Fuel pump turns off while cranking [Archive]

EricF

01-20-2007, 05:12 PM

I thought I had it traced to just weak grounding, but I grounded the fuel pump directly to the battery, and even ran power straight from the battery, and it still shuts off while cranking.

I had the same problem with MS turning off while cranking but after wiring all the relay grounds to the battery it stays on now.

Get good spark while cranking, and should have injectors clicking and MS is reading all the sensors correctly, but the fuel pump turns off. It's just a big WTF moment. I'm running on a dead battery with jumper cables run to another car with the engine on, but they're very good cables with great connections on either end.

Any advice?

EricF

01-20-2007, 05:16 PM

Eh, meant to put this in aftermarket engine management.. Sorry.

Hank Scorpio

01-20-2007, 05:24 PM

Sounds like your relay's 12v trigger is on an running hot only (not running and cranking) fuse.

Apply power from the battery to both sides and see what happens. The ground should be coming from MS. Still no dice, throw a simple spst switch on the relays ground and ground it permanently, atleast you'll be able to see if it starts.

EricF

01-20-2007, 06:28 PM

Eliminated the main pump that may have been frozen and now it seems to be staying on. Getting no RPM signal at all now, time to start reading old threads on that.

740ATL

01-20-2007, 06:45 PM

Eric, what version of the firmware are you using?

EricF

01-20-2007, 06:47 PM

It's a 2.2 board that has sat around for a few years... So likely a very old version.

740ATL

01-20-2007, 06:49 PM

The reason I ask is that I just ran into a similar issue a couple hours ago... first the fuel pump would turn off during cranking, and then I wasn't seeing an RPM signal on megatune. This was on an older version of the firmware... as soon as I reloaded to the newest firmware, the issue went away.

do you know which version of the firmware you're using?

EricF

01-20-2007, 06:52 PM

The reason I ask is that I just ran into a similar issue a couple hours ago... first the fuel pump would turn off during cranking, and then I wasn't seeing an RPM signal on megatune. This was on an older version of the firmware... as soon as I reloaded to the newest firmware, the issue went away.

do you know which version of the firmware you're using?

Nope, will have to go and update though I think after what you described. I will let you know if it resolves the issue :)

benflynn

01-20-2007, 10:40 PM

fuel pumps coming on and off has always been a prob w/the firmware, common issue