Fuel and Ignition Fuel Pumps and Systems, Ignition and Spark Systems

No Fuel Pressure diagnostic help inside please.

Old Oct 5, 2009 | 04:10 PM
  #1  
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Question No Fuel Pressure diagnostic help inside please.

Ok here's the deal. When turning the key forward I get no fuel pressure to the schrader valve with my tool(hopefully the tool is good. It's been a while since I've used it). There is no smell of fuel around the valve and I get no spew when installing or taking the tool off the schrader valve on the back of the fuel rail.

Ok now for the trouble shooting. I do have 11.4 volts to the pink wire going into the fuel relay under the driver seat. I have zero volts to the grey wire on the C210 connector under the passanger kick pannel. I also get zero volts to the fuel pump prime connector in the ingine bay next to the PCM.

This being said I haven't pulled the cover off the fuel tank yet to check in there but I can hear the fuel pump spooling up when I turn the key forward there is just no fuel pressure going to the schrader valve. I also hear the click from the fuel relay after you turn the key forward.

I'm wondering if there is a fuse or something that may have a short causing the said connectors not to have power yet the relay does. I will be in the garage checking the pump out while I wait on replies from you all(o yeah it's a brand new 255lph pump). Stock fuel pressure regulator. Stock fuel lines and rail.

Thanks!
Old Oct 5, 2009 | 04:30 PM
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Confirmed.....no power to the fuel pump at the wires going into the fuel tank. However power is making it to the fuel pump relay. Ok this is pointing straight to the problem but I can't seem to put my finger on it. Off to the random information of fuel system schematics. Next thing i'm looking for is the source of the fuel pump power power.
Old Oct 5, 2009 | 04:40 PM
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According to the schematic on Shbox's page I should be getting power to the grey wire. However, I am not getting any power to that wire. Must be a relay issue. Off to the store to get a relay to check it out. I sure wish I could find my older stock relay. This is a new made in China piece.

Old Oct 5, 2009 | 05:38 PM
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Ok folks this is realy getting to me now. I just bought and put in a new relay and I get the same thing. No voltage coming from the relay. I checked the PCM to confirm power and also retuned the PCM to ensure it had a good tune in it. I also scanned it with datamaster and found no engine codes and the voltage looked normal. What else could this be?

History:

I just finished taking the passanger side head off to helicoil the intake holes in the head and have finished that projuct and have everything buttoned up and ready to go.........or so I thought. I've been doing this over the last 7 months so there may be a ground of some sort or a wire of some sort that I may not have connected that could be causing the symptoms I'm getting. If it sounds familiar by all means chime in. I'll keep looking over diagrams to try and find my bug while I wait for possible input from you all.

Thanks!
Old Oct 5, 2009 | 06:18 PM
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There should not be power at the grey wire unless the pump is on and the relay is energized. Take a jumper wire from the positive side of your battery and touch it to the grey wire, the fuel pump should run and your fuel pressure should go up. After you verify that the pump does work go replace the burnt 15 amp IGN fuse and start the car up. If it's not the fuse then you either have a bad relay or bad wiring.
Old Oct 10, 2009 | 12:23 PM
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The above statement of the grey wire was dead on. I hot wired the "jumper wire" to the battery momentarily and the pump worked great. My problem was a bad fuel pressure sensor tool and my ignition was hooked up backwards.

I have the delteq and I went from a valve cover style to the radiator hook up and while doing so managed to get all the coils backward. I didn't find this out until I took the ignition appart. So basically my issue was the same as if someone had all the wires mixed up going to the wrong cylinder. This is one of those "what's the dumbest thing you've done" thread. Never the less it's good information for troubleshooting the fuel system. Thanks.
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