help, ECU fuse blew?

[bazooka joe]

fuse # 10 (INJ or FIP), 30 amp fuse for the ecu...car was running fine, off to get gas, fill up, turn the car back on off i go...about 1/2 mile away while taking a right hand turn i loose power...everything dies. pull over, try cranking it a few times no go...check fuses and sure enough the above fuse is blown, pull out another 30 amp fues pop it in, turn it over, it blows? any ideas, thoughts?? i'm search the forum as well...i'[m stumped? thanks!

 

[Fudgie]

Have to find a diagram to see whats on that circuit. I'm sure the fuel pump is. Have you looked under the hood specifically at the harness to see if anything is chaffed?

 

[bazooka joe]

not yet, i'm going back out tomorrow to look at the wiring at the ecu too. i did some hacking for my piggy back and o2 clamp...maybe something got shorted out there...i did have a passenger in the car at the time and he's a big fellow...he may have puched down on the ecu cover and with the wires i have spliced, maybe something shorted out...the only thing i did today was a tranny cooler...didn't mess with anything else?

 

[Fudgie]

Keep the fat guy out! You def have a short somehere. Without seeing a diagram, I would be looking at 5v ecu outputs being shorted to ground somewhere. Does it blow key on no crank?

 

[bazooka joe]

now i never said he was fat..just big! haven't checked the key on no crank yet...i'll start there tomorrow, gotta go get some 30I fuses!! i'll bet we'll find it behind the ecu panel..

 

[bazooka joe]

good news...so i go out this morning to get to work on the car....start inspecting all my wires...fuel pump..got power to the plug-good! inspect the ecu wiring...all's good there! go to auto zone get me a handful of 30I fuses (anticipating blowing a few during the test, replace the fuse, turn the key to on...fuse is good (yay!) don't hear the pump though ...go back and turn the key to start, bam starts right up, runs perfect...so i'd like to say that with my mad electro/mechanical skills i fixed it but i can't lie...

 

[pasadena_commut]

...so i'd like to say that with my mad electro/mechanical skills i fixed it but i can't lie...

Do you have a voltmeter? Since your car seems to be working now, pull the fuse, unhook the positive side of the battery, and measure the resistance between the fuse socket and ground. (Be sure that the voltage is applied in the same direction as when the battery is present, most likely that is positive at the fuse socket, but check to be sure. Some electronics do not like to see reversed polarity, although I would hope car electronics are protected against this sort of thing.) With any luck the resistance will be significantly different from zero, say 100 ohms or more. Then the next time you blow a fuse (and you probably will), repeat this trick and you should now measure something close to zero ohms (because of the short). At that point you can proceed systematically to poke around the wiring to locate the short. You may need a helper to keep on eye on the voltmeter reading while you explore the engine compartment.

 

[bazooka joe]

thanks for the advice, and yes i have a multi meter and was about to do as you suggest, but i took a chance after checking a few wires and plugs at the fuel pump and finding no apparent short to ground on the fuse post either. i do have some left over wires from the MPI i installed and one of those may ver well be the culprit. i'll be cleaning them up tonight! i should know better, but i was lazy.

 

[maxchao]

So what was the problem?? Sounds random...


Josh

 

[shane02pro5]

Your weekend sounds as exciting as mine. Ground wire for my alarm (best buy installed alarm and stereo 6yrs ago) shorted to the power wire for my haltech and billowing smoke from under my dash and hood! Cleaned up the spaghetti and good as new.

 

[bazooka joe]

well, to honest...i had a bit of a rat's by the ecu...i hacked it for the MPI piggy when i was running that, then i took that out and installed the FM o2 voltage clamp...so anyway, i had some cut wires that i just threw some tape over (temporarily...6 months!) so for the first time in six months i have this friend hop in for a ride to the gas station...he's a big dude...anyway, i think his feet may have actualy pushed on the stupid cover/harness and maybe something got shorted out...i'm guessing. well spent the last hour cleaning everything up, got rid of any wire not in use, soldered and heat shrinked all the terminations...car runs fine.

 

[maxchao]

LOL Now I'm worry about my sub wiring, there are some connection I was too lazy to heat shrink. Glad that you fix it, must be a PITA to find the cause.

Josh

 

[bazooka joe]

still not sure 100% either, i mean i got all the wires insulated and in a neat bundle, so it was the root cause it's fixed now! time will tell!