Slant Six Forum :: removing lean burn system

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removing lean burn system https://www.slantsix.org/forum/viewtopic.php?t=7301	Page 1 of 1

Author:	kdancy [ Tue Oct 21, 2003 6:33 am ]
Post subject:	removing lean burn system
I know this has been answered at some point. But, what is required in removing the lean burn system from my 1985 D-100 /6. Thank you

Author:	mnecaise [ Tue Oct 21, 2003 8:34 am ]
Post subject:
First, a warning: Removing it may violate your local emissions laws Now that that's out of the way, let's get into ripping out that piece of _________ (<---fill in your own expletives) A question: What carb do you have? Is it an electronically controlled carb with mixture control solenoid (aka a feedback carb)? If so, you'll need a standard carburetor to replace it. If you do need to replace it, there's a bunch of options... The distributor you've got doesn't have a vacuum or a mechanical advance in it. The ignition module is built into the lean-burn computer. So, you'll need a distributor, ignition module and ballast resistor from a non-lean burn car/truck. You'll also have to hack together the wiring harness for it -- you might be able to extract the whole setup, complete, from a junkyard vehicle. The vacuum advance should be connected to a ported-vacuum port on the carb. There's a usefull diagram here: http://slantsix.org/articles/elect_ign_ ... wiring.htm Removing the lean-burn computer means that the EGR valve will no longer work, because the vacuum solenoid is controlled by the computer. Some would consider this no great loss. If you're conscience is bothering you we can discuss ways of fixing this... Not much else needs to be changed. You can unscrew the computer from the aircleaner and replace it with a piece of sheet metal (to cover the opening(s); or, you can leave it in place (disconnect the wiring harness and tie it back, out of harms way)

Author:	Craig [ Tue Oct 21, 2003 7:02 pm ]
Post subject:	WHY Remove "Lean Burn" ESA ???
Why does everyone want to remove their "lean burn"?? Actually, "lean burn" was only used on some of those V8 cars back in the late 1970s. Those ESA (electronic spark advance) systems are neat. They provide timing capabilities that no vacuum or mechanical advance can ever do. The biggest problem probably is that no one understands the system nor knows how to verify that it is working correctly. After studying information from various sources (not only Chrysler publications which seem to be lacking information) this system is AMAZING!! I once found some great information in a OTC (Owatona Tool Company) book covering testing of automotive computers with their testers. One of the unique things I recall is that with a cold engine the ESA system ADVANCES the ignition timing with decreasing engine vacuum (this greatly improves cold engine driveability). Try that one with your vacuum advance pod! Also on the automatic transmission trucks in the 1980s with the dual pickup distributor....... if the "run" pickup coil fails the system will automaticlly switch to using the "start" pickup coil so you can at least drive home or to the repair shop. Hey, it happened to my '87 truck, the run coil failed and worked only intermittently. I drove it that way for several days until the new coil plate came in. On the downside, I realize that this system is not adjustable except for changing the basic timing which will move the whole advance curve up or down.

Author:	typhoon [ Wed Oct 22, 2003 12:49 am ]
Post subject:
If you've ever had a pathetic Lean Burn box fail or play silly buggers on you, then you will know why people ditch them. I used to have ELB on a 318..was interesting how it would surge the rpm to 1500 intermittently on cold warm up, and how it would wig out and bugger up the timing so bad that the thing would backfire through the carb and not go over 2000 rpm..great way to cause an accident. I diagniossed the crap out of that thing and got nowhere, ran great with an Accel distributor in it though. Great idea I guess, but as far as I am concerned, EFI or carb and distributor, nothing in between thanks. As a side note, you can get electronic modules for outboard engines that wil automatically advance ignition timing once rpms fall below a certain rpm(like an engine about to stall), very nice on cranky engines. Regards, Andrew.

Author:	mnecaise [ Wed Oct 22, 2003 6:25 am ]
Post subject:
OK, here's the deal (in my case): I do know how to diagnose it. I'm an electrical engineer / programmer who was a mechanic in a previous life. Unfortunately some person prior to me swapped a junkyard EFC in inplace of the ESC that's supposed to be in my truck (I suspect this is a fairly common occurance). So, I now I have the wrong computer. I have no idea which specific computer should have been there... (Advance Auto lists like 4 or 5 possible numbers). All the sensors (except the O2, which I don't have) are working. But, because it's the wrong computer It's running at the base timing with no advance. This sucks. Believe me, I understand the value of the computer. I wish Dodge would be more forthcoming about what parameters or equations they use to program the thing. If they were, I could re-create the computer and tweak it. But, they're not (proprietary info and all that) so I can't. Let's not get into the other nit-picky problems I have with the design... So, what's the easy thing to do when the computer fails: swap in a standard electronic ignition. This is guaranteed to work.

Author:	Super6 [ Wed Oct 22, 2003 10:07 am ]
Post subject:
While definitely not the cheapest option, MSD ignitions are easier to install in place of lean burn/SCC than a standard electronic ignition IMO. Why? You need ONE wire from the original wiring harness to hook it up--the original coil + lead (ignition-switched 12 V) Every other hookup comes from the MSD box. The MSD does reqire a standard electronic distributor as well though. On the dual dist pickups--I was not so fortunate when my 'run' pickup died--the truck died, would not restart, and i was in the middle of a 5-lane 75 MPH highway during rush hour. Maybe both pickups failed at the same time...but that is when i tore out the SCC. After installing the MSD my truck has never run better. My .02 -S/6

Author:	mnecaise [ Wed Oct 22, 2003 12:06 pm ]
Post subject:
I should qualify something: I found that my truck is built out of the parts from two wrecked trucks and numerous "other" junkyard parts... So, when I describe my setup, ignore it; It's probably wrong. The distributor is a fixed, ESC distributor; but, only has a run pickup. The wiring harness on my engine has connectors for both. That may be another reason the computer in my truck never (since I've owned it) worked right... (it's got the wrong computer AND the wrong distributor) *Ok, I'm ranting * My truck is a Frankenstein type creation I figure that pretty much gives me creative liscense to do whatever I want with it; being as it's already all mixed up. I'm ranting again...

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