Help!!!! Please!!!!

[charlie diaz]

I have a 87 v20 with a 350 tbi and dual tanks. I drove it down to Home Depot, loaded it up with wood, and then it wouldn't start. It would turn over, and I had spark, but no fuel. After having a buddy tow me home, I got out my voltmeter and voltage light, and I found out that I'm not getting power to either pump. I checked all of my fuses, connections, etc... and I found nothing wrong. All of my fuses were good, and my connections seemed fine. I pulled my selector switch for the tanks off, and tested the female connections to see if I was getting power there, but I'm not. I'm about to say screw it and just take it to an auto electrical place here in town, but I figured I would ask you guys first. Thank you in advance for any help.

[krue]

Is there a relay for the fuel pump? If so I'd check that.

[Red_69]

have you tried starting it by dumping a LITTLE gas down the throttle body then cranking it over? If it starts after that it's a bad fuel pump relay.

[charlie diaz]

Yeah, I should have said that to help with the info. It will start with a little gas in the throttle body, and I have already changed the fuel pump relay. Still no dice. The only thing I can think of is that there is a fuse somewhere that I cant find. When I turn the key on to the run position, I can hear the relay click after a couple of seconds, but no whine from either pump.

[pig rig]

the tank switch in the dash has probly gone belly up I've had it happen on a couple of trucks its an easy fix for I think 12 bucks at your local napa

[charlie diaz]

I just replaced the tank selector switch on the dash, and you were right...it was only $12. Unfortunately though, it still didn't fix the problem. Thanks again guys for all of your help.

[shadetree]

check for a god tight ground. You are getting power TO the pumps, a bad ground could be stopping the circuit.

[dammitmitchell]

i would continue chasing the positive side until you find whre power finally is..
set your multimeter to "ohms" and then check the wires to make sure that grounds have proper grounding..
then also check the positive side to make sure that there is No shorting anywhere..
but as a precaution i typicall resand and re do the grounding station of any circuit in my truck i ever work on.. juuust in case..
good luck and happy troubleshooting

[charlie diaz]

I was looking around, I'm not really sure what the ground station looks like. Where is it exactly? I think you're right about the bad ground, because everything else has been checked.

[dammitmitchell]

the grounding station is "easy" to find..
place your multimeter onto the "ohms" prt and check for the wire the gives you a signal to ground..
by that i mean take the black lead form your tester place it on a clean metal suface on your truck (no point rutst etc)
and check your wiring for the one that give you a reading..
u shouldonly ahve two wires on your sender..
so one HAS to be ground
there should be a blac wire that is bolted or sheetmetal screwed to the frame (on stock applications) or any clean surface without paint.. it willl alllwaysbe connect to a clean surface unless the person who did the wiring.. well.. is an unpleasent word..

[James McClure]

Sounds like Mitch has it peged. I will say this. I was Chev mech for 33 yrs and have seen problems with the "thru tank connector" on top of the sender\fuel pump unit. The wires come out of the tank and plug to the vehicle harnace. This connection is usually OK. Inside the tank there is a short harnace that feeds the pump and sender. This is the connection where trouble occurs. It can actually get hot enough to discolor the thru plug. Problem is the connector pins are to small to handle the current flow to the pump when it maxes out pressure wize & slows the pump motor down or when the pump seizes. If you still have trouble you might want to check that connector. jim

[James McClure]

I should have gone with the advanced window, LOL. Anyways, I'll look around here and see if I have an old sender laying around with the problem I mentioned and get a pic of it. I might have some good senders but not sure of years. Wireing should be ok though, just verify the pin out and wire colors. Let me know OK? Hay Mitch. I seen the picture of you in the driveway bleedin all over, you get near a power tool did ya? I know you said something about not getting near them that made my laugh. Be careful man we like haveing you around. jim

[James McClure]

Charly, just went out in the garage to look for that sender. I have 2 senders that are for either a van or a blazer. Both are good senders, no heat problems evident so I can't get ya a pic, sorry. Senders will not fit a truck, but the wireing should work ok. Let me know, jim

[charlie diaz]

Thanks again so much for all of you guys' help. I'm not really any good with electrical issues. When I rewired the tail-lights from the fire wall back on my 69, I couldn't get the right one to work. It took me 3 days to finally figure out that I just had a bad ground. So this would cause it to just die like it did? I'll be sure to check with my multimeter as soon as I get a chance. Any pic's pointing out where I should put my leads would be awesome. I'm pretty sure I understand where to put them, but i just want to make sure. I hope you guys know how appreciative I am for all of your help. This issue has made me want to throw things and say bad words because I can't stand it when something so simple is kicking my a$$. The sad part about it is I'm having a similar problem with my riding lawn mower. When it rains, it pours.

[dammitmitchell]

Originally Posted by James McClure

on top of the sender\fuel pump unit. The wires come out of the tank and plug to the vehicle harness.

hey dude...
was it an electrical pump in 87?
(i honestly dont know)
i was assuming he still had an block mounted mechanical fuel pump...
and i assumed they were the two wire intank fuel sending units....
crap..
im corn-fuzed
=-)

[dammitmitchell]

WAIT! arrgh my brain
what about a fuel filter?
could that be the "most obvious problem"????
sorrie.. its usually the easiest possible answer...
or i could be wrong with all my issues..
and your riding mower.. id clean the intake and the fuel filter..
those r the two biggest issues ive ever had on them..

[charlie diaz]

Oh, something I forgot to ask....so this will cause both pumps to not get power? I cant get power to either tank. It started out that the RH tank wouldn't come on, so I switched over to the LH tank, and neither tanks pump would prime up. That's what baffles me. I took my dummy light and put it to the through tank connector on the truck side with the key in the run position. I tried both leads on the connector, and no dice. This tells me that I'm not even getting power to the tank. I hope this gives you some more info to work with.

[charlie diaz]

on the truck, it is dual tanks each with its own electric fuel pump.
and on the mower, I'm not getting power to my coil. even though continuity from the solenoid to the coil is good.

[James McClure]

Charlie: Electrical issues can be daunting sometimes. I worked for Chevy for 33 years and I still can't say I've seen it all and I still make some lulu mistakes on electrical, not often but when I do it's usually a big one. Think of an circut as a circle. Put in a battery, put in a switch and put in a load. Once you see this concept in your head diagnosis gets easier. Make a break in any part of the circut & it won't work. Any time you have a problem, draw the circut on paper and trace it out. Thru a process of elimination you will find the failure. In all the years I worked as a mechanic grounds seemed to be the most common failure. After that it was switches and then connections. Don't think of a connection as a place where 2 wires come togther either. Starters are a good example of a connection failure where wireing isn't involved. Brush failures are the most common here. It is a connection. Same thing is true with relays and bulbs ect. If you think the circut thru and can visualize the movement of electrons thru that circut the answer becomes easier to find. Finding all the parts of a given circut might throw you, but still, in your head you can see it and from there, find it. You need anything more e-mail me at "jmcclur2@nycap.rr.com" and we will see if we can hook up and fix a problem. Remember there is no such thing as a dumb question. Jim

[James McClure]

OK Charlie, read what I said above about diag. The tank switching valve also switches power for the pumps. If you have power to the switching valve, IF, where do you suppose the failure is? Check the switching valve control switch #1. check the valve itself #2. Switching valves are a common failure. jim

[charlie diaz]

I've checked the plug going into the switching valve with my dummy light, and I didn't get anything. I tested it with a cheapy multimeter also, and it read 6v on the pink wire. Shouldn't it have 12v going to it? When I put the multimeter to it, I put the black lead to the frame, and the red lead to each terminal until I got 6v on the pink wire. I don't know if I'm getting a faulty reading, but it did read 6volts. Somebody here at work told me to check the valve also, but when I was checking the price on it ($140 at NAPA), I was hoping that it wasn't it. I bought a nicer multimeter, and I'm going to check it again with that when I get off of work. Let me know if I was using the proper technique for checking power to it, and I'll let you know what I find out. Oh, and my name is Nic. I used Charlie Diaz for my handle to say C 10. "C"harlie the phonetic representation for C, and Diaz, spanish for 10. I misspelt diaz, it should be diez, but it was too late to fix it. Just thought you should know. Thanks again for staying with me on this one.

[James McClure]

Nic. The pink wire you are testing is the wire feeding the gage. 5 to 6 volts is normal. There will be 2 more wires coming in from the senders, EG 1 from each tank. There will be 2 more wires that do the switching by reversing the polarity, EG +\- left tank. -\+ right tank and then a ground. Thru a process of elimination you'll find the wires that do the switching. Attach the meter to those wires, turn key on and switch the tank L to R and back & check readings. 1 will be 12 v+ the other12 V-. If it ain't so switch is bad if you get these readings at the valve connector the valve is bad. Look at the bright side you won't have to carry $140 around burning a hole in your pocket. jim

[charlie diaz]

thanks a bundle, jim. I'd go out and try it right now if I wasn't stuck at work. I'm going to try it as soon as I get home though, and I'll let you know.

[pig rig]

the more I set and think about this check to see if your dash switch is for a tbi truck and not a carb truck because the switches are different and some parts guys are to lazy to look to see if their is a differant one then what the computer says

the carb switch will switch the valve but it won't turn the pump on

[dammitmitchell]

i officially cant help any more =-(
i worked on apaches for 6 years (yaaay army )
and our troubleshooting .. well it's 21 miles of white wire..
hehehe
and there r "ghosts" in the wire all the time.. i feel and under stand you pain dude.. but troubleshooting.. well it gets better over time..
most people at first r just "well hel ill just replace everything'...
but u dont feel nearly as accomplished as you do when you troubleshoot and find the problem on your own..
then u feel like a champion.. good luck..