Lost Time

I pulled my fuel pump relay to put in a new fuel pump and like an idiot I forgot to put it back in before the test drive. Car fired right up and drove fine all the way thru .9bar. I would think it wouldn't even start up if the relay wasn't in there. Any idea why that is?

DamonB

Yep. The fuel pump will still run through the fuel pump resistor with the relay pulled, albeit at lower fuel pressure. I don't remember the schematic off the top of my head but I remember it is possible.

Lost Time

Interesting. Thanks for the info.

ttpowerd

YIKES! Glad nothing blew up....

Drifter93

I think you lucked out.

BlackR1

Scary.

There goes the idea of pulling the fuel pump relay as a cheap form of theft protection.

jimlab

It sounds like you pulled the wrong relay, but it was an honest mistake.

The relay in the front-mounted relay box (labeled "Fuel Pump Relay") is actually the relay for switching from ~9.6 volts to the fuel pump to a full 12+ volts under WOT. This is the fuel pump speed relay, not the main fuel pump relay. DamonB is right, the car will continue to run with this relay pulled.

The main fuel pump relay is in the main fuse box, behind the battery (in the stock location) and to the driver's side of the engine. It should be a large green relay, labeled "EFI" on the cover, if I'm not mistaken. My harness isn't in my car and I don't feel like dragging it out to verify, but that's the one.

Pull that relay and start the engine and it will run momentarily, sputter, and die, depressurizing the fuel line and ensuring that no fuel is delivered to the engine. This is the relay you want to pull if you ever do a compression test on the engine, or have to replace the fuel pump or fuel filter.

bajaman

Yes, jimlab is correct. I wondered at the labeling/description of those relays, wasn't until I did the fuel filter change that I really checked it out.

Lost Time

Good call Jim. That would explain the car still running. Pulling the (correct) fuse is a pretty inventful way of keeping your car from being stolen....... unless they tow it away that is. Thanks.

jimlab

If someone wants your car badly enough, they can take it whether it runs or not. Your best bet is to A) not advertise where it stays by hot-rodding in your own neighborhood, B) keep it locked up in a garage when you're not using it, if possible, and C) maintain good insurance on the car, and make sure that it covers any parts that you've added.

You can never replace the time and effort that you've put into the car, but don't add insult to injury by finding out the hard way that your extra parts aren't covered.