Edelbrock Proflo 4

[6872xtc]

Well I think that it's time for me to start this thread, as I am past the initial installation and start up.
The back story.
I had a '72 350 which was running fine with TBI on an Edelbrock performer intake with an adapter and 1" spacer. It had a head crack and leak coolant. The heads were milled some, and had screw in studs and guide plates. I made the decision to go with Edelbrock aluminum heads, this forced me to upgrade exhaust as my manifolds were too small.
After these two parts swaps, the TBI was not happy. It had a custom chip already and the data-log wasn't showing a problem, but it wasn't driveable. The 1200 rpm and up was bad. Stumbling and using too much gas. No power. I did consult Howell EFI and he helped me fix a small amount, but it still was bad.
After much consideration, I decided to try the Edelbrock system. It has timing control already, fuel pressure is hooked to a vacuum reference, intake air temp sensor and MAP sensor, progressive throttle bores, which are 44mm each, 4 of them. Sequentially fired injectors with a single plane intake. Wideband O2 sensor included. The ECM is remote mounted, bluetooth accessible and has an IBM (?) port too. I believe that a USB port would be better, but I don't know for sure.
I called Edelbrock tech before I made the decision and was pleased that I had a guy on the line in a few seconds. But I still didn't know that I was going in the right direction.
I liked the fact that I could use an Android device to link to it.
I ordered the system from Summit and got to work.
This is how it showed up.

 

[6872xtc]

It has a distributor included, but no coil. And the fuel system is not included. Intake gaskets are included. It says online that it has a 2 year warranty, but I haven't verified that.
I bought a coil which matched their requirements, primary coil ohms is how they specify them. My truck had the factory TBI system in place, with an upgraded pump already. I had installed an EP381, so it was capable of the 43 psi.
The packing wasn't what I would have preferred for how much I had paid, but nothing was damaged.

 

[6872xtc]

It has progressive linkage on the air valve, as they call it. Throttle body to me. And it's a single plane intake.
Pic of the ECM when compared with a 7747 TBI unit.

 

[Bent77]

 

[6872xtc]

I was not pleased that the injector bosses were so fat, and caused interference with the valve covers. I ground mine to make room. Edelbrock tech says that 5/8" thick gaskets help. I suggested that a little more be milled off for room as I already had reusable Felpro gaskets.
I couldn't install the double sided stud for the brace up to the back of the serpentine bracket. The threaded boss for older engine's accessory braces interferes.

 

[6872xtc]

I didn't tell what I truck I am putting this into. It's my '90 Jimmy so it has the factory TBI harness, and I had installed factory fuel lines and tank for the '90 into the '79 frame.
So I had some of the fuel system in place, I mentioned that I had the EP381 pump, but then I had to get adapters to go to -6 AN, as well as hoses to connect to the fuel rails. I will get pictures of some of that.
But I did mount the ECM in the OEM tray above the glovebox by straightening out the metal strap and using rubber padding. I am wondering if good velcro would be a better option to hold it in place under the strap.
I drilled a hole in the side of the ECM tray for a zip tie to support the wire harness. I may look at something more sturdy later.

I sorted out what I thought was wiring which I wouldn't use anymore, but I hated chopping up a good harness.
Picture of what I took out.
I left the VSS wires and fuel pump relay and wiring.

 

[6872xtc]

@Bent77 already found this..
@beags86
@skunked

 

[Bent77]

Says journey sucks so I found it

 

[pma4x4]

Im looking at doing the same upgrade on my 91 TBI Suburban. I am planning on a roller cam and heads along with the Pro-Flo. Keep us posted.

 

[6872xtc]

@pma4x4 I added info to the above post about my truck. I didn't see where I had previously.

The estimated compression ratio of this engine is not quite 10 to 1. The heads are 64 CC, Edelbrock 5089, 2.02/1.60 valves.
I don't know how accurate my estimate is, and I am not real concerned with it, just how it runs.
I made my own bracket for the throttle cable and TV cable. I have a 700R4.
I didn't like the aftermarket options as I felt that they would either not use my existing cables, or not be stable, possibly both. I tried to match the TBI geometry and I am pleased with the results. It doesn't pull hard on the pedal from idle, so nice and "normal " feeling. I get 100% throttle on the ECM ,too.
The transmission works well, but I don't know what modifications it has for sure. It chirps the 37s easily with 4:56 differential gears.


The center strap is bent upwards to clear the vacuum ports on the back of the throttle body.

 

[6872xtc]

I don't know if I will be able to use the cruise control because the original stud won't work on the throttle lever. The nut for it won't clear the outside of the air inlet, the lever is too close, and I didn't want to bend or weld on it since I felt that it may void warranty.
I was able to get the grommet off of the original wiring and open it up for the bundle that this has. I tucked extra wiring on the back of the intake manifold. All of the wiring and the rear fuel crossover line is why I decided to run the fuel feed and return lines up the front right of the engine like a carburetor system. I still need to finalize clamping and padding the lines. More pictures of that later.

 

[6872xtc]

Excuse the tape tag on the plug wire, I still plan on working on them some more to get more separation from each other. I had built them to run below the distributor to the opposite sides. Now I want them up away from the EFI wiring bundle which is tucked down there.

 

[6872xtc]

I used the original coil power for the ignition feed to the Edelbrock harness. The fuel pump is still fused with the original ECM "B" as original, however I had to rewire the relay control wires since Edelbrock supplies ground to turn on the fuel pump. I didn't use the fuel pump circuit of the oil pressure switch because I didn't have the parts or the patience to make it NOT cause a delay in priming the fuel system until it got oil pressure during cranking. I believe that a diode would have to come into play with some more wiring.

Oh and I forgot to tag @500$k5

 

[6872xtc]

Here is a shot of the carb intake with the custom 1 1/2" tall adapter/spacer and TBI unit, compared to the Proflo 4.

 

[pma4x4]

Good update.

I sent a huge email to Edelbrock this morning with a pile of questions along with my current specs and what I want to do with my truck. I did mention your valve cover clearance issue so will be interesting to see what they tell me. My plan is to get a set of EQ vortec heads probably in the vortec intake bolt pattern so I can use my center bolt valve covers. no price difference on those heads or the 55-86 bolt pattern heads adn as much as I have seen there is not Pro-flo difference either aside from the bolt pattern.

I have not had a chance to examine the wiring diagram yet but is the VSS circuit for the DRAC separate from the ECM?

I would love to dump as much original TBI wiring as possible.

 

[6872xtc]

And since I can't remember who I have told what to previously, I don't see where I said that from what I can tell, this system incorporates a fair amount of GM stuff. The IAC seems to be for an LS according to the part number, the coolant temp sensor and TPS are apparently too.
It uses Delphi connectors, but I haven't looked up the fuel pressure regulator or injectors.

 

[6872xtc]

Good update.

I sent a huge email to Edelbrock this morning with a pile of questions along with my current specs and what I want to do with my truck. I did mention your valve cover clearance issue so will be interesting to see what they tell me. My plan is to get a set of EQ vortec heads probably in the vortec intake bolt pattern so I can use my center bolt valve covers. no price difference on those heads or the 55-86 bolt pattern heads adn as much as I have seen there is not Pro-flo difference either aside from the bolt pattern.

I have not had a chance to examine the wiring diagram yet but is the VSS circuit for the DRAC separate from the ECM?

I would love to dump as much original TBI wiring as possible.

I talked with Edelbrock tech and sales before I ordered mine. I had good results getting someone on the phone quickly. And they seemed decent.
I hole that you have better luck with the valve covers with your cylinder head choice. I could have gone that way if I had known that the TBI wasn't going to be able to work.
And yes, the VSS is separate from the EFI. There is a black with white trace wire in the harness which grounds the DRAC. My speedometer didn't work until I checked and grounded it.

 

[pma4x4]

I checked into the EP381 fuel pump. Edelbrock wants a 56GPH pump and 60psi (roughly) the EP381 only does 27GPH. This was another questions I ask them is if they had a pump recommendation to fit in the stock placement.

 

[6872xtc]

I checked into the EP381 fuel pump. Edelbrock wants a 56GPH pump and 60psi (roughly) the EP381 only does 27GPH. This was another questions I ask them is if they had a pump recommendation to fit in the stock placement.

I am running the 43 psi regulator. But I don't have a roller cam, and I estimated my power level to be low enough to use the lower pressure. I may have not dug deeply enough into the fuel demands, but so far I can't tell that I am lacking. Fortunately, I have an access panel in the rear floor if I need to step up!
I will have to watch fuel pressure at WOT sometime.


I will say that after a couple of days driving it to work, only 7.5 miles each way, I got more confident and pushed the pedal more. It is giving me more confidence and reward!!

 

[pma4x4]

Should see some MPG gains as well. That's something else I will ask them when the reply is what ware all the sensors? If they have Common OEM numbers for replacement. Right now My immediate project is getting the burb back on the road and doing the Windstar fan mod.