502 Procharger fuel system setup problem
 

I have a 2000 502 mefi 3 with a m3sc procharger setup. the boat is new to me this year, and I have had issues with the fuel pressure going to high on me since ive had it. With the ATI boost referenced fuel regulator, it had very inconsistent pressures and would sometimes go up to 70-80lbs+ of pressure. I replaced this with an Aeromotive regulator followed by a Bell boost referenced regulator and have had similar problems, including where I can't adjust it below 70lbs of pressure even at idle. I'm now pulling the engine for a rebuild and want to have this working correctly when it goes back in....

Attaching a diagram of my current setup. I realize the return from should be run back to the tank and not the input to the pump, and will change that, but don't believe thats causing my current issues. Hoping eddie young, articfriends, or anyone else will have some ideas for me.

http://i.imgur.com/0hpR4GW.jpg

get rid of that boost-referenced regulator and tune the mefi3 for boost. Done. You'll never get the Bell regulator, or any other boost-ref for that matter, to remain consistent. Been there...did that.

Griswald- thats not a bad idea, however I can't even get the aeromotive regulator with no boost reference to maintain a constant pressure. Seems like there is something else going on. At one point i ran a return line directly from the Aeromotive Reg Return port back to the tank and the pressure was still 70lbs with the adjustor all the way out.

The issue is that it's returning to the suction side of the pump. I have been running boost dependent regulators with a returned system for a few years now and it's always the same. I have dash mounted fuel pressure gauges so I look at them all the time.

Where are you taking pressure?
By your diagram, there is no regulation to what you're referring to as the end port. If that's straight out of the pump that seems like an issue to me.

FWIW - I ran the return to the inlet of the pump for years without issue. Not saying a return to the tank isn't the right way to do it, but certainly not causing the issues you describe.

Fuel pressure sender on the port of the Aeromotive 13101. Verified the gauge with another fuel pressure tester, was within 1lb

I edited my post - re-read

Mine was never super consistent with it looped back they to the pump.

I see what your saying about the "end port" line, that was one of my concerns, I'm not sure if that's correct or not. There is two ports on the fuel rail- the "end port" i referenced is being fed by a small hose directly from the A1000 supply end. The "middle port" is being fed from a bigger supply line from the A1000 supply end, with it being T'd off at the cool fuel with return to the regulators. I've read Eddie Young post saying you should be supplying both ends of the rail- should both of the ports be supplied from the big line that runs through the cool fuel box then?

I agree return to the tank is best and I will fix that, but I already tried this and still had high and inconsistent pressures. I ran a hose directly from the Aeromotive Reg back to the tank just to test this.

the cool fuel should be on the return side before going back to the pump. Send me your email and I'll dig up some pics of my setup to give you a clear picture. Works perfectly. And, without the boost-ref regulator. You should really think about getting that out of there. The motor will run so much better without it. You will have to find someone to tune it if you're not willing to try it yourself but it will make a huge difference in the long run.
How much boost are you running? Still using the stock injectors?

Griswald, will PM you my email for pics. Are you supplying both ends of the rail then?

Its a stock engine with 5lb boost, stock injectors, 1 bar MAP sensor. What would you recommend for self tuning something like this? I assume I would also need a 2 bar MAP sensor and larger injectors?

I ran stock injectors at 50lbs pressure, mefi4 ecm with 2bar map and tuned myself with MefiBurn/Scanner Pro. M1 Procharger @ 6lbs. I'll share my experience via email and/or a phone call or two. Send me your # as well.

X 1000. The ATI 'fuel system' sucks major Donkey Dick. Excuse the french.

I'd take Griswald up with his offer.

Yes i look forward to talking with griswald, but it does seem like I have a weird issue here. I cant even set a constant 50lbs of fuel pressure with only the aeromotive regulator- while the boost referenced regulator is bypassed completely.

because you have no regulation coming from the pump to that end port...

The onlu fuel pressure anyone wants to see or care about is the pressure the fuel injectors see. Otherwise known as 'the rail pressure.Therefore, it must be before any regulator on an EFI system that has a return line.

Oh, just as a heads up. If you have a permanently mounted liquid filled guage near a heat source, it will read higher and higher as it gets hotter and hotter...lying to you....making you think your fuel psi keeps changing on it's own...even if the fuel psi isn't actually changing.

Just a suggestion, come out of the tank to a 100 micron or less filter, go to the pump, out of the pump to a 10 micron or less filter, go to the fuel rail, come out of the fuel rail to the regulator, return back to the tank. Read your pressure at the regulator. Keep the boost referenced regulator so the fuel pressure increases as you build boost pressure in the intake manifold, Weldon makes a good regulator. Skip the cool fuel, sending it back to the tank will work just fine.

If you haven't already done it I would suggest you check the size of the pick up in the tank. Prochargers like a LOT of top end fuel.

Oh, another BTW: The ATI regulator is an FMU. Meaning, it has a different rate of fuel pi increase than most referenced regulators. Sometimes , they are 3:1, sometimes 5:1, and in some applications something crzy like 10:1 and 15:1.

FMU's are so 1980's and 90's.

All EFI systems with returns need manifold referenced pressure no matter what. But normal style. It's all about correct net psi at injector tip. Ie: manifold vac/psi vs fuel psi to the injector.

I don't have the experience and knowledge that a lot of the other guys commenting on this thread do but I can tell you about my experiences over the last year with a Procharged fuel system. When I purchased my boat my fuel system was set-up just like yours. I think that is the way Procharger recommends to do it. Actually worked pretty good for me.
My set-up was an M3 on a 502 running 7 lbs. of boost. Mefi1 ecu and 1 bar map sensor. Stock 42lb. injectors
Well I put an O2 sensor in my exhaust and found out I was too lean above 4800 rpm. I was running 80 lb. of fuel pressure at full throttle. I also was using the Bell regulator. Since I was too lean I had my Mefi1 reprogrammed to allow more fuel at full throttle. Still was too lean. Since you are at 5 lbs. of boost you might get by with stock injectors. Im not sure about that part.
Anyways this is what I did.
1. Purchased 72lb. injectors from RC Injection. They will fit into the stock rail.
2. Modify the fuel rail per Eddie Young's instruction. Or you can buy one from him. Then you can feed it from both ends and return to the tank.
3. Fab a larger pick up for your fuel tank. I went with .48" ID tube
4. Go -10 line from tank to a fuel/water separator with 1/2" npt fittings then -10 to fuel pump then to the after pump filter. Now -10 to a Y block. Out of
the Y block with a -6 to each end of the fuel rail. come out of the fuel rail to the regulator and return to the tank.
5. The final thing I did was purchased a Holley Hp ECU from Haxby. Everything will plug right into your engine. The Hp is a self tuning unit and Haxby is
a great help with supplying a base tune and helping you out along the way.

Also if you have an older Aeromotive pump you may find that the ethanol in the fuel is eating away at the epoxy in the pump and clogging your injectors with it.

Do you have a vacuum line going to you cool fuel system? Mine increases fuel pressure when the vacuum drop below 10 psi. If not, tune for boost like mentioned earlier. Plumb in an O2 and slowly increase your engine load while tuning. I used MEFIBurn to tune and ran scanpro while running a screen video program to watch RPM, Map and Innovate O2 software. Boats are stupid easy to tune vs. cars.

Good call on the aeromotives too. When the older s5yle epoxy that holds the magnets on fails, and i think they all do, the magnet flees the outer housing becomes one with the armature and your getting towed back to the trailer. Believe the updated ones have a different color glue . Prob Wont help your erattic pressure issue. But may leave ya stranded

as said, the fuel system the way procharger does it is a bandaid at best, need good micron filters, before/after pump, a good boost referenced regulator and a return to the tank, stock fuel rails needed to be modded or replaced, eddie young as stated, and ECM needs to be tuned or a good ECM setup installed. A prochager did was to jack up the fuel pressure into the twilight zone and pray you did not hold it wide open for to long !!!!

That was a nightmare for a lot of us !

I wonder if I have some of my e-mails with the Aeromotive engineer(s) back then. Maybe 15yrs ago ?

Disaster !

BTW: We did not have ethanol fuel in our area then, and I still got bit bad by the epoxy/magnet thing.

I ran my m3sc setup w stock gen 6 502 injectors well into the high 600 hp range 8+psi of boost, have still to this day never made a return loop to tank. I teed my return into suction line of pump but i do buffer it with a fuel filter before the pump. all my fuel to the rails goes un obstructed thru thru a aeromotive regulator to rails , the regulator bleeds the extra fuel off thru a bell regulator like your using that is boost referenced and still today i run it like this over 1000 hp. i am running larger injectors , a giant fuel pump and even back when I was making 680 hp I had ecu tuned to open injectors further. I thik tyour un regulated fuel to the rail is screwing you up plus teeing the return directly into fuel pump inlet. the a1000 pump is garbage, atis red regulator is a pos of garbage if your still trying to use it. when I had their regulator my fuel pressure was never the same twice. if you start regulating all your fuel, get the return line further away from your pump this could be made to easily work , install a 02 bung somewhere in your exhaust once you get your fuel press right and have someone tune it or you will wash rings or lean it out and blow it up, Smitty

Just curious, why wouldn't you run full pressure to the rails and then the regulator for those times when you need the maximum volume. And why wouldn't you return the fuel back to the tank to take advantage of the cooling affects it has on the fuel ? What size is your giant pump ?

Here is a post that I made quite a while back on putting a Procharger on a 502 Mag. I have not read this entire thread, so maybe some of these items were touched on already.
Eddie

IMO, there are several things that should be done if you want it to live a long life and run to its potential.
First, you should change the head gaskets to Cometics. If you are going to run over about 3 psi, then the exhaust valves should be changed to something like Manley's Inconel valves. You will also need to upgrade the fuel system. Take the Procharger regulator and throw it in the garbage. Use a standard 1:1 boost referenced regulator, like an Aeromotive. I would replace not only the fuel filter head to a larger one, but also the fuel lines and the pickup in the tank if it isn't large enough.(most are not large enough in production type boats)

Depending on the year of the 502 mags, there were 3 different versions of the fuel rails. The pre 99 versions have a few issues. The supply hole to the #7 injector needs to be opened up in a mill. Also, the rail should be fed fuel from both ends so that one end isn't run dry. There are quite a few other mods that needs to be done to the rail in order to make it really work correctly. The 99 and up rail needs less mods. It still should be fed from both ends, but it is already threaded for 1/4" NPT, so it's much easier to do.

With 5 psi boost, you should be in the 625 hp area. The stock injectors are good to about 650 hp without killing them by running them to hard. You can make more than 650, but it takes its toll on the injectors. If you have a pre 99 fuel rail, then you will have the Keihin injectors. There are no drop in replacements that are larger than the stockers. You can install larger injectors but it requires drilling out both the intake and the rails and/or replacing the rails with some custom ones. If you have a 99 and up, they use the shorty injectors, so they can be replaced with larger ones if you want to make more power.

The other thing that must be addressed in the ecm. Obviously, it will need to be retuned. The best bet is to put it on the dyno and tune it.

We have done a TON of these. I actually have a few in the shop now that we are doing. If you have any questions or need any help, don't hesitate to give me a call anytime.
Eddie
615-216-7449 shop
504-416-3607 cell

My fuel rail ends butt directly into the distributor on the back end so no way to run return lines off back end, I feed each rail with a -8 hose, all the fuel flows unobstructed thru the 1/2 port on my regulator right before the rails. It has never vapor locked, layed down or been a problem even at 1100hp . I run a fuel cooler after the pump (small oil cooler, not stock garbage). Because its never posed a issue I never wasted my time running a return to the tank, now finding a pump that keeps up without overloading the regulators is another story, was running a a 1000 years ago, couldnt carry past 700 hp, ran a essex, barely carry 950hp even with a voltage booster, went to aeromotive eliminator, couldnt get past 1000 hp without the voltage booster, ran a aeromotive pro series, kept up fine, went back to aeromotive eliminator on the dyno this summer when I quit boost referencing and went to 80 lb injectors doing everything strictly off PW. Its all a moot point at this time since I just bought a twin engine boat w hp 500s, when I build another blower motor to match this one to go in new boat I will be going back on boost and hp as boat will be plenty fast with 300 hp less per motor than what I made with my old motor