HATCHY Posted January 14, 2011 Share Posted January 14, 2011 I dont know what in the hell is happening, I was getting fuel to the front filter this whole time, that Ive been breaking down on the road. So I did a complete tune up, and with your guys info narrowed it down to fuel issue. So now the last time I broke down on tuesday, Fuel filters are dry no gas. I changed my pump brand new, now it only only turns on for a second, when I plug in my ignition (hotwired push button) i hear it click and hum for a second then turns off, I went under the car and unhooked the line to make sure it pumps, and it pumps fine but then shuts off. I checked fuses and everything its just a mystery.. Ive had my hatch on and off the road like 3 times now broke down. from fuel delivery. Thanks a ton guys Ive done all I know, I dont know what to do next besides hot wire it up to the battery on a switch and put on an inline fuse. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 14, 2011 Share Posted January 14, 2011 (edited) Sounds perfectly normal - Subaru's have a Fuel Pump Control Unit located right above the hood release latch - it will run the pump for about 1.5 seconds when you first apply power to it (ignition on) then it will stop till it see's a tach signal from the negative side of the coil (cranking or running). This is to prevent a fire in case of an accident. Make sure you have power to the pump while cranking (check with a meter or test light while an assistant cranks the engine). If you do then it's working as designed - if you do not then you have a problem with the FPCU or the tach signal being provided to it. GD Edited January 14, 2011 by GeneralDisorder Quote Link to comment Share on other sites More sharing options...
HATCHY Posted January 14, 2011 Author Share Posted January 14, 2011 I wish I had a tachometer stock in my car, But I have a standard, I have nothing at all. no defrost none of that stuff, no oil pressure or volts, Ill take a look for that under the latch.. I have a tach installed but it doesnt seem to work anymore chepo from o reillys Quote Link to comment Share on other sites More sharing options...
lostbrat Posted January 14, 2011 Share Posted January 14, 2011 Its a black box above hood release handle.about 8 wire plug...I believe the larger blue with black strip goes to pump...jump the two wires together and bypasses "the black box" Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 15, 2011 Share Posted January 15, 2011 Bypassing the FPCU is a bad idea. Just asking for trouble. It's either blue or black depnding on the config of the orginal carb, and it's a 6 pin connector not 8. They are very simple units - I have used them to add electric fuel pumps to vehicles that had mechanical pumps. Very useful. GD Quote Link to comment Share on other sites More sharing options...
HATCHY Posted January 15, 2011 Author Share Posted January 15, 2011 Can I get a pic. on not seeing anything. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 15, 2011 Share Posted January 15, 2011 The hood release handle bracket - it's bolted to one of the bolts that holds the bracket. Directly above it. Have you verified that you don't have power at the pump while cranking? This could be as simple as the negative wire having come off the coil that signals the FPCU..... GD Quote Link to comment Share on other sites More sharing options...
HATCHY Posted January 15, 2011 Author Share Posted January 15, 2011 It pumps for a second a turns off. But NP fuel will get to the Front filter. All wires on coil are hooked up and tight. And the ground on the fuel pump is hooked up tight and clean Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 15, 2011 Share Posted January 15, 2011 DOES IT PUMP WHEN YOU CRANK THE ENGINE?!? I get that it pumps for a couple second when you turn the key on - that is not going to run the engine. You need to find out why it is not pumping when cranking or running - or if it is and something else is preventing fuel from getting to the carb. One step at a time - tell me if you have power at the fuel pump while cranking.... please? GD Quote Link to comment Share on other sites More sharing options...
HATCHY Posted January 15, 2011 Author Share Posted January 15, 2011 (edited) No it doesn't do anything just cuts off. While cranking. And turning g over. When I get home ill look again for this sensor by the latch again. But I didnt see anything. No power while cranking. And I back blew with a compressor to see if a clog was in the lines, and it was free flowing Edited January 15, 2011 by HATCHY Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 15, 2011 Share Posted January 15, 2011 I would say you have an issue with the tach signal wire from the coil negative side - thus why your "cheap tach" isn't working as well as the FPCU. I would start there. Run a jumper wire from the negative side of the coil to the yellow wire on the FPCU. GD Quote Link to comment Share on other sites More sharing options...
HATCHY Posted January 15, 2011 Author Share Posted January 15, 2011 Cool ill try it out. I Still can't locate this fpcu. Near the Hood latch. My pos doesn't have this unit. My soob doesn't even have a stock tach Quote Link to comment Share on other sites More sharing options...
NorthWet Posted January 15, 2011 Share Posted January 15, 2011 ...I Still can't locate this fpcu. Near the Hood latch... Just to clarify: The box is inside the passenger compartment, not by the latch mechanism under the hood. It is near the hood release "pull" near your left knee. Quote Link to comment Share on other sites More sharing options...
lostbrat Posted January 15, 2011 Share Posted January 15, 2011 It has one. Its saftey device.so when engine not running fuel pump shuts off and doesn't pump fuel to possibly disconnected fuel line. As in an accident ..... it is located on interior above hood release handle. As GD said. Possible to blue box or black.... and he's obviously right about 6 pin connector ..I said. 8 but havemessed or seen mine in years...my bad.. So listen to GD...negative side of coil to yellow wire at fpcu. And check for power to pump while cranking. Quote Link to comment Share on other sites More sharing options...
HATCHY Posted January 15, 2011 Author Share Posted January 15, 2011 Oh OK that makes more sense I've never even heard of that part. I was loooking outside the car. Hahahaa wow. I thought you guys were sayinghood latch outside the car. Not Hood release inside. Good to know. Quote Link to comment Share on other sites More sharing options...
HATCHY Posted January 16, 2011 Author Share Posted January 16, 2011 Problem solved. Short out somewhere in the wire. Spliced in and found something that's got when the cars on. Works perfect. Probably Not the best fix. But should be Just first fine. Thanks for the help folks. I appreciate it a tons Quote Link to comment Share on other sites More sharing options...
NorthWet Posted January 16, 2011 Share Posted January 16, 2011 PLEASE take the time to fix/wire this properly. It really is a safety item, one that prevents/minimizes fuel-fed fires in an accident. Quote Link to comment Share on other sites More sharing options...
Bash Posted January 16, 2011 Share Posted January 16, 2011 Where can that box be bought? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 16, 2011 Share Posted January 16, 2011 Where can that box be bought? Dealer, junkyard, wanted forum..... etc. GD Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.