ummm fuel pump issues.

[static1]

So i bought a 91 k5 about 2 weeks ago. Last sat it left me stranded in the center median. So i wasnt getting any fuel to the tbi. So I replaced the inline fuel filter, still no go. Then i dropped the tank replaced the pump and sending unit. Hooked it all up and still no gas to the tbi. Any one got any sugestions?

 

[static1]

So put a new regulator and changed all the fuses and SHESSSS ALIVE!!!!!!!!!!!!! With my luck it probbably was a fuse from the begining. Well at least I wont have to worry about any fuel issues for a good long while. Now im waiting fo the fuel tank strap i busted to show up with the rear bumper bolt i busted. I hate rust. Thanks for the help. Big E.

 

[static1]

Well got an issue.The blazer went out on me again yesterday. I hit a large deep water crossing where a road was flooded from all the rain we got. Went threw it fine and then made it a good 1/4 mile down from the water and she died again. Blew the ecmb fuse wich is the fuel system. I let her sit for about 2 hours went and got a buiscut and tried to let her dry out. Came back with some fuses and its no good
I was poping fueses as fast as i could put them in. The only thing i can think of is I shorted something out with the water. I dried the negative or the ground connection out and the power control plug going in to the sending unit.And it still pops fueses. Any body got any ideas?

 

[static1]

Im thinking maybe i shorted the fuel pump out again. The pump is under waranty so maybe get a new one and replace it and do something to water proof the sending unit plugs?

 

[4X4HIGH]

Sounds to me like you have a wire somewhere that has rubbed through and is grounding out. Check all along the frame rail for the fuel pump wiring to see that there is nothing wrong with it and also check anything else that is on the same circuit.

 

[static1]

accourding to the haynes diagram the only things that are hot all the time are the pump relay,fuel pump oil preasure switch, and the pump. The injectors and and the spark timing and emissions stuff is all hot only at start up and run. So I would think that this would lead me to focus on the fuel system. Am i rifgt or wrong? The reason i say this is it pops fuses as soon as i reconect the battery. So it would have to be hot all the time. At least I think. Maybe im thinking about this wrong.

 

[dyeager535]

Easy. Unplug all fuel system electrical (pump plug near tank, oil pressure switch, relay). Put new fuse in. Plug each one in until it pops. Once it pops, back trace.

 

[static1]

Is the oil preasure relay switch the regulator that is found up on the fire wall? Im not sure where or what this is and i am having probs finding it in the haynes man.

 

[static1]

wish i had seen your post earlier i just dropped the gas tank again.

 

[static1]

If it is the relay/regulator on the fire wall I unplugged it and its still blowing fuses.
I dont know what to do now.

 

[static1]

that is the only relay i can find and it is unpluged as well as the fuel pump and im still poping fuses as soon as the battery is hooked up. I took the ground off the battery just to be able to put the fuse in becuase as soon as i make contact it pops. But even doing it this way im popin the fuse so what else could it be anybody got any ideas. this is damn frustrating for me i just bought the blazer. i think im the 3rd owner and i keep finding nig rigged stuff all over the place. I am also unemployed so im on a budget. At least i got a 06 gsxr 750 to get around on or the wife when shes home from work. if any one has any ideas id be very apreciative. I think im going to call this auto electrical place thats close by and see if i can dredge them for some info.

 

[dyeager535]

If you are popping fuses before anything is hooked up, you've got a problem somewhere near the battery. Problem isn't the fuel pump, oil pressure switch, or the relay.

I'd test the positive wires in the engine bay for a short to ground. Look for bad splices, cuts, heat damage to insulation, wires crushed between components (like engine block/bellhousing) from others doing work underhood.

 

[static1]

Thanks man I kinda Figured that. Im gonna start at the fuse block and work back toward the battery. I have heard that some times circuts can ground just off of the fuse block screws going into the sheet metal. so first im going to udo the screws for the block and see if i can see behind the block for damage. Or pinched or cracked wireing. Ill post up what ever it is once i get it figured. My Grand daddy figures its between the block anf battery as well. I try not to call him till last resort due to long windedness.

 

[dyeager535]

Not likely for the fuse panel to be the issue. It's all plastic, and the ONLY thing in contact with the sheet metal are the two screws. There should be no flex in the wiring near them, so again unlikely for the wiring to wear through.

It's your vehicle, approach diagnosis as you see fit, just trying to steer you in a more likely direction.

If the wiring has been hacked, all bets are off of course.

 

[static1]

Found a Dark green wire that looks like it has some damage. There was a section of wire loom that was too close to the headers. I didnt notice it earlier becuase im short and have to stand on a chair to see properly into the engine bay. it shows a dark green wire with white strip coming from the relay. Ran out of light will continue on tommorow. I got some new wire loom and zip ties some connectors and some electrical tape and some shrink wrap. just gonna go threw it all and redue anything lokking ify. Not just for this prob but for any possible future probs. There is alot of splices and what not that i dont like the looks of. im not sure that the relay wire is the prob. When i know for sure ill post up.

 

[static1]

I havent looked at the back of the fuse block yet but the way this thing is wired every thing is suspect.

 

[static1]

Does any body have any idea what the price of having a vehicle profesionally rewired is?

 

[xCaliK5x]

Wiring diagnosis isn't too hard if you have a proper manual (I don't think a Haynes will cut it) and a DVOM and some experience. If not, it can be a nightmare like this. Think of the diagram like a road map, the power starts one place and goes whereever the road goes until it reaches its destination. As others suggested, unplugging everything on the circuit, and plugging them in one at a time until you find out where your short is in a component.

If you unplug everything, and its still blows, then you have a dead short in the wire. If its an A-B wire, then you can just disconnect it and run a new wire. If not, then you need to follow the wire to its source. From the fuse panel, to the component.

 

[static1]

whats the best manual to have chiltons? I know haynes is cheaper i was just trying to get by. So whats the best manual ?

 

[xCaliK5x]

Well, I would try to track down a factory manual if you can, borrow or search ebay if you plan on keeping your truck for a while it may be useful. Yeah they are money, but it was written by the company that built it. I'm looking for one for my 87. I bought a Haynes for mine to get some insight for the power windows. It was close but I'm sure GM had a lot of year to year changes which can make things difficult. The Haynes is also ridiculously lacking in info on wiring. I wonder why nobody has scanned the GM ones to the net. Maybe someone has some other input that has more experience in these things then us.