Blowing ECMb fuse 1990 gmc jimmy 350

[bmxer20n]

I have read alot of posts similar to my problem but none exact. The truck had not been driven in about a month. I drove it one day for about 10 miles ran fine. Filled it up the next day and also added some stp fuel system cleaner. 5 miles later it stalled out while driving. I had it towed home and i put a new fuse in the ecmb and it started and ran for a couple miles then stalled. I replaced the fuel pump, still blows the ecmb fuse when you turn the key on. replaced fuel pump relay and still blows the fuse when you turn the key on. with the FP relay unplugged the fuse does not blow. with the fuel pump and fuel sender un plugged it still blows the fuse. With a test light on the fp relay plug the green, blk/wht, and tan have a ground. ???? can anyone give me a direction to go? any help would be appreciated!!!!!!!

[MT-2500]

Originally Posted by bmxer20n

I have read alot of posts similar to my problem but none exact. The truck had not been driven in about a month. I drove it one day for about 10 miles ran fine. Filled it up the next day and also added some stp fuel system cleaner. 5 miles later it stalled out while driving. I had it towed home and i put a new fuse in the ecmb and it started and ran for a couple miles then stalled. I replaced the fuel pump, still blows the ecmb fuse when you turn the key on. replaced fuel pump relay and still blows the fuse when you turn the key on. with the FP relay unplugged the fuse does not blow. with the fuel pump and fuel sender un plugged it still blows the fuse. With a test light on the fp relay plug the green, blk/wht, and tan have a ground. ???? can anyone give me a direction to go? any help would be appreciated!!!!!!!

Tan/white wire from relay feeds fuel pump.
If it is shorted with fuel pump and relay unpluged it is grounded out between the pump and relay.