark Control was a fact of life by that point to get the carbed cars to clean up enough to meet emissions.

Re: Lean Burn Conversion Question [Re: DaytonaTurbo] #928687
02/15/11 01:19 AM
02/15/11 01:19 AM
Joined: May 2005
Posts: 125
Iowa
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dsp Offline
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Iowa
You've got it backward. The Lean Burn computer on the 1978 Omni I once owned provided spark control only - no fuel control. The computer on my 1985 Diplomat provides both spark and fuel control. In fact, the computer is marked "Electronic Fuel Control System" (see picture). The 1985 engine is equipped with an oxygen sensor and a "O2 feedback solenoid" in the carburetor for fuel control. According to my 1988 service manual, this setup was used in 1988 as well. I know I'm going to be flamed by the Mopar gods with fire and brimstone for saying this, but the Lean Burn or "Electronic Fuel Control System" systems are reliable and can be tuned to deliver good fuel economy and driveability. You're not going to win any drag races, but these vehicles can be adjusted to run well and deliver good fuel economy (by 1980's standards). My 1985 Diplomat runs great! Over the years I have read many anti-Lean Burn threads on this board, but as far as I'm concerned, these people don't understand electronic engine controls.

Re: Lean Burn Conversion Question [Re: DaytonaTurbo] #928688
02/15/11 01:25 AM
02/15/11 01:25 AM
Joined: Jan 2003
Posts: 395
Knoxville, TN, USA
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mantonas Offline OP
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mantonas  Offline OP
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Knoxville, TN, USA
I already changed the carburetor to an Edelbrock Performer 1406 (600 cfm with electric choke).

As I said earlier, I replaced the Lean Burn distributor with a Procomp distributor (which I also bought on eBay!) and installed an MSD Blaster 2 coil, MSD Super Conductor wires (probably overkill), and E3 plugs. It seems to not be running so great (it's smooth at idle and at highway speeds, but it feels kind of ragged in between). I want to change it back to a Mopar electronic ignition just to see if it runs better. I appreciate the advice to go Pertronix, but that's not what I want to do. I have an electronic ignition distributor sitting around, and the car apparently has an ECU and a ballast resistor already installed, so I can do this for almost no money.

So I got the cheap part under control, now I want it to be easy. What I wanted to know is, has anybody done this same exact thing, which is change lean burn over to conventional electronic,
and in doing so, can you get lucky and make use of some of the wiring that's already there, and if so, exactly how do you do that.

If I have to, I'll go out and buy all the parts and rewire the whole thing in accordance with the many great information sources available by spending 10 seconds on google (thanks for pointing that out), but the great thing about this whole interweb thing is that you can learn from others' experience before you start on a project.


69 Chrysler 300 Convertible 77 Chrysler New Yorker Brougham 2-dr 03 Jeep Grand Cherokee Limited
Re: Lean Burn Conversion Question [Re: dsp] #928689
02/15/11 03:03 AM
02/15/11 03:03 AM
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo Offline
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Quote:

You've got it backward. The Lean Burn computer on the 1978 Omni I once owned provided spark control only - no fuel control. The computer on my 1985 Diplomat provides both spark and fuel control. In fact, the computer is marked "Electronic Fuel Control System" (see picture). The 1985 engine is equipped with an oxygen sensor and a "O2 feedback solenoid" in the carburetor for fuel control. According to my 1988 service manual, this setup was used in 1988 as well.




Electronic feedback carbs and lean burn are not the same thing. Lean Burn cars did not use the O2 feedback. Lean Burn cars had a throttle sensor on the carb and the carbs were are smogged out as you could get with terrible jetting, and idle/transition circuits. They were setup to run with the advance curve built into the lean burn computer, nothing else. You're right, the later ones had the electronic feedback carbs and the o2 sensor and they were a lot better than the Lean Burn cars. The computer adjustability and o2 sensor to keep things in check was much better in terms of driveability than the Lean Burn cars, which are the one that earned the system the bad rep. The feedback carbs are perfectly driveable when everything is in good shape and functioning properly. I think with the 80's ESC cars, you can swap off the feedback carb and retain the computer spark control with the 80's computers delivering a better spark curve by those years. Trying that with a lean burn computer and you get a real dog. IMO at the end of the day your best bet is to replace everything or keep everything.

You are correct in that in those years the 4cyl cars were available with electronic spark control with or without electronic carbs or lean burn carbs, but you can't really compare them to the V8's of the day which had entirely different equipment.

Re: Lean Burn Conversion Question [Re: DaytonaTurbo] #928690
02/15/11 07:46 PM
02/15/11 07:46 PM
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Posts: 4,145
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5thAve Offline
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Quote:

Quote:

You've got it backward. The Lean Burn computer on the 1978 Omni I once owned provided spark control only - no fuel control. The computer on my 1985 Diplomat provides both spark and fuel control. In fact, the computer is marked "Electronic Fuel Control System" (see picture). The 1985 engine is equipped with an oxygen sensor and a "O2 feedback solenoid" in the carburetor for fuel control. According to my 1988 service manual, this setup was used in 1988 as well.




Electronic feedback carbs and lean burn are not the same thing. Lean Burn cars did not use the O2 feedback. Lean Burn cars had a throttle sensor on the carb and the carbs were are smogged out as you could get with terrible jetting, and idle/transition circuits. They were setup to run with the advance curve built into the lean burn computer, nothing else. You're right, the later ones had the electronic feedback carbs and the o2 sensor and they were a lot better than the Lean Burn cars. The computer adjustability and o2 sensor to keep things in check was much better in terms of driveability than the Lean Burn cars, which are the one that earned the system the bad rep. The feedback carbs are perfectly driveable when everything is in good shape and functioning properly. I think with the 80's ESC cars, you can swap off the feedback carb and retain the computer spark control with the 80's computers delivering a better spark curve by those years. Trying that with a lean burn computer and you get a real dog. IMO at the end of the day your best bet is to replace everything or keep everything.

You are correct in that in those years the 4cyl cars were available with electronic spark control with or without electronic carbs or lean burn carbs, but you can't really compare them to the V8's of the day which had entirely different equipment.




You can't just ditch the feedback carb and keep the computer either because the computer is looking at both parts together- the fuel side and the ignition side. Im not sure when the fuel control system started in the US, probably around 1981? In Canada 1988 was the first year for it.

When the systems work they work great. You can change them out and notice no difference in performance or mileage but if something is wrong anything goes. Sometimes it seems like it's just easier to replace it all instead of trying to fix it and maybe it is. I've only had one that got to that point. It still ran but pinged all the time. I think the computer crapped out.

Re: Lean Burn Conversion Question [Re: mantonas] #928691
02/16/11 06:30 AM
02/16/11 06:30 AM
Joined: Jan 2003
Posts: 395
Knoxville, TN, USA
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mantonas Offline OP
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I took another look under the hood yesterday, and I don't know what I was thinking, there is a ballast resistor installed but there's no ECU in the car. I'll just have to wire one in to make the conversion.


69 Chrysler 300 Convertible 77 Chrysler New Yorker Brougham 2-dr 03 Jeep Grand Cherokee Limited
Re: Lean Burn Conversion Question [Re: mantonas] #928692
02/16/11 08:33 AM
02/16/11 08:33 AM
Joined: Aug 2003
Posts: 2,466
Answering the call of the wild
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ThermoQuad Offline
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Posts: 2,466
Answering the call of the wild
I can't just sit by and let more bad info escape...

There is nothing more reliable and well engineered than the Chrysler Electronic Ignition System. There have been quality control issues with the orange boxes in the recent past but there are several excellent box options out there and a timing light will tell you pretty much if you have a bad box. Bad boxes retard the timing and can cause misfires.

An entire chapter about installing mopar electronic ignition is in the mopar performance engine's manual...That's a reference book...perhaps some one remembers about reference books and how to read a book
Book p/n P4876826

There is an entire chapter on "Replacing Lean Burn/Spark Control Computer Ignition". 10 pages worth of excellent information and "Helpful Suggestions" BTW There were several versions of this system used and called several different names and it worked well for the most part.

On page 324 of the "book" are starter relay diagrams and a "Master Disconnect Chart Cavity Location-Main Ignition Feed." to determine what wires you need to use. Simple. On page 325 figure 2-169 depicts all of the "master disconnect connector styles" Every thing you need to install the reliable, excellent mopar ignition system in a plethora of mopar cars and trucks.

I am not going to scan the 10 pages and post them as they will be forgotten and not archived as they should be. I told you where the proper information is. Go look.

As to the OP if you PM me I will help you.

A couple of notes which are not going to increase my popularity:

Low post count is a measure of NOTHING, so leave those guys alone and just answer their questions. Maybe they are smarter than the rest of us.!

Mr Dayclona once again you have put forth bad information and stuck your foot in your mouth.
As a paid spokesperson for bad advice and poorly engineered mopar aftermarket products you should stay on the porch permanently and keep you foot in your mouth.

As to the people who run this place I am requesting new guidelines for Q&A that are enforced, proper archiving of the GOOD information and a handling/suspension forum.

That's not asking too much.


Re: Lean Burn Conversion Question [Re: ThermoQuad] #928693
02/16/11 03:26 PM
02/16/11 03:26 PM
Joined: Jan 2003
Posts: 10,643
S.E.Ohio
Magnumguy Offline
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S.E.Ohio
What some forget is also it wasn't made for performance, it was for economy. When it worked right, it was a good system. Light years ahead of other companies, how many had onboard processing computers in the mid-70's? None other than Chrysler Corp. Those were put on mid 70's 400/440's as a test.

It is essentially the same computer used through the 80's and early 90's. It was moved from the top of the aircleaner from the heat & vib. that ruined them to around the battery, and they were vitually trouble free at that point.


"Multiple Magnum owner since 1978!!"


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