Im on northampton , the link above is a totally different problem , its blowing sbf5 fuse

Cheers guys

 

Am i right in thinking this has to be a wire issue and not a component issue , any component on that fuse would surely throw a cel and a code ??

 

fuel filter bocked?

 

or injectors .....
fuel line compressed -damaged kinked.

 

bit late with my ideas there , oh well.

 

Aiya mate.Google impreza sbf5.It seems like not an uncommon problem i.e these fuses blowing.Should give you some good leads to chase

 

Also,have you had any work done recently? like sensor replacement or any mods?

 

The only thing ive had done is plugs changed , with regards to fuel filter,where is it , there was a brand new filter fitted with the walbro but im guessing there is another fuel filter in the engine bay ??

Today ive changed the fuel pump relay and also the fuel pump control module

 

Fuel filter is under the bonnet but will have nothing to do with your fuse blowing.Trawl the internet and you will see a variety of reasons for that fuse blowing.as that fuse is responsible for alot.You need to take it to a specialist as said before. Otherwise where all just pissin in the wind.Good luck and let us know how you get on.

 

Ive read every single thread and link on google over 10 times regarding sbf5 and theres bo "common" cause , just a load of frustrated people like myself

Ill try and get it into an auto electrician but they cant find a fault thats not giving a cel or any codes and sometimes going 40 miles plus without blowing

Very annoying this , really not been impressed with my subaru yet , very low mileage yet still problems , after waiting 15 years for my dream im bitterly dissapointed :-(

 

you mentioned Plugs had been done recently. Has the afr sensor wire been bolted back onto the coilpack on cylinder 3 and not left hanging on the hot exhaust. The rear o2 sensor and possibly the front sensor have links into that fuse ?

 

Thats an interesting point , which coilpack is it bolted to standing infront on the car ? Left hand side closest to bulkhead ??

Also what is the afr sensor ? I know both 02 sensors are linked to the sbf5 fuse definatly

 

At what power should i be stepping down a heat range on plugs ? Sti type uk 2003

 

Looking at the engine as your stood infront of your car its the back LH side cylinder, Usually a small bracket bolts on that coil pack with the Sensor wire on it.

AFR sensor is the front lambda located on the exhaust manifold collector before the up-pipe.

Check both sensors for wiring damage too

as for plugs usually if the cars been remapped from std most folk tend to step the plugs up to an PFR7B

 

Cheers for the help , good to have some positive input and ideas , ill check those bits in the morning , the plugs i had put in where 1 step colder and the car is mapped to around 310-315bhp , was running original plugs and fuel pump when i bought it

Cheers

 

Could be a fault in the alarm ecu which isnt unheard of but normally it just wont run. But you fuel pump gets its feed through the ecu

 

Would it blow that fuse though ? Also would i still get ignition lights etc ?

Cheers

 

Problem still persists , very close to selling up , nobody can help or find it , must be a short to earth somewhere but nobody can find or even wants to try , they all say its virtually impossible to find as its so intermittent , im at a total loss now and just feel like trading it in

 

Feel for you mate.Really do.Surely theres some one out there who can help you?

 

If theres nobody on a specialist site like this then theres not much hope really

 

You are asking for us to diagnose this from our computer screens which to be honest is impossible, go to a subaru specialist asap and get it plugged in to see what it is doing

The End.

 

When you changed the pump did you have a good look at the wiring and connectors in the tank, ive seen some dodgy wiring and connectors in there ,when its running try moving wires about to see if anything happens.

 

Harsh as it sounds your pretty much asking the impossible for it to be diagnosed from a laptop screen on the internet. No offence intended. Personally if you know the vehicle blows the fuse and you kinda know what's linked into it, maybe disconnect each sensor and run the car gently plugging one thing back in at a time and see what triggers the fault, as it may be a component fault. if you cant get it to a specialist.

I know it will trigger a cel code before anyone comments

 

But its so itamittent , i done 70 miles last week without a blip , thought id sorted it with relay and controller , then it just blew it again , its got to be a short to earth but the whole loom is so well protected , pointless unplugging everything as the car runs and drives , it wont prove anything or help atall , the car just blows the fuse as and when it chooses , no cel codes

Everybody ive taken it too says exactly the same thing , i cant test for a ground to eath or a fault when the problem isnt constant , and i cant find the fault if theres no fault code , been to subaru and they told me itwould be virtually impossible to find but they can try for me at £80 per hour plus vat

The only thing i can think of doing is breaking the loom apart and putting fusses between everything to try and narrow it down ??

Sorry if you guys think im coming across bad but try to imagine my frustration , 10 years dreaming , big bank loan , high insurance etc etc etc

Im not after a definate answer , just want to know the best way to find a problem like this , i cant be the only person here thats had this issue , surely somebody has had similar ??

 

Looking at the loom diagram the sbf5 fuse feeds the fuel pump relay & main relay first and connects to the data link connector.

The feed from one side of the main relay powers the front afr sensor & the rear o2 sensor, My bets is one of these is knackered on the power supply line and its earthing out.

the other-side of the main relay feeds more or less every other sensor contained on the engine, aka waste-gate solenoid, air flow meter, 4 fuel injectors, etc etc.

The only issue I've seen with fuel pump fuses is when a SIMTEK has been fitted and it blows the abs fuse in the dash pocket

 

Whats confusing me is the fact im getting no cel or codes , would the fact that the sbf5 also controls the diagnostic port and ecu stop me getting a code ? Would a dodgy afr or 02 sensorcause any running issues ? The car runs very smooth and fine when running thats all

Just didnt know if there were any common places that the wiring tends to rub etc , i sort of wrote of all components due to the lack of a fault code tbh

 

Wouldn't cause a cel if the wire isnt actually broken, a short on the power wire would mean the sensor is getting power but earths out to ground aswell and blows the fuse

wouldn't cause any running issues if the wire isnt broken fully.

disconnect both sensors and try it see how it goes, if alls well try plugging one back in at a time to find out which is causing it.

front afr sensor, grey plug in-front of the driver-side strut tower
rear o2 sensor under the car clipped onto the side of the gearbox.

common issues when plugs have been fitted is if the wire hasnt been bolted back on cylinder 3 coil pack and burns through on the exhaust.

the rear o2 if the clip has broken and is rubbing on the propshaft

 

Cheers for the help , could i run the car with the afr and 02 sensors unplugged , thing is that it could go 70-80 miles before blowing again so would need to drive the car to see if the problem still persists , i did look to check if the wire clip was back on coilpack 3 and it is

Do you think it was just a coincedence that this has only been happening since it overboosted and gave me the boost solenoid overboost code ?

Ive tried messing with the boost control solenoid with car running but nothing will blow the fuse , ive also took the car for a few good spirited blasts to see if i can get the same code again but nothing , runs very smooth and boosts well , does smell a bit of petrol though ??

Going to try and find an auto electrician this week who will have a look , been to 3 already and none of them were interested , they all say the same thing , that they doubt they will find it as its so hit and miss , but they all seem to agree that in there opinion its a ground to earth problem

 

Why don't you put some extra fuses in?
Put one just after the fuel pump relay, then 2 on the main relay.
In theory it should blow one of these before the main fuse, which ever fuse it blows will will show you which circuit its on and narrow the possible components down.

It's a suggestion which will be easy and cheap to do, online fuses only cost a couple of quid from halfrauds.
One more thing, the connectors for reading fault codes, is there anyway they are exposed and moving about then shorting.

 

I was going to go down this route but dont really want to start cutting the loom etc , but will do if it comes to it , the diagnostic port is fixed under the steering wheel so cant move

Im going to try to find somebody who wants to look at it this week , if not im going to get it in the unit down at work and start stripping it down and pulling the loom out , if i have to replace the whole loom then i will

Just got back from the jap show (in my brother in laws classic :-( , its made me more determined to fix this , i love the car but so far ownership has been very depressing and frustrating