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Thread: Harder Start When weather is Colder

  1. #1
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    Harder Start When weather is Colder

    With the weather being cold in Hosuton (50+ degrees) my car is hard/impossible to start. I think I am making progress though. I made a few changes to the Tuner Studio program by increasing the Priming Pulse. I was able to get the car started. I'm wondering is I should increase it a little more or tweak another setting.

    I'm thinking i still need to change settings in the Cranking Settings. When I had the car tuned at a Dyno shop they had Cranking RPM at 500. I read up on this and decided to move it down to 300. I have no TPS but it's set at 90 in the Flood Clear %. Should I set that at 0 or 100? For Cranking Fuel Pulse Rate I read that it's good to have it on alternate when dealing with engines that have higher number of cylinders. My car only has 6 so should my setting be at Every Event or Alternating Events?

    Attached is my tune and log.

    2016-01-01 Delorean.msq

    2016-01-01_11.32.54.msl
    Shannon

  2. #2
    President, DeLorean Industries
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    Quick test as changing settings randomly never gets you ahead.

    When starting in the above conditions does the car start easier when you depress the gas pedal slightly (or at all) when cranking?

  3. #3
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    Quote Originally Posted by DPI JOSH View Post
    Quick test as changing settings randomly never gets you ahead.

    When starting in the above conditions does the car start easier when you depress the gas pedal slightly (or at all) when cranking?
    Normally I don't depress the pedal until it starts. Depressing the pedal seems to not help it get started.

    Yesterday we got it started by spraying gas into the manifold nd it started right up. That showed that we were getting spark but no gas. Bumping up the priming pulse seemed to help get it started this morning. Reading about the Cranking RPM seemed to indicate tht getting that set right might affect the starting. Too many variables to tinker with!
    Last edited by lazabby; 01-01-2016 at 02:17 PM.
    Shannon

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    I posted a query on the MS forum. Someone suggested changes to the advance table at the low RPM/High load area. It appears that my advance was set too high. I made the changes and the car starts right up. I had also bumped up the pulse width a little bit in the colder temperature range.

    I was also having an issue with the car bogging down when coming off of a stop. Making changes on the Acceleration Enrichment seems to have eliminated that problem. I'm running off of MAP with no TPS.
    Shannon

  5. #5
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    Here is my current tune and a log from a couple of days ago.
    Attached Files
    Shannon

  6. #6
    Senior Member Josh's Avatar
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    Id take a look though the MS manual and understand what you are changing instead of changing things here and there.

    My method of tuning is:
    Set your afr table to your liking.
    Turn off ego correction
    Get your engine to operating temp
    ensure the idle is nice and solid where you want it (afr, rpm)
    Drive and adjust your fuel table so they correspond with your afr table. Autotune works great. Smooth it out.
    Do the same with your spark table, this takes a little more finesse. Also remember each table impacts the other.
    Once the car idles and drives nice, turn on ego correction.

    Now you can worry about warm up. Start with warm up enrichment. This can take many tries over many days as it requires a cold engine.

    And fine tune from there... this is just the major stuff to get your car running reasonably, not perfectly though.


    WUE is the main thing you want to concentrate on to solve your cold starting issues. Dont be afraid to richen it up to 160-180% around freezing and work your way down from there. This is based on a 14AFR idle, you have it running a bit rich in the idle areas at 13.5AFR. You do want it idling richer than Stoich so this is the right direction.

    Also your spark table needs some work. You need to retard it across the board especially at idle. 10-15deg is closer to what you want, not mid 30s. Also remember to smooth your tables, there are some nasty spikes which will cause the car to run poorly.

  7. #7
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    Quote Originally Posted by Josh View Post
    Id take a look though the MS manual and understand what you are changing instead of changing things here and there.

    My method of tuning is:
    Set your afr table to your liking.
    Turn off ego correction
    Get your engine to operating temp
    ensure the idle is nice and solid where you want it (afr, rpm)
    Drive and adjust your fuel table so they correspond with your afr table. Autotune works great. Smooth it out.
    Do the same with your spark table, this takes a little more finesse. Also remember each table impacts the other.
    Once the car idles and drives nice, turn on ego correction.

    Now you can worry about warm up. Start with warm up enrichment. This can take many tries over many days as it requires a cold engine.

    And fine tune from there... this is just the major stuff to get your car running reasonably, not perfectly though.


    WUE is the main thing you want to concentrate on to solve your cold starting issues. Dont be afraid to richen it up to 160-180% around freezing and work your way down from there. This is based on a 14AFR idle, you have it running a bit rich in the idle areas at 13.5AFR. You do want it idling richer than Stoich so this is the right direction.

    Also your spark table needs some work. You need to retard it across the board especially at idle. 10-15deg is closer to what you want, not mid 30s. Also remember to smooth your tables, there are some nasty spikes which will cause the car to run poorly.
    Let me clarify the issue that I was having. I was having a hard time getting the car started. It would run fine once started and warm up is fine. It idles fine. It was a problem getting it started, not keeping it running. So the changes I made were to the ignition advance and Cranking Pulse Width. WUE was not touched.

    The car was professionally tuned by a Dyno shop. I mentioned the hard start when the weather was cold and I mentioned the bogging down issue. I'm surprised that they didn't even try the AE but told me that I needed to install a TPS and bring it back to them and bring the car back when the weather was cold.

    I think you might have a good point about tweaking the ignition advance. I don't think it is set right. Even though the car will drive ok it doesn't have much zip to the drive so I know there is more tuning that can be done.
    Shannon

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