1. MoparDan

    MoparDan Well-Known Member

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    Even after having the carburetor professionally rebuilt the engine still often stalls at lights with the transmission in gear, and always stalls if the headlights are on, I installed new spark plugs a week ago and now the engine usually idles smooth for a few seconds before becoming very rough and quickly stalls, I did notice afterwards that my spark plug gapper looks to have some wear on it where the . 035 is, I've had it for years and have gapped many spark plugs for 318 engines, so I have hunch that's part of the problem, but then why does the engine now idle good for a few seconds before getting rough? if I gapped the plugs wrong wouldn't the idle instantly be rough? Is the computer causing all this? I've always wanted the computer removed but always get the same response: "technically its an emission device..." all I want is for the engine to not keep stalling, any advice? car is a 1985 Gran Fury with about 203,500 miles and I should add that when the engine stalls it always starts right back up as soon as I turn the key
     
  2. AJ/FormS

    AJ/FormS Well-Known Member

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    Check/adjust the idle rpm, then check your charging system output; I'm not suspecting it, but am suspecting the rpm is low.
    If good, check the voltage at the coil with the engine idling; comparing in Neutral, to in Drive and stalling with headlights on; almost obviously you will need a helper.
    Then; as to the cause of low-idle speed,in order of likelihood,
    I suspect ;
    1) maybe your idle speed is just set too low; the question is why; could be
    2) just set too slow,or maybe the throttle kicker died, or junk in the low-speed circuits
    3) EGR valve or system is malfunctioning
    4) vacuum leaks
    5) incorrect ignition base-timing
    6) fuel quality, freshness, contaminated, low fuel-level in float bowl, or aerated
    7) possibly retarded camshaft due to stretched or jumped chain, jumping around
    8) uneven or poor compression; probably a head problem;such as broken valve springs, or insufficient spring pressure, carbon on the valves
    9) plugged exhaust
    10) bad tank venting system
    11) bad convertor

    It's not the plug-gaps;a good coil will fire .025 to .050, so a few thou either side of .035 is just fine..But pull a couple out and make sure they are not carbon-fouled, which I doubt they are..

    The Computer is rarely a problem
     
    Last edited: Dec 17, 2019
  3. BudW

    BudW Moderator Staff Member

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    How much has vehicle been driven in last couple of years?
    Do you know much history about the vehicle?

    There could be one of several issues or even a combination of reasons – but for now, I will assume the carburetor is OK.

    My ’86 Fifth Ave has three catalytic converters. One under each exhaust manifold and a larger one by the rear of transmission. The cats on my car are about 50% (or so) stopped up and part of reason I haven’t been driving the car that much lately. I found a nice used “Y” pipe from an ’80 Aspen (you might have heard to as referred to as the Canadian “Y” pipe – which is mostly found in cars bound for Canada) which did not have the two front (smaller) cats on them.
    I need to replace the rest of exhaust system on car so was going to replace the entire exhaust system on my Fifth at same time as replacing the rear differential (and get rid of those 2.2 ratio gears - which is like dragging a boat anchor) – which will be in the spring.

    Another possible reason is carburetor is running out of fuel because of fuel pump, rusty fuel lines and/or cracked fuel hoses.
    You did replace the fuel filter along with the carburetor?

    I suspect the timing chain is well past wore out. The way to check is to remove the distributor cap. Get a 1-1/4” socket and a ratchet (or breaker bar) and put on the crankshaft hub.
    First, turn the crankshaft about 1/8th of a turn (either direction), and stop.
    Next, view the distributer rotor and watch it as you rotate the crankshaft the other direction (having a helper helps – if helper can watch both at same time).
    It should move instantly along with the crankshaft. If it doesn’t – the timing chain has excessive wear. These cars came with plastic toothed aluminum timing gears which were cheap to manufacture and made engine quieter – but just don’t last long. With 200k miles on car, I suspect this is the second timing chain set for this far. Timing chain wear will cause ignition timing to jump around more than box with a thousand crickets in it – which can contribute to this. Normally the ignition timing should be dead on, when looking through a timing light.

    The EGR valve is a possible concern. The EGR system is not to engage until you are cruising and engine is hot. If something is wrong and system is opening before, it will kill the engine at idle. For testing, you can disable it and see if problem goes away, then using a hand-held vacuum pump you can open the valve when engine is running to check for idle change. Sometimes carbon deposits can cause an EGR valve to stick in the open position. Sometimes carbon deposits can clog the entire EGR passageways, so the valve works but isn’t actually doing anything.
    Note: it is a ROYAL PAIN to clean out those EGR passageways for those who reside in an emissions state and must have a functioning EGR system.

    Some vacuum brake boosters can go bad over time and cause an excessive vacuum leak when brake petal is pushed. The brakes may work fine but when you push on brakes when engine is not yet hot, it can kill the engine. A good test is to turn off car and wait a while (even better, before you start the car for the day). Push on brake petal and it should have power assist. Release and do it again. This time it will go down but will be more difficult. It should even have a small bit of assist on third attempt. The brake booster should hold vacuum for a long time (years). If it doesn’t hold enough vacuum to stop car once if engine is not running, then it needs to be replaced.

    Fuel tank venting is a possibility. Remove or loosen the gas cap and see if that makes any difference. Retighten the gas cap and again, see if that makes any difference. The filter for charcoal canister might be stopped up and/or metal line going between it and fuel tank might be kinked (or rusted) and causing a major restriction.

    I could go on and on, but this should keep you busy a few minutes while I go home.
    BudW
     
  4. Camtron

    Camtron Well-Known Member

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    I’d be curious of your timing and carb tune. When I first drove my car home, it was a 2bbl with a lean burn delete. The headlights would drop rpm pretty good and they’d be dim and pulsate until I put a load on the engine, car would shake and hesitate and die at intersections.
    Got it home, hooked up timing light and vacuum gauge and proceeded to advance the timing to 12 degrees at idle, while in drive, with the parking brake on and wheels chocked. Then I adjusted the carb and throttle until I had 18” of manifold vacuum and the car idled at 550rpm.
    Now the car ran great, BUT, headlights were still dim and pulsated but, didn’t drop rpm anymore.
    Now, at this time, I grew suspect of my alternator, it seemed old and was heavily oxidized and corroded; May have been factory. I got a replacement and, my headlights were now bright at idle...but, still pulsed with the idle of the engine...I then replaced the, old, corroded, voltage regulator and BOOM, no more pulsating headlights.

    My case anyway, it could be a number/combination of things as others have said. The headlights stalling it out consistently stood out to me.
     
    Last edited: Dec 20, 2019
  5. BudW

    BudW Moderator Staff Member

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    Chrysler alternators have three different legs to them, each leg produces 1/3rd of the electrical power, in waves. When one leg goes out (bad diode) or when two legs go out (bad diodes) then alternator will run unbalanced and will place an inconsistent load on the engine (especially when two legs are down).
    It is normal for lights to be dimmer at idle than at 1200 RPM – but without knowing what shape the alternator is in, it might be a contributing factor.

    Quality of gasoline (and/or fuel contamination) can be a factor. Carbureted engines (any brand, even computer-controlled carburetors) can’t compensate for Ethanol (E10).
    A person must use 100% or you will have problems (cold start, cold drivability, lack of power and so on and on and on and on …).

    If the computer (on air cleaner) is attached and working – it will not do a person any good to adjust the timing for you will get into a tug of war with the computer (computer can be a stubborn mule, in this case). A loose timing chain can/will make ignition timing jump even more so sense computer is controlling the next spark advance and not the one just measured.

    The list that @AJ/FormS mentions in post # 2 is a very good list – but not sure your carburetor has an electric solenoid attached to pump up the idle. Some do, but I suspect yours does not.

    The spark plug gap won’t be an issue. Unrelated, I always add 0.005” to the gap of spark plugs – even for my lawnmower.
    BudW
     
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  6. MoparDan

    MoparDan Well-Known Member

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    Thanks for all the replys I'll start here: I know quite a bit of her history: Owner #1 1985-1994 he was in his late 70s a few years later had a stroke that left him paralyzed on one side so he really didn't drive much only driving 19k miles in those nine years, while all the original dealer paperwork (window sticker ect) still remained there were no service records other then a new battery in 1993. Owner #2 1994-2011 grandson of owner #1 only drove her on the weekends in spring and summer, he kept track of everything so there were plenty of receipts and a notebook full of service records, I bought her from him and there were only 88k pretty well documented miles. I've kept track of everything since day 1 but unfortunately most of the record were lost in an "accidental" hotel fire about a year and half ago everything before May 4, 2015, though I have found things done before that by looking at various old posts on forums and even facebook
     
  7. MoparDan

    MoparDan Well-Known Member

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    The timing chain was replaced on April 30, 2015 (exact mileage unknown but likely 163K-164K miles) so does that rule out timing?
     
  8. MoparDan

    MoparDan Well-Known Member

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    Now the charging system: the voltage regulator was last replaced on December 9, 2018 so its not very old, the battery was replaced on January 26, 2017 and has a 6 year warranty, the alternator was replaced March 7, 2016 about 26k miles ago, but they installed an alt. for an a/c car (with the two belts) and this is a no a/c car (one belt to the alt.) and the belt does not line up all that well and is believed to be the cause of the water pump failing after only three years...the mechanic who installed it said it would be ok, but everything this mechanic "fixed" has had to be replaced along with other parts he broke in the process...the alternator is the only thing he installed that's still in (never trust a mechanic in New Haven CT...) however from day one (2011) I've noticed that the interior lights-especially the gauges always got a little dim when stopped in gear, but they seem to get dimmer now. I've had the charging system checked many times over the years and it always checks out fine-it was last checked this past July. The headlights seem somewhat dim lately though they are several years old. If you look in the picture you can see the belt is at a bit of an angle

    IMG_20191223_153201.jpg
     
    Last edited: Dec 23, 2019
  9. MoparDan

    MoparDan Well-Known Member

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    To answer your first question yes, we replaced the fuel filter along with the fuel pump when the carburetor was rebuilt.

    I did the brake test and yes it does what its supposed to do

    The gas cap saw stolen a few months ago (but they didn't siphon gas for some reason) it was almost two weeks before I had money for a new gas cap, I saw no difference with or without the gas cap. the charcoal canister was capped off when carb was rebuilt if that means anything
     
    Last edited: Dec 23, 2019
  10. MoparDan

    MoparDan Well-Known Member

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    I took one of the spark plugs out a few days ago it looks almost as bad as the old one. old plug is the top picture new plug is the bottom one this is after only 361 miles

    IMG_20191220_170745.jpg

    IMG_20191220_162831.jpg
     
    Last edited: Dec 23, 2019
  11. BudW

    BudW Moderator Staff Member

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    Wow, a no A/C car . . . In Florida.

    The spark plug pictures are not the best quality – but do look fine for less than 1k miles.
    What are they gapped at?

    This is a picture of my (mostly stock) factory no A/C ’77 318 wagon. The water pump pulley is different (you have extra pulley to P/S and to A.I.R. pump, whereas my P/S pump goes straight to Crank (a difference in the year made, only).
    20180622_154607r.jpg
    IMG_20191223_153201.jpg
    The drive belt angle is not that bad (seen may far worse).
    The only thing I see off is what appears to be spacers on the engine side alternator bracket (red arrow).

    There should be a metal spacer and no washers.
    This is a picture of a no A/C alternator bracket setup:
    SB Alternator brackets noAC.jpg
    The actual order on the long bolt is:
    Flat washer, front-most alternator ear, triangle bracket, long spacer, rear-most alternator ear, short spacer and cylinder head (which is not the order as pictured, above).

    When pulling out the bolt, be sure to have fingers on both sides of short spacer or IT WILL FALL. Same on reassembly, insert bolt to where it almost peeks out of the rear alternator bracket. Place the short spacer in and push in the bolt to capture it.

    A/C cars have a bit more tension on the bracket, so the adjustable bracket has an extra leg that goes to engine mount for additional strength.
    SB Alternator bracket AC.jpg
    The alternator bracket with A/C, will work for no A/C cars, but not the other way around.


    I am curious on what voltage is at the battery terminals when car is running at idle and at say 1500 RPM.
    BudW

    Edit, can you take a picture of your charcoal canister, please?
     
  12. MoparDan

    MoparDan Well-Known Member

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    Here's the canister
     
  13. MoparDan

    MoparDan Well-Known Member

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    Let's try that again

    IMG_20200102_152321.jpg
     
  14. MoparDan

    MoparDan Well-Known Member

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    The spacer your talking about has been MIA since the alternator was replaced in New Haven, notice the shiny new bolt on the lower part of the bracket? Well after moving to Florida they had take the alternator off when they replaced the water pump and found the factory bolt had been stripped along with some other parts
     
  15. MoparDan

    MoparDan Well-Known Member

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    The spark plugs are gapped (around) .035
     
  16. MoparDan

    MoparDan Well-Known Member

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    It wasn't until moving to Florida that I learned the value of a/c...:D and twice this car has been my home... I do love that left air vent (wish the right side had one) and it is easier to reach the spark plugs without all the a/c stuff in the way.
     
  17. BudW

    BudW Moderator Staff Member

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    This is what you need to stabilize the alternator and to get belt spacing/alignment correct: 70-78 Mopar A B C E Body Cuda 318 340 360 Alternator OEM Bolt & Spacer Set | eBay .
    SB Alternator bolt set.jpg
    If you were to get this package, I would shoot a bit of paint over the spacers first. The bolt and washer should be coated but spacers are bare steel.


    The large hose from charcoal canister (yellow arrow, below). Where does it lead to? Can you take picture(s) of that hose and the other hoses going to the front and rear of carburetor? It will help to disconnect the air cleaner and tilt up when taking pictures (maybe).
    20200102_152321d.jpg

    According to my ’86 FSM (Factory Service Manual) and yes I know it is a year newer than your car (I don’t have access to a ’85 FSM). It shows a total of four hoses going to the charcoal canister. Two are vapor hoses (fuel tank and carburetor vapors). The other two are vacuum hoses (one is for a valve).
    20200121_130108.jpg

    20200121_130108c.jpg
    This is a closeup of the vacuum diagram. The hose size shown is not something to go by. The two smaller vacuum hoses are normal sized. The two larger hoses are mentioned in paragraph above. Of the two smaller hoses, one has engine vacuum when engine is running – which is what is used to purge the fuel vapors from the charcoal canister.

    The other hose uses a vacuum temperature switch on intake. It controls a valve on top of (on the side, in your case) of the charcoal canister that stops the vacuum from canister when engine is cold. The other port from the coolant switch goes to the vacuum tree at back of intake. I can see the coolant valve on your intake is currently disconnected (red circle).
    20191223_153201b.jpg
    Without vacuum from the switch the vacuum hose from carburetor will not suck those fuel vapors from the charcoal canister – so I suspect that canister is full of fuel vapors or stopped up – which is causing your stalling concern (fuel tank can’t vent).

    This picture from my ’77 shows the larger fuel vapor hose from carburetor (white arrow, below). The smaller vacuum hose is underneath and is not shown. I think the ’85 vacuum hoses are more towards the center of valve cover before they cross to the inner fender (maybe).
    20180622_154607r.jpg


    Is your car a factory no-A/C car?

    I would agree that not having A/C does make working on the car much easier. Even having all the emission items out of the way makes it much easier as well – but that can’t be done in most areas (in some states, the emission cop’s seams to lurk everywhere).

    If you are considering going back to A/C (if a factory A/C car) or converting a no-A/C car to A/C, it might best to start a different thread for that.
    BudW
     
  18. BudW

    BudW Moderator Staff Member

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    My ’86 has factory A/C. Factory A/C cars do get that Left side underdash outside air vent – which I agree is very nice. The older F/M bodies without factory A/C did get a Right side underdash outside air vent but the newer M/J bodies did not.
    20180616_135218r.jpg
    The Left side underdash on my '77 Wagon

    20180616_135314r.jpg
    The right side vent (part of heater case). The knob for it is just off of the picture on Right side.

    I just picked up a Left underdash vent to install into my ’86 Fifth Ave – because I like it so much. It will require some modifications to the firewall/cowl to make it fit, though.
    BudW
     
  19. MoparDan

    MoparDan Well-Known Member

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    Car is a factory no a/c car (people have told this car is amazing rare because of it) I just wish it had the right side vent like your wagon does. converting to a/c is temping but not in the budget right now... anyways I do know the charcoal canister was capped off when the carb was rebuilt. I'll still take pictures of everything and next time I have wifi I'll be posting pictures, I'll also be looking in to getting those alternator bolts sometime in the near future
     
  20. BudW

    BudW Moderator Staff Member

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    The no-A/C cars, the heater case and firewall changed in ’80 (I think) and the ’80 and up heater case design also changed (no more right side outside vent) – which is a shame.

    You are correct, the newer M-body's without A/C is not that common and rare in the Southern states. My wagon can from up-state New York – so no A/C makes a bit more sense (I guess). Oklahoma is a state where A/C is needed (so what was I thinking when I bought the wagon?).

    I will be converting my wagon to the ’80-89 design factory A/C but I also have other chassis modifications to make as well as the firewall (switch out the current 18” wide for wider 26” wide radiator, changing the trunk pan from round ’76-77 trunk pan to wider ’78 and up version (for larger spare tire, more trunk space and to get rid of the ’76-77 hump style fuel tank), to install frame ties and lastly need to modify floorboard for the 5 (or 6) speed manual transmission install).

    Eagerly waiting for your pictures.
    BudW