1jzSC

my car right now cranks, but will not start...so i checked the fues box and found that the engine fuse is blown


but everytime i try to replace it with a 7.5a fuse it blows on the spot...can someone help please?

my car is a S4 N/A

RotaryRocket88

iTrader: (7)

If any fuse blows, you have a short in the wiring somewhere. The room fuse runs power to interior lights, cigarette lighter, the alarm, the ECU, warning lights & audio system. The engine fuse looks like it runs to the turn signals/hazards and rear window defrost. Either that or it runs to the fuel pump; it's hard to tell from the diagram, but looking under the dash will tell you. Pgs. 50-12 & 50-14 in the S4 wiring diagrams will show these connections. The path is battery -> underhood fusebox -> interior fusebox for the room fuse, and then battery -> underhood fusebox -> ignition switch -> interior fusebox for the engine fuse.

misterstyx69

iTrader: (142)

Is the fuse In BLUE the one that is blowing?
or IS it the Engine Fuse?
IF it is the engine Fuse,it calls for a 15 amp fuse NOT a 7.5..take a look at the LID.

1jzSC

could it be that i missed a ground? sry but im not very good with electricals, i recently removed and installed the dash and its wiring harness, maybe i messed up somewhere, does the fuel pump have a ground on the body somewhere?

1jzSC

its the one in blue, "room" fuse with a 7.5a fuse, my bad

1jzSC

i just check again..the 15a engine fuse is also blown

1jzSC

one more question, is the room fuse required for the car to start?

DarrenTRS

iTrader: (1)

If the fuse blows the second you put it in that means you have a short to ground before the load i.e. before whatever that circuit is hooked up to so a light or access. or something has a wire thats grounding out before it gets to its destination.

If it blows when you try to turn it on then its a short to ground after the load somewhere near the ground.

And if your blowing 2 fuses at once then you may possibly be having a short to voltage which could be caused by two wires touching from other circuits.

RotaryRocket88

iTrader: (7)

I already detailed out exactly what the room fuse is for, and it doesn't affect starting at all. If the engine fuse does in fact give power to the fuel pump, then of course that will prevent starting (when blown). A short is a 12V wire shorting out against the chassis or another ground source.

HAILERS

ROOM fuse powers the items shown in the attached jpg from the free online series four wiring diagrams that can be downloaded from this site.

I'd suspect the RADIO if you've been messing around with it lately. Look for a blue/red (L/R) wire as the culprit as shown in the attached jpgs.

I does feed the ECU but it plays little to no part in the operation of the engine. Its there for memory purposes and your series four car has little to no memory to deal with. Car will run just fine with that fuse blown or removed from the car.

So look at the items in the jpg and disconnect one at a time to see if the problem goes away as you disconnect each one ...one at a time. Or disconnect all of them and reconnect them one at a time. Whatever.

Or look at the third jpg from the free online wiring diagrams that can be downloaded from this site. See the line at the top of the dwg that is labled *B* for battery bus? See the number 9 followed by the number 3? Say yes. That power comes from your ROOM fuse and feeds the items in the dwg that have the L/R wire colors.

So go to each dwg in the diagrams and look only for the B line that has the 9 followed by the number 3. THOSE are the items fed by the ROOM fuse and one of those items is the one shorting the fuse out. There's only about ten pages of wiring dwgs and it takes but a few mintues to look at each one of them to determine if that page has the B followed by the number 9 and number 3.

1jzSC

thank you guys for the detailed explanations, i just replaced my blown engine fuse(15a) but my engine still doesnt wanna start, its probably flooded since i shut the car off immediately after i moved it in the garage from outside

HAILERS

ENGINE FUSE ROOM FUSE ILLUMINATION FUSE god only knows what fuse is/was blown.

Jumper the fuel pump check connector and put the key to ON. IF you wired things right the fuel pump should run proving at least that the engine fuse is good and the circuit opening relay was reinstalled right.

ericgrau

iTrader: (1)

You don't need the room fuse. It handles some interior lights and junk. I've pulled mine before so I know. Figure out that engine fuse then worry about the room fuse later.

If it's flooded do this: Pop the hood, remove the EGI INJ fuse from the fuse box under the hood. Press down the gas pedal and crank a bit to clear the flood (it won't start). Put the EGI INJ fuse back in and try to start it. You might need to repeat these steps once or twice, but don't crank the starter too much without letting it cool off.

1jzSC

ok so i went over the car today alittle, and heres basically whats happening

Deflood procedure = DONE
Compression = GOOD
ENGINE fuse = GOOD
MAIN fuse = GOOD
Jumper yellow sockets(fuel pump) = DONE, and fuel pump runs
Main relay = CLICKS = GOOD

Spark = None... i pulled a plug out to see if theres spark and there was none...what could be causing this?

1jzSC

anyone know wahts up?

ericgrau

iTrader: (1)

Gotta trace it back and see where the weak link is. Try it with a new spark plug. Ok, next see if the wire is shorted out and sparking to the chasis. Ok, next see if the coil has power (I dunno how). Okay, now measure the 12V connection to the coils with a voltmeter to make sure it's powered.

IIRC a timing light could also check if a wire and plug is working without taking anything apart. Flash = spark. But if there is a problem you still need to trace it back to find out where it is.