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Discussion Starter · #1 ·
Hello all. First post on this forum. Spent about 2 hours trying to search for an answer on here but didn't get any results. The car, 1980 LaBaron, collector plates, 318 auto. Lean burn replaced by Chrysler dealer at some point, long before I got the car ten years ago. Carb is not original. The problem: car starts fine, accerates fine to a certian point then just boggs down and runs rough. If I back off on the accerator the engine "unbogs" and runs fine, pressing down again and it boggs down, can barely make it up a hill when bogged down. Feels like it is not getting enough gas. The car hasn't run right since I got it. What I've done to try and fix this problem. Replaced, fuel filter in tank, fuel pump, fuel filter at carb, ALL rubber and steel gas lines (outside rust, just on spec), igintion coil, and ignition wires. Attempted to burn up the engine by using ether to look for vacuum leaks (didn't find any) but did discover that powdered fire extinguisher material is a bitch to clean up.
Next thought was to replace the carb . But I don't know which carb to put in. I do want a factory option carb, one without emissions restrictions. Any thoughts on what this problem can be and or what else I might try. Should I rebuild whatever carb is there rather than buy a refurb one?
 

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It may be something as simple as the carb floats having sunk due to saturation or pinholes, and therefore running too rich. Pull the spark plugs and see what shape they're in. If they are fouled black, the engine is running rich. If they are pure white with blister marks, too lean. Proper color should be very light tan insulators, clean tips, with no cosmetic damage.

You say you replaced the coil and wires, but how about the ignition rotor, distributor cap and spark plugs? They need to be replaced every 20-30 thousand miles on these cars.
 

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Another thing to check is the vacuum advance. If there isn't one, that may be the problem. The distributor should have one set of wires coming out of it, not two, the two sets of wires is the Lean Burn distributor and it has nothing to make it operate so no advance.
You didn't mention if it was a 2bbl or 4bbl carb, assume 2bbl on a 318 from that era, wasn't until the mid 80s (86 or 87) that 4bbl was available for the 318, but proper adjustment is key, too high or low float doesn't help, needles set improperly doesn't do any good either.
When Lean Burn is removed, both the carb and the distributor has to be changed because the LB "computer" controls the advance and fuel/air ratio through temp sensors of air and engine water, and neither have external adjustments on them.
 
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Discussion Starter · #4 ·
Wow, what quick responses, thanks.
#1 spark plug. Dist has been replaced and readjusts when engine speed changes. Vaccum line to dist is OK, checked a few years back while trying to fix this problem. Yes 2 bbl carb. To be clear, the engine bogs whether on flat for hill, just that I feel it more when heading up a hill because it is under more load. Amazingly this car drives well within a few seconds of start up from cold. Unlike my 75 D200 which takes 10 minutes to warm up before it's drivable (in the summer).
 

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Discussion Starter · #5 ·
Wow, what quick responses, thanks.
#1 spark plug. Dist has been replaced and readjusts when engine speed changes. Vaccum line to dist is OK, checked a few years back while trying to fix this problem. Yes 2 bbl carb. To be clear, the engine bogs whether on flat for hill, just that I feel it more when heading up a hill because it is under more load. Amazingly this car drives well within a few seconds of start up from cold. Unlike my 75 D200 which takes 10 minutes to warm up before it's drivable (in the summer).
Oh, forgot to mention, the electronic ignition module appears to be melting the potting material, as it is running down the inner fender. Defective??
 

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Originally it would have had the Carter BBD:


The 1980 Lean Burn was before fuel control (exc. CA emissions) and is strictly for spark advance with a 'lean' calibrated carburetor.
The computer must ground at warm idle against the idle stop screw. When the throttle is opened, it is running ungrounded.
If it runs better with the choke on for the first few minutes, it sounds lean.
Spark plug tips may tell a story about mixture. The correct spark plugs should be Champion Copper RN14YC.
You may not be able to post pictures for a couple of days when first becoming a member.
 

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A 1980 LeBaron with a 318 would not have had Lean Burn. For whatever reason, 1979 had it and 1981 had it, but the 1980 318 did not.

Also the 318 was offered with a 4bbl in 1980, so it’s either got the 2 bbl BBD carb above (most likely) or the 4 bbl Thermoquad carb.
 

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If you want a replacement carb, the best one in my experience would be for a 73 year model. Last year before they were calibrated for lower power and also before they were set rich to feed catalytic converters. I've done the Lean Burn delete on the same car you've got, converting it back to prior electronic ignition.
You want to get a four pin amplifier, not a 5 pin. 5 pin uses the notorious dual ballast resistor which is prone to die with no warning just like a light bulb burning out. Direct swap, just plug the four pin in, no change to harness. 80-81 trucks used the four pin if I recall correctly so you can look for that part.

The bogging is most likely carburetor or a vacuum leak.
 

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Discussion Starter · #11 ·
If you want a replacement carb, the best one in my experience would be for a 73 year model. Last year before they were calibrated for lower power and also before they were set rich to feed catalytic converters. I've done the Lean Burn delete on the same car you've got, converting it back to prior electronic ignition.
You want to get a four pin amplifier, not a 5 pin. 5 pin uses the notorious dual ballast resistor which is prone to die with no warning just like a light bulb burning out. Direct swap, just plug the four pin in, no change to harness. 80-81 trucks used the four pin if I recall correctly so you can look for that part.

The bogging is most likely carburetor or a vacuum leak.
Great, that's the information I was looking for on the carb (73 carb), I assume the bolt pattern is the same for all 318's. The amplifier is already a 4 pin unit, with a single ballast resistor. It was running hot (the amplifier) and caused the potting compound to run down the inner fender. I sub'd in a 5 pin unit today, and all seems to be running well except for gunning the car now causes it to almost stall (the 5 pin module does not heat up at all). I'm going to test the power transistor in the 4 pin unit, and see if it's flakey.
Thanks every one for your help. It may be several days before I can test it further.
 

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If it's an Autolite of any model, it definitely is not the right carburetor. I did a search on the number and basically came up with everything Ford from early 60s, and from a 289 to a 390, so this is a very good culprit to work on replacing.
 

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A Motorcraft (Autolite) carb can be used to replace the Carter BBD. It’s a somewhat common modification as the BBD can suffer from wear and other issues.

Regardless, either this carb likely needs rebuilt or find a BBD and use it.
 

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Warning: any replacement carb you install must be adjusted from scratch. My experience with rebuilt carbs has been that they are just as sloppily assembled as new ones. Get the FSM and go through every adjustment. Set it up EXACTLY right, not just close or in the ball park. There's been no real margin for error since maybe 1970 when jetting first got very lean to meet emission rules.
 

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And about the only way to set up the jetting properly is to have a tailpipe sniff probe to make sure she is not rich or lean. If the carb hasn't been rebuilt, the accelerator pump can be bad, which always causes a bog during acceleration. If you say the carb is an acceptable replacement, as I found, there is a pretty wide variety of engine sizes the Autolite was used on, so jetting could be way off.
 

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First of all make sure your ignition is working correctly!
- change the cheap things like plugs, wire , cap and rotor.
- check timing and advance, beware of that you may have one of these very long advancing emmissions distributors. So check how much fully advanced is with vac disconnected. Some were around 33- 34 deg btdc is usually ok on a LA Engine.

Omce youre shure that ign is working good, then you start fiddling with the carb..
 

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The distributor vacuum advance is being fed ported vacuum (vacuum above idle and at cruise) and not intake manifold vacuum, correct?
A dealer removing the Lean Burn system and converting it to a conventional electronic ignition would have been unlawful (Federal rap).
It would also open Pandora's box with likely mis-matched and out-of-calibration fuel and ignition components.
It does sound lean. The mixture adjustment screws at the base of the carburetor are only for idle mixture and will not affect cruise or full throttle operation.
Does the car have a catalytic converter and is the internal element intact?
 

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Again, there is a very good chance this car NEVER had Lean Burn. Most all 1980 318's had the standard electronic ignition - especially the 318-2 federal emission version. Can't speak for the California or high altitude versions.
Therefore the original carb should have a vacuum advance port and the original distributor would have a vacuum advance.

1980 is a very unusual year, with Lean Burn appearing on 1979 and 1981 318s, but not on 1980. I know, I've owned a few of them.
 
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