No electricity to fuel pump

metalman

Registered User
This is a continuation for another thread I posted about my car not starting after I replaced my dashboard.

I know now I have a fuel distribution problem.

Initial findings:
-Fuel pump not buzzing w/ key on
-Check fuel pressure at schrader valve-no pressure
-Checked continuity at Fuel Pump Motor fuse in power dist. box-no voltage
-Checked inertia switch-ok

I went to the library today I copied wiring schematics from a Mitchell book for an '89 T-bird. I have a '90 which is the same, yes? As far as I could tell nothing was different in the wiring or colors of wires. It was 16 pages of 11x17 paper. It cleared up alot for me.

Does anybody have a suggestion or answer as to what's up? Does anyone know the route the electricity takes in the fuel pump circuit? I'm assuming is would start at the ignition switch to the fuse, or am I way off?

Any help would be apreciated. Thanks,
Metalman
 
Did you check the fuel pump relay in the trunk, just below the inertia switch?

They aren't expensive, paid about $12 for mine.

David
 
I haven't checked that yet. I will. But, if I'm not even getting power to the Fuel Pump fuse in the engine compartment fuse box, then the power lose is before the fuse, right?
 
I wish I could tell you something else to look for. I'm sure there are some evry knowledgeable people on the site, just don't know where they are right now. My son has a problem with his 90 Integra and we think it's a fuel pump problem. WE checked the pressure today and there was nothing. The pump ain't even coming on. He's been able to start it with starting spray and it might run after that, but mostly not. So we are thinking bad fuel pump.

You aren't getting any power to the fuse. Hmmmm, did it run fine before you took the dash out? I'd go back and pull the dash and sart checking things there. I know that might be a pain, but if it ran fine before and it won't run after the dash install, then the problem may lay somewhere in what was done on the install.

Good luck, this sounds llike a toughie!

David
 
relay

1990 fuel pump relay is part of the IRCM ...so check high current fuses ...like ECC relay fuse and fuel pump relay fuse in the High current fuse box ..91 and up had fuel pump relays in the trunk .....dave
 
yeah mines did the same, i dont know what it was, but it worked when i switched the FUEL PUMP fuse with the fuse next to it. Then it worked.
 
My fuel pump relay is in the trunk under the Inertia Switch. I have a'90. But I did some continuity tests and voltage tests. The right contact of the fuel pump fuse has juice-12V but the left contact has nothing. I checked the ICRM and the wire coming from the fuel pump fuse also has juice @ 12V. So I'm assuming that the connection is making power from the the ICRM to one side of the fuse. That is the black/yellow wire. The other black/yellow wire on the fuse goes to the fuel pump relay in the trunk.

So if relay side of the fuse wire isn't getting power, what is the assumption?
This electrical stuff is kinda like looking at the Matrix to me :confused: But I'm learning.

Oh, and on a related note, my radiator fan turns on with the key "on", my horn doesn't work, and the OBD code tester hookup isn't getting juice either. Ouch!

Thanks for your input. I need it!

Metalman
 
Anthony..I spoke with Ben today about your problem,he said it must be a pinched wire...as simply swapping out the dash and reconnecting the wiring harnesses shouldn't cause this problem,recommended that you start tracing wires from the fuel shut-off forward till you find it....hope this helps.
z
 
Stop

fuel pump relay is not in the trunk...relay under fuel cut off switch/inertia switch is not the fuel pump relay ...not sure what relay 9345 is ...but I know it's not fuel pump ....IRCM or intergrated relay control module or CCRM constant control relay module....is behind passenger head lite ..and it's home to the fuel pump relay...ecc relay and high and low speed fan relays ....also A/C WFO cut off switch ...first I would check your connections ..if dash was out @ fire wall and under dash driverside and tighten the harness connectors ...also @ the IRCM all 10mm bolts on those connectors ....fan comming on with key could be A/C control panel in dash not connected or Max A/C button is on ...or again could be related to the IRCM ...why was the dash out ? ....dave
 
His dash was cracked/torn so he r/r'd with a better one.....switched out the ICRM w/ a known good one yesterday and still same results,car will crank but has no fuel pressure,no horn,strange things like that.
z :confused:
 
moving on then...mearsure continuity @ inertia switch ..turn key on ...for there to be power there ..the EEC relay is turned on by the key ..and that powers the injectors the EEC and MAF sensor and others...... also power to the coil side of the fuel pump relay.. via the inertia switch curcuit...that will mean the EEC is powered...the igntion coil curcuit is feeding power to the EEC relay and DIS/spark plugs /crank and cam sensors ..all that's needed is gas ...and power to the fuel pump ......if power is there ..from the fuel pump fuse to the ircm ...black/yellow wire to the Ircm...pink/black out of the IRCM to fuel pump/EEC ....and there's power @ the inertia switch... key on ...all that should be working ...or there is a bad ground on the fuel pump ..if not... it's not the fuel pump curcuit..but EEC curcuit or ignition coil curcuit...not allowing the fuel pump curcuit to be completed ....simple form that's how it all works ...but feel it is a dash related problem ...and possibly and ground connector is loose ..I recall a few of them around the floor board area on both sides of the car ....dave
 
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