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Thread: Cold Start better without CSV??

  1. #1
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    Cold Start better without CSV??

    What would cause a cold start that's been sitting overnight to be shorter with the CSV disconnected (2 seconds), than with it connected (5+ seconds)? It's like thc CSV is spraying too much gas or the engine is not getting enough air. Another weird symptom is Dave's hot start relay also extends the cranking time for both cold and hot starts to about 10 seconds, and I believe that relay extends the CSV spray for longer.

    I've done the CSV in a jar test - seems to be functioning as designed, and adjusted the CO mix with a dwell meter, which helped my idle a bit but not the cold starts. The car has always started instantly if I restart it is less than 10 min or so after she's been running.

    I know what you're thinking - just keep the CSV disconnected, idiot! But, I still get the pretty regular 5 seconds of cranking anytime other than after a quick restart, and I'd like to track this problem down to help with summer starting.

  2. #2
    Senior Member Rich's Avatar
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    Quote Originally Posted by TheFover View Post
    What would cause a cold start that's been sitting overnight to be shorter with the CSV disconnected (2 seconds), than with it connected (5+ seconds)? It's like thc CSV is spraying too much gas or the engine is not getting enough air. Another weird symptom is Dave's hot start relay also extends the cranking time for both cold and hot starts to about 10 seconds, and I believe that relay extends the CSV spray for longer.

    I've done the CSV in a jar test - seems to be functioning as designed, and adjusted the CO mix with a dwell meter, which helped my idle a bit but not the cold starts. The car has always started instantly if I restart it is less than 10 min or so after she's been running.

    I know what you're thinking - just keep the CSV disconnected, idiot! But, I still get the pretty regular 5 seconds of cranking anytime other than after a quick restart, and I'd like to track this problem down to help with summer starting.
    It sounds like you've had the car for some time.

    Did it ever have a (normal) quick-start behavior with the CSV connected? If so, do you know whether the setup changed since then?
    March '81, 5-speed, black interior

  3. #3
    DMC Midwest - 815.459.6439 DMCMW Dave's Avatar
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    Might depend on your ambient temp. There is a range where the TTS will fire the valve when it isn't really needed causing a slight flooding condition. Since you are in south Texas this could be the case.
    Dave S
    DMC Midwest - retired but helping
    Greenville SC

  4. #4
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    Quote Originally Posted by DMCMW Dave View Post
    Might depend on your ambient temp. There is a range where the TTS will fire the valve when it isn't really needed causing a slight flooding condition. Since you are in south Texas this could be the case.
    Yes, typically this has been a concern, not knowing for sure if its a true hot or cold start and what the TTS was doing, but it was in the 40s these past two mornings when I tested it, so I think that rules out the TTS. Having it start much quicker first thing on a cold morning with the CSV disconnected, than with it connected, is such a weird symptom to me, I figured I'm taking this to the forum to see if anyone else experienced it.

    Plus Dave's hot start relay bypasses the TTS, so I really don't think that's it.

  5. #5
    Senior Member Bitsyncmaster's Avatar
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    I've found faster summer starts without the CSV working. It may be your mixture is set to rich. Have you unplugged the thermal time switch when running my hot start relay? Mine is removed as is the wiring for it.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  6. #6
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    Very common to find all kinds of problems with the CSV system. From wiring issues to a bad TTS. If the rest of your adjustments are too rich, the CSV will make it worse. Make sure the CSV does NOT work if the ambient temperature is too warm. Check the specs in the Workshop Manual. It is also only supposed to squirt during cranking and only for a short period of time. If you are in an area of the US where it never gets cold, you wouldn't care if the CSV never works but you should fix it anyway just in case you get really cold or you drive it to where it does get cold.
    David Teitelbaum

  7. #7
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    Quote Originally Posted by David T View Post
    Very common to find all kinds of problems with the CSV system. From wiring issues to a bad TTS. If the rest of your adjustments are too rich, the CSV will make it worse. Make sure the CSV does NOT work if the ambient temperature is too warm. Check the specs in the Workshop Manual. It is also only supposed to squirt during cranking and only for a short period of time. If you are in an area of the US where it never gets cold, you wouldn't care if the CSV never works but you should fix it anyway just in case you get really cold or you drive it to where it does get cold.
    Another 40 degree morning, another quick 2 second start with the CSV wire disconnected. I'm guess I'm just going to keep it disconnected forever and call this a good gremlin. It bothers me a bit to not understand why this is happening, but of all the tweaking I've done the best starting results are when the CSV is simply disconnected.

    Does anyone else run like this?

    My CO mix is set to DMC Houston specs which is between mid teens and high single digit dwell on a 6 cyl setting, which they say is a little rich, but "where the car likes it", which does seem to be the case in terms of power, idle, and now starting.

  8. #8
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    Quote Originally Posted by TheFover View Post
    Another 40 degree morning, another quick 2 second start with the CSV wire disconnected. I'm guess I'm just going to keep it disconnected forever and call this a good gremlin. It bothers me a bit to not understand why this is happening, but of all the tweaking I've done the best starting results are when the CSV is simply disconnected.

    Does anyone else run like this?

    My CO mix is set to DMC Houston specs which is between mid teens and high single digit dwell on a 6 cyl setting, which they say is a little rich, but "where the car likes it", which does seem to be the case in terms of power, idle, and now starting.
    You must be more than "a little" rich. Check your gas mileage. Yes, they do like to run richer than spec but you don't get all that much more power and you burn out the catalytic convertor. See if it glows red at night.
    David Teitelbaum

  9. #9
    Senior Member Bitsyncmaster's Avatar
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    Quote Originally Posted by TheFover View Post

    Does anyone else run like this?

    My CO mix is set to DMC Houston specs which is between mid teens and high single digit dwell on a 6 cyl setting, which they say is a little rich, but "where the car likes it", which does seem to be the case in terms of power, idle, and now starting.
    If your running a stock lambda ECU, I don't think it can even drive to single digit dwell. With your car set that rich is probably the reason your to rich starting. The stock engine setup is very rich anyway if adjusted to book values. When engine is cold that mixture adjustment really does set the mixture since the lambda is not running cold loop.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  10. #10
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    Quote Originally Posted by David T View Post
    You must be more than "a little" rich. Check your gas mileage. Yes, they do like to run richer than spec but you don't get all that much more power and you burn out the catalytic convertor. See if it glows red at night.
    Is that CO setting crazy rich on a 6-cyl scale? Is there a better way to check other than gas mileage and glowing cats?

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