Tank Selector Switch Problem??? Won't Start

[87r10shorty]

87 r10 Short bed ~ Super Sexy

My fuel tank selector switch went out on me for the third time just recently. I just installed a brand new switch and now it won't switch over from left to right in fact it seems to be stuck in the middle not pulling gas from either side and as a result my truck is not starting. Any suggestions on how to remedy the current situation? If not how can I quickly and easily resolve this with an work around, say using only one tank and thus not needing the switch.

[Captkaos]

Are you talking about the switch or the switching valve that has gone bad 3 times?  Where are you getting the switch from? Or the valve?
Have you seen this: http://forum.73-87chevytrucks.com/smforum/index.php?topic=6537.0

[VileZambonie]

Do a search. you will find I posted a diagnostic flowchart and schematics on the switch and switching valve.

[87r10shorty]

Ok.... In an attempt to clean up my posts.

The problem started as my truck was running really rough, bouncy needle, hesitant starts, right tank running a little smoother than left.
Then one day the truck just wouldn't start at, and hasn't started since.

1. Checked coil,plugs,wires... all working order, great spark.
2. I replaced starter as it wouldn't crank at all.
3. I replaced actual in-cab fuel selector switch
4. I disconnected the switching valve, and have since learned it was good to go.
5. I ran lines directly to passenger tank.
6. I replaced oil pressure switch.

I have ordered a new fuel pump relay, hoping that will be my saving grace.

But up until now Still no luck! Truck will not start.... Any help would be greatly appreciated.

[Captkaos]

IF you hear the pump priming in whichever tank you are on, I would start at the engine and remove the feed line and see if you are getting fuel to the TBI.
If you are getting fuel to the TBI along with spark and air, it should crank.  You didn't say if you verified fuel at the TBI.

[VileZambonie]

Yeah your next logical step is to check your fuel pressure after you reconnect everything.

[87r10shorty]

where the heck is the fuel pump relay located?

[VileZambonie]

In the engine compartment. Slow down there cheif. Stop changing parts and unplugging things and bypassing this and that. There's a simple systematic approach you can take to diagnose it. There is a test lead right next to the fuel pump relay. Jumpering B+ to the test lead will energize your fuel pump. You can do this to determine if it's the control side of the circuit or the load side of the circuit that's causing your problem if in fact no fuel pressure is even your problem to begin with.

[VileZambonie]

Here's a pic of the relay for you. It's on the passenger side

[Captkaos]

I agree, we got more than 1 thread on this same topic that you branched out.  Find out if you are getting fuel, air and spark and then work you way back.  Ignore that there is a computer controlling everything and start with the basics.

[DnStClr]

If there's no fuel at the throttle body, don't forget to check the fuel filter located along the frame rail on the passenger side of the truck. When you energize the pump, the fuel goes thru the filter first.

[87r10shorty]

ok i got spark 100%
i got air 100%
i removed air filter, poured gas into tbi, truck started right up.

so i'm not getting gas to engine.
replaced oil sensor switch
replaced both fuel pump relays
replaced fuel filter

no joy!
where do i go from here?

[VileZambonie]

Well I should hope you have air unless you moved to the moon. lol

Ok so do you have fuel pressure? Y or N?

Do you have injector pulse Y or N?

If you need help on how to check for either of the two please ask and I will walk you through it.

[87r10shorty]

i need all the help i can get

[VileZambonie]

Get yourself a TBI pressure gauge and tee in where your fuel filter is.

Get a noid light or test light to check for injector pulse. I will post how to if need me to.