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Fine tuning setup on a SBC 350

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  • ddsmith
    replied
    Originally posted by scottastew View Post
    I don’t know if my fuel system is vacuum referenced. I installed the Edelbrock fuel sump system. Also, I can’t see any option to limit fuel pressure to something other than 58. The MAP I have loaded is 43, but I can’t change the actual pressure once I’ve got it loaded. I think my charging system is adequate, although my battery is probably on the lower end of power necessary...
    If you are running the Edelbrock Fuel Sump then it has an adjustable regulator on it. That is also where the vacuum hose gets attached to provide vacuum reference. If you did not install a vacuum line from your manifold to that nipple, then it is not correctly setup. To adjust the regulator, loosen the lock nut and adjust the regulator to get 43 psi with the engine running. Then tighten the lock nut. Then get a vacuum hose and install it from the manifold to the nipple and you will be setup correctly.

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  • scottastew
    replied
    I don’t know if my fuel system is vacuum referenced. I installed the Edelbrock fuel sump system. Also, I can’t see any option to limit fuel pressure to something other than 58. The MAP I have loaded is 43, but I can’t change the actual pressure once I’ve got it loaded. I think my charging system is adequate, although my battery is probably on the lower end of power necessary...

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  • scottastew
    replied
    Ok, so I adjusted timing a bit and also drained old gas and put new gas in the tank with an additive. I thought it may have fixed my issue of running rough. I drove to my brothers house about 2 miles away, let it idle over there for a few minutes and then on my way home it started to run crappy again. I barely made it home because it was wanting to stall at stop signs. Here is a video of when it is running rough with some screenshots of the settings.
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    This gallery has 5 photos.

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  • CMerchant
    replied
    Originally posted by scottastew View Post

    CM-I've got a basic GM 350 crate motor, so I've chosen the stock CAM setting. I the white fuel injectors. I tried to mess with the AFR at idle yesterday, but the higher I went with the number, the quicker it would die. If I dropped it to 12.0, it would stay idling longer but still not sound great.

    I'm using the Edelbrock sump/fuel system setup so I'm not sure if that is considered to be vacuum referenced.

    I'll admit I struggled at first with timing and I couldn't get it to start after the initial install. I was having a hard time finding TDC and ended up on the phone with Edelbrock a couple times to figure this out. I thought I figured it out with the hose and balloon method to figure out my first cylinder compression stroke and after fiddling with that the truck started up fairly easy, but has never been able to idle for a prolonged long time or go into gear without adding stepping on the gas pedal a little. I've driven it around the block a few times but always in fear that I was going to stall out. Again, It's been over a year since I messed with the timing. Do you think my symptoms could be related to the timing being off?
    Possibly. If you have no way to verify you dropped the distributor in at 12*BTDC then you're whole set up is going to be off. That's The most critical step in the process. Find TDC. Then find 12 BTDC and then take the cap off the distributor. If it's not pointing directly at the #1 spark plug post you need to pull the dizzy and reset it. From there I'd reload a NEW calibration and start over.

    Also just going back to my first reply - is your fuel pressure regulator vacuum referenced? And is your charging system up to snuff?

    I addition if you have a stock 350 with 29lb injectors you should probably be on map 5006 which is a 43 PSI map. You need to lower your fuel pressure and get on this map when you reset it.

    And do what 2700 Cast suggested - needs more idle timing in the tablet.
    Last edited by CMerchant; 04-19-2021, 06:54 PM.

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  • scottastew
    replied
    Originally posted by CMerchant View Post
    Three things I'll note:

    Your AFR seems super rich at idle. Would likely be better suited in the hight 13's.

    Also your battery voltage seems pretty low. I understand both your fans were on but still. I don't know if you charging system would have an connection with your issue but just pointing it out.

    Next your fuel pressure seems high considering you're pulling 21+" vacuum. Is your fuel pressure regulator vacuum referenced?

    So I just want to clarify - you've NEVER been able to get it into gear without it stalling at any temperature?



    Please give some more info on your setup:
    Cam specs
    Map loaded
    injector size/color
    Timing specs as entered into the tablet
    CM-I've got a basic GM 350 crate motor, so I've chosen the stock CAM setting. I the white fuel injectors. I tried to mess with the AFR at idle yesterday, but the higher I went with the number, the quicker it would die. If I dropped it to 12.0, it would stay idling longer but still not sound great.

    I'm using the Edelbrock sump/fuel system setup so I'm not sure if that is considered to be vacuum referenced.

    I'll admit I struggled at first with timing and I couldn't get it to start after the initial install. I was having a hard time finding TDC and ended up on the phone with Edelbrock a couple times to figure this out. I thought I figured it out with the hose and balloon method to figure out my first cylinder compression stroke and after fiddling with that the truck started up fairly easy, but has never been able to idle for a prolonged long time or go into gear without adding stepping on the gas pedal a little. I've driven it around the block a few times but always in fear that I was going to stall out. Again, It's been over a year since I messed with the timing. Do you think my symptoms could be related to the timing being off?

    Leave a comment:


  • scottastew
    replied
    Thanks both for the quick response.

    CM-I'll get more information when I get home tonight. But to clarify, I can get it into gear if I get on the throttle a bit. I've driven it around the neighborhood, but it has stalled when I slow down and get under 5-10mph. I wonder if my battery isn't sufficient?

    2700-I'll try that and get the other info and later and post it.

    Leave a comment:


  • 2700 Cast
    replied
    Idle spark is too low ....try 19 -20 degrees.

    More data will help====>

    What engine?
    Vehicle make & model?
    What MAP # is it on?
    Fuel pressure ?
    Hot engine idle vacuum?
    Injector size ?
    HP level ?
    Spark control settings ?

    Leave a comment:


  • CMerchant
    replied
    Three things I'll note:

    Your AFR seems super rich at idle. Would likely be better suited in the hight 13's.

    Also your battery voltage seems pretty low. I understand both your fans were on but still. I don't know if you charging system would have an connection with your issue but just pointing it out.

    Next your fuel pressure seems high considering you're pulling 21+" vacuum. Is your fuel pressure regulator vacuum referenced?

    So I just want to clarify - you've NEVER been able to get it into gear without it stalling at any temperature?



    Please give some more info on your setup:
    Cam specs
    Map loaded
    injector size/color
    Timing specs as entered into the tablet

    Leave a comment:


  • scottastew
    started a topic Fine tuning setup on a SBC 350

    Fine tuning setup on a SBC 350

    I installed the pro-flo 4 last year on my 1985 GMC K1500 but I could never get it dialed in right and it kept stalling during idle and shifting into gear. It got me pretty frustrated and I didn't really mess with it over the past several months. I'm now trying to get my truck back up and running. I made some fuel adjustments in the settings hoping and got my IAC down to a manageable level, but I'm still stalling when I shift and if I leave it idling. Can someone take a look at my gauge settings and see if anything stands out as a problem? Thanks. Truck guage.jpg Truck guage.jpg
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