Log1call Posted July 7, 2009 Share Posted July 7, 2009 (edited) Put the volt gauge across the battery posts(not the clamps) and check you have twelve volts. Crank the motor and check the voltage, it should drop to about nine volts. If it goes below nine the battery is crook or the starter is drawing too heavier load, which can be caused by a tight motor. If there is not more than one volt drop then there is a fault with the starter or wiring. Put a volt gauge from the battery positive terminal(not the leads clamp if you can manage it, get someone to hold the test lead on the batteries post)to the starters positive terminal(the threads, not the starter lead) and see what it reads as you crank the motor, it shouldn't read more than a half volt. Note that this is not the same test as suggested earlier. This tests the connectors on the ends of the cables are connected properly. Then connect the volt gauge from the battery negative post to the motor, anywhere there is a good contact will do, crank the motor and check there isn't more than a half volt drop. This checks cable terminals. Edited July 7, 2009 by Log1call Doh... Didn't read carefully. I see you have progressed, disregard those suggestions. Quote Link to comment Share on other sites More sharing options...
sub_dont_touch Posted July 7, 2009 Author Share Posted July 7, 2009 ok, got someone to help me. There are 4 wires in the connector plug, Blue with yellow stripe, thick black wire, thin black wire and green. thin black and green gave around 4volts when turned on position. must be the gauge? blue with yellow stripe and thick black wire gave up to around 11v when turned on position but then dropped back to 0v. Postive probe in thick black wire and negative on a ground bolt gave a around a constant 0.05v Double checked for any noise when turning on and can't hear anything from the fuel pump. Quote Link to comment Share on other sites More sharing options...
Cougar Posted July 8, 2009 Share Posted July 8, 2009 The blue/yel wire you saw 11 volts on briefly sounds like the wire running to the pump and is operating normally. Since it sounds like power is getting to the pump you have two possibilities for trouble. Either the pump motor is bad or the ground side for the pump isn't working. The ground side of the pump circuit may run through the ECU and is controlled by it if that is so. You could try to power the pump by directly applying power to the pump and see if that works. If it does then you may need to replace the ECU if the ground is controlled by it. Quote Link to comment Share on other sites More sharing options...
sub_dont_touch Posted July 9, 2009 Author Share Posted July 9, 2009 I've removed the fuel pump assembly. Everything looks fine. No bad wires or connections. I tried connecting the connector plug with the unit out. Tested for power at the terminals on the fuel pump and only showed 0.01v (turned to on position), which is weird as there was 11v at the connector plug. how do i connect power straight to the pump? Wires from battery to pump? Quote Link to comment Share on other sites More sharing options...
Cougar Posted July 9, 2009 Share Posted July 9, 2009 The power to the pump only happens for a few seconds when you turn the ignition to ON and the engine isn't running. The safety system shuts the power off to the pump if it doesn't see ignition pulses occuring. By running power directly from the battery or a 12 volt power source you can test the pump motor. Quote Link to comment Share on other sites More sharing options...
sub_dont_touch Posted July 9, 2009 Author Share Posted July 9, 2009 (edited) I have my brother turning the key on and off to the on position while I check for power. There seems to be no power after the connector plug and down to the fuel pump. The fuel gauge wires have power tho (around 0.5v) and they are using the same plug. Just tried connecting power straight to pump, sounds like its working fine, a whizzing sort of sound. Edited July 9, 2009 by sub_dont_touch Quote Link to comment Share on other sites More sharing options...
4x4_Welder Posted July 10, 2009 Share Posted July 10, 2009 (edited) Ok, most likely it's your relay. Over time the contacts in there get burned up. I don't know off hand which one it is on your car, but you should be able to swap it with your A/C relay to verify. If it isn't the relay, and turns out to be the computer, then you can bypass the whole mess and have the key switch turn the relay on directly. Not safe if you wreck since the fuel pump will stay running, but it'll get you around. As for the voltage issues, checking the voltage with no load against it will usually show full battery voltage, but once you put the load on that circuit, the voltage will drop. If you think of electricity like water in a garden hose, it gets much clearer- With the end capped and no flow (no load), even if the valve is barely cracked open, you'll get full line pressure (voltage) in the hose. Open it (apply a load) and the pressure drops. Edited July 10, 2009 by 4x4_Welder Quote Link to comment Share on other sites More sharing options...
sub_dont_touch Posted July 16, 2009 Author Share Posted July 16, 2009 (edited) I've got the fuel pump relay out from under the dash. I've called up some places but can't find anyone who sells one. Is the a/c relay the white plug on the same bracket as the fuel pump and main relay? I think I understand the voltage thing now. Edited July 17, 2009 by sub_dont_touch Quote Link to comment Share on other sites More sharing options...
sub_dont_touch Posted July 20, 2009 Author Share Posted July 20, 2009 (edited) I swapped the fuel pump relay with the relay from a white plug next to it. Still not starting. Checked for power at the fuel relay plug, 12v. Edited July 20, 2009 by sub_dont_touch Quote Link to comment Share on other sites More sharing options...
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