oldred95

As of now I've got a Mallory regulator inline of an empty stock regulator. All that is left of the stock one is the diaphragm and a stack of washers in the spring cup to support it. The regulator is hooked inline on the return line between the throttle body return outlet and the hard return line going to the frame rail and to the tank. I still however seem to be having some issues with pressure drop/fluctuation. My idea now is to completely block off the return passage inside the stock regulator and have the only line to the throttle body being the supply line. To do this my supply line from the pump would be hooked to the regulator inlet, a line to the throttle body would be hooked into one of the regulator outlet ports, and the return line would hook to the return port of the regulator. By doing this I should be able to completely eliminate the stock regulator and have no possible chance of it causing a restriction in flow or pressure fluctuation would it not?

xch3no2

You got it! OOPS! nix that,
I blew it & didn't read your post close enough!

If you do it that way the injectors will be subject to pressure fluctuations from the regulator.
Information corrected below.

dimented24x7

iTrader: (2)

The stock return passages are a restriction with high flow fuel systems. Thats definitely the way to go to solve it. I had the same issues with mine as well when using a walbro 255 at 35 PSI.

oldred95

The easiest way to plug the return outlet on the injector pod would be to find or make a plug. I've got a spare or two to work with but I would like to eliminate the regulator housing all together so that I don't have to use a block off plate or anything. Might help unshroud the throttle bores as well. I'm thinking of just cutting the regulator portion of the housing off and having it tig welded shut. Any reason why that wouldn't work?

Ronny

iTrader: (1)

I used a plate of .125 aluminum and carefully cut shaped to produce a block off plate(used dremel) and small rat file using reg as template. Drilled holes. Then with a small utility blade specialty knife cut a gasket out of carb gasket material. I used stock regulator screws to attach plate to TBI. Neither TBI nor reg was damaged. It did not leak.

xch3no2

uh oh I think I read too quickly through your post.

Fuel pump supply goes to pod inlet,

use the method Ronny described to block off regulator mounting pad,

your regulators input is connected to the pods outlet,

the regulators return to the tank return line.

Just like you have it with a blockoff plate in place.

http://stores.ebay.com/TBIPARTS_TBI-...=p4634.c0.m322

Ronny

iTrader: (1)

Reg is downstream after TBI unit. I can place a pic when photobucket is up runnin. Gauge can be placed at reg as well.

oldred95

I think I know how I want to do this but I have a few more questions too. A long time ago someone posted pics on here of a stock pod that had the regulator housing cut off the upper half of the pod itself. I am thinking of doing that to mine and then having the hole tig welded shut.



Doing so will kill a couple of birds with one stone. It will block the throttle body so it won't have a return passage anymore and it will help to unshroud the throttle bores once I do a little more work. I plan on completely grinding off the return passage in the lower half of the pod as well and having that welded shut so there is no unmetered air leak.



My other question is what is the orfice or jet in the center of the lower portion of the injector pod for? It looks like possibly some sort of air bleed but looking it over I don't see that there is much space for excess fuel to bypass inside the injector pod housing and make its way back to the regulator and on to the tank.

Orfice in question:


Looking the pod over it appears the fuel enters the bottom of the lower portion of the pod through a passage in the pod housing and then flows to and around the injectors through the small holes in the housing shown in this pic.



So it looks like the fuel enters the lower hole in the side of the injector bore and then the excess flows out through the upper hole in the injector bore, to the center of the lower portion of the pod and so on. Looks like by cutting the regulator housing clean off and welding it shut I can eliminate the restictions and just feed the injectors a steady flow of metered fuel. Main thing in question is the orfice. Can I remove it or drill it out? Seems like it would promote better flow to the injectors with it out of there.

For what its worth I am using a 97 vortec 350 pump.

oldred95

Had some free time at work and started cutting into the injector pod. I cut the regulator housing off the upper half of the pod. This left an angle drilled hole that needs to be filled. I had a 1/8" pipe fitting and it appears it will self thread pretty easily into the hole. I need to get a 1/8" pipe plug and either screw it in or try to tap some threads for it, put JB weld on the threads then cover the entire area with JB weld to be safe. I don't have access to a tig welder otherwise I would do that.

Started looking over the lower portion of the pod and measured some things. The steel fitting on the supply side between the hard line and injector pod chokes down to a 9/32" passage. From there it goes down to a 1/4" passage thats cast into the lower portion of the injector pod. It then turns and goes forward into the floor of the pod. I drilled the 1/4" passage out to 5/16" as well as the steel fitting so the supply side should at least be equal to the ID of a 3/8" steel line if not a little bigger.

I ended up drilling out the orifice that sits in the center of the lower half of the injector pod. Its pressed into a passage that goes down to join the fuel supply passage coming into the bottom of the injector pod. I drilled out the passage the orifice was pressed into to 3/8" as well. The pod should now be able to flow some serious fuel when the time is needed. The only problem I see is a potential for an air pocket to get trapped in the injector pod since it will be returnless but I don't see that causing any real issues.

xch3no2

All I can say is this will be a learning experience for you,
and
buy a new pod now.

Returnless systems have a quite complex pump/pressure control design.

While not completely returnless, your injectors will feel far to much variance in pressure. I woulda tried to stop you, but yesterdays pics showed the pod already cut.

Have fun!

oldred95

Why? This is my spare pod for what its worth.

Its not going to be returnless entirely, just the fuel flow to the injectors will be returnless and it will source its fuel from an outlet on my external regulator. I don't see how you are saying there will be a variance in pressure. There is already a huge variance in pressure as it is with the stock pod in place just bypassing fuel to the external regulator.

Nothing has been cut on in those pics.

xch3no2

My bad, pod is not cut in photo.

Continue, let us know how that works out for ya.

oldred95

I got the fuel feed hole that went to the regulator housing plugged today. Got a 1/8" brass pipe plug and it self threaded into the hole. I didn't get wild with it but I put JB weld on the threads for sealant, screwed it in, then put a layer of JB weld on the inside as well as the outside of it. Going to apply a second coat tomorrow just to be sure.

Fast355

iTrader: (2)

I had no issues with the Walbro 255 and I was running 16-18 PSI @ idle and 28 PSI @ WOT. 350 Vortec Marine TBI and 28 PSI VAFPR. Same pump is pushing 50 PSI on my LT4 injectors with no issue.

oldred95

We've been over this. You are you and everything always works perfect for you.

oldred95

Well its on and working. Had a heck of a time getting the big orings back in around the injectors but I guess when you've used them twice already they tend to swell a tad over time. I was hoping to stack my ebay injector pod spacer and the stock 454 spacer together for what would give a 12mm thick spacer but the screws weren't long enough. Anyone know what thread the injector pod screws are?

The JB weld held great, actually not a single leak anywhere at all which is good. First thing I noticed was the extra pressure. Engine running before I had 30 and was idling at 14.5:1 AFR. On first start I had a solid 38 psi and I backed it down to the 30 I wanted and cracked the throttle a few times and all that happened was the gauge stabilized at 30 psi instead of bouncing at idle with each injector pulse. I didn't get a chance to drive it yet, that will be tomorrow but as of now it seems promising.

dimented24x7

iTrader: (2)

Which pod did you use? Not all pods where equal. The later pods for use with high pressure had larger passages, and where less subject to problems with pressure drop thru the regulator. This is something that can be verified by setting the pressure at a constant value and revving the engine. If the return passages are a restriction, the fuel pressure will drop with the engine under load. In that situation, you should swith to an external regulator and just feed the TBI fuel w/o any return. Its not ideal as you can get trapped air in the pod that cant be removed, but it solves the issue of pressure loss thru the regulator.

The best pods to have are the late model BBC high pressure ones, but they are not easy to come by.

oldred95

Went and drove it and it ran good just going down the road, light throttle and so on. When I got into it some it did seem pretty lean under load from about 6000 hz on up but I don't believe its fuel pressure related. Before the drive I had a steady 30 psi on a liquid filled gauge and after driving 45 miles I was showing a steady 26 psi and the gauge was warm to the touch. I know gauge reading vary with temp so I'm not worried about the slight change, I'm fairly confident the pressure stayed steady at 30 psi the entire time.


Watching the gauge while cracking the throttle resulted in no pressure drop at all. The only thing that did happen was the gauge did not bounce with the injector pulses like it does at idle but it stayed steady at 26 psi after the drive.

I still however can't seem to figure out whats going on with AE. Sitting in the driveway in park I can crack the throttle to say 25% and it pegs rich on the wideband and hesitates and stumbles until it gets the fuel burnt out. I can do the same thing only putting it to the floor and it shows rich on the wideband and has the same hesitation and stumble. Sometimes I can actually make it kill the engine. Now then while driving its just starving for AE fuel. Lets say I'm taking off from a stop at 20% throttle. It gives a nice little lean bog while taking off, part throttle up shifts make it go lean, and on a WOT stab from a stop it goes lean to the point of almost killing it if I don't back out of it. I'm not sure what to believe. Its like their needs to be two seperate AE vs MAP tables, one for in gear and one for in park but it shouldn't have to be that way. The only thing I can figure is its too much AE all together and in park the load on the engine is light enough it can go ahead and burn enough of the fuel to indicate rich on the wideband and in gear the load is so high the fuel just drowns out the spark and the engine is more or less pumping air which is making it show lean on the wideband. Does that even remotely make any sense?

Here is what my AE is currently set to:

MAP AE correction vs RPM:
1.99
1.99
1.99
1.99
1.99
1.99
1.99
1.99
1.50


Delta MAP AE:
19.81
19.81
19.81
19.62
19.23
18.93
18.45
17.76
16.79
15.32
12.79
9.47
5.95
3.22
1.56
0.68
0.00


Delta TPS AE:
20.02
19.04
17.97
16.99
0.00

Fast355

iTrader: (2)

Both of the last setups I ran were Marine high pressure setups. One had the high pressure 46# injectors and the other a set of high pressure 61#. The first was off a 320 HP TBI 350 with L98 aluminum heads and the later was off of a 405 HP TBI 502 Mercruiser.

Ronny

iTrader: (1)

A trick I learned with o rings on 2 cycle heads is to place them in freezer to restore size. try that with injectors.

oldred95

Haha yea I guess things do tend to shrink when they get cold.


Well its raining, has been all day, so there is no point trying to play around with the AE because it will just blow the tires off and not give me any real data.