I was looking into the pro flo 4 4150 style for my auto 1989 c4 and was wondering how it works with the ECU. Does it replace all functionality of the stock ecm also what all tuning is there i saw that it includes 42lb/hr injectors which is much higher than the stock 24lb/hr can that be tuned down?

 

Totally different characteristic from TPI, so although it may barely run, it needs a significant amount of tuning.. friend of mine built one with aftermarket heads, cam, longtube headers, and he needed to tune it quite a bit. Personally I think that a ported SuperRam is much stronger although peak power may be close to the same and if the exhaust and cam support it, perhaps a little more with the ProbFlo above 5500rpm

 

I believe he was referring to the ecm that comes from Edelbrock with the pro flo 4 complete package.

 

I believe you can get different packages with the Pro Flow 4, some packages have the smaller injectors, I have never used the Edelbrock system
but you have to consider if it is can control things like torque converter lock up, your fans, and ac and will work with factory gauges.
I had the Chinese version of the Pro Flow 4 intake and ran it with the factory ecm, it took some work making the tune work but when I was finished
it ran really well, the Chinese copy was junk and I liked the power curve of the TPI better for the way I drive and use the car so I ended up going back to the TPI.

 

Could also consider the XT style system...

This would probably produce a power curve and characteristics similar to a Miniram (which IMO is a good thing... I absolutely love my Miniram).

However the Miniram is notorious for low speed air/fuel distribution issues when you run the earlier GM batch fire EFI systems. It's something I've had to go to great lengths to minimize/eliminate.

But the advantage the Edelbrock system has is that it's a sequential system, so that would mostly mitigate the A/F distribution issues by being able to tune cylinders individually... something GM was finally able to do in 1994 with the LT1s.

 

I have the 4150 version with 29lb injectors. It tunes down well-you input the camshaft and displacement into the app and it auto-adjusts. It runs rich until 165* when it starts its loop with the O2 sensor. After that it runs good. It depends on two things-accurate fuel pressure under all conditions, and accurate O2 sensor information=no exhaust leaks.

I ran into a bunch of snags with installing the Pro Flo 4. Here is a list:
1. Distributor turning itself because the intake manifold and dist mating surface was too smooth and the gasket just twisted as well. Had to sand down both surfaces to increase traction.
2. Custom made brackets for fuel lines, ignition coil and throttle cables.
3. Cruise control no longer works due to butterfly open/close actuation force is too high.
4. Distributor too tall and causing interference with cowl. When the engine rocked under load, the distributor twisted (caught on cowl) and threw off timing. I cut the cowl=water coming down the distributor, which is fine, its well sealed. At this time there isn't a smaller cap.
5. Distributor rubbing against hood. I suspect this is the case but I need to confirm with clay. I installed spacers on the hood to windshield area mounts to gain a few mm's bit of clearance.
6. Air cleaner rubbing against hood-after modification to make it lower-this is the 10"round low profile version from Edelbrock. Honestly this is the biggest snag. The Pro Flo 4 is very low, but the air cleaner situation is just too small of a packaging area. My air cleaner rubs against the hood and twists under load. Not good. Also, the underhood temperatures are too high to suck in air from-it needs colder air. As much as I hate to say it, I'm going to have to cut the beautiful, streamlined hood to gain clearance to the air filter and vent radiator exit air. It's unavoidable. I'm also going to cut the distributor area too, so that it is for sure not an issue.
7. Walboro 255lph fuel pump in a new fuel sender asm. Not an issue, just something that I did that helped get the fuel pressure up to snuff.
-I know this all sounds negative, but I am completely free of the GM system. It also has more power. I got to experience my engine with TPI and then Pro Flo 4, and the pro flo just has the top end the TPI doesn't. The loss down low isn't a whole lot. And the best part is, I can run any camshaft or wild combo of small block engine one can dream of, and run it reliably. You simply cannot do that with a stock ECU. I have an 85 that has the soddered in chip so it wouldn't take well to engine mods. I will say this OP....sell and get a C5 unless you love your C4, and don't mind making it a racecar. I tore out all my HVAC and did a full heads/cam/EFi/exhaust. I'll just say this-the C4 takes more power very well. I'm going to put a 383 and a hood scoop/vents to my car.

 

With modern aftermarket ECU's and modern injectors I wouldn't worry about tuning or the 42 lb injectors. The self learning functions on the new generation of ecu's is amazing for tuning fuel maps. Even if you have no idea what you're doing the software is made to help you figure it out. And the more you drive it the better the fuel tune gets. Just remember you NEED a good wide band O2 to make that happen with no exhaust leaks. Setting the correct frequency for a knock sensor helps a little too. This is so you can dial in the timing table. But this is optional.

As for the injectors, I'm running 72 lb Holley injectors in mine. It idles fine and I could daily drive it if I wanted to. I ran Delphi 38 lbs before that and they also ran fine.

 

Thank you for all the problems i was also curious what did you do for the vacuum lines and everything that goes to the stock tpi?

 

thank you for the advice i was going with edelbrocks pro flo 4 efi kit wich comes with all the sensors i need.

 

I cut the original stuff and keep it in a box. I could put it back on if needed but it's no longer necessary. Vacuum lines I disconnected and deleted with the HVAC. Since the cruise control doesn't work, it isn't hooked up to vacuum. The only vacuum is to the brake booster. I still need to redo/route the gas tank vent hose differently since I haven't touched it. For the serpentine belt I have two delete kits, one for the HVAC compressor and the other for the vacuum pump. I still use the original serpentine routiong and belt size but it is longer than necessary now. At some point I will delete those and get a shorter belt routing.

 

alright, i want to keep my ac is there any vacuum lines that id need to route for that? and where does the brake booster connect to? also any other connections going to the tpi that had to be removed?

 

Brake booster has a big line that just pushes into a port in the PF4. Simple. If you want to keep your A/C then its a different story and I don't know the specifics for it. I would deep dive into the search function or use google and find diagrams of the vacuum lines to the HVAC. You have to be careful as there is vacuum lines that go underneath the dash. When I replaced my radio I found three vacuum lines going into the HVAC controls. You'll have to check every line start to end to make sure you don't have leaks from a disconnected hose. You'll probably have to replace the lines as they are likely 30+years old now. I found tears in the lines that I had, or cracks, from I assume to be heat cycling and age. I would buy in bulk of the diameter of hoses the car has.

 

would I be able to use a splitter for the brake boost and hvac system off of the port labeled fuel pressure regulator vacuum reference port?