Bloody EFI fuse

[msherry21]

Hi all, Why would the bloody EFI fuse(the blue 15amp one) keep blowing in my car to prevent it from starting? Hence the reason I couldn't start my car for the last few days, I managed to get the car home, but I want to know why that would blow the fuse twice now? Its also revving at 3000 rpm on idle, anyone any ideas, previously it hadn't been driven for 2 weeks due to a seized caliper.

cheers for any info.

yours sincerely,

Dick head.

[adamh]

hello mich, mine kept blowing due to a loose positive cable in the bay was shorting on the gearbox and blowing the fuse, it happened on odd occasions i.e; when it wanted to, it was difficult to find. i managed to find it by chance where i put a 25 amp in (stupidly) and then watched for what set alight!... i saw smoke coming from my reverselight switch positive feed which had dislodged from the reverse light plug and swung about randomly touching the gearbox casing and shorting the 5amp efi, it also had symptoms of high idle about 2krpm this because the battery doesnot charge when the efi is blown so the engine needs to rev more to keep going. i wouldnt recommend doing it that way, i was uprating the fuse only to get me home! and stuck my head in the bay after fitting and saw the smoking cable!

[Murf]

Does it blow straight away or after a wee while? My money is on a cable being chafed and shorting out against the bodywork somewhere.

[msherry21]

going to start the hunt now to find this cable, That sounds like it could be the problem.

Hopefully if the weather stays dry I'll get it upto knockhill tomorrow!

[msherry21]

RIGHT!!! checked every cable that I could see, fired up the car and all is well, took for a slow drive...fine, booted it in 2nd just before fuel cut and the whole thing shuts down, EFI fuse blown again, swap over to another fuse and drive home normally, what the hell is wrong with this??

[Paul Woods]

michael im trying to remember the wiring on that car... the engine bay fan might be on the same circuit,if its got one! cant remember.....sometimes fans can seize or cause an extra load on the circuit.

Easily tracable though,pull the fuse out and stick a multimeter across the fuse terminals in the fusebox,set meter to amps and note the reading..... then start disconnecting stuff to find whats causing the draw...id start with the 4th ecu plug and then alternator etc

If the car was with me id find this fairly quickly mate,it sounds like a dodgy component like alt etc but could be a wire chaffing i suppose

[Murf]

If its only blowing at full load surely its something that only comes in or reaches full current at high load?
If it was the fan being siezed or shorting to earth wouldnt it blow all the time, even at idle?

Deffo check the alternator, at high revs this would change in output if the voltage regulator was faulty.

[msherry21]

I've taken the car out for a bit of a drive today, normal driving its absolutely fine, I can even gradually build up the speed to motorway speed, its only when I nail it and it and after a few seconds, around 5000rpm or thereabouts that it blows the fuse, I've also noticed when i replace the fuse and start the car it revs at 3000rpm and doesn't seem to settle at all.

I'm so stumped!

[GaryA]

Are the VSVs on that circuit you might not have them anymore though havin the charger ?

[Paul Woods]

michael can you check the charging rate at 3000rpm for me please mate

[msherry21]

how do I do that Paul?

[biteme]

Press the accelerator till the revs hit 3000rpm... Someone else will fill in the blanks :P

[Paul Woods]

stick a multimeter on the battery and note what it reads at 3000rpm...... what is the dash voltmeter saying roughly?

[msherry21]

the dash volt meter always reads three quarters full, I'll go out and check the battery now...


Johnny jazz hands!

[msherry21]

Oooooh,that reminds me....Tommytank....you have my multimeter!!!!

dam it! I'll need to get back to you with that Paul, I'll see if one of the glasgow lads can help me out with that.

[Paul Woods]

no probs mate,we will work the problem out though,easy peasy

[msherry21]

Hi Paul, I checked the readings today and it was 13.5 at 1krpm and 13.5 at 3krpm. It fluctuated a bit at 3krpm between 13.1 and 13.5 if that makes a difference, but mainly stayed at 13.5.

I'm still none the wiser!

[biteme]

Why don;t you pull the plug off the Alternator and then go for a drive to pop it - if it pops, it discounts the alternator.

[Paul Woods]

i was just about to suggest that!

[biteme]

pfft .. beat you

:D

[msherry21]

What do you mean "pop"?

[msherry21]

...and what plug? not the earth?

[biteme]

pull the plug off the alternator - the plug that provides the voltage back to the battery - take that off as they're on teh same circuit.

[msherry21]

right, pulled the plug off the alternator, drive for about 10 seconds with the engine and battery light on then the car died, fuse blown, It was revving at 3krpm when I started it with the plug pulled.

put plug back in, went through a few fuses then she fired up and I drove slowly home.

Anyone understand?

[biteme]

I understand the alternator is not the issue!

Paul ...

[weegaz22]

is it only popping if its driving? not doing it while revving it stationary? would suggest to me that its a cable chaffing out due to movement/vibration,
if it is doing it while stationary i would wait till its dark and open the bay and see if you can see a spark when its earthing out

[msherry21]

It doesn't do it when stationary, I can rev the nuts off it when its standing still (happy neighbours) only when actually driving.

[OlberJ]

Same thing happened to my 205, before it went on fire.

Check the loom with a fine tooth comb.

[msherry21]

where do you get said "fine tooth comb"?

I couldn't find anything rubbing or looking like it could be rubbing when I looked. What things are most likely to move alot under hard acceleration?

[welsha]

the engine for one

[Paul Woods]

michael is there an engine bay fan on that car?

[msherry21]

Nope, unless its fallen off!! Where would you have put it? beside the air vent I assume. definately not one there Paul.

[weegaz22]

is this on the v6 sc?

[msherry21]

yeah, thats right weegaz.

[Paul Woods]

its just sometimes fans can cause problems overloading circuits when they go bad,but yours doesnt have one so its not that.

michael pull the N1 connector apart in the boot and check it isnt full of water,thats the large cream coloured plug with 22 wires in it

[msherry21]

Is that the one that connects just short of the ECU then eventually into it Paul? Wires either end of it? I've pulled that apart, didn't seem wet but sprayed with wd40 anyway.

[msherry21]

I've possibly found a wire that could be a candidate for the chaffage award, here are some pics of it, can anyone tell me what it does?

http://www.twobrutal.co.uk/forum/images/recovered/2007/11/94.jpg

http://www.twobrutal.co.uk/forum/images/recovered/2007/11/95.jpg

I disconnected it and the car wouldn't start( could have been the cold weather) the fuse blew again, I re-attached it and the car started after a few attempts with blown fuses. Car eventually started and I wiggled above wire but couldn't get the car to cut out. This wire does seem to be quite stretched though and could easily be chafing somewhere. I'll need to get under the car later to see where it goes.

Any idea what this wire is for?

[MartG]

When you disconnected it did the engine turn over - just thinking it may be the starter wire which is only energised when you're cranking the engine, hence why it doesn't blow the fuse once the engine is running

[msherry21]

Hi Mart, the engine doesn't turn over when the wire is disconnected.

[MartG]

definitely sounds like the starter motor wire from the ignition switch then :thumbsup:

[Paul Woods]

thats the front lambda sensor wire michael.... check its not chaffing anywhere along its length

[msherry21]

Going to do this today when I get a chance. Could this wire be the one causing the problem?

[msherry21]

Jacked the car up had a look at the above wire and nothing wrong whatsoever, took it for another spin with the wire a bit looser, still blowing the fuse, not even under any real power this time, just sticking to 30! Its doing my F@~king head in now!!!

Could the rad fans be linked to the same fuse? they are both running just now, they don't seem to be a problem.

[msherry21]

...and why when the fuse blows and I replace it straight away and try to turn car over does the fuse blow again? I'm running out of fuses due to this.

[biteme]

...and why when the fuse blows and I replace it straight away and try to turn car over does the fuse blow again? I'm running out of fuses due to this.

best buy some more :thumbsup:

[msherry21]

Cheers for that, just when I thought somebody couldn't pop up and say something stupid, there you are Johnny. Always on hand to enrichen my day.

[biteme]

Jazz Hands to the rescue.

On a more serious (!) note. Is there anything left on that electric circuit now that could cause this?

Make a list of what's been discounted and how you checked versus what's on the the circuit - see if anything's been overlooked?

[msherry21]

how do I know whats on that circuit? I'm shit at this whole car malarky!

[biteme]

We'll get a list going of what's on the that circuit - but can you list what you've checked, how you've checked it and what the result was? Will give us a headstart :)

[msherry21]

I've checked all the wires I can find, and the Alternator, thats it I think. A blind man would be better at this than me!!

[biteme]

We don't doubt that mate - but we have to work with what we have. :)

[msherry21]

I work best with cheques.

[msherry21]

Could it be the lambda sensor itself? any way to test this?

[biteme]

Apart from insulating the wire as much as you can, I'm not sure. It could certainly cause a spide if it grounds out somewhere?

[msherry21]

what about if the sensor itself was broken?

[biteme]

Then you'd just run like a pig IIRC, but I don't think it'd pop a fuse.

[weegaz22]

if it was the lambda then it "should" throw a fault code, but that depends on if your using the stock managment or not, lambda wires are usually well insullated due to heat transfer from the exhaust

[weegaz22]

id also disconnect the negative wire from battery, you dont want to wake up one morning with a burnt out car like olber did, just till you get this sorted, better safe than sorry

[GaryA]

I don't think the lambda would do it as it puts out a voltage that the ECu reads , if anything coming out(controlled by) of the ecu was shorted you would have a check engine light but the ECU has protection so won't blow the fuse . I think you need to find what stuff the fuse powers before the ECU could branch off and do solenoid valves other relays power for sensors and stuff. try to print out the ECU wiring diagram then start at the fuse and follow the lines round with coloured pens . No easy way to do this when it's intermittent now if it shorts all the time this will make it easier to find .

[biteme]

exactly, it's method of elimination

[msherry21]

where can I get the wiring diagram for the 3vzfe?

[biteme]

You have PM - you quimmer!

[msherry21]

What the fuck do I do with that?????

Wheres the bit thats says "kick tyre to fix car"

[Marksman]

Really stupid question this one, forgive me if it's been checked already, but is it the right value fuse being used, and if there are any extra gubbins on the circuit has the value of this fuse been increased to compensate? Also I presume the car was OK up to a certain point in time? Was anything changed around then?

Cheers,

Owen.

[msherry21]

the car was working great before Owen, was sitting for 2 weeks while I replaced a seized caliper, back on the road and this problem starts, nothing else changed, seems too weird. 15amp fuse as always has been there.

Could the spark plugs or ignition components be an issue? they wouldn't cause a fuse to blow surely.

[weegaz22]

if you need a hand looking it over then give me a shout, another set of eyes looking at it wont go wrong

[snowtigger]

sounds like something has furred up cause its been standing and caused a short it would be interesting to find out how much amps have been going through when it blows.

[Paul Woods]

michael if you get mega pissed off id like the car back please and i will sort it for you mate....theres not a lot i can suggest via the internet....its def something on the efi circuit,but what im not sure.... there are a few tests you can do for me to help though....

put your meter onto ohms.
connect one terminal onto the efi fuse (the little bits of metal sticking out the top)
Remove the plug from the amplifier and coilpack and stick the other probe into the white/red wires,does it have full continuity? im trying to establish what things ive wired onto the EFI circuit,sometimes i use the efi and other times i use the engine main relay,both good sources of power.

Do the same test with the probe on the power side of any injector plug please.

[Paul Woods]

michael ive been putting some thought into it,very hard to fix via the internet! but we know its something on the efi circuit... thats pin 7 on your N1 connector...

http://www.mr2mk1club.com/turbo_files/turbo120.jpg

now then....unravel the insulating tape from your harness in the boot and report back which wires are joined onto pin 7....

[msherry21]

Thanks very much for going so far out your way Paul. That seems like something I can do, I'll give it a go tomorrow when I get some free time and report back. Cheers mate.

[Paul Woods]

ah no worries mate,shes one of my babies,lifetime warranty support n all that :thumbsup:

[msherry21]

Hi Paul, just checked the N1 plug and the wires that come out of the number 7 pin are:

4 orange and black wires, they go through a grommet and vanish into the engine bay all wrapped up in the loom.

Another 3 orange and black wired go to the E10 plug in the ECU and go directly into numbers 11, 22 and 21. From what I've read they seem to be:

11 - starter relay
22 - park, neutral position switch
21 - is blank.

Does this make any sense? do you need me to try and rip out the loom in the engine bay?

[Paul Woods]

and thats all ive got going to pin 7? crikey! go me....i thought id used it for more than that... its pins 1,12 and 13 they go to on the ecu plug but i knew what you meant.

Ok i wonder if this is an injector playing cupid stunts,those other black/orange wires feed them,i wonder if theres water in an injector plug...

or if one of the injectors has gone closed circuit or too high a resistance.... can you at least check the front bank of 3 for me mate... take the plugs off the injectors,set meter to 20ohms and put the terminals on the injector pins....report back the readings.

It would be cool if you could also check the rear bank but that means taking the supercharger off....

good this internet mechanics isnt it! :) we will get there bud

[Paul Woods]

oooh just had a thought....steady now! you know the 3 B/O wires that go to the ecu plug? cut them at pin 7 and whack them onto pin 12 which is the B/R engine main relay output.....then take the car up the road and see if it pops the efi relay fuse or if its now popping the engine main relay fuse.

[msherry21]

Lets hope its one of the top 3 injectors then!!

I'll check them tomorrow morning mate and let you know the results.


Thanks again mate.

[Paul Woods]

michael if you could do the test in my second post first that would be better matey,it will tell us if its something on the ecu blowing the fuse or if its the injector circuit

[msherry21]

I'll do that tomorrow first then mate, I'll need to get some new fuses first, is the main relay fuse a 15amp aswell?

[msherry21]

Oh and how easy is it to fit them onto pin 12? I've never fitted them into a harness berfore.

[Paul Woods]

there will be a thick black/red wire on the right side of the N1 connector ,T the B/O wires onto this after cutting them off pin 7.

[msherry21]

Ok Paul and anyone else with more of a clue than me. Changed the 3 B/O wires over from pin 7 to pin 12 then fired her up, she starts then cuts out straight away(no idle) no fuses blow though, just cuts out, I can put my foot on the accelerator and she keeps running till I remove my foot.

Any ideas?

[lodgeman]

try doing a reset? just remove the battery for 30 secs and then connect. it may then reset the idle speed:thumbsup:

[Paul Woods]

so after moving those 3 wires it runs but wont idle? did you take the battery off for that? as al says prob needs a reset.

Also check the engine main relay fuse is ok

[msherry21]

I'll reset the battery 1st thing tomorrow, good shout!

How do I check the main relay fuse? its not like any other fuse is it?

[Paul Woods]

its right beside the efi fuse michael

[msherry21]

hi guys, well........

I reset the ecu(negative off battery) fired her up and great,back to normal idle, let her warm up for 10 minutes whilst I searched for a few spare fuses.

Took her out for a blast, nailing through any gear from any speed just about and nothing blew, she was just flying!! What the hell does that mean, surely something was supposed to pop?

I'm going to take it out again tonight when its quieter and see if anything changes.

[Marksman]

Well that sounds like an improvement :jump: Does the circuit you've moved the wired to have a larger fuse in it?

Owen.

[msherry21]

no, its smaller I think at a 10 amp, where as the EFI is 15amp.

[Marksman]

:confused: :icon_conf :shrug:

Owen.

[snowtigger]

dodge e fuse block

[Paul Woods]

well im thinking the 15amp is being overloaded for some reason so moving some things to the engine main is a good idea....but why it wasnt blowing the efi before now i have no idea....keep us posted mate

[mr2aw11turbo]

Theory, maybe all the conections on the the 15 amp were to much for it so it kept blowing fuses, as if it had enough to deal with in the first place but with the extra load it could not take it, now even though you have "down graded "to the 10 amp there was room to allow more power to be run through it, as if there was room to spare?

i'll go back into me box and hide again now. :hidesbehi

[Bev]

Hmm... interesting problem you've got there. If you've got a good multimeter, try wiring it in series with the fuse (fuse still in the circuit!!!) and seeing what amperage is being pulled through that fuse normally. First check the current rating on the meter, and make sure it's higher than the fuses rating, otherwise you're multimeter fuse will burn rather than the EFI fuse!! :freak3: That way you can find out what the difference between your opperating amperage and the specified amperage that the fuse blows at.

If you want to run some wires into the car at this stage, you could splice into individual wires rather than across the fuse. Just remember to make sure that the extension wire can handle the amperage. Whilst you go for a burn and try and get the fuse to pop, get a mate to watch the multimeter and see if you get a current spike. If you find something all of a sudden go way out of whack, investigate what's on that wire. If you don't get anything interesting, move onto the next wire connected to that plug pin associated with the EFI fuse...

You could always use a clamp on ammeter if you can get your hands on one, and don't have a normal ammeter with a high enough rating. It also has the advantage of not needing to be spliced into the wires. With a clamp on, you can also measure wire by wire, individually. Disadvantage is that you can't really watch it whilst you're driving...

Best of luck with the troubleshooting,
Bevan

P.S. Have you checked that the EFI fuse in the Camry has the same rating as the standard MR2 EFI fuse? It could specify a higher rated fuse. I take it you were reading the fuse value when replacing off the top of the MR2 fuse box???

[weegaz22]

dont think its a problem now as he sold the car in question

[sidewaysfreak]

all seems well now :thumbsup: