1990 Toyota Corolla Keeps Blowing 15 amp EFI fuse at idle w

NORTHCAMAN

MEMBER
1990 TOYOTA COROLLA
4 CYL
FWD
MANUAL
140,000 MILES

I posted yesterday about my EFI fuse problem on my 1990 Totota Corolla SR5 with 4AFE engine and it was recommended that I check the resistance on my fuel injectors and check my fuel pump. The EFI relay was found to be ok because I swaped it with the exact relay that was in the headlight circuit. Does anyone know how I check my electric fuel pump? Can I do a resistance check on it also? Should I do these resistance checks with the engine warm? Thank you.

Wednesday, August 19th, 2009 AT 2:29 PM

1 Reply

MMPRINCE4000

MECHANIC
8,548 POSTS

Check injector resistance with engine warm, if low 2-4 ohms it will raise the amperage significantly and cause a fuse to blow (Ohm's Law).

The pump can be checked by shorting +b and Fp in diagnostic connector, this will byass relays though, and is used to simply check the pump operation.

Go to junk yard and get the entire fuse box from a 90-92 Corolla, Prizm and try replacing it ( they unplug and are simple to remove).

If problem persists, either you have a pinched wire shorting to ground, or pump is drawing to many amps.

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Thursday, August 20th, 2009 AT 8:35 AM