86 blazer 4X4 fuel pump issues
 

Hello, Ive got an 86' blazer 4X4 with a 2.8 V6, which is only used to launch boats in the yard. I tried to start it the other day, and it cranks fine but wont run unless fuel is poured down the carb. Ive got a half tank of new gas, (guage works fine) I can put 12vdc on the small wire by the fuel pump relay and the you can hear the pump running in the tank, but no fuel comes out of the fuel line to the carb. (It has throttle body injection.) My question is, If the pump is running, could it still be bad/ Is it a common failure for the pick up tube to fall off, or is there some other issue. Im contemplating cutting a hole in the floor to access the fuel pump, but thought someone may have a simple thing I could check before getting extreme. Thanks in advance.

When is the last time you changed the fuel filter? It's the first thing I would check. It's located on the inside of the frame about the middle of the driver's side door. 16mm and 20mm wrenches will hook you up. You only need about 13 psi (if I remember correctly) and it doesn't sound like you're getting it at the TBI.

actually the fuel filter is located in the engine bay behind and underneath the power steering pump.

The fuel filter is located beneath the power steering pump. I removed the fuel line from the carb and Im getting no fuel at all. I can hear the pump running in the tank, and i was wondering if there was some sort of solenoid valave for the fuel, or if the pick up had fallen off the pump, or if the pump was possibly failed. Im not really fond of draining and dropping the tank, if necessary i will just cut a hole in the floor to acess the pump. Thanks for your responses!

its possible the relay is bad. When is the last time the filter was changed? is the fuel pump original? Im not sure if there is a solenoid, Im pretty sure its just the relay for the pump. I would start with the filter and if that doesnt fix it, then try the relay, and if that doesnt work, the pump would be next.

I bought the blazer just for pulling boats around the yard and launching them. It isnt road worthy because the previous owner couldnt keep the front end aligned and was tired of dumping money into it. The carb isnt getting any fuel to the throttle body at all( the fuel line has been removed to check) The filter is located bhind the power steering pump, and has never been changed, i would doubt seriously that it is completetly clogged, as there no fuel at all coming from the fuel line to the carb. My question is, Can the fuel pumps in these blazers be failed if you can here it running in the tank? It would be great to hear from someone who has actually changed a fuel pump in the tank and can verify the setup. A few of my redneck freinds have suggested using an outboard fuel hose to see if the line will prime with fuel, from the tank, and they suggested an inline pump to eliminate the need to drop the tank(which is 3/4 full of fuel) Im just not sure which type of pump to buy, due to conflicting fuel pressure requirements- im hearing 13 psi and 35 psi to pressureize the throttle body. Thanks in advance guys!

Is your truck TBI or is it the stupid feed back carb? Pressure requirements for the TBI engine is 9-13psi.

And I have definitely seen a fuel filter stopped up enough to not get any fuel through it. Especially if it has never been changed since '86. I would want to change the filter before going through the trouble of pulling the tank. that will likely be a pretty lengthy project.

I have replaced quite a few in tank fuel pumps. You won't get good flow if you are trying to pull it through the old pump. I would suggest you verify the fuel pressure out of the pump before even thinking about replacing it.

Im thinking its got the TBI, but it has 2 metal fuel lines going to it. Could you describe the feedback carb to me? thanks!

You should have the TBI engine in your truck, but my references still detail the old Rochester E2SE carb. Provided you have the TBI engine, the throttle body should have two pods that extend up over each of the bores through the throttle body. If that doesn't describe what the top of your throttle body looks like, then you have the older carb setup.

But from your description of having two lines running to the throttle body, it sounds like you have the TBI engine. There isn't a return line on the carb setup.

You said on your original post you have TBI. Yes psi should be 9 - 13. I would definately check/change the filter and you might even give the pump a start while you have the line off. I'll bet in 25 years it has accumulated a lot of garbage especially with the filter not being changed. I have dropped a few S10 tanks (present 94 twice) and if the pump is running and you hear it like you say then you have blockage somewhere. The pump would have to come off inside the tank and that's highly unlikely given how it's put on. If you pull it you'll see what I mean. If you do remove the pump make sure you replace the strainer attached to the bottom. Actually I can hardly believe it's lasted 25 years. I'm not a fan of cutting holes to access the pump/sender. I don't think the tank is that hard to pull. Just remove the left rear wheel and it makes getting to the lines a lot easier.
I think if you just disconnect the fuel line upstream of the filter you'll immediately see the problem.