hey all i have a question of what could be causing my ecm b fuse to blow when key is turned to start. Couple of ideas that i had would be could a manual transmission analog cluster from a 91 s10 work with a 91 automatic transmission analog cluster or can the wires be needed in different spots for pins becuase they are different? and another would be Ecm. this ecm is out of a 89 s10 blazer with a superchip prom in it. not sure if anything of these could cause the ecm b fuse to blow but the truck will not fire up. cranks and has lights n all but fuel pump i believe isnt coming on or and injectors, probably from ecm b fuse ecm cannot run. s0 if anyone can help please do its going to be snowing here soon and it has to run

 

Check for broken wires on the distributor and check the ECM plugs. look for wires that could be shorting out on the engine etc, something could be grounding out.

 

iv checked none could do that i have new conduit plastic on the wires to prevent that and looks like its going to be never ending. am i able to run 10 amp wired fuse to the orange on the ecm to power everything up?

 

You have a short somewhere, in theory you could run a fused wire directly to the orange wire and power it up yes, however the ECM wire would only have power while the vehicle is running, ( some one correct me if wrong ) so you would have to put a switch on the wire or route it to a wire that gives voltage during the run of the vehicle. I do not know what voltage is going to the ECM, it could have a a voltage of 5volts, 10 volts etc. you need to make sure you what the voltage is to the ECM before you just go and wire it up to the battery.
Do a voltage test at the fuse, check to see if the ECM fuse has voltage with the key in the on position. check the orange wire to see if there is voltage, trace that wire to see where it goes. the best thing to do is find out where the short is and rectify the issue.
You also stated that there is a superchip prom installed, try removing and installing a stock prom, you need to find the short before you attempt to directly wire the EMC. this could cause a electrical fire.

Do some detective work and trace the wires, check voltage and see if you can find the short, also do as i said above and install stock prom, replace fuse and retry.

Post the outcome and if you need more advice il be glad to assist.

-Alex

 

been tracing wires down and havnt came up with a bad wire or short yet everything is in place. swapped ecms out but that didnt help. i was wondering if that cluster could be shorting it out.. any more suggestions? thanks

 

ECM B fuse runs orange to computer c16 pin and b1 pin. no others and it runs to fuel relay and oil sending unit. Could i somehow be getting too much power at the fuse box other side which is red. supplying orange side with the power? Also this fuse only blows when i go to crank the motor when key is all the way for crank. Maby Ignition in the steering column?

 

check the wires going to your oil pressure sending units. It most likely is the orange wire that has been heated up by the exhaust manifold and is now shorting to it. That's what happened to my 87 S10 blazer. I repositioned the wires and insulated them with a good electrical tape and wire ties.

 

see i have a 87 with a 4.3 and NV 3500 five speed little bit different but if that is shorting on somthing wouldnt i have continuity in other wires or even grounds>?

 

I am just thinking the oil pressure sending wire is shorting out when you start the motor just by vibration.

 

checked all wiring from fuel relay to oil pressure switch that run to the firewall to ecm. im still stumped could it be a bad oil pressure switch or no still must be in the wires?