s10 pickup fuel pump !!AGAIN!!

[hound]

OK, for some reason pump worked again but only a half a day now nothing again. Have disconnected the plug at tank, cleaned with contact cleaner, still nothing. When turn key to on can hear relay kick in. When check with test light i get juice in plug,only one contact though, should one contact be hot when relay activated and then it's off and the other contact is hot then. I assume one contact is hot and one is neutral and the ground is separate and to the frame. Oh, by the way i have checked the ground and it seem to be clean and shinny. Will admit , the test light is a little dim when it does light. My chiltons manual has no schematic., so i'm lost. What next, new pump????. thanks Hound

[NovaRod]

I really think this has got to have a common source because of all the S10 owners having this problem.

Possible fixes:
1- Oil Pressure Switch
2- Wiring on the fuel pump
3- Coil pack/ECM
4- Fuel Pump
5- Fuseable Links
6- Ignition Switch
7- Crank Trigger
8- Injectors
9- Fuel Filter (good call on this! Causes strange problems on an EFI engine)
10- Bad gas
11- Clutch safety switch
12- Low oil pressure
13- Fuel pressure
14- Possibly other electrical problems that deal with Relays/ignition, etc.

I'd like to see a schematic of the electrical wiring as it deals with ignition and fuel delivery.

[no2guncntrl]

I don't know what yr your ride is, but late 1st Gens have a
black connector around the heater/a-c housing that looks
like it should be hooked up to something and isn't. This is
the fuel pump test connector. Keep the key off and run a
fused hot jumper wire to this connector, and have someone
back at the gas tank filler door listen for the pump to come on
at the same time. If it does, it means you have a problem
other than the pump. If it doesn't it COULD mean the pump's
history, but cking all wiring, the relay, the oil press sender
and the ign module inside the dist is very important.

Here's an example. Many times the ign module is the orig that's
inside the dist. It's sits on a mounting pad and has a
film of die-lectric between this pad and the bottom of
this module..The film will dry up and get hard, allowing a
heat sink of the ign module and either shorting it once it
gets warm and hot, or will altogether just wastes it.

The ECM/PCM must see a crank signal for the fuel pump
to come on and stay on. If the ign module is heat sinking
it could shut down the pump as well as the ign spark..

If you decide to look at the bottom of the module, disconnect
the neg batt cable so's not to spike the module..HTH's.

[amac209]

if the test light is dim there's some extra resistance in the circuit follow the wires back from the tank and look for any loose conections/corosion the relay contacts might me burnt out. you could try jumping 12V directly to the pump and if it doesn't kick on you need a new one. there are 4 wires going to the tank 2-black(grounds) grey(pump power) purple(gas gage signal) make sure the blacks are grounded when you jump the gray wire. good luck

[my s-10 problems]

I have possibly the same problem you have today I put a new coil,spark plugs and oil pressure switch and nothing helped. Tomorrow I plan to connect the test wire on the fuel pump and see what happens....please keep me posted on this,

[xtremetrk]

I had the same problem in the other thread of the 2.2 Fuel pump. It was a bad connection at the fuel pump and the grey wire is the 12 volts that goes to the pump. Connect the test light to the wire while its plugged into your fuel pump(strip wire) when you go to turn the key to on, does it light up? If so and you cant hear the pump you have a bad pump. A good way of kick starting your pumps is to hit your gas tank with a rubber hammer under the pump location. Hope this helps