What year is this?

[kmccabe56]

Hi Stan

I know you're the wrong guy to ask this, knowing how you feel about Lean Burn, but since you posted the picture of the ATC diagnostic unit, has anybody every tried one of the Chrysler Lean Burn diagnostic units to see if it can actually find a problem?

(Yeah, I've hacked the thread.)

 

[commando1]

Hi, Kev.
The Lean Burn System was a marvelous piece of engineering when it was introduced. Basically it was a big clunky thing to what almost ever vehicle has now in their engine management system black box. It worked great............. for about six months. A year tops. Durability was absolutely horrid. Chrysler, after replacing a gazillion units under warranty finally threw in the towel and authorized conversion kits when the LB failed. If you study the LB tech manuals you really get an appreciation of it of how good it was.
That said, I seriously doubt that there are many cars left on the road today with its original LB system that runs properly. If you do have a great running LB system, it's damn good. Leave it. If you have a vehicle that has the LB removed when it originally had it, there is no carb out of the box where it will run right on the original but otherwise unmodified engine. 'Run right" is very subjective. Most people can throw an aftermarket carb on and be happy with it. I need it to idle and accelerate as if it had FI. But that's just me so out of the box carbs have never felt right to me. Sending out my Thermoquad for a restoration (not a rebuild. Re$toration), metering rods, and a few sets of jets was still cheaper than a new intake and carb. Unfortunately TQ's are scary SOB's.
In summary, if it's working. Leave it. It's a good engine management system, albeit ancient.
If it's not working, a simple aftermarket intake & carb works fine. I recommend a low rise dual plane intake and a 750 cfm carb with electric choke and vacuum secondaries. Don't forget to buy the Mopar throttle adaptors. With the dual plane, the air cleaner wing nut just barely clears the hood. As far as an LB diagnostic unit, I've never seen one. An ill running LB engine can only be fixed by a new computer anyway (the bread box attached to the air cleaner) so what's the point? Even Chrysler didn't repair them. Just replaced tham and finally ditched the whole system.

 

[Mr C]

I concur with Commando on LB with only a couple of added comment:
1) In my experience it either worked out of the box or didn't...I remember my Dad having fits with the LB on his new 76 T&C and I've seen cars 20+ years later with still fuctioning LB. No rhyme or reason there, probably why Mopar eventually gave up on LB.

2) LB seemed better/ lasted longer on the LA/ slant 6s than the B/ RB engines...probably due to less heat on the brain box. On the B/RB cars, the computer sits right over the drivers side rocker/ exhaust manifold with little clearance. I can't imagine that was good for thelongevity of the electronics.

Otherwise, I couldn't have said it better.

 

[cm23uoc]

Location should have a lot to do with life expectancy of these parts. We have a couple models with f.i. that had their brains inside the pass.compartment and these are rarely affected, mostly sensors etc. in the engine compartment.

 

[kmccabe56]

Load levelling debuted on the Imperial in 75 and was one of the Imperial things carried on after the badge re-engineering, unkie the rear discs.
Are you sure its an 8.25? is your NYB one of the small block cars? Only C bodies that I've ever seen with the smaller diffs were the small block cars....rare in an NYB.

Last fall I parted a '78. It had a 400, H/D suspension and an 8.25 rear axle. I was astounded to see it there, but I got the broadcast sheet for the car, and it confirmed it. What was really bizarre was that the broadcast sheet coded a straight heater, but the car had the base a/c in it.

 

[kmccabe56]

I've thought about that...only two problems:

1) Finding one since it seems that 90% of formals came with Auto temp.
2) Finding one since it seems that 90% of formals came with Auto temp.

I know its only really one problem, but I thought it was so important that I'd mention it twice.

I think there's another problem. Having a NYB with NO a/c!!!! The first '78 I parted out was ORDERED with no a/c.

 

[commando1]

Northwest U.S. or Canadian car I bet!

 

[70NPORT]

In the end , it all doesn't matter.

I am a "Formal" ignorant fool, so keep that in mind whence I pose this to you (I gotta know). Who was trying to copy who those years? Chrysler Imperial vs. Lincoln Town Car. This is not to tip over a bee's nest. Its academic, I truly want to know, the resemblances between the two are uncanny. Is there a story?

 

[1978 NYB]

I am a "Formal" ignorant fool, so keep that in mind whence I pose this to you (I gotta know). Who was trying to copy who those years? Chrysler Imperial vs. Lincoln Town Car. This is not to tip over a bee's nest. Its academic, I truly want to know, the resemblances between the two are uncanny. Is there a story?

The formal fronts are similar to a Lincoln and the rear taillights are similar to the Cadillac.

 

[1978 NYB]

Last fall I parted a '78. It had a 400, H/D suspension and an 8.25 rear axle. I was astounded to see it there, but I got the broadcast sheet for the car, and it confirmed it. What was really bizarre was that the broadcast sheet coded a straight heater, but the car had the base a/c in it.

I think there's another problem. Having a NYB with NO a/c!!!! The first '78 I parted out was ORDERED with no a/c.

My 78 NYB has a 400, not a Auto Temp II, has load leveling suspension and a 8.25 axle. The 400 was the base motor for 1978 NYB's, all that I've seen had 8.25 axle. All the 78 NYB's with the optional 440 that I seen all had 9.25 axles.

A formal NYB without A/C is very interesting. Would you have any pictures by chance?

 

[polara71]

I am a "Formal" ignorant fool,

Two of us .........

 

[70NPORT]

The formal fronts are similar to a Lincoln and the rear taillights are similar to the Cadillac.

Yes, they are. But who conceived what first. Is there any story behind that....or just a "quirk" of god, which I doubt.