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Edelbrock Proflo 4

folkenheath said:
I realize this isn't a full on 16x16 or 32x32 grid to set timing, however, this single number for the vacuum advance could be greatly improved if they made it just two numbers. One number for the "max vacuum advance" meaning a limit to hit it won't go above, and then another number for the ramp rate, like 1 deg/inHg or something. This way, if you wanted to, you could be all in by 8 or 10" if ones cam doesn't produce much vacuum at idle, and it still wouldn't go above the max amount at cruise. This would also allow tuning the vacuum advance to almost any engine combination by changing the max and/or the ramp rate.

As for the vacuum advance at idle, I would surely hope it would be active at idle, what is your timing shown at idle(hopefully more than your set idle timing)? It would be nice if they had a check mark for that (active or not active at idle). Most applications would want it active at idle unless its for emissions testing or something.
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Well I'm not sure it is adding the vacuum advance. I have it set at 20 for idle and I ran the vacuum advance up to 15. I think at most I saw 24 at idle, but most times it was closer to 20.

Shawn said:
Gotcha on the tank/sending unit. I didn't have any problems on my new TBI sending unit but that was a year ago. I do need a new tank since my baffle is loose so thats going to suck if they are out of stock. Might be able to find something used on car-part.com.

I'd keep on eye on the fuel pressure when it starts acting up since it appears thats when it has issues and drops in the low 30s.

When I called Edelbrock tech (you have to wait) and put my name and number down, one of the knowledgeable tech's called me back and had me input all the values they suggest. This helped me tremendously and it ran great after that even on the dyno with some minor timing tweaks. I'll have to go back and see what those numbers were but this was a SBC and I know you you have a big block. Don't leave your number to be called back. For some reason that doesn't always work.
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I did hear that about just leaving a number not working. I didn't have any trouble getting the TBI tank, so you're probably okay there.

Actually this is in the C10 and it's a stock 350. I'm pretty sure it's the original motor, but certainly not anything too special even it's not.
 
I made some adjustments to the timing and idle setting. All I did with the idle is turn the idle speed screw so that the IAC was reading 4-6%. I adjusted the timing specs. Turned the idle timing up to 20 and vacuum advance up to 15.

Nate stopped by so he rode around with me for a test drive. twice the engine stumbled, but it didn't completely die. I drove the it on my 20 mile commute home and didn't have any glitches. So we'll see if this continues.
 
It was 22° this morning. It started and stayed running. After the O2 sensor was warmed up I put it in gear and it stayed running. Progress!

To recap from when it wouldn't start and stay running in the cold and then was dying when I put it in gear. I have left the idle at the default 750 RPM set with the idle speed screw so that the IAC was hovering between 4% to 6%. AFR targets are at the default values. Idle timing is 20°, and vacuum advance is +15 (but I'm still uncertain that adds in a idle) and the other timing points are at default.
 
Also the whistle sound has changed TPS values a couple times. So I'm thinking it may be IAC related. For now I'm not worrying about that until I've got it running consistently good with no random dying.
 
mrk5 said:
Also the whistle sound has changed TPS values a couple times. So I'm thinking it may be IAC related. For now I'm not worrying about that until I've got it running consistently good with no random dying.
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Are you still maintaining the manifold vacuum numbers you told Dave the other day?
When mine sucked the intake gasket, it was 12-15 Hg.
I never did hear a whistle, but theres a possibility that I'm deaf
 
Yes, it idles at around 21.

@folkenheath, just did some searching on the Pro-Flo 4 forum and vacuum advance is inactive at idle.
 
Well I didn't exactly have the best weekend with the PF4. It was randomly dying again. I did finally figure out it was acting like I had turned the key off. Ultimately it wouldn't run anymore. When the key was in run the pump wasn't coming on and the ECU wouldn't connect. Had to take the drive of shame, 17 miles on the strap.

You know how it is, you end up assuming the worst and I was afraid the ECU had died. However, I figured the first thing to check was the wire I connected the pink wire from the ECU to. I put a weather pack connector on that wire so I unplugged it and put the multimeter on it. Read 11.8V, same as the battery. Well shoot, my worst fear might be true.

So I'm standing there with the hood up and staring vacantly at the engine bay, and I suddenly realize there's a wire laying against the exhaust manifold. What the heck is that wire? It's the pink wire! I had never tied up the excess length and it had fallen against the exhaust manifold.

20201129_122953.jpg

20201129_123039.jpg

So this is surely the cause of the random dying. I'm guessing the wire was probably bouncing off and on the exhaust manifold.

It's a lot easier to get everything else dialed in when it's not randomly dying on you.
 
mrk5 said:
Well I didn't exactly have the best weekend with the PF4. It was randomly dying again. I did finally figure out it was acting like I had turned the key off. Ultimately it wouldn't run anymore. When the key was in run the pump wasn't coming on and the ECU wouldn't connect. Had to take the drive of shame, 17 miles on the strap.

You know how it is, you end up assuming the worst and I was afraid the ECU had died. However, I figured the first thing to check was the wire I connected the pink wire from the ECU to. I put a weather pack connector on that wire so I unplugged it and put the multimeter on it. Read 11.8V, same as the battery. Well shoot, my worst fear might be true.

So I'm standing there with the hood up and staring vacantly at the engine bay, and I suddenly realize there's a wire laying against the exhaust manifold. What the heck is that wire? It's the pink wire! I had never tied up the excess length and it had fallen against the exhaust manifold.

View attachment 361650

View attachment 361651

So this is surely the cause of the random dying. I'm guessing the wire was probably bouncing off and on the exhaust manifold.

It's a lot easier to get everything else dialed in when it's not randomly dying on you.
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:doah: That sucks but at least you found it.
 
@mrk5 , I like that post because you made some progress, even though it sucks, but you also showed that stuff happens! Honest information!
:waytogo:
 
Lets hope this is mystery solved. That would explain all of it including lack of fuel pressure. I assume it starts and runs now after you fixed that.
 
6872xtc said:
@mrk5 , I like that post because you made some progress, even though it sucks, but you also showed that stuff happens! Honest information!
:waytogo:
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You would think looking at wires would be have been an early thing to check, but it never occurred to me. So I figured it was a good reminder for someone else in the future.

Kain said:
i would clear learn data mrk5
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Haha! I'm laughing because when it was giving me trouble before being strapped home, I probably reset the learn 3 times. Plus I even went thru the setup wizard again too. Once I fixed the wire I did reset the learning... again... :rotfl:

Shawn said:
Lets hope this is mystery solved. That would explain all of it including lack of fuel pressure. I assume it starts and runs now after you fixed that.
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Yes it's running. Now that it shouldn't be randomly dying on me, I can drive it and let it do some learning and see where it goes. It still didn't like starting this morning when it was 10°. I made some crank and cold start enrichment adjustments so see if that helps. I figured I run those a couple mornings and see how things develop. If it's still a problem, I'll give the tech people a call for some advice.

I was also thinking more about what you'd pointed out about the fuel pump location. It occurred to me this morning, I have a couple inches of room on my bracket to drop the pump down lower. I wouldn't want to do that on a wheeling vehicle, but not worried as much about a street truck.
 
Did you start it up this morning? How did it do?

I'm taking notes because the few times I did start mine in the teens or single digits it would die so I assume I'll be making some cold start adjustments as well.
For now I'm waiting for a new O2 sensor to show up, because mine now only reads max or minimum values all the time.
 
This morning it was 40°. It started and ran, but I don't know if it was a good test. It actually reminded me so much of how the carb would run it was almost like I didn't install the PF4. Basically it kinda chugged for a bit, then cleared up and idled smooth. I didn't directly observe it, but I think it smoothed up when the O2 sensor warmed up and stopped reading 10.0; which would make some sense. However it did die when I put it in gear. I'm thinking some of this will clear up as it learns more.

I'm also experimenting with something and I will report further once I have some more more data but it is in regards to how I'm setting the idle and something I read on the PF4 forum.
 
Where are you guys connecting your booster vacuum source? I have two nipples on the back of the throttle body, both are too small unless I run some sort of reducer fitting.
 
skunked said:
Where are you guys connecting your booster vacuum source? I have two nipples on the back of the throttle body, both are too small unless I run some sort of reducer fitting.
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Does the big block one have a pipe thread port on a rear runner?
I believe that is where I put mine.
 
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