Fuel pressure at the rail & rotor wiggle?

djhedges · August 25, 2017

These forums have been super helpful and I believe I've narrowed my no start issue down to fuel. I have a few quick questions.

What should the fuel pressure at the fuel rail be? This is a 93 VR6 Corrado. I've read the manual but I find the diagrams confusing.

With a gauged hooked up to the fuel rail and ignition on I'm seeing 7psi fuel.

This is the port I'm measuring the pressure at. Turning the ignition on & off several times bumps the pressure up to 18psi. It'll gradually leak down.

Does your rotor wiggle like this? The metal under the rotor doesn't move at all. I suppose with the rotor spinning this doesn't affect anything but it seems wrong to me.

https://goo.gl/photos/Wnarzio8J7H1qzSX9

What does your voltmeter show in the car with the car running? I see usually 1v drop compared to what a voltmeter reads at the battery. In this picture the car was running and battery read 14v.

The short back story. This is a race car which we towed to the track for the weekend. We were able to start the car and load/unload from the trailer just fine on Friday. Saturday we struggled to start the car. Bought a new battery and the car ran great the rest of the day. Sunday we missed out because we couldn't get the car started.

I've tried several things

Tried new spark plugs & old wires
compression test yielded 180-195psi on each cylinder
cleaned the battery/starter grounds & power connectors
replaced the battery ground terminal, it was janky and held on by a hose clamp
reseated the relays, they were a bit loose
tried a 109 relay from a different car. No difference
bypassed the killswitch (there is a killswitch between the main battery power & the car's main power)
I can hear the fuel pump make a humming noise for a fraction of a second after the ignition is on
Verified spark with a ignition light and a spark plug grounded to the intake manifold

The car's no start behavior while connected to a battery charger is that it cranks but fires once per crank. IE cranking for 10 seconds isn't better then cranking for 3 seconds. Yesterday I got home proceeded to cycle the ignition several times and tried to crank the car. Silly me forgot I had pulled the rotor & cap off. Reseated these and the car fired right up. A/F ratio read 14:1 and leaned out to 16:1. I can't recall the previous behavior of the A/F gauge on a cold start.

Went for a walk and tried to start the car again. Fired right up. Tried to warm the engine up by revving @ 2k rpms. Without a throttle input change the engine speed dropped. A/F ratio leaned out to 20:1 at which point I shut off the car.

I currently suspect the fuel pressure regulator. But would like to verify the fuel pressure at the fuel with the ignition on before trying to start the car again. Thanks for help.

djhedges · September 17, 2017

To follow up if anyone else has this issue. Fuel pressure at the fuel rail while running should be 50psi. The fuel pump had a gasket which deteriorated by the pick up.