what does the ignition relay do

[Yuta]

I ran into a no spark issue..after my dad cleaned up the grounds..

Before the car always have sparks... Now it has no spark.

Before when I turn the key on, the fuel pump won't come up, I will have to hot wire it to prime the system, which should be the normal situation.

Now when i turn the key on, the fuel pump is always on....

I am wondering what is wrong...

The ignition relay (G2) is a bit hot... I swap the relay with some other relays, still not spark. there is only one spark when i crank, then that's it.

[sausagehacker]

Are you talking about a 944?

1) there is no relay for the ignition coil. It comes right through the ignition switch from the battery. The DME controls the ground side of the coil. So whenever the key is on, you should have +12v between the + side of the coil and any ground.

2) the fuel pump won't run unless the engine is spinning at 200 rpm or more. It's a safety thing, so unburned gas isn't pumped into the engine bay in the event of a crash. If the fuel pump won't run without a jumper it tends to be the DME relay (aka fuel pump relay, it's actually both) that went bad.

[Yuta]

Originally Posted by sausagehacker

Are you talking about a 944?

1) there is no relay for the ignition coil. It comes right through the ignition switch from the battery. The DME controls the ground side of the coil. So whenever the key is on, you should have +12v between the + side of the coil and any ground.

2) the fuel pump won't run unless the engine is spinning at 200 rpm or more. It's a safety thing, so unburned gas isn't pumped into the engine bay in the event of a crash. If the fuel pump won't run without a jumper it tends to be the DME relay (aka fuel pump relay, it's actually both) that went bad.

Thanks, Michael. My problem was the fuel pump is always on. I am suspecting a bad DME

[Yuta]

Originally Posted by sausagehacker

Are you talking about a 944?

1) there is no relay for the ignition coil. It comes right through the ignition switch from the battery. The DME controls the ground side of the coil. So whenever the key is on, you should have +12v between the + side of the coil and any ground.

2) the fuel pump won't run unless the engine is spinning at 200 rpm or more. It's a safety thing, so unburned gas isn't pumped into the engine bay in the event of a crash. If the fuel pump won't run without a jumper it tends to be the DME relay (aka fuel pump relay, it's actually both) that went bad.

So, If I am not getting spark, that should have nothing to do with any fuse or relay (except the DME relay which powers DME), is that correct?

[sausagehacker]

If the fuel pump is always on and you know for a fact that the DME relay is good, you're looking at a bad DME. The DME actually controls the fuel pump portion of the DME relay.

If you aren't getting spark, two parts to check before anything else are the ignition switch and the coil itself.