My EFI relay gets very hot. Is this normal??

[amichie]

The main EFI relay on my MX83 Grande gets hot. Is that normal??

[oldcorollas]

hot or very hot? can you still touch it or is it melting?

hot is usually not so good...

[ra_28]

Depends on what you call hot a relay will be warm to touch espically if its on all the time. I call touching an exhaust hot.

[amichie]

Too hot to leave your finger on for more than about 2 seconds.

[Robbos_Toyotas]

Too hot to leave your finger on for more than about 2 seconds.

no that is not normal then. is it earthing properly? feel the wires going to it when you find the relay is hot\...are they hot too?

[amichie]

I thought that was too hot.

Its hard to see the wires going to the relay since the fuses and relays are plugged into a module near the radiator overflow bottle. There is a 20amp fuse in line with the relay that has never blown and I have no ECU fault codes at all. No other real symptoms.

[Robbos_Toyotas]

I thought that was too hot.

Its hard to see the wires going to the relay since the fuses and relays are plugged into a module near the radiator overflow bottle. There is a 20amp fuse in line with the relay that has never blown and I have no ECU fault codes at all. No other real symptoms.

you need to see if the wiring is hot too. then you can find out if its just a rooted relay or if it is a problem which is in the car....

[cambelt]

That is normal , touch it after driving melb to sydney and you will find out a new meaning of hot . seems silly to make them get so hot but in my 16 years exp with them i havent had a single one fail.
Dave

[kewp]

The coil (assuming 60 ohms) on a relay dissapates about 3 watts so if you leave it on long enough, then yes it will warm up - but not that hot that you can't touch it.

[cambelt]

Im telling you that they do get that hot you cant leave your finger on them , it must on for 1 hour or more for them to get that hot.
Dave

[spoon]

maybe the relay you're using isnt rated for the current you're drawing. or close the to max anyhow.

[o_man_ra23]

The coil (assuming 60 ohms) on a relay dissapates about 3 watts so if you leave it on long enough, then yes it will warm up - but not that hot that you can't touch it.

60 ohms is a lot for a couple of metres of wire. that sized wire doesnt go at 5ohms a metre, its more like half an ohm a metre or less probably closer to 60 ohms a kilometre. Usually there is a resistor in there to up the resistance so you dont have so much current draw. You may have a faulty resistor. Other hotspot item is the contact inside the relay. If it is faulty, it can generate a lot of heat without blowing the fuse or producing an EFI fault. Pull the bastard apart and have a sticky beak at it. Also measure the resistance across the coil pins.

Cheers, Owen

Oh, and yeah, they get freakin hot normally too.

[CrUZida]

Every EFI relay I've ever touched has been too hot to touch.

Its perfectly normal in this case.

[amichie]

Thanks to all.

I'm now satisfied that it's normal. I checked the battery volatge and the ECU B + voltage and there was only about 2mV difference. So i guess there is almost no voltage drop across the relay contacts. All the heat must be coming from the little coil inside the relay. As per previous post.

Now I can go and tinker with something else.