Re: 1983 Lean Burn
[Re: Redbaron314]
#2413793
12/05/17 08:18 PM
12/05/17 08:18 PM
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Joined: Jan 2003
Posts: 1,760 Windsor, ON, Canada
Diplomat360
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,760
Windsor, ON, Canada
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Man, that's a tough one...it's been years now since I've worked with the LB stuff, but with the car parked (shift selector in P or N) and timing light hooked up, what happens to the timing when you take it off idle???
The LB computer is programmed to control the timing once the carb comes off idle setting. I am thinking of this simple test as a way to at least determine if the LB computer is the problem, or maybe something else?
If the timing jumps (could advance, or it could retard) then the LB box is probably not the culprit, because the change in timing would indicate the LB ECU is reacting to the change...mind you, it could of course be reacting incorrectly...grrhh....
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Re: 1983 Lean Burn
[Re: Redbaron314]
#2413796
12/05/17 08:22 PM
12/05/17 08:22 PM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
About to go away
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About to go away
Joined: Sep 2007
Posts: 14,889
up yours
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Sounds like the accelerator pump in the carb is bad. I'd check that before I got all worked up about the LB.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: 1983 Lean Burn
[Re: Redbaron314]
#2413824
12/05/17 09:05 PM
12/05/17 09:05 PM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
About to go away
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About to go away
Joined: Sep 2007
Posts: 14,889
up yours
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There is no kit, per se. You replace the carb with a non-lean burn one and put an electronic ignition conversion kit in http://www.manciniracing.com/ma27331834033.html
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: 1983 Lean Burn
[Re: Supercuda]
#2413830
12/05/17 09:15 PM
12/05/17 09:15 PM
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Joined: May 2004
Posts: 588 Courtenay, B.C.
DarrenS
mopar
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mopar
Joined: May 2004
Posts: 588
Courtenay, B.C.
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Sounds like the accelerator pump in the carb is bad. I'd check that before I got all worked up about the LB. I'd agree not to get worked up. Most problems I've had with lb cars have been attributable to the standard stuff (vacuum leaks and carb or ignition problems). I would not just swap it all out unless you wanted to start upgrading everything for performance...
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Re: 1983 Lean Burn
[Re: DarrenS]
#2413835
12/05/17 09:30 PM
12/05/17 09:30 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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What Supercuda & Darren said, check the squirt for immediate tip in/quantity then if good I would search for a vac leak.
live every 24 hour block of time like it's your last day on earth
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Re: 1983 Lean Burn
[Re: Redbaron314]
#2416183
12/10/17 02:24 PM
12/10/17 02:24 PM
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Joined: Jan 2003
Posts: 3,704 MICHIGAN
DynoDave
master
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master
Joined: Jan 2003
Posts: 3,704
MICHIGAN
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Certainly have to check the basics, like accelerator pump shot, before moving on.
I'm not as familiar with the later system...have worked on '77 and '78 models. But they used a ground wire on the throttle stop so the system knows when the throttle is closed. Also, they have a throttle position transducer (TPS in modern terms). If accelerator pump action seems good, checking the condition of these may help. The computer can't react if it doesn't know the throttle is moving.
If you have a set of '83 factory service manuals, they're sure to be of help. If you don't have a set, and get stuck, let me know. I have a set, and can check through the diagnostics for you, post some photos of those pages, etc.
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Re: 1983 Lean Burn
[Re: Redbaron314]
#2417165
12/12/17 02:52 AM
12/12/17 02:52 AM
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Joined: Jan 2003
Posts: 1,760 Windsor, ON, Canada
Diplomat360
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,760
Windsor, ON, Canada
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Given the OP's comment below: ...it has a Complete tune up recently done, timing verified with a timing light, new fuel filter and pump... ...I honestly can not even imagine such a tune-up not covering something as basic as Carb 101: is the accel pump working? is it providing good enough volume of fuel? etc, etc. But anyways...so my feedback is based on personal experience with different LB computers, specifically the timing differences programmed in on a 2 bbl vs 4 bbl setup. In my case (many many years ago, so memory is a little faint) I picked up a 4 bbl setup at a swap meet. Given that I just installed my first 4 bbl carb (Carter TQ) I thought this would have been a great improvement. Well, something was probably wrong with that LB module because that very night I took the car out I had a massive backfire after a WOT run which literally blew off the muffler...LOL, yeah, impressed all my buddies, but gave me a busted exhaust pipe. Sooo...off I went digging into the specs and all that, eventually found out that the 4 bbl unit did have a different timing amount (initial, off-throttle and vac-advance) that would have been the right move for my setup had it worked correctly. Who's to tell if I simply missed an additional input of some sorts though...I studied that darn hook-ups, but was just cutting my "teeth" on LB era Mopars at the same time. Anyways, like I said, for what it's worth given my hands-on experience.
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