1990 Suburban wont start!!

[SoCalSlaughter]

So my 1990 Suburban V2500 4X4 quit running. I had put the truck in reverse and it just shut off. I had to push it into my parking spot. Popped the hood trying to figure out what happen. Only thing I can find is that the fuel pump is not priming or turning on or sending any fuel. ECMB fuse blew the day before, replaced fuse and truck started. Ive changed out relay, and I can feel it click when the key is turned to on, removed fuel filter and turned key to on and no fuel pressure. Cannot figure out why it wont start. been out looking and checking things for 3 hours now. Im at a loss. Any ideas? Also, put a known good fuel pump in and still no start.

[bikerbomber]

It is pretty funny, I am having a similar issue. I would recommend checking the wiring at the fuel pump and the ground there. I am convinced it is an electrical issue but haven't been able to find it either. When I attempt to crank the engine, the lights dim to almost nothing, and the truck struggles to turn over despite a brand new battery. One electrical short off the wrong wire can cripple the truck. I'd chase wires...

I'll keep you posted on my progress, if I make any. Good luck.

On a purely cynical note, I think there are guys out there who have had the problem, and fixed the problem, but out of laziness or sense of "did my time, they do theirs" they don't post any replies. Or.... maybe they are just not online.

[SoCalSlaughter]

I checked all the wires and even replaced the pump with an extra from another truck and still nothing. I put the truck in reverse and it just died and wont start back up. The ecmb fuse blew a few times and got a code 42 but it went away. I cant figure this one out

[68Timber]

This has the in-tank pump, right? Are the wires to the tank good?

[SoCalSlaughter]

Yes, in tank pump. All wires are good. I put 12v into the pump and it will run but the truck wont make it run. so it has a good ground but when i turn key to on, no prime and no fuel when I try to crank.

[68Timber]

There's a fuel pump relay on these isn't there? Maybe not getting hot to it, that could be the short that's popping the fuse.

[SoCalSlaughter]

When I turn the key to on all the dash lights come on and I can hear the relay click. Ive also tried another relay and same result. Everything seems normal except the pump wont run. Truck cranks and no fuel. Checked all grounds, wires, relays, fuses. the ecmb fuse doesnt blow anymore. But the pump wont run when you turn key to on.

[Ski-me]

Fuel pump relay ($11.44):

http://www.rockauto.com/catalog/more...027&cc=1061536

Or possibly the oil pressure sender ($29.79):

http://www.rockauto.com/catalog/more...762&cc=1061536

I'm going through the same thing but the opposite! My fuel pump won't turn off! I turn the truck off, pull the key out, lock it. Come back an hour later and can still hear my fuel pump running!

So, there are two items that could control it. Fuel pump relay on the firewall in the engine compartment and then the Oil pressure sender (to Gauge). Apparently, the oil pressure sender also tells the pump to stay on if the fuel relay fails. I think if it reads over 4 or 6 psi, it kicks the pump on.

So, this is what I'm hoping will fix mine. I unplugged my fuel relay but still stayed on so my last resort is the oil pressure. I'll let you know if it works out for me!

[SoCalSlaughter]

Ive tried new fuel pump relay and nothing. Ive tried unplugging the oil pressure switch and same result. Fuel pump will not prime or run

[68Timber]

I'm blue skying here, haven't fixed this type problem before. Next I'd try a jumper wire from the fuel pump relay to the fuel pump. Process of elimination type work.

[cfan10]

Any updates?

[cfan10]

Just realized how old this is...sorry.

[RaTcheTmasTer]

Well, they should have updated. Guys like us who are experiencing something simular would really being able to search and find answers.
I now have a similar problem.

[Corts60]

Just throwing it out there that the oil pressure switch is a normally open switch. So unplugging it does nothing to help your troubleshooting.

[SoCalSlaughter]

Update: Still have the truck. Problem ended up being a wire behind the engine, was rubbed through on the top of the transmission. The fuel pump power wire that runs from relay to the pump. Repaired wire, re-wrapped wiring harness with new loom and its been fine ever since.