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Discussion Starter · #1 ·
I own a 1976 Dodge Royal Monaco Brougham
As a project car and there is a couple problems with it and some I can’t seem to find the answers to.
  1. Shifting linkage is very loose
  2. Idles very rough and stalls
  3. Stalls when shifting gears
  4. Jumps forward after coming to a stop
1976 Dodge Royal Monaco Brougham
Engine: 400 ci 6.2 V8
Has automatic transmission
 

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I’d bet most of the problems are carb related. When was the last time up? What did the spark plugs look like? Has the carb been rebuilt recently (2 or 4 bbl?)? Is the gas fresh? Has the car been sitting?
The shift linkage may have worn bushings, but if it’s the kickdown that’s bad, it needs adjusted or you can burn up the transmission.
 
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I've seen the insides of 45 year old fuel tanks. 😳
If it isn't in danger of perforating, it may be boiled out in a hot alkali solution. The sock, lines and fuel pump may need replacement. The carb may be in trouble also.
If the car sat, fresh fuel may have dissolved the crud in the tank and sent it forward.
Evaluate what you have.
 

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I had a good friend whose dad had a similar 1977. After taking it to a local shop and having it tuned up, he was still complaining about it running very rough, and asked me to take a look at it and tune it. Many of the 1976 - 1980 400s (6.6L) had the gawdawful Lean Burn systems. If yours has a spark control box that looks like this, I can tell you that there is not much you can do to "fix" this CLUSTER! It comes with a myriad of miles of vacuum hoses as well, affording plenty of opportunities for vacuum leaks. If you have this type of system, the only real fix is to ditch it, plug up and ditch the miles of hose, and replace the distributor with a good old fashioned earlier gen electronic ignition system.

As for the shift linkage, I'd try to scrounge some better used linkages from a junkyard, and replace any bushings with new.

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I've seen the insides of 45 year old fuel tanks. 😳
If it isn't in danger of perforating, it may be boiled out in a hot alkali solution. The sock, lines and fuel pump may need replacement. The carb may be in trouble also.
If the car sat, fresh fuel may have dissolved the crud in the tank and sent it forward.
Evaluate what you have.
Do you know when they switch to plastic gas tanks?
 

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KOG
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Agree with going to earlier electronic ignition. 1973 model year distributor has about the best advance curve. Get a four pin amplifier so you don't need the double ballast resistor which has a nasty habit of burning out at random. I know the lean burn is supposed to be great when it's working, but I've had bad experiences with three of those. You will have to work out ported vaccum for the advance or also change to an earlier carburetor whihc has ported vacuum..
 

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Lean Burn was so great that it wasn't covered under the emission performance warranty if it flat out failed. We had a special tester for them and the trick was to get it to even attempt to run which allowed us to use the emission warranty. If we couldn't get anything from it, sometimes the tester would give us a valid (for warranty) failure code. If not, the customer was just out of luck.
 

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I've seen the insides of 45 year old fuel tanks. 😳
If it isn't in danger of perforating, it may be boiled out in a hot alkali solution. The sock, lines and fuel pump may need replacement. The carb may be in trouble also.
If the car sat, fresh fuel may have dissolved the crud in the tank and sent it forward.
Evaluate what you have.
I have seen (and worked on) one that had sat for 18 mos with our government's ethanol enriched corrosion inducer. It wasn't pretty. It was a 1967 Mustang, LT1 swapped by the owner of my favorite salvage yard. It had a Camaro pump in it. The inside the tank picture was taken with a bore scope attachment for my cell phone.
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I would not disable the Lean Burn system yet. Your symptoms sound like fuel-related problem.
 

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The Lean Burn system was introduced in 1976, it did not affect the 400-2 engine, only the 400-4. Most Lean Burn problems were still carb related.
 
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Do you know when they switch to plastic gas tanks?
It wasn't during the Royal Monaco’s run.

I have seen (and worked on) one that had sat for 18 mos with our government's ethanol enriched corrosion inducer. It wasn't pretty. It was a 1967 Mustang, LT1 swapped by the owner of my favorite salvage yard. It had a Camaro pump in it. The inside the tank picture was taken with a bore scope attachment for my cell phone.
View attachment 83993 View attachment 83994
Y'know, you're talking about a FIFTY YEAR OLD car. But sure, make it into a political statement.
 

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Plastics fuel tanks were becoming popular in the mid-'90's. Maybe the first was the '93 ZJ?
 

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It wasn't during the Royal Monaco’s run.



Y'know, you're talking about a FIFTY YEAR OLD car. But sure, make it into a political statement.
Gas tank was new 18 months before, but since I didn't specify that, I will accept your remark, albeit wrong about the age of the tank.
 

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B vans had them on the 70s. 36 gallon tank was always plastic.
 
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B vans had them on the 70s. 36 gallon tank was always plastic.
Interesting. I didn't know that. First plastic tank I ever came across was in the 1980s.

Gas tank was new 18 months before, but since I didn't specify that, I will accept your remark, albeit wrong about the age of the tank.
On the Mustang or on the Royal Monaco?

One thing I've learned is even non-ethanol gasoline will congeal into an ugly gel if left in the tank too long.
 

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Dave that was on the Mustang (I actually refer to it as a Chevstang). Pete Medlin, owner of Pete's Custom Auto in Newport News VA built it, it was his last "project" before he passed away in his 80s. I had helped him with the wiring. He had finished it and put it in a shipping container for the winter and as his health had declined, never gotten it back out. When it was taken out for his memorial service at the business, as soon as the battery was connected, smoke came out from behind the cluster. The car sat out in front of the shop area until his son texted me "Have you got room for pop's car?" When I told him yes, he said it would be delivered to me and it was. While I was working on it I swear I could sense Pete looking over my shoulder a few times.
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Discussion Starter · #18 ·
I have tried getting it started sometimes it runs on its own sometimes it will stall out if I let my foot off the gas. I just recently changed the spark plugs out and the valley pan gasket and a while back the starter. I also cleaned out the carb like 4-5 months ago.
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Ugh. Get rid of the Autolites. You would do much better with Champion Copper Plus RJ14YCs.

The old 2-bbl Holleys had issues of bending the float cover up if the air cleaner wingnut was overtightened.
We installed a 'bridge' kit to distribute the pull of the wingnut stud. The stud was originally only threaded into the float cover and easily bent the cover up when tightening the wingnut, creating vacuum leaks.

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