NO VOLTAGE TO FP / INJ FUSE

Kent Buckles

BBBAAD 6
Joined
Feb 8, 2002
HAVING TROUBLE...FUEL PUMP AND INJECTORS ARE NOT WORKING. CAR WAS RUNNING FINE AND THEN JUST DIED. I NOTICED THAT THE FUEL PUMP WAS NOT WORKING AND CHECKED THE FUSE. FUSE WAS NOT BLOWN. I DROPPED THE FUEL TANK AND REPLACED THE FUEL PUMP. STILL NOTHING! I CHECKED THE VOLTAGE AT THE FUSE BLOCK AND WAS NOT GETTING ANY VOLTAGE TO THE FP / INJ FUSE BLOCK. I REPLACED THE THREE FUSABLE LINKS AT STARTER, NOTHING. I HAD ALSO SWAPPED OUT THE FUEL PUMP RELAY. IS THERE ANYTHING ELSE I NEED TO LOOK AT FOR THE PROBLEM. IT IS POSSIBLE THE FUEL PUMP RELAY I SWAPPED WAS BAD BUT WITH A BAD RELAY, I WOULD STILL SHOW FUEL PRESSURE AND HEAR INJECTORS WHEN I MOVE TURN THE KEY TO TRY TO START??? ALSO NOTE I HAVE ONLY DROVE THE CAR A FEW HOURS OVER THE LAST COUPLE OF WEEKS AFTER HAVING PULLED THE TRANSMISSION TO REPLACE A LEAKING TORQUE CONVERTER. SO THIS PROBLEM MAY BE RELATED / CAUSED BY THE R&R OF TRANSMISSION. ANY HELP OR SUGGESTIONS GREATLY APPRECIATED.
 
I'm more inclined to think ecm or wiring in between ecm and fusebox, since you have no power there. Check to see if you have power everywhere else in your fusebox, if so, try borrowing an ecm and check it then. If then you have power, there's your problem, if not, time to play with wiring. Gnttype has wiring diagrams I believe, also check vortexbuick. HTH
 
I'm more inclined to think ecm or wiring in between ecm and fusebox, since you have no power there. Check to see if you have power everywhere else in your fusebox, if so, try borrowing an ecm and check it then. If then you have power, there's your problem, if not, time to play with wiring. Gnttype has wiring diagrams I believe, also check vortexbuick. HTH
I have not checked every fuse but I did check a few a others and had voltage at the others I checked. I think I have an extra ECM I can try. THANKS for your help.
 
Do the turn signals and back up lights work?
Actually the front signals work and turn signals work but the back ones don't. I have the sequential taillights from Scott and sometimes I have to give them a "jump" to get them working by hitting the hazards so I wasn't real concerned. But funny you ask...Is there something I am missing or not considering?
 
The power to the fuse panel comes from the C100 connector that feeds various circuits, if the turn backup work the fuse panel should have +12 on the FP/INJ fuse.

Double check the fuse holder for power on that fuse, the IGN switch must be in the RUN, bulb test, or START position to have power on that fuse.
 
The power to the fuse panel comes from the C100 connector that feeds various circuits, if the turn backup work the fuse panel should have +12 on the FP/INJ fuse.

Double check the fuse holder for power on that fuse, the IGN switch must be in the RUN, bulb test, or START position to have power on that fuse.
OK, SORRY! CAN WE START AGAIN. I SWITCHED TO A DIFFERENT METER(DONT ASK) AND I AM GETTING VOLTAGE TO THE FUSE HOLDER. MY FRONT TURN SIGNALS/HAZARDS ARE WORKING BUT DONT SOUND/LOOK RIGHT. BLINKS A COUPLE TIMES, THEN HOLDS LIGHT ON. BLINKS AGAIN A COUPLE OF TIMES, THEN HOLDS LIGHT ON. MY REAR TURN SIGNALS/HAZARDS ARE NOT WORKING AT ALL. MY BACK UP LIGHTS AND BRAKE LIGHTS ARE NOT WORKING EITHER. QUITE A FEW THINGS ALSO NOT WORKING, RADIO, DOOR CHIME, INTERIOR LIGHTS. SOME ARE WORKING LIKE AC BLOWER AND DIGITAL DASH. SHOULD I SWAP OUT THE ECM. NOT SURE HOW TO TRUBLESHOOT C100 CONNECTOR? WHAT NEXT. I APPRECIATE EVERYONE WHO IS TRYING TO HELP. THANKS
 
Have you got power on all fuses? With this new info, I'm not as inclined to think ecm. The C100 connector is the big plug in the dash. I would look at it and also pull the fusebox and look over all the connections for corossion, burned wiring etc.
Electrical issues are difficult to diagnose without being there, hope this helps. The sequential brake lights that don't work work without "jumping " them concerns me also. I would look at these items before I swapped ecm.
 
I will check the fuse box out later today. My scanmaster is working so I guess it is not the ECM. The sequential tail lights have been that way for years since day 1. Not good but I don't think it is related to the current problem. I will let you know what I find out looking at fuse box and C100 connector. THANKS
 
do you have power to the orange wire that goes from the battery to the ecm? my memory is kinda fuzzy, but i think it has an inline fuse about a foot away from the battery...

another thing to check- look for corrosion on the ecm connectors... i was having a similar problem with my car- it would die at random times and sometimes start right up and sometimes not start for a while... i noticed that if i wiggled the plug on the ecm it would start and run. and that the check engine light didn't work when the car wouldn't start... when i unplugged it from the ecm, the terminal stud on the orange power wire came right off with the plug... i needed a new ecm, so i upgraded to a junkyard one for an 87 for the amazing price of $35.. i later figured out that it was all caused by a plugged heater drain that was overflowing right on top of the ecm, which caused the pin to corrode to the point of breaking.
 
do you have power to the orange wire that goes from the battery to the ecm? my memory is kinda fuzzy, but i think it has an inline fuse about a foot away from the battery...

another thing to check- look for corrosion on the ecm connectors... i was having a similar problem with my car- it would die at random times and sometimes start right up and sometimes not start for a while... i noticed that if i wiggled the plug on the ecm it would start and run. and that the check engine light didn't work when the car wouldn't start... when i unplugged it from the ecm, the terminal stud on the orange power wire came right off with the plug... i needed a new ecm, so i upgraded to a junkyard one for an 87 for the amazing price of $35.. i later figured out that it was all caused by a plugged heater drain that was overflowing right on top of the ecm, which caused the pin to corrode to the point of breaking.
Thanks for the input. I am going to check the ECM out but I did swap it out with a spare I had and it made no difference. The digital dash is resetting back and forth metric to standard each time I break connection to the battery too. My scanmaster is reading out with the correct / normal readings also. Going to check out the C100 connector and fuse box now that I am home from job #1 :)
 
Just a random thought but do you have voltage at the bolt behind the alternator? If not, then the small red wire that is connected to the positive battery cable is defective.
 
Dig dash reset , metric to U.S. is common each time you break power , ignore as to your condition evolves. Wish there were a real dig dash conversion but not so far?? Good Luck
 
Dig dash reset , metric to U.S. is common each time you break power , ignore as to your condition evolves. Wish there were a real dig dash conversion but not so far?? Good Luck
thanks I was aware of the metric/standard changing with disconnect of battery. I just mentioned that to rule out ECM as the problem. Also Digital has a nice speedo /gauge replacement. THANKS
 
Back to the OP, look at the connector that once went to your oil pressure switch. If it's been hanging in the engine bay, it may have hit the up-pipe, and once it does, it tends to short the pink/black wire in it. That's the same wire that powers the injectors and fuel pump. If the FP/INJ fuse is blown, that's the first thing to look at.
 
Does your battery light come on before you start the car?....maybe a bad ground to the ecm making the pump relay incapable of complementing the circuit. you also could jump the relay and see if the pump runs.
 
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