relay board Options

[lonnie152]

problematic relay board - can not get power for fuel pump from side of board to the other. did search and note some have stripped and rebuilt them. so does anyone:
1. have an inexpensive rebuilt option;
2. know of a service or shop that does this;
3. have a fix to simply wire around problem?

thanks in advance for any help.

[swl]

CSOB hint #1. If your headlight motors are working you have a source of two known good relays. They are the same as the ones on the relay board. You can just swap them in for the fuel pump and master power relays and know if you need to buy new ones.

CSOB hint #2. Old relays sometime can be brought back to life through terminal cleaning. Perhaps this is a RCSOB hint (IMG:style_emoticons/default/smile.gif)

Probably one of the first things you should check is the fuse block. Remove power from your coil (to avoid the chance of frying your points while troubleshooting). Key on. With Volts selected on your multimeter measure from ground to each side of the fuse - it should be whatever your battery voltage is on both sides of the fuse.

[lonnie152]

thanks for suggestions.

to be precise the black wire that seems to run the pump comes in one side of relay box but exits the other end with no power. we can jump it at the relay to get it to work. but in short that is the problem. so can we just by pass the box ??

[swl]

we can jump it at the relay to get it to work.

hmm. You do understand that the pump only runs for a second when you key on. It then stops until the ecu detects that the engine is turning over. You can over ride this by removing the 4 pin plug at the back left of the relay board and jumpering pin 3 to ground. Then the pump will run continuously.

[ericread]

we can jump it at the relay to get it to work.

hmm. You do understand that the pump only runs for a second when you key on. It then stops until the ecu detects that the engine is turning over. You can over ride this by removing the 4 pin plug at the back left of the relay board and jumpering pin 3 to ground. Then the pump will run continuously.

Isn't there a negative issue with keeping the fuel pump running continuously? Or maybe not, with the return line providing pressure relief. What are your thoughts?

[lonnie152]

sorry, i have not made it clear that i have converted this car to carbs. also did the switch to correct rotary fuel pump,etc.

[bperry]

sorry, i have not made it clear that i have converted this car to carbs. also did the switch to correct rotary fuel pump,etc.

So maybe you could tell us how you wired this up and what changes you made
in wiring including any jumpers and the location and colors of
all the wires you tapped into.

If we know that, we can easily help you locate where your loss of power is
or offer a simple work around to get you up and going again.

--- bill

[lonnie152]

made no changes in wiring other than ground wire for new fuel pump. was running ignition through MSD before i made switch to carbs and am still now doing this. my problem is getting power (for fuel pump) from one end of box to the other. so looking for good fix to box or how do i wire around it.

[bperry]

made no changes in wiring other than ground wire for new fuel pump. was running ignition through MSD before i made switch to carbs and am still now doing this. my problem is getting power (for fuel pump) from one end of box to the other. so looking for good fix to box or how do i wire around it.

Another thought occurred to me.
When you say "other than ground wire" are you saying a ground for pump
are are you talking about a ground wire that is plugged into T4b connector
pin III.

I had assumed you meant the T4b pin III ground wire. If that isn't what you meant.
See the technical article on this subject:
Fuel Pump wiring for Carbs

--- bill

[lonnie152]

very much appreciate all the suggestions. Unfortunately am not smart enough to understand all which has been offered and so i remain stuck. since i have now replaced all the fuses and relays believe the problem to be in the board itself.

So unless i get any advice to the contrary, tonight i will pull the board, chip away the underneath coating and use a voltmeter to test all the connections. any suggestions on how best to do this would be great and again thanks to all for the help.

[bperry]

very much appreciate all the suggestions. Unfortunately am not smart enough to understand all which has been offered and so i remain stuck. since i have now replaced all the fuses and relays believe the problem to be in the board itself.

So unless i get any advice to the contrary, tonight i will pull the board, chip away the underneath coating and use a voltmeter to test all the connections. any suggestions on how best to do this would be great and again thanks to all for the help.

We can help you debug this, but you need to be our "eyes" and "hands".
Don't let this get you bummed out.
We do need a bit more information to help isolate the problem.

The biggest question we still need to know is how you have wired in your
fuel pump and what you have tried.

Are you referencing/using the online technical article?
Here is the link to it: FuelPump wiring for Carbs
It shows a simple way to hook up a fuel pump for carbs and has some
really good photos which identify and label relays, connectors & wires.

If you scroll that WEB page down, you will see a photo of a relay board.
That is the picture that has the locations that I was referencing in the
very specific questions I asked in post #23 and post #25.

From the information you've provided so far, it isn't clear that it is a relay
board problem yet.
It's not worth tearing into the relay board looking for something
before other possibilities are ruled out.

Should it turn out to be a relay board issue you don't have to chip away any
of the undercoating in order to test the relay board,
so I wouldn't mess with any undercoating yet.
Also, a big clue on relay board failure can be how the undercoating looks
before you remove it. If there are open areas or melted areas, that area
should be looked at very closely because the rivets in those locations
may have oxidized or worked loose. But again, I wouldn't touch the
relay board, until other possibilities have been ruled out.

If you are totally stuck and want to talk directly, PM me
and we can exchange phone numbers. I'll be happy to help
you out. Just let me know.


--- bill