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Lean Burn Conversion Question
#928674
02/14/11 12:49 PM
02/14/11 12:49 PM
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Joined: Jan 2003
Posts: 396
Knoxville, TN, USA
mantonas
OP
enthusiast
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OP
enthusiast
Joined: Jan 2003
Posts: 396
Knoxville, TN, USA
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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
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Re: Lean Burn Conversion Question
[Re: mantonas]
#928675
02/14/11 01:07 PM
02/14/11 01:07 PM
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Joined: Dec 2007
Posts: 18,167
Mass
DAYCLONA
I Live Here
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I Live Here
Joined: Dec 2007
Posts: 18,167
Mass
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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
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Re: Lean Burn Conversion Question
[Re: DAYCLONA]
#928677
02/14/11 02:43 PM
02/14/11 02:43 PM
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Joined: Oct 2010
Posts: 606
Montana
Yancy Derringer
mopar
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mopar
Joined: Oct 2010
Posts: 606
Montana
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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.
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Re: Lean Burn Conversion Question
[Re: RapidRobert]
#928681
02/14/11 06:40 PM
02/14/11 06:40 PM
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Joined: May 2003
Posts: 15,494
Florida
scratchnfotraction
I Live Here
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I Live Here
Joined: May 2003
Posts: 15,494
Florida
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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 
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Re: Lean Burn Conversion Question
[Re: a12rag]
#928683
02/14/11 08:54 PM
02/14/11 08:54 PM
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Joined: Jan 2003
Posts: 4,214
Canada -- Posts: 4034 -Registe...
5thAve
Doesn't care what this says anyway
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Doesn't care what this says anyway
Joined: Jan 2003
Posts: 4,214
Canada -- Posts: 4034 -Registe...
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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.
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Re: Lean Burn Conversion Question
[Re: 5thAve]
#928684
02/14/11 09:19 PM
02/14/11 09:19 PM
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Joined: Mar 2003
Posts: 1,806
Newfoundland Canada
Mopar1
top fuel
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top fuel
Joined: Mar 2003
Posts: 1,806
Newfoundland Canada
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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.
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Re: Lean Burn Conversion Question
[Re: Mopar1]
#928685
02/14/11 09:35 PM
02/14/11 09:35 PM
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Joined: Jan 2003
Posts: 18,436
UPPER MICHIGAN, MARQUETTE COUN...
NITROUSN
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 18,436
UPPER MICHIGAN, MARQUETTE COUN...
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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.
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Re: Lean Burn Conversion Question
[Re: Mopar1]
#928686
02/14/11 09:39 PM
02/14/11 09:39 PM
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Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo
Too Many Posts
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Too Many Posts
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
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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.
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Re: Lean Burn Conversion Question
[Re: DaytonaTurbo]
#928688
02/15/11 12:25 AM
02/15/11 12:25 AM
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Joined: Jan 2003
Posts: 396
Knoxville, TN, USA
mantonas
OP
enthusiast
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OP
enthusiast
Joined: Jan 2003
Posts: 396
Knoxville, TN, USA
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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
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Re: Lean Burn Conversion Question
[Re: dsp]
#928689
02/15/11 02:03 AM
02/15/11 02:03 AM
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Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo
Too Many Posts
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Too Many Posts
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
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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.
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Re: Lean Burn Conversion Question
[Re: DaytonaTurbo]
#928690
02/15/11 06:46 PM
02/15/11 06:46 PM
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Joined: Jan 2003
Posts: 4,214
Canada -- Posts: 4034 -Registe...
5thAve
Doesn't care what this says anyway
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Doesn't care what this says anyway
Joined: Jan 2003
Posts: 4,214
Canada -- Posts: 4034 -Registe...
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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.
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Re: Lean Burn Conversion Question
[Re: mantonas]
#928691
02/16/11 05:30 AM
02/16/11 05:30 AM
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Joined: Jan 2003
Posts: 396
Knoxville, TN, USA
mantonas
OP
enthusiast
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OP
enthusiast
Joined: Jan 2003
Posts: 396
Knoxville, TN, USA
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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
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Re: Lean Burn Conversion Question
[Re: mantonas]
#928692
02/16/11 07:33 AM
02/16/11 07:33 AM
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Joined: Aug 2003
Posts: 2,483
Answering the call of the wild
ThermoQuad
top fuel
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top fuel
Joined: Aug 2003
Posts: 2,483
Answering the call of the wild
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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.  
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