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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Fine tuning setup on a SBC 350
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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
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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 ?
Don't get too caught up in the numbers.
Just give the Engine what it wants &
Let the numbers be what they are.
Jim McFarland....
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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.
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Originally posted by CMerchant View PostThree 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
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?
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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?
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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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.You do not have permission to view this gallery.
This gallery has 5 photos.
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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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Originally posted by scottastew View PostI 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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Originally posted by ddsmith View Post
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.
Last edited by scottastew; 04-23-2021, 08:04 PM.
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If you have the vacuum reference hose installed now. Disconnect it at the sump and plug the hose. Adjust the regulator and then reinstall the hose at the sump. If you are pulling a good vacuum it will lower your fuel pressure noticeably. Did you installed the vent hose from the sump back to the tank? I have seen this being the biggest problem with the install other than heat related fuel issues.
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Originally posted by ddsmith View PostIf you have the vacuum reference hose installed now. Disconnect it at the sump and plug the hose. Adjust the regulator and then reinstall the hose at the sump. If you are pulling a good vacuum it will lower your fuel pressure noticeably. Did you installed the vent hose from the sump back to the tank? I have seen this being the biggest problem with the install other than heat related fuel issues.
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When I first installed the vent hose, I used a 1 way check valve because I was worried about fuel traveling back up into the sump for some reason. Now that I think about it, I’m not sure why that would ever happen. I removed that valve tonight so it is just vented straight back to the fuel tank with no valve in the way. Maybe that was causing an issue...I also installed the fuel vacuum reference hose and adjusted the fuel pressure to the correct amount.
I tested it out with another test drive and I am cautiously optimistic that one or both of these things solved my problems. It ran very well (other than a slight hesitation when accelerating from a stop).
Thank you three who all helped me get this figured out. I’ve been ready to rip it all out and go back to a carb, but turns out it’s just my own dumb fault for not paying enough attention to the instructions. I plan on testing it more tomorrow and make sure we are good. Felling good tonight!
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Small block Chevys like more advance at idle which will help with your idle and stumble also. 2700Cast recommended you set your idle advance at 20. My experience with this system on 2 separate SBC's is that 20 to 22 is the optimal idle advance. Also idle speed on mine have been best at 850 to 900 rpm.
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