'81 V864 "floods" itself after sitting awhile??
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500, 472, 425, 368 Discussion, '81 V864 "floods" itself after sitting awhile?? in Cadillac Engine Technical Discussion; Now that the weather is warming up here (IL) I've started running into a problem with my "new" '81 Fleetwood ...
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    fleetwood96 is offline Cadillac Owners Member
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    '81 V864 "floods" itself after sitting awhile??

    Now that the weather is warming up here (IL) I've started running into a problem with my "new" '81 Fleetwood with the V864 engine (although I don't think this problem is related to that mechanism). It just turned 97k miles. When the car is cold (3+ hours off) the engine starts up just fine and idles fine without me having to touch the gas pedal. Once it is up to normal operating temps, when I shut it off and leave it off between 1/2 hour and 2 hours and try to restart it, the engine acts like it's flooded. It either cranks & cranks without starting or will start briefly then die, unless I start revving the engine (sometimes it even stumbles & dies when I'm attempting to immediately rev it up). Once it stalls, I have one heck of a time getting it to restart (it sometimes takes 5 minutes of on & off cranking, during which it sometimes acts as though it has no gas at all and at other tries it wants to run VERY roughly and slow enough for the ALTERNATOR light to be on for a few seconds, then dies again; repeated attempts will finally will get going). Eventually it will restart, and after a few more minutes of revving it and letting it idle fast, it starts acting normal again. It's just a pain when we go out for dinner, etc.

    This is a new one on me! I've replaced electrical stuff (spark plugs, wires, distributor cap, rotor, and coil) as well as the fuel filter, but this sure seems like a fuel delivery problem (maybe too much fuel!)

    Any guidance would be appreciated!! Doug

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  3. #2
    tripleyellow78cad's Avatar
    tripleyellow78cad is offline Cadillac Owners Fanatic
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    Re: '81 V864 "floods" itself after sitting awhile??

    Quote Originally Posted by fleetwood96
    Now that the weather is warming up here (IL) I've started running into a problem with my "new" '81 Fleetwood with the V864 engine (although I don't think this problem is related to that mechanism). It just turned 97k miles. When the car is cold (3+ hours off) the engine starts up just fine and idles fine without me having to touch the gas pedal. Once it is up to normal operating temps, when I shut it off and leave it off between 1/2 hour and 2 hours and try to restart it, the engine acts like it's flooded. It either cranks & cranks without starting or will start briefly then die, unless I start revving the engine (sometimes it even stumbles & dies when I'm attempting to immediately rev it up). Once it stalls, I have one heck of a time getting it to restart (it sometimes takes 5 minutes of on & off cranking, during which it sometimes acts as though it has no gas at all and at other tries it wants to run VERY roughly and slow enough for the ALTERNATOR light to be on for a few seconds, then dies again; repeated attempts will finally will get going). Eventually it will restart, and after a few more minutes of revving it and letting it idle fast, it starts acting normal again. It's just a pain when we go out for dinner, etc.

    This is a new one on me! I've replaced electrical stuff (spark plugs, wires, distributor cap, rotor, and coil) as well as the fuel filter, but this sure seems like a fuel delivery problem (maybe too much fuel!)

    Any guidance would be appreciated!! Doug
    Have you checked to see if your electric fuel pump is not worn out?
    In my 90 gmc tbi 350 truck it was hell on earth trying to get the thing to start sometimes , and i had a bad in the tank pump.

    When my pu would not start i tryed pouring a little fuel down the throttle body and it ran so i knew it was a fuel delivery problem (do this at your own risk it could kill you, put the air cleaner top back on if you attemt to do this, and stand back, also have a some type of device to put out a possible fire)
    And yes i replaced my wires cap rotor as well

    also try to see if the fuel injectors are spraying fuel(take the air cleaner off and from a distance have some one crank the engine while you watch the bottom of the injectors to see if fuel sprays out.
    well thats all that i can think of,
    Oh one more thing get yourself a cadillac service manual this will tell you how to use your onboard diagnostics try ebay they always have some kink of cad service manuals avalible
    here is a link to one on ebay right know
    http://cgi.ebay.com/ebaymotors/ws/eB...tem=2469863084

    i hope some of what i posted here helps:coolgleam

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    capn_zoom's Avatar
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    Re: '81 V864 "floods" itself after sitting awhile??

    tripleyellow78cad is right. It's time to start isolating components to see what's wrong with what. I would first check to make sure that no sensors have been unplugged, no wiring is broken, etc. You'd be surprised what a visual inspection will reveal, and an unplugged (or faulty) coolant temp or map sensor might do what you've described. I would use starting fluid (instead of gasoline) to check for fuel starvation. It comes in aerosol cans and you can pick it up almost anywhere they sell any car stuff (Wal-Mart, etc.) When the engine refuses to start, spray some into the throttle body (1-2 second blast). If it is a fuel delivery problem, the engine will start normally when you turn the key. As tripleyellow78cad said, put the air cleaner on when you do this to keep a backfire from setting the hood insulation on fire. If the car starts, it will stall again almost immediately as the ether is consumed, but it will tell you if the engine is getting fuel or not. If the ether doesn't help and the engine continues to crank without starting, pull a few spark plugs. If they're wet with fuel, it would indicate a flooding problem. On many fuel injected engines, this can happen when the coolant temp sensor goes bad (the engine thinks it's -40 degrees out and really dumps fuel). I too would recommend a factory service manual, as the fuel injection used on the older Cads is a little different from what's in cars nowadays. Does the engine ever backfire thru the air cleaner? What happens when you shut it off and then immediately try to restart it? Sorry to be longwinded, but I hope this info gets you started. Let us know how you make out.

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    fleetwood96 is offline Cadillac Owners Member
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    Re: '81 V864 "floods" itself after sitting awhile??

    Thanks for the advise, guys, and I'll try a few things this weekend. I forgot to mention that I do have an '81 factory service manual and I have been into Diagnostics mode, and there are no codes reported at all. The coolant temp display on the ECC seems to work fine (aka it rises normally as the engine warms up & in fact the V864 mode won't start working until the reading is a certain temperature).

    The car always seems to restart OK immediately upon turning it off (or within a few minutes of doing so). It only has a problem between about 45 minutes to 3 hours of "resting" after running awhile. I've also wondered about the fuel pump - I don't know its age. Sometimes while going around corners and trying to accelerate with low fuel in the tank at the same time, it stumbles as if it weren't getting enough gas as well.

    What I think I'll do next is to get it in this non-starting mood and then have my wife crank it while I look to see what the fuel injectors are doing (or not doing). I'll report back once I have the results. Doug

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    Caddy_freak's Avatar
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    Re: '81 V864 "floods" itself after sitting awhile??

    My guess would be fuel pump too! but let us know what you find out.

    I had an impala a long time ago that acted weird, similar to yours and it turned out that the gas line had a small pin hole in it. and after leaving the car sitting for awile, it would drain the line, and I had to crank and crank to get started again, but only if sitting for a long time. now that car had a mechanical pump at the motor, so it's not exactly the same thing but still pretty interesting.

    so a visual inspection of the under body (gas line) might be helpfull too.
    I also have a 1981 fleetwood with a v4-6-8 (368) Motor. mine has 87,000 miles on it. it runs like a jem now, but later on who knows I might find myself in your shoes. old cars are bound to develop little quirks once and awhile, you just got to fix'em and keep on smilling

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    lux hauler is offline Cadillac Owners Connoisseur
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    Re: '81 V864 "floods" itself after sitting awhile??

    Would heated fuel do this.....possibly vapor locked?

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    capn_zoom's Avatar
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    Re: '81 V864 "floods" itself after sitting awhile??

    Vapor lock tends to be more common on carbureted vehicles, because the fuel pump pulls fuel from the tank (creating a vacuum). If you remember high school physics, as pressure drops, so does the boiling point for most liquids. So, under a vacuum, gasoline turns to vapor in the fuel line and starves the engine. With EFI, the fuel pump pressurizes the fuel in the line, reducing the chance of vapor lock (in most cases). The only exception is when there is a restriction before the pump (clogged filter, kink in the line, etc). I think these injected Cads used two pumps (in-tank and frame-mounted), but I'm not sure. Fleetwood96's problem is strange because there's a time window when it will occur, suggesting it might be temperature-dependent. Then again, I could be out of my mind. If I think of anything, I'll post.

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    fleetwood96 is offline Cadillac Owners Member
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    Re: '81 V864 "floods" itself after sitting awhile??

    Well, gang, last weekend I decided to replace the fuel pump in the '81. After wrestling to get the fuel tank off the car and again back on it, it's been almost a week now and so far (fingers crossed) I have not had any problem getting her to start & stay running under various conditions without having to touch the gas pedal at all! I was surprised that once the tank was off that replacing the pump itself was pretty easy work!!

    By the way, on this car (and I believe the HT4100 cars are this way too), there's just one electric pump in the gas tank, and there's a replaceable fuel filter in the fuel line near the driver's side rear tire (which I replaced a month or so ago as well).

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    Caddy_freak's Avatar
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    Re: '81 V864 "floods" itself after sitting awhile??

    Cool! that's great. I`m enjoying the hell out of my caddy. Glad to see you are back into fun mode with yours.

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    lostDTS is offline Cadillac Owners Member
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    Re: '81 V864 "floods" itself after sitting awhile??

    Just wondering if changing the fuel pump did cure the problem? I have the exact problem in my 81 2door Fleetwood. It only has 40K on it.
    Like to hear from you if you still have the car, or that the problem was corrected with the new fuel pump. Thanks

  12. #11
    lostDTS is offline Cadillac Owners Member
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    Re: '81 V864 "floods" itself after sitting awhile??

    I replaced my fuel pump, and cured the problem. I would say any intermitant problems with fuel delivery should point to the fuel pump. Its not to hard to change. It will also save alot of headache and hopefully not having to be towed home.

  13. #12
    djkenny619 is offline Cadillac Owners Member
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    Re: '81 V864 "floods" itself after sitting awhile??

    after owning 50 some vehicles mostly gm and most of those where cadillacs i finally owned one that had a collapsed fuel strainer in the tank. it was somewhat hard to stat when cold, generally would idle ok but suffered when warm, since the computer is now longer leaning out the fuel mixture and with the clogged strainer it just ran very poorly. anyways since it was my first and the vehicle sat for years i pulled the tank, the strainer was all sucked in and black, new ones are white, the fuel pump case was really dark as if its been over worked and heating up. i replace the strainer, pump and filter near the driver rear tire and it ran like new. this was a low milage 83 cadillac eldorado but it sat off and on for so many years i gather the sock/strainer just dried out and clogged.

  14. #13
    CaddySeville is offline Cadillac Owners Member
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    Re: '81 V864 "floods" itself after sitting awhile??

    i have the exact problem with my 81 seville with the 368
    the fuel pump must be the problem

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