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Discussion Starter · #1 ·
Just drove my new to me 87 Fifth Ave home today. The car idles unevenly, seems like it may be vacuum leak. I’m not familiar with the function of these two units on the firewall. One seem not to have the top vacuum connection. I can see no hanging vacuum line. I did loosen the air cleaner and have a look. Does not seem like the carb has not been serviced in some time. Are the Holley’s hard to rebuild?
 

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It’s part of the EGR system. There are supposed to be uncapped connections on it. There should be a vacuum routing diagram under the hood.
 

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Discussion Starter · #3 ·
I thought from previous models, with simpler units, this might be the case. Thank you!
 

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2017 Charger Pursuit AWD
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EGR solenoid pack. They rarely fail, but the hoses may need attention.

A rough idle can mean one or more problems. Certainly, a carb kit would be #1 on the list, and the 6280 is an easy build.

After that, basic diagnostics -

Fuel
  • replace the fuel filter with the correct part (inlet/outlet/vapor return)
  • check the fuel pump, replace as required
  • check fuel lines, tank, pickup/inlet filter

Air
  • filter
  • cold air duct
  • heated air duct (left exhaust manifold to air cleaner)
  • choke functions

Spark
  • plugs (Champ copper)
  • wires (Echlin)
  • coil (make sure it's correct, no ballast)
  • dizzy, if NG - replace with new not reman
  • test SCC functions, replace with reman if NG

Other
  • check all sensors/switches at their connections (connectors are most common point of failure), most all are still available
  • check EGR function
  • check rubber and plastic vacuum lines, especially PCV and cruise (including the check valve and grommet on the brake booster)
  • check BVV and purge valve functions
  • adjust the throttle and cruise control cables at the carb.
  • adjust lockdown linkage.
  • 2bbl cars had a tendency to carbon up and clog the intake heat crossover port. These are usually cleaned out and returned to service.
  • Correct oil is 10W30, with the "090" Mopar filter. Since the 1985+ 2bbl 318 has hydraulic rollers, they are not as zinc-sensitive as the flat-tappet 4bbl police engine.
  • check alternator/voltage regulator, replace with new, not reman, if NG
  • if battery is in doubt, use AGM
 

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Do you have Lean Burn (spark control) computer still?

Ditch that asap! Swap that problematic carburetor too! That also causes your car to run rough!

When the lean burn&carb is removed the car runs smooooth and you will have a lot more power and better gas mileage!

I cant remember what carburetor to use(I usually put a 4bbl on when removing the lean burn)..

*Vacuum advanced distributor,orange box ecu and replace the carburetor!!
 

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Most lean Burn problems were carb problems, the system on my 88 Gran Fury and 89 Fifth Avenue were completely reliable.
 
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Most lean Burn problems were carb problems, the system on my 88 Gran Fury and 89 Fifth Avenue were completely reliable.
Agree, 1000%.

Proper diagnosis is far more effective than tearing out everything, instead of doing the job right.

The newest of these cars are now 32 years old. Test the connections, check for vacuum leaks, then go after Fuel/Air/Spark.

Regarding the Lean Burn cars - and this is an old, old story - the only way to fix them correctly is to perform a full diagnosis, which is something most younger owners don't know how to do. That info, however, is all in the FSM.
If it can be proven that the SCC is bad, replace it. Except for the 4bbl squads (which were set up for maximum durability), the SCC has a much better advance schedule and curve than you'll get with a regular electronic distributer.

On a street-driven car, there is no power in ignition.
 

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1974 Plymouth Valiant - 2013 Dodge Dart - 2013 Chrysler 300C
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Most older owners didn't know either. But enough people use these today to assure me that a little time and trouble figuring out what's wrong is better than tearing it all out.

Lean Burn never died, though the name was dropped; it morphed into the auto feedback carbs on the 2.2, 2.6, etc. They fixed what was wrong over time, and even added a diagnostic port (1984-85).

I've been told to tear out my electronic ignition, too, and a $3 ballast resistor fixed that problem. Admittedly not everyone (knows) they can replace capacitors.
 
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