I have the SRM 3 speed fuel pump controller running my brushless fuel pump. It runs off of the MAP sensor signal and speeds up as the voltage increases with manifold pressure, thus also fuel need. One issue is that it takes the little computer a bit to boot so it doesn't prime my lines when I turn the key on. I have to crank the starter for about 7 seconds for the computer to boot and the lines to pressurize before the car will start. My solution is to install a switch that will jump the relay to a button on the dash below the PSM and rear wing switches to the left of the radio screen so I can manually prime my fuel lines before I turn the key. Do they sell these switches blank? I guess I could buy another PSM on/off switch and scrape off the lettering.

 

I'm thinking maybe a defrost switch would work, I like the light it has: https://www.ebay.com/itm/EXCELLENT-U...Cclp%3A2334524

 

No blank switches that I'm aware of, but yes, you should be able to remove the text with some acetone.

However, keep in mind that there are two finishes for the switches: glossy and matte. I'm guessing you'll want to be sure to get one that matches what's in your car.

 

Alright. I ordered a used defroster switch from ebay. It seems to have the needed functionality based on playing with the switches in my car. It has a few extra electrical connections so I'll have to figure it out, I might have to power the switch to get the light and all to work.

 

We have it set up that when the ignition turns ON, the fuel pump runs for a brief moment instantly priming the system. When the key is rotated to start, the engine fires right away. Additionally, the fuel controller is programmed to send a signal to the fuel pump to run as soon as engine rpm > 10. We are using a Motec DHB fuel pump controller.

 

I know the controller was sort of designed for an aftermarket ECU so I've got to just work around the issue. I need my car to be emissions compliant when it needs to be so I'm not going too far with it. My pump controller has its own relay so it is going off of two relays basically. In the time it takes the controller to boot it misses the fuel priming window. It works great other than this little problem. I'll just hit the switch to fire up the pump, no big deal.

 

Let us know how this works for you, I have a new one in the tool box for my trans cooler that I need to wire up now that you mention it.

 

Isn't that how all cars operate?

 

Should work fine as the defrost is just a simple rocker switch.

 

Wouldn't it make more sense to just wait 7-10 seconds before starting the car once the key is turned to the first position?

 

I have no idea. Probably some version of that. I just know how we set it up.

 

All VW/Audi since the Mk4 days - around 1999 - use the driver's door to trigger the fuel pump for a prime.

 

I think the ecu primes the lines for a few seconds and then shuts off so that your pump isn't running while you are waiting to start the car or listening to the radio or whatever. During this time I believe that my pump controller is booting up and I miss this priming window.

 

Will do. I plan to splice some of the various power and ground lines from other adjacent switches so that the little indicator light in the switch works and everything.

 

Are you checking fuel pressure? Is it losing it?