Step Side 88

First I apologize for not finding this in the search first but I wasn't able to formulate the correct question it seems.

I do have the FSM and am about to give the diagnostics a shot but I still have a few posts to go before I hit the magic #15 so here goes...
I picked up this 47K mile 88 efi PU project and it was minus the fuel tank. Picked one up at the local yard and hooked it up but as I'm still 'bedless' there is no fill tube connected, return vapor line or gas cap. Is that something I'll need to have in place first?
I'm new to FI systems and miss the 'look in the bowl and see if there's gas' of a carb... but I can change, if I have to.... I guess.
So My question becomes what ducks do I need to line up in order to get fuel from the gas tank to the spark plugs or to put it another way, do I need to prime/bleed the system ?
Also, is there a difference in fuel relays? I have one from the donor rig and the original. 2 different part#'s.
I don't hear a fuel pump when I turn the ign on. Engine cranks fine.

Thanks

abecedarian

When you turn the key to "start", the circuit opening relay (COR) should close and give the fuel pump power. This means it may take a moment before sufficient fuel pressure is built up and the engine can run. Once the engine starts and you release the key to "run", contacts in the air-flow meter will keep the "COR" on.

If you find you have to crank several seconds before the engine starts EVERY time you try to start it, I'd suggest checking the fuel pump, fuel pressure regulator and maybe even the injectors for leakage, in particular the cold start injector.

The fuel rail should hold pressure for quite a while once pressurized.

osv

at the minimum, you should be able to put 12v to the fuel pump directly, to hear it run.

i'm not sure that it needs bleeding, because you have a fuel return line going back to the tank, so the incoming gas should push the air back through the return line?

one thing you could do right now is to crack the cold start injector bolt, and see if there is fuel pressure in the system... it may spray out.

Step Side 88

Thanks... but I'm not that far yet. Still need to fire it up for the first time, but your pointing me in a good direction.
Is there an easy way to check for fuel @ the rail or someplace else to verify the pumps pumping and building pressure?

Thanks OSV... (got your post while I was typing this)
I now have a better idea where to begin looking. I'll see where that gets me.

abecedarian

If you want to "prime" the fuel system, there is an Fp+ terminal in the check connector to which you can connect B+ to; jumper between the two should run the fuel pump.

Step Side 88

And Thanks to ABC... I'm sure I can find this in the manual now that I have a few "proper names" to look up. Bunch of help guy's I'll post when I either get it running or get stumped which ever comes first.

abecedarian

ABC?

Step Side 88

My bad Abe... I was checking your name on my phone and those letters just sorta dislecticated themselves for some odd reason

scope103

You do have the fuel return line hooked up, don't you? The fuel goes through the Fuel Pressure Regulator and back to the tank. The Vapor line goes from the tank to the canister.

As abecedarian says, you don't need to prime it (the pump is in the fuel tank), but if you want to push the air out of the rail you can hook FP to B+ (with key on) just to force the pump to run without the racket of the starter. Without the starter cranking, you should be able to hear the fuel pump, and a slight whine as it pushes the air through the fuel pressure regulator.

You CAN "crack" the connection to the cold-start valve to see if fuel sprays all over the place, but the aluminum crush washers are one-time use and you're taking a chance of a leak if you don't replace them with new ones. If you can hear the pump running, it's "likely" you have fuel pressure. If you're concerned that the pump is not pumping anything, you can disconnect the return line (put it into a container) and see that fuel gushes out when the pump runs. (The return line is low-pressure so you don't need to worry as much about crush washers and the like.)

Step Side 88

Yes Scope I have the return line and the sending unit and vac/vapor? lines.
I'm just now heading out to try/test all the suggestions and have the FSM to follow as well now that I have the vernacular and references in synch.
In the mean time I have the donor door stripped down and ready to start sanding/prepping for paint, which I'm hoping my wife takes a shot at. She Loves to clean things

Step Side 88

using the FSM fuel tank install diagnostic all shows good up through the open circuit relay. What a hidden little unit! But that sucker has been checked and showed good so that whole glovebox speaker bit is back in place and will resume the list later. FSM rules for a nu b like me...

wyoming9

iTrader: (1)

You do have a tank from a EFI vehicle?? With the pump in the tank.

Might be a good idea to have pulled the pump and at least put on a new sock.

Then one never knows just what kind of crud the fuel pump may have been in since the tank was removed.

New filter might be a good idea once you get it running

Step Side 88

Didn't pull the pump to check it as I wanted to see what the 'starting' point is... I'm going with 'it works' as my default starting point. We'll see how that works out...
Already have a new filter in place, just need to continue the FSM diagnostic at this point and see where that leaves me.

Step Side 88

OK. The pump pumps but I'd don't have an electrical signal at the connector. Hooked up a bat. direct and could hear the pump pressurize the system.
tried the ign and still no running. (note I need to check the plugs for fire I just realized)
When I check the Fp and +B terminals I get nothing still.
Fuses are good (dbl checked)
haven't split the lines... figuring if the pumps working but not getting proper signal no need to go there.

reading the elec schematic it says the Fp = Circuit opening relay (checked out) to fuel pump circuit and the +B = the VSV(fuel pressure) which I think is what I need to check out next.
At this point I'm trying to step back and make sense of it al but I think I need to focus on wiring and connections till I find out why there's no power at the check point.

if I'm missing something please let me know and... I'll make sure there's spark at the plugs next.

scope103

Try re-reading your post, from the standpoint of someone trying to figure out the sequence. You say the pump pumps; is that ONLY with a direct-to-battery connection? "No electrical signal at connector"; when is that? I assume you're not talking about with the direct connection. There SHOULD NOT be 12v on the fuel pump with key-on, engine-off. (The pump does not run until you turn the key to START.)

"When I check the Fp and B+ terminals I get nothing ..." What does that mean? You checked each with a voltmeter? You jumpered them together and you did not hear the pump run? Was the key on? (With key on, jumpering those two causes the pump to run, even though key is not all the way to START.)

You're reading the schematic backwards. B+ is 12v straight from the battery when the key is ON. 12v also goes to the fuel pressure VSV and a hundred other places, you don't need to check all 100 of them (unless one is a dead short, and you'd know that from the flames). Fp goes straight to the fuel pump, which is how B+ to FP runs the fuel pump. The COR also goes to the fuel pump (that's the part that picks up the signal from the VAF to keep the pump running when you let go of the key.)

I'd like to help you, but I just can't figure out what you've done so far. Sorry.

Step Side 88

Thanks scope
Yes, the pump works if given a direct 12v.
I get that the pump is suppose to run when those terminals are shorted... but it doesn't. so I started down the bullet list on pg FI 51 in the FSM.
Fusible link (skipped, I have power)
fuse efi 15A (was blown and replaced and since dble checked) and IGN 7.5 OK
COR checked OK per manual specs
Fuel Pump worked per manual with external 12v supply

following the prescribed steps using a volt meter for each component in each bullet I came back to the wiring issue and no voltage showing between Fp and +B.
Your telling me that the pump only runs when the engine runs lets me forget about the connection back at the tank and focus on why I get nothing at B+.
There is what looks like white lithium grease covering the check terminals which I have assumed was factory and for corrosion control. I have used small electonic 'spear point' (for lack of a proper name) connectors as probs to make a solid connection and clipped to them.
I'm going to open up that connection box and get a lead on the B+wire itself next.

scope103

If you have no 12v to ground on B+, it's either the EFI Main relay or the EFI fuse. The EFI relay coil is powered through the ignition switch through the IGN fuse.

So start there. With key on, do you get 12v to ground on BOTH sides of the IGN fuse? Can you hear the EFI relay when you turn the key? (Under he hood, called MFI here: http://personal.utulsa.edu/~nathan-b.../2powersou.pdf) Is there power to pin 2 of the EFI Main relay with key-on? Pin 2 goes straight to B+.

Step Side 88

after getting into the back of the check connector I got 12v on the b+ (blue)wire.

Still no pump action when jumped to Fp.

scope103

Does FP have continuity to ground? Does FP have continuity to the fuel pump connector? It's just a matter of finding the broken wire.

Step Side 88

If I did this right...
Hooked up a lead back on the gas tank connection and ran it to the Fp pin with the ohms meter in line and got continuity. same to the ground pin on the connector and the ground bolt on the fender well.
How would I check the efi/fuel (relay?) thats mounted in "Relay Block #2" location of the link you showed?
I grabbed the one from the rig the tank was out of and have tried both. No joy.