what circuits use 16A fuses?

[anonymous-user]

My kit car has a small fuse box with about 8 fuses , there are 2 16A fuses which are the largest. They are continental style fuses, not blade types, so a plastic cylinder with a metal strip up the outside.

One of the 16A fuses has melted a bit, although it's not actually blown the fuse, but its been hot enough to melt the plastic fuse body a bit and cause a bad contact, which sometimes prevents the car starting. If I compress the contacts the engine starts fine, remove the fuse and it stops instantly. The starter motor still turns the engine over at full speed with the fuse removed, but it won't fire up.

I did not build the car, and the wiring is still a mystery to me as its mostly wrapped up in loom tape and has been hacked around a bit as far as I can tell by some of the previous owners, so can anyone suggest what a fuse of that capacity is likely to be for so I can try to figure out what size fuses it actually needs, or if there is a problem.

Its a 1994 2L Zetec , throttle bodies and an Emerald ECU.

It broke down on my previous trip out as the alternator was not charging (which I've now discovered was because I'd got it connected wrong) and was started with the breakdown chap's huge jump-start pack in place of the battery, in case that could have been responsible for heating up the fuse?

[stevieturbo]

Any number of things...find out exactly what it does first, measure how much current that circuit actually draws too.

And it could be anything from too much current to a simple poor connection causing heat

[Penelope Stopit]

First of all you need to remove that fuse box and replace it with a blade type box, at present you have whats known as continental fuses and they proved to be a complete failure, these fuses have a tendancy to overheat rather than blow (more so when fusing circuits with long wires)
Once you have upgraded the fuse box you need to check out what current is being drawn through each fused circuit and fuse it to the correct rating
The fact that the car cuts out when you remove that melted fuse could mean that the ignition feed for the coil has been fused, it is good practice not to fuse the coil feed
Check it out and post back here if you are not sure about anything

[anonymous-user]

If it completely stops the car starting, then it's probably one, or all of the following:

1) coils
2) ECU
3) Injectors
4) fuel pump


However, if it's the fuel pump, it might still splutter a bit on cranking if there is any residual fuel pressure in the rail. Time to break out the multimeter and trace the wiring before replacing the fuse box with something a bit more modern!

[anonymous-user]

Yeah I was planning to swap it to a blade fusebox at some point, maybe now is a good time

I've been out and got some new fuses, so I'll check the current draw tomorrow (if it ever stops raining) and see what is being pulled through that fuse, then see if I can determine where the cables go to.

Edited by anonymous-user on Friday 8th April 20:20

[Steve_D]

The fuse melting may not be a function of the current drawn by the circuit.
It is more likely the contact between fuse and holder had become corroded and in doing so increased the resistance which then produced the heat.

As has been said, time for a new fusebox.

Steve

[AER]

Snetterton and Brands, but at Silverstone you may need 20A or more...

[anonymous-user]

I've done some checking and that fuse was for the high-pressure fuel pump in the engine bay, cleaned up the fuse box and added a new fuse and all is working correctly and the fuse seems to stay cool. The current draw through it is about 7 amps at idle (or 7 something, I still dont understand how my multimeter works).

I've ordered one of these blade fuse boxes so I can hopefully stop this happening again:

http://www.carbuildersolutions.com/uk/blade-fuse-b...

thanks for the help everyone.