Engine fuse keeps blowing

[bboypuertoroc]

aiight PLEASE GOD I NEED HELP. I've had my car at TWO shops now and they can't figure out the problem. My engine fuse (20 amp) keeps blowing for no apparent reason. First time it happened I swapped in a 30 amp fuse. That one blew too. Took it to a shop and after a couple days they couldn't figure out the problem. They let the car run for hours on end but the fuse was fine so they thought they fixed it by just putting a new fuse in. That on blew. So i took it to another shop and they found that my tranny bracket was broken and the tranny mount rubber insert was ripped in half. So they thought that when the engine rocked during shifting (and did it ever, like 6-10 inchs out of place) it was pinching a wire somewhere and shorting it. No, thats not the problem. It's still blowing. So beefore I return as much of my car to stock as possible so I can take it to Mitsubishi, I'm wondering if anyone has ever had this problem and if any electrician magicians out there might now the problem/fix. It seems to happen when i shift at higher RPMs (somewhere above 4k). It won't cut off at the higher RPM but once it drops back down within a couple of minutes the car just dies. Everything works (lights, radio ect.) and the car turns over but it doesn't actually start. I don't know what runs to that fuse but the car needs that fuse to move. Sorry I made this a novel but I'm trying to explain this as best i can. I appreciate help from anyone. Peace.

 

[Maxximillion]

i totally agree. do not keep putting in higher amp fueses. they were designed to protect circuitry and that fuse is doing its job.

Jason.

 

[Batmobile]

um...when that fuse is blown you odn't get spark/fuel

DUH...sorry...I should of thought before I posted forgive me.

 

[bboypuertoroc]

I understand the fuse thing completely and I normally wouldn't swap in higher fuses BUT this is my only car right now so it's my way to work and all that type of stuff. If I start yanking shit out I'll be out of a ride. But nevermind that... where do I go now? Like I said earlier the relay and ECU are fine. So I'm guessing it's a problem with the line. Any ideas?

 

[gsxgota]

i fixed my problem just now with my engine fuse blowing, it turns out my mfi relay was bad, it was a hunch, so i just bought a new one fromt he dealer for $36 and it cured my problem.

adam

 

[suncad03]

I am haveing the same problem as you
BUT my Ing 30 amp fuse it blowing
3 shop's can't fix it
dang high speed shift's

 

[suncad03]

my bad fuse IS blowing

 

[gsxgota]

my bad, i thought i had fixed my car, it ran a good 24 hrs. before i blew the fuse again. then it would run for a good 30 min before it blew another fuse, i went though 3 fuses that lasted 30 min before they blew, now i have another problem. when i needed to start my car, i put a short finder inplace of the fuse, and it always started and ran with no problems. now it wont even startn at all with the short finder. Do you guys think i caused another problem? grr, this is frustrating, i need some help.

 

[98EclipseTurbo]

Not much of a solution here, but if yu need your car really , buy a circuit breaker from auto store , and if it looks a flat fuse get small test wires -walmart and electricical tape.
Do not use it for a longer period of time or use better wires maybe. Good luck

 

[bboypuertoroc]

aiight so i couldn't figure out what was wrong because everything checked out OK (MPI relay, wires, ECU, cam/crank sensor). I took it to Mitsubishi in Woodbridge, VA (mod friendly) and they hooked me up. They put my car on the diagnostic machine for like 5 or 6 hours but only charged for 2 1/2. The machine didn't come up with anything (which is wierd cuz I don't have a cat). They found out though that my positive battery cable connector was f'd up. It didn't completely clamp on the pos terminal so the car would be connected then disconnected continuosly and that kept screwing with the fuse. Whatever the case, they fixed it and now 150 miles and a hell of a lot more than 30 minutes of driving time and the 20 amp fuse is going strong. Thanks to everyone that gave me good advice and I hope someday I'll be able to return the favor. Hope to see all North VA DSMers at the GMU meet next month. Aiight then everyone, PEACE!

 

[superman77]

Where is the MFI relay located at? and also is it hard to Change out?

 

[Chrispy0530]

I had this same exact problem. I didn't read through all the other posts, so sorry if this was already said.

What kept causing my engine fuse to keep blowing was a short that a bare wire was touching near the intake manifold. Search all your wiring for anything that might be exposed, and tape it up with electric tape. You mention it only happens while shifting in high gear, so that's saying that when the engine is under load, it's moving and something is coming in contact causing the short.

Good luck.

 

[pindlepiper]

Sorry to bring this back from the dead, but i am having very similar problems and I can not really find much about it. I bought the car with an AEM EMS and decided to switch over to ECMLINK V3. When switching over, i noticed the previous owner had done a horrible job on the wiring of the car. The soldering looks like Helen Keller did it. No heat shrink was used only electrical tape and it all seems to be coming off now. I went through the wiring by the ecu very carefully one at a time redoing all the connections correctly with good solder joints and heat shrink. Zip tied and grouped wires together. Car runs horrible under recommended settings for my injectors with 2g mafs. Made a couple of posts on link with logs and was told it seemed i had a deadtime issue and needed to bump it up to 1000-1100. Car idles pretty good now, but my afr's are high 15s and 16s and no matter what i do i cant get them lowered. I was told to do some WOT logs and cruise logs to further diagnose the problem. Now, this is when i am blowing my engine fuse. Seems to idle fine all day, seems to cruise slowly without having an issue, but as soon as i give it a little throttle and start to build boost it gets real bucky and dies. It will typically start up two or three more times and continue to die. After two or three times restarting it wont start anymore at all. This is the third time I have blown this engine fuse. Triple checked all wiring that i messed with, even swapped back to the AEM EMS and still my problem exists. Also, prior to switching over the car left me stranded on the side of the road. I had the car towed home and it turned out my problem was the Power transistor unit. Replaced it, verified car started but did not drive it. Then proceeded to fix the wiring and everything else so i dont know if this is somewhat related. This only seems to happen under power, if it were shorted out, wouldn't it blow the fuse as soon as i start the car? Seems maybe under load its triggering something thats shorted or possibly the relay is shorted. I have the two separate MFI/Fuel relays instead of the one piece design. I cant seem to find a test procedure for the 96-99 style. Any help would be greatly appreciated as i am getting pretty burned out trying to diagnose this problem.

 

[AlaskanDsm]

I unfortunately can't help much here but take a look at the electrical diagrams for the car and see if you can trace the wiring back. You may find additional areas of problems that are causing the fuse to blow... GL.

90-91 Electrical

97-99 Electrical

(your picture is confusing me to which you have haha.)

 

[pindlepiper]

Thanks, i will check out the wiring diagram for it and see what i can come up with. The 1ga in my avatar is far from road worthy so ill change it to my 2g for less confusion haha.

 

[pindlepiper]

I have been reading over the schematics for the 20a Fusible link. There is so much that is tied into that circuit. I have traced and checked several things but just can't seem to figure out why i keep blowing this fuse. Someone suggested a weak fuel pump pulling to much current, but i do not know if that could cause it or not. I have pulled the battery looking for shorts around the battery tray and also unbolted the fuse box and looked for any kind of bare wire on the bottom. So far everything seems normal, still no culprit.

 

[gst_man]

Well pundlepiper did you ever figure out what's causing your issue? I have the same problem now on my 2g with a 6bolt swap :/ lots of weird wiring anyways. My fuse is blowing as soon as i turn my key to the on position.

 

[pindlepiper]

It turned out to be a short in the o2 sensor causing all of my problems. Mine would run and idle fine, but under load it would pop the fuse. It sucked one little issue kept me down for two weeks.

 

[yoshi_tony]

ok im having this problem for 2 days now but this is how i did it because that fuse is connected to so many things this is how i did it (98 tsi awd with 6 bolt swap) ok

test 1: disconnected all 4 clips from the ecu (battery connected) turned the key to "ON" the fuse didnt blow

test 2: connected the smallest clip ONLY (12 pins, battery connected) turned the key to "ON" the fuse didnt blow

test 3: left small clip connected and connected the other small clip (16 pins, battery connected) turned the key to "ON" the fuse didnt blow

test 4 left those clips connected and connected the biggest clip (26 pins, battery connected) turned the key to "ON" the fuse didnt blow

test 5 I disconnected all clips and connected the one i havent connected(22pins, battery connected) turned the key to "ON" the fuse BLEW UP RIGHT AWAY

So i shortten my possibilities to this clips

92 Ignition switch - IG
91 Park/Neutral position switch (used on ATs only)
90 Volume air flow sensor
89 Crankshaft position sensor
88 Camshaft position sensor
87 Closed throttle position switch (Idle switch)
86 Vehicle speed sensor
85 Barometric pressure sensor
84 Throttle position sensor
83 Coolant temp sensor
82
81 Sensor impressed voltage
80 Backup power supply
79
78
77
76 O2 sensor (front)
75 O2 sensor (rear)
74
73 Manifold differential pressure sensor
72 Intake air temp sensor
71 Ignition switch - ST

now im going to disconnect all sensor that are on those pin outs and go step by step see which one blows ill be back in an hour

 

[2000Eclipse]

So I have a 2000 Mitsubishi eclipse that blows a 15 amp fuse that has a picture of an engine on it
(Not sure what it's called, sorry not so bright about that stuff) so that fuse,"when blown" turns the car off but the lights and radio still stay on, and it only blows the fuse when it changes gears, I will turn the car on and start driving (it is automatic transmission) once it switches gears the fuse blows and turns the car off, but will turn right back on after swapping it for a new fuse. Anybody have an idea of what this could be ? Been searching for months now for an answer please help ! Thank you.

 

[chrysler kid]

It's a short circuit on the main engine harness.

On the fbody's camaro and trans am the most common cause of the engine fuse blowing is a frayed 02 sensor arching against the chassis.

As mentioned previously it could be another frayed wire to another engine or transmission sensor as well.