Lean Burn Question

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e50095

e50095

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If you could I'd appreciate a little advice. I have an 87 D150 with the lean burn computer controlled ignition and carb. Most of the vacuum lines (of which there are many) are gone or not connected to anything. It will run, but it misses and has no power. I checked the compression, which is good, and changed the plugs and wires. No change. I'd like to go HEI, but my question is (and yes this may sound stupid) is could I pull the computer controlled carb and distributor and run a point distributor with vacuum advance and the matching carb I know to be good as a temporary measure while I take some time to go through the rats nest of wires and vacuum lines from the lean burn running all over the place? I have the distributor and carb in stock from days past. I appreciate any suggestions. My daughter is moving away and I need the truck to run to avoid a big U-Haul bill.

thanks...
 
Yes but I would not. Run an electronic dist and either an HEI module or a Mopar module. Do you HAVE the points dist? If so I could see tossing it in there to get things going
 
...or at least go Mopar electronic.

Fairly easy to do.
 
67Dart273 said:
Yes but I would not. Run an electronic dist and either an HEI module or a Mopar module. Do you HAVE the points dist? If so I could see tossing it in there to get things going
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I have the points dist and carb, yes. I was afraid that with no ballast resistor I might fry the coil....I thought I had read that somewhere.
 
e50095 said:
I have the points dist and carb, yes. I was afraid that with no ballast resistor I might fry the coil....I thought I had read that somewhere.
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Doesnt the lean burn use a ballast? If it's a 4 pin ballast, the half that's hooked to the coil is same

EXAMPLE:

Let's say you have a Mopar electronic ignition and the box or the dist. goes bad. You can actually unplug the box, drop in a points distributor, and hook the dist wire right up to the coil NEG and start it right up.

Could be wrong, don't think "that part" of the lean burn is different.

You can confirm this by doing following:

Turn the key to run with all the original components connected. Put a meter on the coil POS post, and for good measure, jumper the coil NEG post to ground. If it has a resistor, the voltage will be considerably below battery voltage, perhaps 6-8V
 
Found this link at Hemmings:

https://www.hemmings.com/magazine/hmn/2013/08/Chrysler-s-Lean-Burn-System/3728501.html

470421-450-0.jpg


That is a bit hard to read, but it looks like the basics are the same. The resistor is still used. One difference is that the coil bypass voltage in starting no longer comes from ignition switch. They are using the newer starter relay with one more contact, and that is what gives you hot coil voltage during cranking. In any cause you SHOULD be able to simply unplug the lean burn, leave the coil wiring as is, and simply unhook the coil NEG wire and put the dist. points wire in it's place
 
67Dart273 said:
Doesnt the lean burn use a ballast? If it's a 4 pin ballast, the half that's hooked to the coil is same

EXAMPLE:

Let's say you have a Mopar electronic ignition and the box or the dist. goes bad. You can actually unplug the box, drop in a points distributor, and hook the dist wire right up to the coil NEG and start it right up.

Could be wrong, don't think "that part" of the lean burn is different.

You can confirm this by doing following:

Turn the key to run with all the original components connected. Put a meter on the coil POS post, and for good measure, jumper the coil NEG post to ground. If it has a resistor, the voltage will be considerably below battery voltage, perhaps 6-8V
Click to expand...
awesome...thanks brother.....
 
I have a Mopar coil stamped "for use with electronic ignition". I think it is a "ballasted coil", i.e. there is an internal ballast or at least a primary winding which acts the same. I had the same "spark computer" on my 1982 Aries 2.5L. Once it wouldn't start which I think was due to the poor Molex-type connector they used at the computer. That was before better Weather-pak and Metri-pak connectors. Try squeezing the female pins in slightly w/ needle-nose pliers for tighter contact with the male pins. That worked for me, or at least the problem went away. I don't recall seeing a ballast resistor in my Aries, but doesn't mean it wasn't there. Don't run w/o ballast on a normal <1 ohm coil or it will soon overheat to melt the paint and the spark will start missing. I tried that once. Worst-case you can jumper from BATT+ thru a ballast to coil+ and just remove the jumper to stop the engine. Insure the ballast isn't broken, since that is a common problem. If the engine fires while cranking, but dies the second you relax to "run" position, the ballast is likely broken.
 
AJ/FormS said:
Just for kicks what did you get for compression?
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All 6 cylinders were in the 115-130 range, nothing less than 115. I bought the truck from a landscaping company, so I assume it has a lot of miles on it. I have multiple motors to upgrade to down the road, both slants, a 318, and a 340. I just need the thing to run decent for a month and get to some sustained good weather so I can have at it.
 
Yes you can as has already been said. I've just finished a lean burn swap in my 87 w150, if you run into any issues feel free to PM me. I'm no expert by any means but I learned alittle from that whole deal.

By 87 im going to assume yours is carb'd? The brand new 2 barrel mine came with had a couple wires going to the LB box. Never would run right with the box out
 
BigBlockMopar28 said:
Yes you can as has already been said. I've just finished a lean burn swap in my 87 w150, if you run into any issues feel free to PM me. I'm no expert by any means but I learned alittle from that whole deal.

By 87 im going to assume yours is carb'd? The brand new 2 barrel mine came with had a couple wires going to the LB box. Never would run right with the box out
Click to expand...
thanks brother, I appreciate it. Yes, it's a carb with some solenoids on the side I don't even recognize. It's gotta go......did you go to Chrysler electronic or HEI?
 
e50095 said:
thanks brother, I appreciate it. Yes, it's a carb with some solenoids on the side I don't even recognize. It's gotta go......did you go to Chrysler electronic or HEI?
Click to expand...
Gonna be honest with you, tried both. HEI (as in externally mounting the module), never did get it to hit and I couldn't figure it out. Then went 4 pin Chrysler with a 4 prong ballast and it sparked well but somewhere along the line that blue coil + wire on the factory harness sparked something (unplugged and wasn't taped), and I blew a fusible link. After that I never could get the 4 pin box to work, had an old mechanical 6al box laying around, hooked that up and it ran like a top, and still does.

I'm not sure if that blue coil + wire can be used on the Chrysler setup, but the way I had the ballast setup the starter would stick when I tried to use it for a keyed hot going to the ballast, ended up using a power wire in the lean burn harness by the battery that had power when keyed on and when cranking, for the MSD.
 
BigBlockMopar28 said:
Gonna be honest with you, tried both. HEI (as in externally mounting the module), never did get it to hit and I couldn't figure it out. Then went 4 pin Chrysler with a 4 prong ballast and it sparked well but somewhere along the line that blue coil + wire on the factory harness sparked something (unplugged and wasn't taped), and I blew a fusible link. After that I never could get the 4 pin box to work, had an old mechanical 6al box laying around, hooked that up and it ran like a top, and still does.

I'm not sure if that blue coil + wire can be used on the Chrysler setup, but the way I had the ballast setup the starter would stick when I tried to use it for a keyed hot going to the ballast, ended up using a power wire in the lean burn harness by the battery that had power when keyed on and when cranking, for the MSD.
Click to expand...
I believe your truck would have used the Mpar 5 pin ECU.
 
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