92 tpi conversion that won't run

I'm not sure if this would be the right forum, but I'm sure it's a good place to start. I have a 72 toyota Land Cruiser with a 92 tpi conversion V-8 (70-Lt1)
It has always run well, but with fuel delivery problems. Mostly vapor lock and the fact that I'm running 2 tanks.
Recently, in an attempt to solve my problems I installed 2 low pressure pumps, (1 per tank) intended to supply a small reservoir, mounted High on the firewall to supply the high pressure pump. That pump now mounted on the fenderwell. The bottom of the reservoir is about even with the pump so the supply hose drops a little below the pump before feeding it.
The reservoir has a feed and return, to and from the tank. Then the high pressure pump has a supply line, then the return from the engine feeds back to the reservoir.
I read about this trick in the TPI conversion hand book from JTR.
Now the problem. After I did this it seemed to run fine. (in the driveway) I went for a test drive and ran GREAT, to the corner.
Then it shut down as if I turned the key off, except for the fact that I still had power to everything.
I have good spark and fuel is feeding to the reservoir. I replaced the High pressure pump, since it was questionable. It still won't even fire.
I'm wondering If I should check elsewhere, Like the o2 sensor. Can anybody tell me what voltage the o2 runs, for testing?
I can probably figure it out on my own with time. I'm currently working 80 hours a week, between that and looking for a new job I'm a little pressed for time. Thanks in advance.

Id suggest you go to www.thirdgen.org and post this in the TPI section. Atleast therers alot of people there that are quite familiar with this motor.

actually the tpi is my baby, i love em, eat, breath, and sleep em, so lets see if i can help ya out here. if you have a fuel pressure guage, i would install it on the fuel rail on the back side of the passenger side fuel rail. you should be running 41 psi minimum. you said you have spark, im assuming you have compression, so testing for fuel is the next step. also, a trick to see if youre getting fuel is to get a can of gum cutter and spray it into the trottle body while the engine is cranking and see if it starts. also, check to see if you have power to the injectors. now, when you did the swap, did you also include all the propor sensors, the ECM, wiring harnesses, and DLC connector. and the bulb for the check engine light???? if you have the light then i can tell you how to test the engine for codes. if you dont have that light hooked up, take it to the dealership and have them scan the computer for codes. probly tell ya what ya need to know. or at least point you in the right direction. now, if you have neither of these items (the DLC connector or check engine light bulb) then ill have to do a little homework and tell you what terminals to wire in order to check thecodes at home. but it is still possible. but it does sound as if something isnt correct with the engine controls, rather than a fuel delivery problem, although that does sound like a pretty complex system you have there. but let me know what electronics you have transferred over from the doner car, and ill see what i can do to help ya out here.

I'm wondering If I should check elsewhere, Like the o2 sensor. Can anybody tell me what voltage the o2 runs, for testing?
it's pretty low. i think the O2 creates a variable voltage anywhere 1/2-1 1/2 volts. dont quote me on that. but even if it is bad, it should run fine for atleast 2 minutes.
guess i'd have to see your set up to understand this, but why do you have 2 low pressure pumps pumping into a resovor? why don't you either use one pump with a Y-fitting to both tanks or use a valve to select a tank, with a return line spliting to both? seems a little expensive to run 3 pumps

oh, and are your low pressure pumps putting out enough volume to keep the resovor full? they dont have to put out much pressure just plenty of volume

Thanks for the help.
sorry, it took so long to reply. Turns out I had another bad fuel pump.
I just don't have much luck with these inline fuel pumps.
Here's another question for you. The pumps I'm running push 100-125
psi. I know that is overkill, but can anyone tell me where to get or what brand name to look for. I need an inline style pump for T.P.I. I have concidered reducing the voltage to the pump but I don't know how to do that without buying a $300 controller that is realy intended for n.o.s. applications.
If I want to spend that much, I will get a custom built tank for an intank pump. Hell after all the time and effort I have spent, I soppose I should have done that a long time ago.

What if you had an adjustable fuel pressure regulator and kept the pumps you were running?

well, even though it was the fuel pump, for 02 sensors, the voltage varies quite rapidly and wildly from anywere around 90mv to 900mv or so, which is normal. they shouldnt be putting out a single voltage to be meansured.

What if you had an adjustable fuel pressure regulator and kept the pumps you were running?
Well the T.P.I. has a built in regulator. My theory for dropping the voltage by 1 or 2 volts is to take some of the stress off the pump and perhaps gain some reliability

holley makes a replacement pump for their aftermarket port injection set-up's. i bought one a few weeks ago, no problems yet