the problem....

had engine out to work on some battery tray rust. removed the fuel pump to paint hell hole and battery tray. i replaced all the fuel lines. put everything back and hooked up. turning over but not firing. pull the lines to the fuel rails and i am not getting any fuel. messed around with the connection at the fuel pump and snapped off the wiring. went to splice a new connection and after checked and i have 0 volts comming from the positive lead to the fuel pump.


things that i have checked......

1. fuel pump is good-runs when hard wired from battery.....

2. next step is to go to the main power relay and check voltage at pin 87 and then 86. i did this and i get 0 volts at pin 87....

i get 12v at pin 30 on all of my relays but at 87 nothing. what does this mean? i have been looking over the schematics and i am kind of stuck.

do i dig into the relay board and start trouble shooting those connections or do i go somewher else? did I forget to plug something in? i have had the engine out plenty of times and have never had a problem.

are there any electrical guru's out there that have delt with pin 87.....????


thanks,
craig

I'm looking at my schematics now.
About your measurements:
Main Power Relay:
Pin 87 0V
Pin 86 12V
Pin 30 12V

Pin 30 is 12V supply to relay contact output Pin 87. If Pin 87 is 0V, then relay if off. If pin 30 has 12V, then the 25A fuse on the relay board is ok.

Pin 86 and pin 85 are the relay coil wires. 12V across 86 and 85 will energize the relay. If pin 86 is 12V, then pin 85 should be 0V.

My schematic (for a 73) shows pin 85 for the fuel pump gets 12V from the relay for power supply from pin 87.

The other side of the fuel pump relay coil (pin 86) should get grounded out on the pin III of the 4 pin connector on the relay board which connects to the FI brain, pin 19. Pin 19 on the ECU should be low (0V) to energize the fuel pump relay. Check the 4 pin connector to the ECU. Pin III should be low.

spoke

looking at my schematics to follow your logic. i have never done electrical before. sounds good though.......i will check pin III.

I checked pin III on 4 pin to ecu......I get a reading of 12v instead of the low to zero.

does this mean i have a short somewhere.....

I think what is connected to the ECU on pin 19 should pull pin III low, thus turning on the fuel pump relay. Check that the wire from pin III to the ECU is indeed connected.

The 12V measured on pin III is from the relay being connected to this pin. The ECU should pull this pin low to energize the relay. If you removed the engine, chances are there is a connection issue, not a burned part. Check connections to this signal at pin III and pin 19 on the ECU.

Spoke

just to confirm: on the relay board, the rearmost socket is for heater fan. Forward and to the left is the socket for fuel pump. Forward, to the right of the fuel pump socket is main power socket. Frontmost on the left is rear window relay. Right? You gotta have the the relays for pump and power.

try this: jumper fuel pump socket 30 to 87 (ignition on). Does the pump come on?

will do.......

brp914:
yes to confirm..........

i will try your 30 to 87........

check all of your fuses????

yes......all fuses good. and getting 12v accross..........

checked pin 19 in the ecu and it was connected......this is going to be fun......probably something stupid like not plugging something back in.....

Was pin 19 also at 12V? Just checking if the wires and connections are ok. With power off, remove fuel pump relay and check resistance from pin 19 on the ECU to pin 86 on the fuel pump socket. Should read near zero ohms.

If the ECU is not pulling pin 19 to ground to energize the fuel pump, then the ECU may not be energizing the fuel pump relay for a reason. Is the ECU operational? Maybe a sensor is not connected that would cause the ECU to turn off the fuel pump relay?

Spoke

hey spoke.....

i will try this tomorrow.....i am going to keep bugging you till i fix this......thanks

Probably just how that is worded but if you get 12 volts 'across' the fuse - measured between the ends of the fuse - the fuse is blown. 12 volts to ground at each end is what you are looking for. Or 0 volts across the fuse.

You can emulate the ecu by jumpering pin III to ground. If that turns on the pump then maybe something in the harness between the relay board and the ecu.

Go here:

http://members.rennlist.com/pbanders/FPChecklist_frame.htm

did you try jumpering pump socket 30 to 87 (ign. on)?

btw: if you;re going to leave the ign. on for more than a minute or so, you should disconnect power to the coil so you won't overheat things there.

i am still here. watching football.....a true gear head would be out in the garage....

yes....i meant to say 12v to ground on the fuses....actually i didn't, but i took my reading this way....after thinking about i see what you are talking about....

i am retarded when it comes to electrical...

i will try to jump pin 30 to 87...good idea about disconecting the coil...thanks

stay with me guys.....i really appreciate all your help........

i am leaving for hawaii tuesday, so i don't think i will get this thing running anytime soon. i plan on staying over there for about a month....going to stay for the pipe masters.....

thanks....i owe you all a beer