Car wont start cause fuel pump isnt getting power (wont prime). I checked the main relay and its fine cause it worked in my other integra. The #38 fuse in the main box under the hood blows everytime I turn the key to accessory. The acura service manual says the #38 is the main relay fuse. Now with the main realy removed the fuse does not blow, as soon as I hook the relay up the fuse blows. I decided to take my ecu out to see if anything was wrong with it. When I opened it up I got the worst smelling thing i've ever smelled. I noticed this one piece, might be a resistor idk. The thing looks completely burnt and melted. Now I dont think it happend recently while I was messing with the relay cause no smoke came out when I opened it and nothing was hot or anything. Now, when I took the ecu out and turned the key to accessory with and without the relay plugged in, the fuse did not blow. Could this melted piece in the ecu be causing the #38 fuse to blow everytime? Thank you in advance for anyone who can shed some light on this problem!





FYI: the engine is a b18a1 and the ecu is a pr4

 

That thing is (or rather was) a diode. I've never seen one fail like that before though.

 

and a diode does what? would that cause the fuse to blow everytime?

 

A diode is like a one way gate, power can pass in one direction and ground in the other direction... http://www.the12volt.com/diodes/diodes.asp

My guess is it was there to block the ground on the other side and now that it is blown, [gate wide open] that part of the circuit is a dead short to ground, fuse blows.

Fuse 38 - 10A is the input for the injector relay, [one of two relays in the PGM-FI Main Relay] the output from the injector relay, [from fuse 38] goes to the injectors, IACV, heated 02 sensor and the ECU/ECM.

You will need to replace the ECU/ECM, but before you do so, check the ECU/ECM harness, only the 2 black leads and the brown/black should have full continuity to ground, check the harness for shorts to ground. 94

 

That ECU is still quite salvageable. I'd just replace the diode personally.

 

alright ill have to check the harness out first. i dont know how to replce the diode itself, ive never messed with any electrical things like that, thanks

 

Bump

So will a new ecu fix the fuse blowing problem?

 

Doesn't hurt to try it out. Those obd 0 pr4 are abundant and really cheap.