The previous owner, in addition to hooking up a manual button for the glow plugs, also hooked up a toggle switch which controls the fuel shutoff solenoid.

I wasn't able to get a straight story on why this was done -- I got some mumbling about a relay going bad -- but to make a long story short, I want to get rid of it. It drives me nuts because if the truck isn't running (like it has been lately -- getting air in the lines and won't start) I often forget to turn the switch back off. It's hot all the time since it's wired to the battery, and so I come back days later to a set of dead batteries.

I want to hook it back up to the ignition switch. But I don't know how to do so.

I'm also installing an electric fuel pump and getting rid of the mechanical pump. I've already got a blockoff plate and all that.

What I'd like to do is hook both the fuel shutoff solenoid <b>and</b> the electric fuel pump up to the ignition switch, both preferably through the same relay.

How much current does the fuel shutoff solenoid draw? My electric pump says it takes just a hair over an amp when going full tilt, so unless the solenoid draws a lot more than that, I should be able to get away with a smallish relay.

Any advice? The biggest part of the problem is that I don't have any idea where/how to hook a relay up to the ignition switch. Although I have a wiring diagram, it doesn't make that clear, especially for a diesel.

 

while I maynot be able to help you out on the relay wiring problems, on the air suction problem I believe there is a fuel/water seperator on your truck, the drains on them DON'T seat properly check that out or bypass it. Goodluck with your other issue's

 

Hi, yeah -- the water separator has already been bypassed. In fact I'm going to put a valve on the drain line and undo the bypass, since I want to have a separator.

 

I would hook the FSS wire to the relay. When the FSS is activated, that is when you need the pump to switch on. Any other time is a waste of power because the engine is not running.

 

I would find a wire coming from the switch on the column that is hot with the key in the run and start postions. Splice into that to run a relay for the pump and FSS. That is what I did on mine. In my case I used the wire in the harness that used to run the coil when it was a gasser.

 

Here is a schematic of what the starting system should be:


Check the threads at the top of the forum for information on the glow plug system that is on your truck. hope this helps also this schematic may differ from your truck it is for a newer model but it should be close.

 

You can power your FSS from its original factory source, which is directly off the GP relay's small post (important - SMALL post) with the red wire which is hot in start and run. The wire should run to the FSS, then the temperature switch, then the cold timing advance and cold idle advance.

Run a wire from the same post to your relay's 85 terminal, ground to the 86 terminal, battery to the 30 terminal, and your pump to the 87 terminal. It would be advisable to put a fuse between the battery and the 30 terminal, rated at 1.5x or so of your pump's rating.

A standard automotive relay typically has a 40A rating on the 30-87 terminals, so you're well within the limits. You could likely wire the pump directly to the same feed as the FSS at 1A, but I'd bet the pump surges at startup and you don't want to pop the fuse on your GP trigger/ FSS circuit and be stuck somewhere.

 

Thanks everybody, especially Dark Horse and NorthernDiesel. With your help, I think I've got everything I need to do the job.

 

All done!

Deleted the mechanical fuel pump, ran all new fuel lines, and installed a new fuel selector valve and electric fuel pump. The truck fired right up, hiccuped a few times, then ran normal.

The real test will be to let it sit for a few days and see if it will restart.

Thanks for the help guys.

 

Glad to hear you're burnin oil again.

 

Wat is fss?

 

Fuel shutoff solenoid. It's on your injection pump and needs +12V for the pump to get fuel. Cutting the power shuts off the engine.

 

Not to rehash old items but I have a ?. There are 2 wires on the connector for the fss. Both are white with red stripe, I believe. Which 1 gets cut and spliced into the relay for an electric lift pump?

 

mine are red w/green stripe on my '93.but anyway,either one.they are both the same wire so to speak.hooked directly together in the clip.when you turn the key forward,both sides of this line becomes hot.so it makes no difference where you tap into it.
whats important to remember is then after you cut the line,that you now have three wires to go into a connecter.the two sides to the line you just cut,along with a now new line.so you'll have to use a 3 way butt connecter or simply hook two wires together into one side of the butt connecter (that's all i did.) the blue connecter was used to simply extend this side of the wire from the fss clip.i took that into a yellow butt,where i crimped it together back with the other fss line i cut,then hooked my larger gauge into the single side over to the relay for,important: not for power for e-pump.to trigger open relay only.
you may be tempted to use a blue scotch lock connecter for this because they're much easier.resist the urge!

e-pumps are rated for just a couple amps.
iv been using a 5 amp issue free for my duralift/transicold.