Choking in D gearbox related ?

Transmissions and Rear Ends

  1. Toro67

    Toro67 Well-Known Member

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    Hi over there.

    My 79 LeBaron with a 904 + overdrive has a problem accelerating when warm and in D. It can crawl along in a little over idle speed, but it dies when I try to accelerate any harder. There are no problems revving in P.
    All the lean-burn stuff has been removed and replaced with a conventional electronic ignition, and the carb has just been replaced with a new Carter BBD.
    The car is right now with my mechanic, who has looked around on the web, and found that maybe the fault could be in the gearbox...
    I think this forum is the best source of Mopar knowledge in the world, so I ask you:
    Can the 904 have a fault that "chokes" the engine in D, but does not appear in P ?

    Thanks in advance :)
     
  2. Mikes5thAve

    Mikes5thAve Well-Known Member

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    Has it always done it or have issues like that? It could easily be a problem with the transmission, it could also be a carb related problem with the engine under load vs being in park.
    904 doesn't have over drive unless someone installed a gear vendors unit or similar. It does have lockup which some people say can feel like overdrive when it engages.
     
  3. Toro67

    Toro67 Well-Known Member

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    Sorry I meant lockup not overdrive - got the two confused.
    No the problem started last fall after it had driven all season with no problems. I discovered that the ballast resistor was cracked at the end of the season, and thought that it might have damaged the coil, but it has been changed with no change.
     
  4. AJ/FormS

    AJ/FormS Well-Known Member

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    So it drove fine all season, then,
    just like that, you had this problem? and you made no changes just before it took a dump, right?
    and no changes after; as in the engine has the same carb and distrubutor in it today that it had last season when it was running fine.... right?
     
  5. AJ/FormS

    AJ/FormS Well-Known Member

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    What is your definition of choke? and
    What makes you think the engine is being choked?

    Does it behave the same in manual low?

    If yes, then get the rear wheels off the ground and try it again. Lets rule out a seized stator inside the TC.
     
  6. Toro67

    Toro67 Well-Known Member

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    Correct. It had been running all Summer with the lean-burn removed and a completely new ignition kit from Summit. In September when I wanted to take it for a last drive, it started having this fault. It started as small engine cut-outs after about 5 miles and it got rapidly worse when I kept driving. When I headed for home it would only drive with a very light foot on the gas. If I tried to speed up more or quicker it would die.
    I posted the problem on this board and some said it could be weak spark. At about the same time I found the cracked ballast resistor, so I thought maybe the coil was the problem. Then came Winter and I haven´t tested the new coil until now. I took it out for a test recently, and the result was depressing. It dies if you try to accelerate normally; it will only crawl along at 20-30 mi tops. I then concluded that the coil was not the issue.
    During the Winter I also found the new Carb with the help of BudW from this forum. I decided to have my mechanic (he deals in old US cars, so he should know his way around) install it, which he did, and the result was the same.... However at the same time he heard a rattling from the exhaust and took the muffler off (it only has 1). It sounds like its filled with rusty bits, so maybe that could cause the problem ? However, it has always been able to start and easily rev in P. If the rusty bits have blocked the exhaust, wouldn´t the problem also occur in P ?
    Right now he is still waiting for a new muffler, so he has not been able to test it yet.
    Then he started looking for other possible faults, and came up with the gearbox and the way its controlled electrically. That´s why I posted this in the gearbox forum.
    I have never had any problems with the gearbox; it always shifted nice and smooth when the car was running. But can it develop a fault that slows the car down in D like this ?
     
  7. Toro67

    Toro67 Well-Known Member

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    Choke is my way to describe that it dies when you try accelerate normally. (English is not my native language).
    I haven´t tested it i manual low yet.
     
  8. Toro67

    Toro67 Well-Known Member

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    A seized stator inside the TC - What is that ?
     
  9. XfbodyX

    XfbodyX Well-Known Member

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    You ever consider the fuel pump is failing? Does it still have a cat converter?
     
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  10. Toro67

    Toro67 Well-Known Member

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    The fuel pump and filter is new. The cat was removed in the beginnig when I had lean-burn problems.
     
  11. XfbodyX

    XfbodyX Well-Known Member

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    Have you checked your advance plate in the distributor? I see its new but still.

    If you pull the cap and apply vac to the advance plate be sure its not mis functioning and grounding or I think it could increase or decrease the reluctor gap? I know what im thinking but not sure if I wrote it right.

    Or just unplug the advance and see if it drives, but that sounds too easy.

    And no stuck metering rod in the carb? Or acc pump jacked up?
     
  12. Toro67

    Toro67 Well-Known Member

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    I hope my mechanic has checked the advance when he put the new carb on, but I will mention it to him.
     
  13. Mr C

    Mr C Well-Known Member

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    Can you show us a picture of your engine compartment? It helps to know what we're dealing with...ie if the EGR is still there etc.
     
  14. Duke5A

    Duke5A Well-Known Member

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    Sounds like vapor lock to be honest. The freely revs in park, but progressively gets more choked the more gas you give it when driving down the road until it eventually comes to a stop is indicative of it.

    What type of fuel filter you got on the car? The kind that has an in on the top, an out on the bottom and another hose coming out the side? The hose coming out the side is for the return back to the tank. Take that hose, kink it and place a tie-wrap on it to keep it kinked. Take it out for a drive and report back to us.
     
  15. BudW

    BudW Moderator Staff Member

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    The first thing that comes to my mind is a stopped up catalytic converter(s). The converters are currently stopped up on my Fifth Ave and it is doing the same thing as you describe.
    BudW
     
  16. Davesmopar

    Davesmopar Well-Known Member

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    I agree with BudW.....

    That is exactly what a clogged catalytic converter does...... and the "rocks" in the muffler are the broken catalyst/honeycombs existing the converter and collecting in the muffler......

    Be careful driving it now, a converter can catch the carpet on fire from how hot it can get, or grass....
     
  17. Davesmopar

    Davesmopar Well-Known Member

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    Nevermind I think you said you removed the converter..... lol
     
  18. Toro67

    Toro67 Well-Known Member

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    The EGR has been removed along with all other lean-burn stuff except for the vapor canister.
     
  19. Toro67

    Toro67 Well-Known Member

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    Hi Bud. Good of you to chip in :) The cat was removed as one of the first things in the search for the first wave of problems coming from the lean-burn system. However it may have already filled up the muffler. My mechanic has taken it off the car and it rattles like a set of maracas :)
    A new muffler has arrived, but not been installed yet. When it is on, he can test it again. If this doesn´t work, next thing to check is the stator in the TC. (he did some digging around on the web and came up with that possibility).
     
  20. Toro67

    Toro67 Well-Known Member

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    The filter is new, but otherwise exactly as you describe. I will mention it to my mechanic so he tries that also when testing.