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1978 NYBS tech questions

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  • 1978 NYBS tech questions

    I installed a new fuel pump and filter on my '78 NYBS a couple of weeks ago, after the fuel pump died back in May. Obviously, the car hadn't been driven all Summer. I drove it afterwards, and the car drove fine, without problems.

    Forward to today. I was prepping the car for a '78-older car event, where the route is 120 miles long with three stops. Put two new valve cover gaskets on the car, checked my work, and drove to the gas station. The gas gauge barely moved, so gas was a priority! It was running like crap on the way to the gas station. It felt like I was pulling a travel trailer, as the car was surging somewhat through the powerband. It idles ok, but when I hooked the vacuum gauge up to the car, it showed only 3 inches! Idle should be a steady 16-20 inches. When sitting in Park, I can run the throttle up without any issues at all, and the vacuum gauge held steady at 20" at roughly 3,000 RPM (gauging that by ear). Re-checked all the vacuum lines, then took it out for a nine-mile run. Still ran like crap. It really hates 55 or higher right now! It feels OK at a steady 45 mph, but other than that, it's just not right. Plus, it dieseled on two occasions at shutdown.

    I'm running 87 octane 100% gasoline (NO ethanol!) that I have been getting from the same station for several years. It ran the same before and after fill-up. Before the fuel pump quit, it ran like a top! I have done nothing to the 440 in the interim, other than the valve cover gaskets. It ran the same before and after that, too. Fluid levels are good. Vacuum lines visually appear OK. Air filter has maybe 1,000 miles on it. Runs like crap, cold or warm.

    Oh, and another thing. As I'm driving down the road, it sounds like I've got a subwoofer on at low volume in the trunk, as there is this droning coming from the rear, or the trunk. The spare is secured, with no other cargo in the trunk. This is audible with the windows up or down. I checked for bodies. None there.

    So, the questions...First, could the rear diff be going out, causing the surge feeling? There doesn't appear to be any bearing noise. I've had a Mopar 8-3/4" go out before, and the noise this makes is not the same at all. Could I be having a tire separate? I've had that happen before, as well, and it made the car handle like crap.

    Second, the engine. I can not figure out why I'd have just three inches of vacuum at idle! I've put a total of 17 miles on this full tank of gas, and the gauge already moved down to 7/8 of a tank, so that's nearly two gallons of a 22-gallon tank gone! That means eight and a half miles per gallon! The engine is the original, 102K mile, bone-stock 440 with a TQ and electronic ignition. No LB on my car! That's long gone.

    Two problems, guys. Any ideas???


    1966 Coronet 500, 1968 D100(x2), 1978 NYB Salon, 1979 Dodge B200 Street Van, 2006 PT Limited ragtop


  • #2
    Does the car have a cat on it? If so and it's original, I'm betting it's finally clogged up. If it doesn't have one, what shape is the exhaust system in? No crushed muffler or pipe? Does it rev up freely and quickly in neutral? I don't like to do that in park with a Mopar because the trans pump doesn't move any fluid to the front seal in park. Usually an engine with no load can rev up pretty freely in neutral when the converter is clogged up but it won't pull very well under a load. The way you describe things, man, that's what I would check right off the bat. I've seen them act like just like this before due to that....

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    • #3
      Does it have an egr valve? Might be stuck open. Possible timing chain jumped caused by nylon gear breaking? Blockage in exhaust, (dead critter)??

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      • #4
        No cat, it was removed long ago. I have a generic turbo muffler on the car that is about three years old. No blockages or crimps in the pipe. The exhaust tone hasn't changed, so I don't believe it is clogged up.

        It does have the stock EGR, but I removed the smog pump in 2009 when it locked up and quit, and also removed the air pump plumbing. The EGR is still in place. Don't know if it gave it up or not, I can replace it cheap enough, if needed.

        I'll check the throttle response in Neutral, also. Thanks guys!
        1966 Coronet 500, 1968 D100(x2), 1978 NYB Salon, 1979 Dodge B200 Street Van, 2006 PT Limited ragtop

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