Blown Fuse V8S

[TVR05]

Hi all

Hope all out hooning in the Tiv's in the sun, wish I was too............

Got a blown 10 amp fuse and having trouble identifying what it is for, please see pic

When I start the car, the fuse blows, also currently replacing the earth strap as the old one has ssen better days and think this maybe the issue (Poor earth), anyways, I would like to know what this fuse is for and hoping someone may know - the wiring going in & out is Brown with Green trace and Orange with Green trace, looked in the S series & Chimaera bibles and just end up scratching my head, has anyone any ideas please................

Looking at the wiring, it looks a heavier gauge than the rest and just wondering if the fuse that was in there, was wrong in the first place. However I have been driving the car fine for the last 18 months........?

Any assistance would be greatly appreciated.

Cheers

Lee

[v8s4me]

Have you got heated seats fitted to yours?

[TVR05]

Hi and thanks for the reply

No heated seats, well I don't think it has! all switches and knobs accounted for and none left spare, so I'm guessing no heated seats.

[v8s4me]

Have you looked under the seats for the connectors? On mine the switch is under the dash, to the left of the steering wheel.

If no heated seats, then what is not working?

[TVR05]

Just been down to the car and double checked under the seats and dash, no wires and no switches, therefore safe to say I unfortunately I don't have heated seats. That would've been a very nice surprise though............

Turned on the ignition and noticed there is no priming of the fuel pump, would that possibly be due to no engine earth at present, as I have removed this and getting a replacement hopefully tomorrow?

Apologies in advance, but electrics are not really my forte!

Thanks again

Lee

[Oldred_V8S]

I would be inclined to get your earth strap sorted before trying to diagnose any other electrical issues. Poor earths or no earths can give some really weird faults.

Once the earth strap is in place check what isn't working.

[TVR05]

Thank you very much for your help, its much appreciated and will update once all connected again and see what happens.

[v8s4me]

TVR05 said:

....I unfortunately I don't have heated seats. That would've been a very nice surprise though...........

Don't worry, you're not missing anything, they are rubbish.

TVR05 said:

...Apologies in advance, but electrics are not really my forte!...

Nor mine, but as you have two fuses along side each other with the same colour wires my guess would be that you are looking for a pair of something.

If the fuel pump isn't priming when you turn the ignition on, the first thing to check is the fuse.

Follow the advice above and get the earths sorted out first.

If you want to PM me I'll email you a large format .pdf of the wiring diagram, and you can get it printed off on A1.

Have fun

[Oldred_V8S]

TVR05 said:

Thank you very much for your help, its much appreciated and will update once all connected again and see what happens.

You're welcome, let us know how you get on.

[Sandgrounder]

Don't know the set up on a V8 as I have an S3, but when my fuel pump stopped priming (intermittently), it turned out to be (after much searching) the earth lead attached to the rocker cover. I had some work done on oil leaks and my mechanic managed to get a little bit of silicone under the bolt head.

[phillpot]

Sandgrounder said:

it turned out to be (after much searching) the earth lead attached to the rocker cover. I had some work done on oil leaks and my mechanic managed to get a little bit of silicone under the bolt head.

It's "mechanics" like that that get mechanics a bad name



Does no one with a V8S recognise those two additional fuses?

Other looks like a 20A, should they both be? Wiring colours are very similar, would suggest a pair of something?

Can you stick a metre probe into the holder and see which side is live (I'd guess the brown) then all you need to do is search the car for two somethings fed by a bright orange wire!

If the fuse is blowing it must go somewhere?

Can you do a continuity to earth check? Straight down to earth would suggest wiring shorted out or whatever it feeds is totally fubarred, and if it's not down to earth could be it is just the wrong fuse (wiring does look hefty for 10A)?





...... After you've ensured all your Earths are in order

[v8s4me]

The brown/green trace wire from the 10A fuse goes to this relay.



This might be the ECU relay. This should click a few seconds after you turn the ignition off. Does it?

Both Orange/green trace seem to go to this connector.



The thick brown wire from the 20A fuse goes to this relay..



These are all part of the Range Rover ECU loom.

TVR05 said:

...Apologies in advance, but electrics are not really my forte! .....

They will be soon!

Can I put my loom back in the car now?

[v8s4me]

Further probing () shows that the thin blue/red trace wire from the relay connected to the 20A fuse goes to the ECU and the brown/orange ring wire goes to the AFM plug. So this relay is probably the ECU one and the other one might be the fuel pump. I'll check on the car tomorrow if it's dry.

If it is the fuel pump relay, then it explains why the pump isn't priming but not why the fuse is blowing. Try swapping the relay. If it's gone west it may be blowing the fuse.

[zombeh]

v8s4me said:

Further probing () shows that the thin blue/red trace wire from the relay connected to the 20A fuse goes to the ECU and the brown/orange ring wire goes to the AFM plug. So this relay is probably the ECU one and the other one might be the fuel pump. I'll check on the car tomorrow if it's dry.

If it is the fuel pump relay, then it explains why the pump isn't priming but not why the fuse is blowing. Try swapping the relay. If it's gone west it may be blowing the fuse.

The fuses are a TVR addition I think, they're not on the wiring diagram anyway, though a fair bit of it is not the same colours as I was expecting.

The relay in v8s4me's first photo powers the fuel pump and the lambdas and purge valve if you have them

The big whiteish connector is what joins the half a rangerover in the footwell to the TVR loom, everything the other side of that looks sortof similar to a v6 sometimes. The big orange one I think is the power from the car, the big white (and purple?) one goes to the fuel pump

The relay in the last picture powers the ECU, the injectors and the AFM

[v8s4me]

zombeh said:

...The fuses are a TVR addition I think, ....... everything the other side of that looks sort of similar to a v6 sometimes........

This is a Range Rover loom, nothing Ford or V6 here, and so the fuses are part of the RR loom.

zombeh said:

.....The big whiteish connector is what joins the half a rangerover in the footwell to the TVR loom, ....

That makes sense, although I don't remember that type of connector in mine. I'll need to have a look when the weather improves.

Wait till you find see how the permanent live feed to the ECU is rigged up

[TVR05]

Hi all

Thanks for your replies and apologies for delay, Wow what a week trying to source high quality earth leads/straps, everywhere seemed to just stock skinny and flimsy Chinese leads. However, finally found a place that makes them and now well happy, 25mm insulated cable with proper eyelets.

Replaced battery earth and engine earth, ballast resistors replaced also, as they were shot, see pics, oh and replaced the 10amp fuse.......


|http://thumbsnap.com/qpNLuHiX[/url]
Turned ignition on, fuel pump primed okay and everything seemed to click and buzz as it should, however, when trying to start (it sounds much crisper tho!) it does not want to fire up?

Hooked up ecumate and code 21 popped up?
[url]

Turned ignition off, unplugged ecu, removed Green tune resistor and that looks okay, although if being picky, it does feel brittle, cleaned terminals gently, also managed to obtain some new Green Non cat resistors, wow these really are very hard to come by.


I have tried the existing and new Green tune resistors, fault code 21 on all occasions, however it started today, coughing & chocking and sounding rough due to limp mode I guess. Both ecumate and roverguage state Tune resistor out of range, code 21................Arrrgh................!!!!

The car now has great earth, voltmeter very healthy, new ballast resistors, new Green tune resistor, head is somewhat hurting now, any ideas on where/what to do/go from here fellow "S"ers please

Thank in advance

[Oldred_V8S]

I purchased one of the pre-decessors to the ecu mate a good few years ago. The car had been running fine and nothing untoward was noticed. I plugged the unit in and guess what? Code 21, tune resistor out of range and yet the car was running OK. I replaced the tune resistor and OK, I put the old TR back, still OK. I think these can throw up 21's when there is nothing wrong. Don't get side-tracked by the code 21 issue.

When was the car last running OK and what has changed since?

Is the fuel getting through OK, are the plugs wet? The pump might be running but that doesn't mean it is able to pump fuel due to broken impeller or clogged tank/filter.

Have you checked the voltages at the AFM?

Is the coil and amplifier working OK? These normally fail when hot but could do so when cold.

Plugs / leads?

Disti cap / rotor arm. If your rotor arm is black with a rivet holding on the contact, they are known to fail in the area of the rivet and can track down to the stem of the disti. There are some red ones on the market that don't have the rivet.

Take a deep breath and start at the basics, fuel and ignition. Most problems are something simple.

Good luck and let us know how you get on.

[v8s4me]

Have you cleared the historical error codes? 21 could be a left-over from a previous fault. Check your permanent live feed to the ECU, it's the brown wire (I think).

Also check the colour bands on the resistor to make sure it is the same as the old one.

[GreenV8S]

You may have a wiring fault on the ECU loom. If you disconnect the ECU plug and measure the resistance between terminals 5/27 on the loom, you should see between 446 - 494 Ohms for a green (non-cat) tune resistor.

[v8s4me]

Hello Pete - good to see you on here again. This is very like the problem you helped me with a few years back and as you can see, I now have a spare loom of my own to help with diagnosing the problems. Thanks for the tips