You would need the older style of fuel pickup, otherwise you can't suck fuel up through the non-working electric in-tank pump.

 

When you changed over to a carb, did you put in a fuel regulator?  Have you tried changing the fuel filter?

 

I tried to put in a fuel regulator. it went up to 9psi.  it would idle but die on a higher rpm. so i took it off 
it has a new fuel filter.
it was running fine for three months, but now it is acting up every once in a while.

  the return line is not hooked up because the regulator was taken off. i wonder if it was pumping too much pressure continully and ruined the pump.

  from what i can tell their is a check valve in the stock pump to hold pressure for the initial startup
on the tbi set-up. would that stop fuel flow if i put a mecanical pump on it.
    i dont have a  pump to test it with. just wonder if anyone has done this

 

i did the same thing to a 89 and iirc it would not pull the fuel thru a dead eletric pump. i had a old tank so i swap that in and everything runs great.

 

Tear diaphragm out of electric pump and mechanical pump can use it as a pickup tube... Let me know if it works, I have never done this...

 

one other thing to think about is the ecentric (the oblong thing) that drives the mechanical fuel pump probably won't be on your engine (wasn't on my 89). no real problem but takes time to bolt on. (you have to remove the timing cover to put it on)

 

one other thing to think about is the ecentric (the oblong thing) that drives the mechanical fuel pump probably won't be on your engine (wasn't on my 89). no real problem but takes time to bolt on. (you have to remove the timing cover to put it on)

He will also need the cam extension for it to bolt one on. The cams are not long enough stock to hold the eccentric and still have the key hit and hold it's mounting position.

 

Tear diaphragm out of electric pump and mechanical pump can use it as a pickup tube... Let me know if it works, I have never done this...

I don't think they are diaphragm pumps, think they use rotors.

 

I don't think they are diaphragm pumps, think they use rotors.

oops! Guess that wont work.

 

well i got to looking at the manual, pics for the stock pump.
it looks like the pump is at the bottom of the housing. 
there is a tube from the pump to the top of the tank cover or lid. 
  i am thinking of dropping the tank and pulling the pump out, and putting a hose from the lid to the bottom of the tank. then puttin and strainer of some sort on it.
    i looked at autozone and other places for inline fuel pumps.
  found a few that were 5-9 psi for $50 -200
think i will use one of those for it as i beleive everyone about not having the cam lobe for a mecanical pump.
  the said in a couple adds to use the oil pressure  switch to run it from.

  the oil pressure switch would send the negitive to the pump right?


can i just run a wire from the switch to it? i am thinking that the oil pressure switch sends ground to the gauge, and it gets it from the block . so that when you have no psi you dont have a ground.
  would this be enough ground to run the pump?

 

the said in a couple adds to use the oil pressure switch to run it from.

the oil pressure switch would send the negitive to the pump right?

can i just run a wire from the switch to it? i am thinking that the oil pressure switch sends ground to the gauge, and it gets it from the block . so that when you have no psi you dont have a ground.
would this be enough ground to run the pump?

To me that doesn't make sense, because if you let it sit for too long and the fuel evaps out of the carb, you will not have the fuel to start the truck to get oil pressure to have fuel to run the truck........ you get the point.

Just fish a wire from an "acc" so it gets power when the key is turned on.

 

No tony, that's not the case.

You use a starter bypass wire, just like old ballast ignition systems. So when key is all the way forward "start", the pump runs no matter what the oil pressure is. By time you release the key you should have filled the bowls and/or built the obligatory 5psi or so of oil pressure.

This method continues to use the factory relay and harness.

Relay is better than toggle switch. Handles more current, no extra bs wires having to be ran in the cab either. Cheap and available 24 hours a day. Semi universal, meaning you can take one from another slot or vehicle.

Not a oil psi sending unit. A switch. Turns off when psi drops below a set point, such as during a roll over, stall, when key is on/engine not running, or when fuel line is damaged in a collision.

 

No tony, that's not the case.

You use a starter bypass wire, just like old ballast ignition systems. So when key is all the way forward "start", the pump runs no matter what the oil pressure is. By time you release the key you should have filled the bowls and/or built the obligatory 5psi or so of oil pressure.

This method continues to use the factory relay and harness.

Relay is better than toggle switch. Handles more current, no extra bs wires having to be ran in the cab either. Cheap and available 24 hours a day. Semi universal, meaning you can take one from another slot or vehicle.

Not a oil psi sending unit. A switch. Turns off when psi drops below a set point, such as during a roll over, stall, when key is on/engine not running, or when fuel line is damaged in a collision.

Ok that makes sense now..........

 

I get what you are saying about hooking up to the starter side of wire, in order to prime it. 
    right now it is just hooked up to a hot line when the key is on.      probably not the safest set-up.
  you are saying that im not to hook to the (sending unit) of the oil pressure, but to a switch .
like a solinoid switch?  have hot lead coming from it to positive side of pump, and the line from the oil pressure sending unit send ground to the switch to activate it?
  i will look at summit racing to see if they show the set-up and or the switch.
  i was wanting to put in a oil pressure gauge thagt was a live feed or had the tube from the sending unit to the gauge. but if i have to change that idea i will.

 

I get what you are saying about hooking up to the starter side of wire, in order to prime it.

Yes

right now it is just hooked up to a hot line when the key is on. probably not the safest set-up.

Correct. Plus it is drawing fuel pump current directly off the ignition switch. Ignition switch=expensive (relatively speaking) relay=cheap $5. (emergency situation, a jumper wire will get you home)

you are saying that im not to hook to the (sending unit) of the oil pressure, but to a switch .
like a solinoid switch?

Not a solenoid switch, basically the exact opposite of an idiot light switch. Idiot light switch normally closed (turned on) and breaks contact when oil psi goes above a certain psi. Safety switch is normally open (off) and turns on when enough oil pressure has forced the switch closed. Simple ball and spring action. A simple tee can be used where the stock sending unit is, so both continue to work as designed.

have hot lead coming from it to positive side of pump, and the line from the oil pressure sending unit send ground to the switch to activate it?
i will look at summit racing to see if they show the set-up and or the switch.
i was wanting to put in a oil pressure gauge thagt was a live feed or had the tube from the sending unit to the gauge. but if i have to change that idea i will.

You can use any gauge you want. See the tee comment above.

Jegs does show a diagram of how to set this up. I think it is in the fuel section, once you find the switch they have instructions listed.

The thing is, they run full fuel pump current directly through oil psi switch. This can/has worked.

I am trying to draw up a diagram in my head so that no switch carries any significant current except for the relay. A increase in durability over the jegs instructions.

I thing I have figured it out by wiring a 5 pin relay backwards.
Normal 5 pin relay has well, 5 pins. ground pin #85, a trigger (low current +) pin #86, 1 input (wired to battery) pin #30, and 2 outputs. pin 87 and pin 87A. 87a makes contact with pin 30 when the system is shut off. Switches to pin 87 when system is on.

(you should have on of these relays for the stock tbi system, it powers pump/coil/injectors/alternator) of course you ditched injectors. Basically, the output of the stock relay is a switched hot, but can carry up to 40amps when ever the switch is on/engine running. Your ignition switch could smoke if you loaded it like that.

This is basically how your stock relay is wired (not 87a not in use, 85&86 are backwards on this diagram, sometimes not polarity specific)

Second image shows how the relay is when it is at rest, not powered on 85/86. Continuity on 30-87A. When powered, arm moves to 30-87.

Now what I mean by reverse or back feed,
instead of pin #30 connecting to battery, connect it to fuel pump.
Connect 87a off of starter solenoid wire, hot ONLY in start position. Not the big main cable, the S terminal, AFTER starter relay. When switch is turned to start, current flows from solenoid, through 87a to 30 to pump.
87 is connected to battery.
86 is connected to any ignition hot source. It is low current so can be connected anywhere, as long as 12v is supplied. NOT the ignition coil, although you can connect to coil hot wire BEFORE ballast resistor. Preferably a wire that is NOT hot while turning over engine, but it is not critical.
pin 85 connect to oil psi switch. Ground switch to block.

Ok so what happens? You turn switch to start. As mentioned, current feeds off of S terminal on starter, through relay, to the pump. Pump primes until engine has built oil pressure or you let off the starter.

You let off starter because engine has fired. Almost immediately, oil pressure is above the minimum required to close the oil switch. The closed switch allows ground from engine block to pin #85. The ignition switch is on, which allows + to #86. Hot+ground=magnetism (in relay) which moves the contact arm from 87a to 87. 87 allows power directly from battery to #30 to fuel pump.

You stall out. Oil pressure drops for any other reasons (roll over, cut fuel line) anything that kills engine. With oil pressure at 0, the psi switch opens, no more ground to relay, arm snaps back to #87a, and power to fuel pump is cut until either the starter is engaged, or oil pressure magically recovers on it's own (push start for example)

Sounds tough, huh?

 

i think i have the jest of it. i am not good with electical on more complicated systems. i can make harnnesses for my old triumphs and harleys, but thats a simple set-up. charging and ignition lights. 
  i will check out jegs, just got off off summets site and didnt find what im looking for.
looked through fuel air sec.

 

i think i have the jest of it. i am not good with electical on more complicated systems. i can make harnnesses for my old triumphs and harleys, but thats a simple set-up. charging and ignition lights.
i will check out jegs, just got off off summets site and didnt find what im looking for.
looked through fuel air sec.

This setup is actually very simple, and a few rerouting of wires, will work for most anything, like head lights for example. Then cheap relay (try to use bosch brand)

As mentioned, jegs has them, forget about the instructions though. Should be around $23

If using your factory relay base, you have to switch around a few wires, nothing major. Give yourself 20-30 minutes, use a multimeter to verify connections (this is safe for test light testing, I just prefer solid readings)

Maybe this diagram will help?

 

ok just found them at jegs $21.00.   they have three poles so i am guesing that it is a solinoid switch.  hot lead in, ground in ,and hot lead out when oil psi is built up.  now can that run enough amps to go directly to the pump?  or do i need to go to a relay with a higher amp feed?
  i have plenty of hot leads when the ignition is on, due to the mass amounts of crap i took off when i d.x. ed the fuel infection.
 i basicly took the looms and every wire that traced back yo the computer on the fender well i cut off.
and the hot leads from the fusebox to the computer i cut at the computer and sealed them off.
 i then ran leads to ignition and made a harness for the alt and reg.
   i did not figure out the relay for fuel pump.   so i took a lead from the fusebox that was hot when the key was in the on position and ran it to the relay box.
    so whenever the key is on the pump is running.


   I am thinking that i could run the hot lead from the oil switch to the relay that i have now .
 right?

 

ok just found them at jegs $21.00. they have three poles so i am guesing that it is a solinoid switch. hot lead in, ground in ,and hot lead out when oil psi is built up.

No, it has a normal open and normal closed position. DO NOT hook up + and - to this switch unless you want to turn your wire into a toaster element. As a matter of fact, do not hook any + wire to the switch. Regardless of the instructions. Forget what instructions say, go with *modified* diagram.

now can that run enough amps to go directly to the pump?

Generic motors will tell you yes. The oil psi fuel cut out is the method they use, and they draw pump current through switch. Having seen many fail, I will tell you no. Plus it's harder and more expensive to replace oil psi switch.

or do i need to go to a relay with a higher amp feed?

This is a more fail resistant idea. I like heavy duty. I like cheap. I like easy. I LOVE the rare occasion I can get all of the above.

i have plenty of hot leads when the ignition is on, due to the mass amounts of crap i took off when i d.x. ed the fuel infection.
i basicly took the looms and every wire that traced back yo the computer on the fender well i cut off.
and the hot leads from the fusebox to the computer i cut at the computer and sealed them off.
i then ran leads to ignition and made a harness for the alt and reg.
i did not figure out the relay for fuel pump. so i took a lead from the fusebox that was hot when the key was in the on position and ran it to the relay box.

Ok, most any ign hot wire will work. When placed on pin #86 (look on bottom side of relay for number markings) pin #86 will only draw approx .2 amps.

Pin #85 (connected to oil psi switch and eventually engine block) will also have this current flow of ~.2 amps. With such a low draw, your wires are safe, and so is your $21 oil psi switch. It SURELY can handle .2 amps of the electromagnet coil. PLUS a real sweet benefit. With the switch located on the ground side, they will statistically last 2x or even longer than same switch on + side. Ground side erodes switches LESS, because they do not arc as much. The oil psi switch could conceivably last the life of the truck (as long as it is not damaged by water/heat) since it is only carrying .2 amps and on ground side. Double whammy.

so whenever the key is on the pump is running.

We will get rid of that and give you a safer ride at the same time.

I am thinking that i could run the hot lead from the oil switch to the relay that i have now .
right?

No hot wire on oil psi switch. We are doing "ground control" for above mentioned reasons. Yes the relay you currently have will work, just gotta modify the pinout slightly. Carry a few quality spares. MUST have 5 pins with 87a marking (some only have 4 and will fit same plug in) Cheap relays will get you home when walmart is the only place open, but may leave you stranded when you are in the woods. Bosch/Tyco.

 

ok you lost me . no hot lead to the oil psi.  just  one ground coming from it to where?  the  ground lead on the relay?   
  the three lead posts on the switch i saw at jegs would be for the afore mentioned chevy? 
one neg lead for the gauge , one neg lead for the fuel relay, and one neg lead coming in from power source.      i think that the lead that i took off just had one lead on it .  i could be wrong it was a while back.    i was thinking that the stock one got its neg from being grounded to block.
and it sent signal to gauge. 

 

ok you lost me . no hot lead to the oil psi. just one ground coming from it to where? the ground lead on the relay?

See above diagram.

the three lead posts on the switch i saw at jegs would be for the afore mentioned chevy?
one neg lead for the gauge , one neg lead for the fuel relay, and one neg lead coming in from power source.

No, it's not a sending unit and does not interfere or connect to gauge. It is based similar to oem chevy stuff. We are not going to use it for it's intended GM direct to pump crap. Need heavy duty/reliability. OEM engineers are not necessarily the brightest, so we deviate from the plan. Fuel pump or gauge either one, should not be connected to this switch in ANY way if you follow diagram. You will have 1 terminal unused, put some rtv over it if it bothers you.

i think that the lead that i took off just had one lead on it . i could be wrong it was a while back. i was thinking that the stock one got its neg from being grounded to block.
and it sent signal to gauge.

This is not sending unit, in order to have oil psi reading on your factory cluster, you must use factory sending unit. If you use a mechanical gauge, well that's self explanatory. If you want a gauge and switch (you do ) you need to install a tee in the factory port so you now have 2 ports. If you want the switch and both mechanical and stock gauge you simply add a 3-1 manifold like used in pneumatics/hydraulics. (no need for that non sense, 1 mechanical gauge is plenty)

This switch is totally unrelated to the gauge.
It will not give you an oil pressure reading.
No hot wires connected.
1 terminal unused.

 

went out to get some lunch. its my birthday so had a few shots of turkey and some pool. 
after looking at your diagram i get it now.
  that or a few shots brought on some mental clarity.

  thank-you for all your input.
      if it warms up this week i will get under the rc and pull the tank and see if i can either pull the pump and plumb it up with a new hose or gut the innards out of the old pump. 
  and wire it up for inline pump.
  we are getting more snow so have to see how it goes    thank-you again  mike fox