Fuel pump problem
12-22-2008, 08:25 PM
#1
Thread Starter
Join Date: Aug 2005
Posts: 18
Fuel pump problem
I finished putting the new engine in the car and I was excited to start it...but no, no fuel! The pump is not priming when I switch the ignition on. I've done a lot of research, searched the forums and done some troubleshooting without success. The car is a 93 and while the engine was out I replaced the heater core, what a pita! The red wire into the fuel pump relay under MAF has 12.2 volts to it and none of the others do when the igniton is on. The inertia switch is depressed but the green wire only has 6.6 volts. I'm clueless and aggravated. Any ideas?
12-22-2008, 09:21 PM
#2
D.R. THE PATHETIC DORK
Join Date: Jun 2007
Location: West Virginia
Posts: 30,863
http://www.my5oh.com/forum/viewtopic.php?t=524 scroll down until you get to the no fuel tests and ecm not turning on tests
12-25-2008, 10:46 AM
#3
Thread Starter
Join Date: Aug 2005
Posts: 18
Thanks for the link. I haven't had a lot of time over the holidays but hopefully over the weekend I can figure this out. The post says I should have 5vdc on the orange/red wire of the TPS, I have 12.1v. I believe the ecm is turning on and I have a problem with the fuel pump wiring/relay. I am troubleshooting this by myself so it is hard to tell if the fuel pump relay is clicking. A friend of mine said I should have power in to the relay, I was figuring the 12v from the red wire, and power out from one of the other 3 inside the relay. Thanks.
12-27-2008, 10:04 PM
#5
D.R. THE PATHETIC DORK
Join Date: Jun 2007
Location: West Virginia
Posts: 30,863
the ecm controls the ground side of the relay windings and is done when the PIP signal is sent as an input from the stator to the ecm so that the ecm knows the engine is cranking and therefore sends an output command out grounding the windings triggering relay operation.......simply put once you start cranking identify the wire out of the relay that goes to the FP and if it becomes hot while cranking than you have a working FP circuitry and that is assuming the ground for the FP is good, if you don't hear the pump coming on and no FP is registered on a gauge that you should tap into on the fuel rail via a FP tester then you might assume you have a bad pump....that's to say your car is not starting due to lack of fuel
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